Journal articles: 'APR-246'

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Jonsson-Videsater, Kerstin, Dina Ali, Hareth Nahi, Sofia Bengtzen, Stefan Deneberg, Christer Paul, and Soren Lehmann. "In Vitro and Ex Vivo Studies On Cell Lines and Primary Human Leukemia Cells of the Effects of APR-246 Alone and in Combination with Conventional Chemotherapeutic Drugs." Blood 114, no. 22 (November 20, 2009): 2751. http://dx.doi.org/10.1182/blood.v114.22.2751.2751.

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Abstract Abstract 2751 Poster Board II-727 Introduction: Mutations of TP53 are associated with an extremely poor prognosis in hematopoietic malignancies and is found in 10 to 15% of patients with AML. APR-246 is a methylated form of the small molecule PRIMA-1. It primarily targets mutated p53 protein, but has cytotoxic and apoptosis inducing effects on primary leukemia cells from AML and CLL patients irrespectively of p53 status even though cells with mutated p53 have been shown to be more sensitive. In May 2009, a first-in-man trial has been initiated evaluating the effect of APR-246 in hematologic malignancies. Patients and Methods: Leukemic blast cells from 32 untreated patients with AML were isolated and analyzed. Sixteeen selected patients had normal karyotype and 16 selected patients had complex karyotype. All patient DNA were sequenced at exon 5-8 of TP53 gene. Cells were exposed to APR-246 (2.5μM and 5μM), Ara-C (0.5μM), daunorubicin (0,05μM) and fludarabin (1μM) alone and in combinations. Different timing schedules of the exposure were also used. Cell viability was assayed by bioluminescence measuring ATP. Expression of p53, Bax, Bcl-2 and active caspase –3 and induction of reactive oxygen species (DCF-fluorescence) was analyzed by flow cytometry. We also analyzed two leukemia cell lines, KBM3 and NB4, with and without p53mutation respectively, in order to study the combination effect with chemotherapeutic drugs and the role of preincubation with either of the drug. The Combination Index (CI) was calculated according to the additive model where a CI of less than 0.8 indicates synergy (Möllgård et al CCP, 2008). We also performed global gene expression analysis with Affymetrix platform 1.0 after 18h of APR-246 treatment at 15μM and 25μM in vitro. Results: APR-246 induced dose dependent cytotoxic effects in primary AML samples with a IC50 value of 5.0 μM after 4 days of incubation. A statistically significant increase in the expression of active caspase-3 after 48h treatment with APR-246 (p<0.001) and a tendency to p53 up-regulation (p=0.056) could be detected in patient cells with both normal and complex karyotype. Patients that up-regulated p53 after APR-246 exposure were more sensitive to APR-246 (p<0.05) and had a significantly lower level of Bax (p<0.05) before APR-246 treatment. The seven patients with TP53 mutation had significant lower sensitivity to daunorubicin and fludarabin (p<0.01) in vitro but not to APR-246, indicating a possible treatment alternative in multidrug resistant cells. In primary AML cells, the combination of APR-246 and daunorubicin was the most effective drug combination and gave strong synergy at simultaneous incubation. The TP53 mutated KBM3 cell line was significantly more sensitive to APR-246 (p<0.01) than wt TP53 NB4 cell line with IC50 of 15μM and 45μM respectively. Simultaneous exposure of APR-246 and conventional chemothperapeutic drugs showed synergy in drug combinations tested in both the mutated and the wild type cell line. Pre-incubation with APR-246 gave significantly stronger synergism with all tested drugs combined with 15μM APR-246 (CI for DNR 0.76, for Ara-C 0.65 and for fludarabin 0.60). Pre-incubation with conventional chemotherapeutic drugs showed significantly less synergy. Flow cytometry demonstrated a 2-fold increase in reactive oxygene species (ROS) after 24h and a 15-fold increase after 48h of APR-246 treatment in the TP53 mutated cell line. Global gene expression analysis showed that 50 % of the genes that were upregulated more than a 2.0 fold by APR-246 were associated to the redox status of the cells. Genes that were significantly upregulated were SLC7A11 and oxygenase 1, indicating that APR-246 may exert some of its cytotxic effects by incuding oxidative stress. Conclusions: We conclude that APR-246 exhibits a concentration and time dependent cytotoxic effects in wt and p53 mutated cell lines and primary AML cells ex vivo. APR-246 shows strong synergism together with conventional chemotherapeutic drugs, especially with pre-incubation with APR-246. The anti-leukemic effects are associated with an increase in ROS. A first-in-man trial with APR-246 in haematological malignancies has been initiated and an update of the trial will be given at the meeting. Disclosures: Paul: Aprea AB: Consultancy, Research Funding. Lehmann:Aprea AB: Consultancy, Membership on an entity's Board of Directors or advisory committees.

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Ceder, Anna Sophia, Sofi E. Eriksson, Emarndeena Haji Cheteh, Vladimir J. N. Bykov, Lars Abrahmsen, and Klas G. Wiman. "Impact of combined MRP1 inhibition and mutant p53-targeting compound APR-246." Journal of Clinical Oncology 37, no. 15_suppl (May 20, 2019): e14712-e14712. http://dx.doi.org/10.1200/jco.2019.37.15_suppl.e14712.

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e14712 Background: The tumor suppressor gene TP53 is the most frequently mutated gene in cancer. Mutant p53 protein is often expressed at high levels and accompanied with gain-of-function activities that promote tumor development and resistance towards conventional treatment. APR-246 is a mutant p53-reactivating small molecule undergoing a Phase III clinical study in myelodysplastic syndrome (MDS), and several phase II studies. APR-246 is non-enzymatically converted to its active product methylene quinuclidinone (MQ) which binds to cysteine residues in p53. This stimulates proper folding of p53's DNA-binding core domain, leading to cell death. APR-246 also exhibits pro-oxidant activity as the electrophile MQ binds and inactivates important antioxidants such as glutathione and thioredoxin reductase, which both are essential for cellular defense against oxidative and electrophilic stress. Methods: All results are in vitro experiments by LC-MS as well as experiments in cultured cells, including 14C-APR-246/MQ detection, cell viability measurements, LC-MS analysis, enzyme recycling measurements and Western blotting. Results: We have utilized 14C-labelled APR-246 to investigate the effect of APR-246 and its active moiety MQ in tumor cell cultures upon inhibition of efflux transporter multidrug resistance protein 1 (MRP1) or cystine-glutamate transporter (xCT). Transient downregulation or small molecule inhibitors (MK-571, reversan, sulfasalazin) targeting MRP1 or xCT increased drug content and shifted intra- and extracellular thiol status. Missense mutant TP53-carrying cells exhibited higher sensitivity to APR-246 and combination therapies. MRP1 inhibition showed strong synergy with APR-246 and increased intracellular levels of MQ conjugated to glutathione (GS-MQ). We found that GS-MQ conjugate formation is reversible, and suggest that the intrinsic reversibility of MQ adduct formation is an important aspect of the mechanism of action of APR-246. This reversibility may also in part account for the benign safety profile reported from clinical studies with APR-246. Conclusions: Sensitivity to APR-246 is affected by MRP1 efflux activity and the redox status, reflected in ratios of cysteine/cystine and reduced/oxidized glutathione (GSH/GSSG).

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Müller, Michael, Lisa Rösch, Sara Najafi, Charlotte Gatzweiler, Johannes Ridinger, Xenia F. Gerloff, David T. W. Jones, et al. "Combining APR-246 and HDAC-Inhibitors: A Novel Targeted Treatment Option for Neuroblastoma." Cancers 13, no. 17 (September 5, 2021): 4476. http://dx.doi.org/10.3390/cancers13174476.

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APR-246 (Eprenetapopt/PRIMA-1Met) is a very potent anti-cancer drug in clinical trials and was initially developed as a p53 refolding agent. As an alternative mode of action, the elevation of reactive oxygen species (ROS) has been proposed. Through an in silico analysis, we investigated the responses of approximately 800 cancer cell lines (50 entities; Cancer Therapeutics Response Portal, CTRP) to APR-246 treatment. In particular, neuroblastoma, lymphoma and acute lymphocytic leukemia cells were highly responsive. With gene expression data from the Cancer Cell Line Encyclopedia (CCLE; n = 883) and patient samples (n = 1643) from the INFORM registry study, we confirmed that these entities express low levels of SLC7A11, a previously described predictive biomarker for APR-246 responsiveness. Combining the CTRP drug response data with the respective CCLE gene expression profiles, we defined a novel gene signature, predicting the effectiveness of APR-246 treatment with a sensitivity of 90% and a specificity of 94%. We confirmed the predicted APR-246 sensitivity in 8/10 cell lines and in ex vivo cultures of patient samples. Moreover, the combination of ROS detoxification-impeding APR-246 with approved HDAC-inhibitors, known to elevate ROS, substantially increased APR-246 sensitivity in cell cultures and in vivo in two zebrafish neuroblastoma xenograft models. These data provide evidence that APR-246, in combination with HDAC-inhibitors, displays a novel potent targeted treatment option for neuroblastoma patients.

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Hong, Yuheng, Tianyuan Ren, Xiaoxuan Wang, Kai Fu, Xianhuo Wang, and Huilai Zhang. "APR-246 Reveals a Therapeutic Potential Via Triggering Different Cell Death Mechanisms in Diffuse Large B Cell Lymphoma." Blood 138, Supplement 1 (November 5, 2021): 3521. http://dx.doi.org/10.1182/blood-2021-150582.

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Abstract Background: Diffuse large B cell lymphoma (DLBCL) is the most common lymphoid malignancy and is characterized by its pronounced genetic and clinical heterogeneity. Although the first-line therapy (R-CHOP) improves the curability of patients with DLBCL, nearly 40% remainder ultimately undergo relapsed or refractory disease. Emerging evidence has shown that TP53 mutations correlate with the recurrence and progression of DLBCL. APR-246, also known as PRIMA-1MET, can reactivate the trans-activation of TP53 mutants by facilitating their DNA binding to target genes, making it a promising therapeutic compound for mutated TP53 carcinomas. Although APR-246 in combination with other chemicals has been applied in clinical trials for non-Hodgkin lymphoma (NHL), the efficacy and the underlying molecular mechanisms of APR-246 on DLBCL remain unclear. The arms are to investigate the TP53 mutations and the correlation of mutated TP53 with the prognosis. Furthermore, we evaluated the effect of APR-246 on DLBCL in vitro and in vivo. Methods: Multiple datasets, including the Gene Expression Omnibus (GEO) and cBioPortal, were searched for available data for DLBCL. For evaluation of APR-246 effect on DLBCL in vitro, ten DLBCL cell lines harbouring different and representative molecular properties, especially distinct TP53 mutation status, were tested. To validate the therapeutic effect of APR-246 in vivo, NSG mice were injected subcutaneously with the DLBCL cells with TP53 mutations to establish a xenograft animal model, and then these mice received the APR-246 administration. The cell viability of DLBCL was measured post addition of APR-246. Pharmaceutical inhibition of different cell death pathways was applied to elucidate the mechanisms by which APR-246 functions. Results: Total 2204 patients with DLBCL were evaluated, of which nearly 15% contained TP53 mutations. The missense mutation of TP53 was up to 76% and mutations occurring in the DNA binding domain (DBD) was about 90%. Patients with TP53 mutations had poor OS (p=0.0118). Further, we found that patients with TP53 mutations in GCB and UNC subtypes exhibited inferior OS (p=0.043; p=0.049, respectively), but no in ABC subtype. Notably, TP53 single mutations located in the DBD (exon 5-8) led to an unfavorable survival (p=0.0263), while patients carrying TP53 multiple mutations and single mutations in other domains exhibited no difference in survival time than those with wild-type TP53. APR-246 induced the cell death in a dose dependent manner for all DLBCL cell lines. DLBCL cells with TP53 missense mutations in the DBD were the most sensitive to APR-246 than those with intact or other types of mutated TP53. APR-246 mediated the cell death via p53-dependent ferritinophagy for DLBCL cells with TP53 missense mutations in the DBD. In addition, APR-246 also induced the ferroptosis for other DLBCL cells harbouring wild type TP53 and other forms of TP53 mutations. Conclusions: Nearly 15% of patients with DLBCL harbouring TP53 mutations had inferior prognosis than those with wild-type TP53. Patients with TP53 single mutations occurred in the DBD (exon 5-8) showed poorer prognosis than those with TP53 multiple mutations and single mutations in other domains. APR-246 induced the cell death of DLBCL through different mechanisms, depend on different forms of TP53 mutations, which provided an evidence for clinical application of APR-246 in the treatment of DLBCL. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

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Synnott, Naoise C., Alyson M. Murray, Norma O'Donovan, Michael J. Duffy, and John Crown. "Combined treatment using the anti-p53 drug, APR-246 and eribulin: Synergistic growth inhibition in p53-mutated breast cancer cells." Journal of Clinical Oncology 35, no. 15_suppl (May 20, 2017): e14098-e14098. http://dx.doi.org/10.1200/jco.2017.35.15_suppl.e14098.

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e14098 Background: TP53 is the most frequently mutated gene in triple-negative breast cancer, being present in approximately 80% of cases. APR-246 is a novel anticancer drug that acts by reactivating the mutant p53 protein, thereby converting it to a form with wild-type properties. Previously, we showed that APR-246 had antiproliferative, anti-migratory and pro-apoptotic activities in a panel of 23 breast cancer cell lines, including triple-negative (TN) cell lines. The aim of this study was to investigate if combined treatment with APR-246 and different cytotoxic agents resulted in enhanced growth inhibition. Methods: Cell viability was determined using the MTT assay. Combination index (CI) values were calculated using Calcusyn software, based on the Chou-Talalay method. Apoptosis was detected using Annexin V-FITC Apoptosis Detection Kit followed by FACs analysis. Results: Highly synergistic cell growth inhibition was found when APR-246 was combined with eribulin (Eisai Ltd.) in 6 different p53-mutated cell lines (mean CI values range from 0.38 to 0.77). In contrast, enhanced growth inhibition was not found using this combination in the 3 p53-WT cell lines investigated (mean CI values ranged from 1.13 to 2.9). Overall, p53 mutated cell lines had a significantly lower CI values than p53 wild-type cells (p = 0.008). In all the 4 p53-mutated cell lines investigated, a significant increase in apoptosis was also seen when APR-246 was combined with eribulin. This enhanced apoptosis appeared to result from increased mRNA expression of the pro-apoptotic factors PUMA and NOXA by the drug combination compared to either compound alone. In contrast to our findings with eribulin, combined treatment with APR-246 plus docetaxel, doxorubicin, cisplatin or carboplatin was cell line-dependent. Thus, docetaxel plus APR-246 was synergistic in 1/6 cell lines, while doxorubicin, cisplatin or carboplatin plus APR-246 was synergistic in 3/6 cell lines. Conclusions: Clinical trials investigating the combination of APR-246 and eribulin should be considered in patients with a p53 mutation such as triple-negative breast cancer.

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Xin, Qian, Qinghong Ji, Ying Zhang, Weihong Ma, Baoqing Tian, Yanli Liu, Yunsong Chen, et al. "Aberrant ROS Served as an Acquired Vulnerability of Cisplatin-Resistant Lung Cancer." Oxidative Medicine and Cellular Longevity 2022 (June 20, 2022): 1–17. http://dx.doi.org/10.1155/2022/1112987.

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Lung cancer has become a global health issue in recent decades. Approximately 80-85% of cases are non-small-cell lung cancer (NSCLC). Despite the high rate of resistance, cisplatin-base chemotherapy is still the main treatment for NSCLC patients. Thus, overcoming cisplatin resistance is urgently needed in NSCLC therapy. In this study, we identify NADPH metabolism and reactive oxygen species (ROS) levels as the main causes accounting for cisplatin resistance. Based on a small panel consisting of common chemotherapy drugs or compounds, APR-246 is proved to be an effective compound targeting cisplatin-resistant NSCLC cells. APR-246 specially inhibits proliferation and colony formation of cisplatin-resistant cells. In details, APR-246 can significantly cause G0/G1 accumulation and S phase arrest of cisplatin resistant cells and gives rise to severe mitochondria dysfunction as well as elevated apoptosis. Further study proves that it is the aberrant ROS levels as well as NRF2/SLC7A11/GSH axis dysfunction accounting for the specific antitumor effects of APR-246. Scavenging ROS with N-acetylcysteine (NAC) disrupts the inhibitory effect of APR-246 on cisplatin-resistant cells. Mechanistically, NRF2 is specifically degraded by the proteasome following its own ubiquitylation in APR-246-treated cisplatin-resistant cells, which in turn decreases NRF2/SLC7A11/GSH axis activity. Our study provides new insights into the biology driving cisplatin resistance of lung cancer and highlights APR-246 as a potential therapeutic reagent for overcoming cisplatin resistance.

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Mohell, Nina, Charlotta Liljebris, Jessica Alfredsson, Ylva Lindman, Maria Uustalu, Thomas Uhlin, Mats R. H. Linderholm, and Klas G. Wiman. "Preclinical Efficacy and Toxicology Studies of APR-246, a Novel Anticancer Compound Currently In Clinical Trials for Refractory Hematological Malignancies and Prostate Cancer." Blood 116, no. 21 (November 19, 2010): 1806. http://dx.doi.org/10.1182/blood.v116.21.1806.1806.

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Abstract Abstract 1806 The tumor suppressor protein p53 is a transcription factor involved in cell cycle arrest, senescence and apoptosis. The p53 gene is frequently mutated in cancer, and cancer cells carrying defects in p53 are generally more resistant to conventional chemotherapy. Thus, restoration of wild type function of p53 is a promising novel strategy for cancer therapy. APR-246 belongs to a new class of small molecules (quinuclidinones) that reactivates non-functional p53 by promoting its correct folding and triggering apoptosis (Lambert et al. Cancer Cell 15, 2009). The lead compound of APR-246, PRIMA-1 (p53 Reactivation and Induction of Massive Apoptosis) was identified by a cellular screen of a NCI (National Cancer Institute) library, and an optimization program led to the discovery of the analog APR-246 (PRIMA-1MET). In various in vitro,ex vivo andin vivo cancer models, APR-246 has shown good antitumor activity. It reduces cell viability and/or induces apoptosis in a large number of human cancer cell lines with different p53 status, including leukemia, lymphoma and myeloma cell lines (Mohell et al. Blood 114, 2009). Ex vivo efficacy of APR-246 alone and in combination with conventional chemotherapeutic drugs has been shown in primary cells from patients with acute myeloid leukemia (AML) (Jonsson-Videsater et al. Blood 114, 2009). Ex vivo efficacy of APR-246 has also been shown in primary cells from patients with chronic lymphocytic leukemia (CLL). APR-246 was 4–8 fold more potent in killing malignant than normal lymphocytes, whereas common cytostatics often have negative ratio (Mohell et al. Blood 114, 2009). In vivo efficacy of APR-246/PRIMA-1 has been demonstrated in xenograft studies using many solid tumor cell lines (Mohell et al. Blood 114, 2009). Here we present results from studies with APR-246 using in vivo systemic and metastasic xenograft model with the human AML primary cell line AML-PS. This model was established by Giovazzi et al. (Int. J. Cancer 61, 1995) and is considered as a predictive in vivo model for human AML. In addition, some key results from preclinical safety and toxicology studies are reported. Briefly, SCID (severe combined immunodeficiency) mice were inoculated i.v. with 5×106 human AML-PS primary cells. Three days after inoculation treatment with i.v. injections of APR-246 (200 and 300 mg/kg), twice daily for 10 days, was initiated. Mice were monitored daily for health status and mortality. Blood samples were collected for determination of the percentage of circulating human leukemia cells by FACS analysis. Human leukemic cells were detected using a fluorescent antibody against the major histocompatibility complex (HLA). In parallel, pharmacokinetic experiments to measure the concentration of APR-246 in the blood were performed. We found that APR-246 had a statistically significant antitumor effect by decreasing the percentage of circulating human AML-PS cells and increasing the survival time of the mice (P=0.0024, n=10). A good correlation between increase in survival time and decrease in circulating tumor cells in the blood was observed. Further in vivo efficacy studies using various treatment schedules and combinations with conventional cytostatics are ongoing. APR-246 was also investigated in pivotal toxicology studies using single and repeat-dose regimen. In dogs, APR-246 was well tolerated when administered as 2 h infusion with NOAEL (no observed adverse effect level) of 200 mg/kg/day (4000 mg/m2/day). In both dogs and mice, Cmax levels less than 100 μg/ml did not induce any toxicity, regardless of the administration protocol. No systemic target organ toxicity was observed in mice or dogs, including blood and bone-marrow parameters. In conclusion, APR-246 has in various efficacy models demonstrated significant antitumor activity and a unique pharmacological profile. In preclinical safety/toxicity studies no toxicity at predicted therapeutic plasma concentrations was observed. Thus, APR-246 appears to be a promising novel anticancer compound to treat patients resistant to common chemotherapy. Currently, APR-246 is investigated in a dose escalating Phase I/IIa First-in-Man study for refractory hematological malignancies and prostate cancer. The Phase II Proof of Concept study is planned to start in 2011. Disclosures: Mohell: Aprea AB: Employment. Liljebris:Aprea AB: Employment. Alfredsson:Aprea AB: Employment. Lindman:Aprea AB: Employment. Uustalu:Aprea AB: Employment. Uhlin:Aprea AB: Employment. Linderholm:Aprea AB: Consultancy. Wiman:Aprea AB: Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

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Venkatesh, Divya, Judith Michels, Cailian Liu, Sadna Budhu, Mariam M. George, Lars Abrahmsen, Roberta Zappasodi, Jedd D. Wolchok, and Taha Merghoub. "Abstract 1291: APR-246 enhances tumor immunogenicity even in the absence of p53." Cancer Research 82, no. 12_Supplement (June 15, 2022): 1291. http://dx.doi.org/10.1158/1538-7445.am2022-1291.

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Abstract Despite the significant success of immunotherapy, more than 40% of cancer patients remain unresponsive or exhibit an insufficient response. Well-designed combinations of targeted therapy and immunotherapy have the potential to increase effectiveness of cancer treatment and overcome the absence of response to either therapy alone. Since targeted therapies that enhance tumor antigenicity can enhance the effectiveness of immune based therapies, we have built a compendium of in vitro and in vivo assays to evaluate the effect of multiple immunogenic drugs. In these assays, we use the preclinical melanoma cell line B16-F10 model as it is highly metastatic and responds poorly to immunotherapy alone. The tumor suppressor p53 is a key target both in terms of targeted therapy owing to its role in halting tumor progression as well as in combination with immunotherapy, since p53 has varied roles in immune modulation. APR-246 can activate p53 and elicit some p53-independent effects in various tumor models predominantly through the induction of endoplasmic reticulum stress and oxidative stress. Since these cellular stressors (including p53) have been shown to be capable of rendering tumor cells immunogenic, we hypothesized that APR-246 may also increase the antigenicity of tumor cells. Indeed, we observed that treatment of B16 cells with APR-246 increases their MHC expression. Additionally, in our in vitro co-culture assays, cells treated with APR-246 were able to activate antigen-specific cytotoxic T cells either directly or via CD11c+ cells. We also observed that mice immunized with APR-246-treated B16 cells and then implanted with healthy untreated melanoma cells, were able to confer prolonged tumor free survival. Taken together, we believe that APR-246 has the potential to make for a strong combination with immunomodulatory therapies owing to its immunogenic potential. Based on these observations, we rationally designed a combination treatment regimen that would further enhance the immunogenic effects elicited by APR-246 on tumor cells. The triple combination of APR-246 with the TLR4 agonist, Monophosphoryl lipid A (MPL) and the anti-CD40 antibody significantly reduced the growth of B16 tumor in C57BL/6J mice. Strikingly, using CRISPR generated B16 p53 KO cells, we have discovered that these effects of APR-246 exist even in the absence of p53, albeit slightly reduced. Therefore, our results indicate that combination of APR-246 with immunomodulatory agents may be effective in treating cancers irrespective of their genetic status of p53. Our finding suggests that drugs with immunogenic potential, in addition to their original therapeutic indication, such as APR-246 are good candidates for the improvement of various clinically relevant immune modulatory therapies. Note: D.V. and J.M. contributed equally to this work. Citation Format: Divya Venkatesh, Judith Michels, Cailian Liu, Sadna Budhu, Mariam M. George, Lars Abrahmsen, Roberta Zappasodi, Jedd D. Wolchok, Taha Merghoub. APR-246 enhances tumor immunogenicity even in the absence of p53 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1291.

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Nagourney, Adam J., Joshua B. Gipoor, Steven S. Evans, Paulo D’Amora, Max S. Duesberg, Paula J. Bernard, Federico Francisco, and Robert A. Nagourney. "Therapeutic Targeting of P53: A Comparative Analysis of APR-246 and COTI-2 in Human Tumor Primary Culture 3-D Explants." Genes 14, no. 3 (March 19, 2023): 747. http://dx.doi.org/10.3390/genes14030747.

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Background: TP53 is the most commonly mutated gene in human cancer with loss of function mutations largely concentrated in “hotspots” affecting DNA binding. APR-246 and COTI-2 are small molecules under investigation in P53 mutated cancers. APR binds to P53 cysteine residues, altering conformation, while COTI-2 showed activity in P53 mutant tumors by a computational platform. We compared APR-246 and COTI-2 activity in human tumor explants from 247 surgical specimens. Methods: Ex vivo analyses of programmed cell death measured drug-induced cell death by delayed-loss-of-membrane integrity and ATP content. The LC50s were compared by Z-Score. Synergy was conducted by the method of Chou and Talalay, and correlations were performed by Pearson moment. Results: APR-246 and COTI-2 activity favored hematologic neoplasms, but solid tumor activity varied by diagnosis. COTI-2 and APR-246 activity did not correlate (R = 0.1028) (NS). COTI-2 activity correlated with nitrogen mustard, cisplatin and gemcitabine, doxorubicin and selumetinib, with a trend for APR-246 with doxorubicin. For ovarian cancer, COTI-2 showed synergy with cisplatin at 25%. Conclusions: COTI-2 and APR-246 activity differ by diagnosis. A lack of correlation supports distinct modes of action. Cisplatin synergy is consistent with P53’s role in DNA damage. Different mechanisms of action may underlie disease specificity and offer better disease targeting.

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Macha, Shawn J., Balakrishna Koneru, Trevor Burrow, Charles Zhu, Dzmitry Savitski, Jonas Nance, Kristyn McCoy, Cody Eslinger, and C. Patrick Reynolds. "Abstract 6228: APR-246, which restores p53 function, is highly active against alternative lengthening of telomere (ALT) cell lines and PDXs." Cancer Research 82, no. 12_Supplement (June 15, 2022): 6228. http://dx.doi.org/10.1158/1538-7445.am2022-6228.

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Abstract Introduction: Most cancers proliferate by activating telomerase (TA+) while 10% of cancers utilize alternate lengthening of telomeres (ALT). ALT has been associated with resistance to DNA damaging agents, p53 loss-of-function (p53LOF), ATRX mutations, and very poor survival. ATM kinase, which activates functional p53, is constitutively activated in ALT cancers (Science Translational Medicine 18:eabd5750, 2021). We hypothesized that the constitutive activation of ATM kinase in ALT cancers would confer high sensitivity to pharmacological reactivation of p53 function. Methods: We used patient-derived ALT (telomeric DNA C-circle positive) and TA+ neuroblastoma, sarcoma, colorectal, and breast cancer cell lines and xenografts treated with the clinical-stage p53 reactivator eprenetapopt (APR-246) and irinotecan. In vitro cytotoxicity was assayed by DIMSCAN digital imaging microscopy, ATM activation by immunofluorescence microscopy, and protein expression by western blotting. Results: ALT p53LOF cell lines were significantly (p<0.05) less sensitive to DNA-damaging agents relative to TA+ p53LOF comparators. Constitutive phosphorylation (activation) of ATM kinase and the DNA damage marker 53BP1 were observed at telomeres in ALT but not TA+ cell lines. APR-246 induced p53 targets p21 and NOXA and was significantly more cytotoxic (p<0.001) for ALT relative to TA+ cell lines, regardless of TP53 status. Overexpression of p53 in a TP53-null ALT cell line increased sensitivity (p<0.0001) to APR-246. Knockdown of p53 or ATM kinase in ALT TP53 mutated and wild-type cell lines antagonized (p<0.0001) APR-246 activity. Induction of telomere dysfunction in a TA+ p53LOF neuroblastoma cell line using dominant-negative TRF2 (a shelterin protein that blocks ATM activation at telomeres) activated ATM and sensitized cells to APR-246 (p<0.01). APR-246 enhanced the cytotoxicity of irinotecan (as SN38) in ALT cell lines in vitro to a higher degree than in TA+ p53LOF cell lines (p<0.05). Single-agent APR-246 significantly (p<0.0001) increased event-free survival (EFS) of mice with ALT xenografts relative to controls. APR-246 enhanced (p<0.0001) the activity of irinotecan in 3 neuroblastoma, 2 rhabdomyosarcoma, 1 colorectal, and 1 triple-negative breast ALT xenograft models with most mice (47/56) achieving complete responses and an EFS of >100 days (45/56) compared to no complete responses (median EFS ~ 34 days) in mice treated with only irinotecan (p<0.0001). APR-246 + irinotecan had no significant effect relative to irinotecan alone (p=0.08) on EFS of mice with TA+ p53LOF xenografts (median EFS ~ 40 days). Conclusion: ALT cancers of a variety of histologies are highly resistant to DNA damaging agents, have p53LOF, and constitutive activation of ATM kinase, which confers high sensitivity to p53 reactivation by APR-246. APR-246 warrants clinical testing in patients with ALT cancers. Citation Format: Shawn J. Macha, Balakrishna Koneru, Trevor Burrow, Charles Zhu, Dzmitry Savitski, Jonas Nance, Kristyn McCoy, Cody Eslinger, C Patrick Reynolds. APR-246, which restores p53 function, is highly active against alternative lengthening of telomere (ALT) cell lines and PDXs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6228.

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Liang, Yayun, Rolf A. Brekken, and Salman M. Hyder. "Inhibiting Growth of Human Triple-Negative Breast Cancer Cells by Activating Mutant p53 Protein Alone or in Combination With a Phosphatidylserine-Targeting Antibody." Journal of the Endocrine Society 5, Supplement_1 (May 1, 2021): A1022—A1023. http://dx.doi.org/10.1210/jendso/bvab048.2093.

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Abstract Triple-negative human breast cancers (TNBC) lack three proteins commonly targeted by chemotherapy; estrogen and progesterone receptors, and her-2-neu. Most current protocols used to treat TNBC are largely ineffective and aggressive tumors frequently re-emerge, leading to metastasis and patient death. Thus, new therapies for TNBC are needed. Recent studies show that around 80% of TNBC express mutant p53 (mtp53), a functionally defective form of the p53 tumor suppressor protein. If mtp53 is converted into the active wild-type protein (wtp53), tumor suppressor functions are recovered. Most p53 mutations occur in the DNA-binding domain, causing normal regulation of p53 target genes involved in apoptosis, cell-cycle arrest, and angiogenesis to be blocked. This promotes metastasis and renders tumors resistant to chemotherapy. APR-246 is a small-molecule drug that re-activates mtp53 by covalent modification of the DNA-binding core domain of the mutant protein through alkylation of thiol groups and has been shown to reactivate mtp53 and restore p53 function. We examined whether APR-246 could inhibit TNBC growth, both in vitro and in vivo. Cell viability assays and FACS were used to measure in vitro TNBC cell growth and apoptosis respectively, in MDA-MB-231 and MDA-MB-468 cells, with MCF-7 cells (which express wtp53) as controls. Analysis of TNBC growth in vivo was assessed in a mouse model of MDA-MB-231 derived xenografts. Nuclear extracts of APR-246-treated TNBC cells exhibited significantly increased p53 DNA binding compared with untreated cells, indicating that APR-246 converts mtp53 to wtp53 in these cells. APR-246 significantly reduced TNBC cell viability in vitro, but had no effect on normal mammary cells or wtp53-expressing MCF-7 cells. Pro-apoptotic proteins, Bax, p21 and caspase-3 were elevated in APR-246 treated cells, while the cell survival protein Bcl-2 was suppressed. In the xenograft model, animals were given an intravenous (iv) tail vein injection of APR-246 alone (100 mg/kg/day) once tumors reached 100 mm3. A second group received an intraperitoneal (ip) injection of 2aG4 antibody (100 µg/mouse/day), which targets phosphatidylserine and disrupts tumor blood vessel formation. A third group was given both APR-246 and 2aG4 using the same doses above. A control group received antibody C44 (100 µg/mouse/day, ip) and/or PBS (0.1 mL/day, iv). A total of 18 treatments were used. Administration of APR-246 alone or in combination with 2aG4, significantly reduced TNBC tumor growth, as well as two markers of angiogenesis (vascular endothelial growth factor expression and blood-vessel density). APR-246 in combination with 2aG4 completely eradicated almost 20% of the TNBC tumors. We conclude that TNBC is inhibited by APR-246 and 2aG4. Such treatment could represent an effective and innovative means of combating these particularly aggressive and deadly types of cancer.

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Mohell, Nina, Charlotta Liljebris, Jessica Alfredsson, Ylva Lindman, Maria Uustalu, Klas G. Wiman, and Thomas Uhlin. "Further Preclinical Studies with APR-246, a Novel Anticancer Compound Currently in Clinical Trials for Hematological Malignancies and Prostate Cancer." Blood 114, no. 22 (November 20, 2009): 3773. http://dx.doi.org/10.1182/blood.v114.22.3773.3773.

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Abstract Abstract 3773 Poster Board III-709 Introduction The tumor suppressor protein p53 induces cell cycle arrest and/or apoptosis in response to various forms of cellular stress, through transcriptional regulation of a large number of down stream target genes. p53 is frequently mutated in cancer, and cancer cells carrying defects in the p53 protein are often more resistant to conventional chemotherapy. Thus, restoration of the wild type function to mutant p53 appears to be a new attractive strategy for cancer therapy. APR-246 is a novel small molecule quinuclidinone compound that has been shown to reactivate non-functional p53 and induce apoptosis. Although the exact molecular mechanism remains to be determined, recent results suggest that an active metabolite of APR-246 alkylates thiol groups in the core domain of p53, which promotes correct folding of p53 and induces apoptosis (Lambert et al., Cancer Cell 15, 2009). Currently, APR-246 is in Phase I/IIa clinical trials for hematological malignancies and prostate cancer. In the present abstract results from in vitro, ex vivo and in vivo preclinical studies with APR-246 are presented. Results The lead compound of APR-246, PRIMA-1 (p53 reactivation and induction of massive apoptosis), was originally identified by a cellular screening of the NCI library for low molecular weight compounds (Bykov et al., Nat. Med., 8, 2002). Further development and optimization of PRIMA-1 led to the discovery of the structural analog APR-246 (PRIMA-1MET), with improved drug like and preclinical characteristics. In in vitro experiments APR-246 reduced cell viability (WST-1 assay) in a large number of human cancer cell lines with various p53 status, including several leukemia (CCRF-CEM, CEM/VM-1, KBM3), lymphoma (U-937 GTP, U-937-vcr), and myeloma (RPMI 8226/S, 8226/dox40, 8226/LR5) cell lines, as well as many solid cancer cell lines, including osteosarcoma (SaOS-2, SaOS-2-His273,U-2OS), prostate (PC3, PC3-His175, 22Rv1), breast (BT474, MCF-7, MDA-MB-231), lung (H1299, H1299-His175) and colon cancer (HT-29). In human osteosarcoma cell lines APR-246 reduced cell viability and induced apoptosis (FLICA caspase assay) in a concentration dependent manner being more potent in the p53 mutant (SaOS-2-His273) than in the parental p53 null (SaOS-2) cells. The IC50 values (WST-1 assay) were 14 ± 3 and 27 ± 5 μM, respectively (n=35). In in vivo subcutaneous xenograft studies in SCID (severe combined immunodeficiency) mice APR-246 reduced growth of p53 mutant SaOS-2-His273 cells in a dose-dependent manner, when injected i.v. twice daily with 20 -100 mg/kg (64 – 76% inhibition). An in vivo anticancer effect of APR-246 was also observed in hollow-fiber test with NMRI mice using the acute myeloid leukemia (AML) cell line MV-4-11. An ex vivo cytotoxic effect of APR-246 and/or its lead compound PRIMA-1 has also been shown in primary cells from AML and CLL (chronic lymphocytic leukemia) patients, harbouring both hemizygously deleted p53 as well as normal karyotype (Nahi et al., Br. J. Haematol., 127, 2004; Nahi et al., Br. J. Haematol., 132, 2005; Jonsson-Videsater et al., abstract at this meeting). APR-246 was also tested in a FMCA (fluorometric microculture assay) test using normal healthy lymphocytes (PBMC) and cancer lymphocytes (CLL). It was 4-8 fold more potent in killing cancer cells than normal cells, indicating a favorable therapeutic index. This is in contrast to conventional cytostatics that often show negative ratio in this test. Furthermore, when tested in a well-defined panel of 10 human cancer cell lines consisting of both hematological and solid cancer cell lines, the cytotoxicity profile/activity pattern of APR-246 differed from common chemotherapeutic drugs (correlation coefficient less than 0.4), suggesting a different mechanism of action. Conclusion In relevant in vitro, in vivo and ex vivo cancer models, APR-246 showed unique pharmacological properties in comparison with conventional cytostatics, by being effective also in cancer cells with p53 mutations and by demonstrating tumor specificity. Moreover, in experimental safety/toxicology models required to start clinical trials, APR-246 was non toxic at the predicted therapeutic plasma concentrations. Thus, APR-246 appears to be a promising novel anticancer compound that may specifically target cancer cells in patients with genetic abnormality associated with poor prognosis. Disclosures: Mohell: Aprea AB: Employment. Liljebris:Aprea AB: Employment. Alfredsson:Aprea AB: Employment. Lindman:Aprea AB: Employment. Uustalu:Aprea AB: Employment. Wiman:Aprea AB: Co-founder, shareholder, and member of the board. Uhlin:Aprea AB: Employment.

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De Sousa, Carla. "Errata ao artigo “Impacto do Confinamento em Crianças e Adolescentes”, Publicado em Acta Med Port 2021 Apr;34(4):245-246." Acta Médica Portuguesa 34, no. 5 (May 2, 2021): 406. http://dx.doi.org/10.20344/amp.16383.

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On page 245, header of the article, where it reads (marked in red):“Acta Med Port 2021 Apr;34(3):245-246”It should read:“Acta Med Port 2021 Apr;34(4):245-246”Article published with errors: https://www.actamedicaportuguesa.com/revista/index.php/amp/article/view/15854

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Barutello, Giuseppina, Antonino Di Lorenzo, Alessandro Gasparetto, Chiara Galiazzi, Elisabetta Bolli, Laura Conti, and Federica Cavallo. "Immunotherapy against the Cystine/Glutamate Antiporter xCT Improves the Efficacy of APR-246 in Preclinical Breast Cancer Models." Biomedicines 10, no. 11 (November 8, 2022): 2843. http://dx.doi.org/10.3390/biomedicines10112843.

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Breast cancer is the most frequent cancer in women. Despite recent clinical advances, new therapeutic approaches are still required. The cystine-glutamate antiporter xCT, encoded by the SLC7A11 gene, which imports cystine in exchange with glutamate, is a potentially new target for breast cancer therapy, being involved in tumor cell redox balance and resistance to therapies. xCT expression is regulated by the oncosuppressor p53, which is mutated in many breast cancers. Indeed, mutant p53 (mut-p53) can induce xCT post-transcriptional down modulation, rendering mut-p53 tumors susceptible to oxidative damage. Interestingly, the drug APR-246, developed to restore the wild-type function of p53 in tumors harboring its mutation, alters the cell redox balance in a p53-independent way, possibly rendering the cells more sensitive to xCT inhibition. Here, we propose a combinatorial treatment based on xCT immunetargeting and APR-246 treatment as a strategy for tackling breast cancer. We demonstrate that combining the inhibition of xCT with the APR-246 drug significantly decreased breast cancer cell viability in vitro and induced apoptosis and affected cancer stem cells’ self-renewal compared to the single treatments. Moreover, the immunetargeting of xCT through DNA vaccination in combination with APR-246 treatment synergistically hinders tumor progression and prevents lung metastasis formation in vivo. These effects can be mediated by the production of anti-xCT antibodies that are able to induce the antibody dependent cellular cytotoxicity of tumor cells. Overall, we demonstrate that DNA vaccination against xCT can synergize with APR-246 treatment and enhance its therapeutic effect. Thus, APR-246 treatment in combination with xCT immunetargeting may open new perspectives in the management of breast cancer.

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Demir, Salih, Galina Selivanova, Eugen Tausch, Lisa Wiesmüller, Stephan Stilgenbauer, Geertruy Te Kronnie, Klaus-Michael Debatin, and Lüder Hinrich Meyer. "Targeting Mutant p53 in Pediatric Acute Lymphoblastic Leukemia." Blood 126, no. 23 (December 3, 2015): 903. http://dx.doi.org/10.1182/blood.v126.23.903.903.

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Abstract Mutations of the tumor suppressor gene TP53 have been described to be associated with aggressive disease and inferior prognosis in different types of cancer, including hematological malignancies. In acute lymphoblastic leukemia (ALL), TP53 alterations are infrequently found at diagnosis but have recently been described in about 12% of patients at relapse. This suggests an association with therapy resistance in high risk/relapsed ALL and patients with TP53 mutated ALL have in fact an inferior outcome. Small molecule compounds targeting mutated TP53 such as APR-246, initially described as PRIMA-1MET (p53-dependent reactivation and induction of massive apoptosis) leading to apoptosis induction have shown activity in several types of malignancies with mutated TP53. In ALL, however, mutant TP53 has so far not been addressed as a target for therapeutic intervention. In this study, we investigated a large cohort of patient-derived pediatric B cell precursor (BCP)-ALL primograft samples to identify cases with mutated TP53. Further, we analyzed the effects of APR-246 and evaluated its activity on BCP-ALL cell lines and primografts with mutated (mut) orwild type (wt) TP53. Altogether, 62 BCP-ALL primograft samples established from patients at diagnosis (n=53) or relapse (n=9) by transplantation of primary ALL cells onto NOD/SCID mice were screened for TP53 mutations by denaturating high-performance liquid chromatography (dHPLC) followed by Sanger sequencing of exons 4 to 10 to confirm detected mutations. We identified 4 cases with TP53 mut, 3 obtained from diagnosis (5.6%) and one at relapse (11.1%), corresponding to frequencies described in clinical studies. Mutated cases were further analyzed by fluorescence in situ hybridization (FISH), revealing a 17p deletion in one TP53 mut sample. Similarly, we analyzed 6 BCP-ALL cell lines and identified 2 TP53 mut and 4 TP53 wt lines. Exposure of BCP-ALL primograft (TP53 mut n=4, TP53 wt n=4) and cell line (TP53 mut n=2, TP53 wt n=4) samples to the DNA damaging agent doxorubicin showed, as expected, resistance of TP53 mut leukemia cells for cell death induction, reflected by significantly higher half maximal inhibitory concentrations (IC50; TP53 mut 49 and 143 ng/ml, TP53 wt mean 12 ng/ml) and lower induction of cell death (TP53 mut 16 to 23%, TP53 wt 10 to 60%) in TP53 mut ALL, corroborating the tumor-suppressive function of p53 in ALL. We then investigated the sensitivity of BCP-ALL cell lines for cell death induction by APR-246 (kindly provided by Aprea, Stockholm, Sweden). We observed high sensitivity for APR-246 in TP53 mut (IC50: 5 µM for both cell lines) as compared to TP53 wt ALL (mean IC50: 58 µM). DNA fragmentation and Annexin-V/propidium-iodide (PI) positivity revealed apoptosis as mechanism of APR-246 mediated cell death. Reactive oxygen species (ROS) have recently been described to mediate APR-246 induced cell death in multiple myeloma cells. Therefore, we investigated ROS levels by detection of oxidation-specific fluorescence of dichlorodihydrofluorescein diacetate (DCFDA) in ALL cells. Interestingly, ROS quenching by N-acetyl cysteine abolished induction of cell death in TP53 mut but not TP53 wt ALL cells indicating ROS as a mediator of APR-246 induced cell death in TP53 mut ALL. Furthermore, we addressed p53 activation in response to APR-246 by assessing phosphorylation of p53 (p53pSer15) using phosphoflow cytometry. Most interestingly, APR-246 led to 6-fold increased p53pSer15 levels in TP53 mut compared to no activation in TP53 wt leukemia cells, indicating restoration of p53function upon APR-246treatment in BCP-ALL. Based on these findings, we addressed the effectivity of APR-246on primary, patient-derived primografts and compared sensitivities for cell death induction in TP53 mut (n=4) and TP53 wt (n=4) samples. Importantly, the pattern of responsiveness of TP53 mut ALL was also identified in TP53 mut patient-derived ALL samples with induction of significantly higher cell death rates in TP53 mut ALL (TP53 mut 48%, TP53 wt 18%, 5 µM APR-246, 24 h). Taken together, we showed that TP53 mut BCP-ALL can be targeted by APR-246 leading to re-activation of p53, induction of ROS dependent apoptosis and effective leukemia cell killing. Thus, targeting and re-activation of mutated p53 provides a promising novel strategy for therapeutic intervention in this high-risk subtype of BCP-ALL. Disclosures Selivanova: Aprea: Patents & Royalties: APR-246. Tausch:Gilead: Other: Travel support. Stilgenbauer:Gilead: Honoraria, Research Funding.

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Makhale, Ashwini, Devathri Nanayakkara, Prahlad Raninga, Kum Kum Khanna, and Murugan Kalimutho. "CX-5461 Enhances the Efficacy of APR-246 via Induction of DNA Damage and Replication Stress in Triple-Negative Breast Cancer." International Journal of Molecular Sciences 22, no. 11 (May 28, 2021): 5782. http://dx.doi.org/10.3390/ijms22115782.

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Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer lacking targeted therapy. Here, we evaluated the anti-cancer activity of APR-246, a P53 activator, and CX-5461, a RNA polymerase I inhibitor, in the treatment of TNBC cells. We tested the efficacy of individual and combination therapy of CX-5461 and APR-246 in vitro, using a panel of breast cancer cell lines. Using publicly available breast cancer datasets, we found that components of RNA Pol I are predominately upregulated in basal-like breast cancer, compared to other subtypes, and this upregulation is associated with poor overall and relapse-free survival. Notably, we found that the treatment of breast cancer cells lines with CX-5461 significantly hampered cell proliferation and synergistically enhanced the efficacy of APR-246. The combination treatment significantly induced apoptosis that is associated with cleaved PARP and Caspase 3 along with Annexin V positivity. Likewise, we also found that combination treatment significantly induced DNA damage and replication stress in these cells. Our data provide a novel combination strategy by utilizing APR-246 in combination CX-5461 in killing TNBC cells that can be further developed into more effective therapy in TNBC therapeutic armamentarium.

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Abrams, Stephen L., Przemysław Duda, Shaw M. Akula, Linda S. Steelman, Matilde L. Follo, Lucio Cocco, Stefano Ratti, et al. "Effects of the Mutant TP53 Reactivator APR-246 on Therapeutic Sensitivity of Pancreatic Cancer Cells in the Presence and Absence of WT-TP53." Cells 11, no. 5 (February 24, 2022): 794. http://dx.doi.org/10.3390/cells11050794.

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The TP53 tumor suppressor is mutated in ~75% of pancreatic cancers. The mutant TP53 protein in pancreatic ductal adenocarcinomas (PDAC) promotes tumor growth and metastasis. Attempts have been made to develop molecules that restore at least some of the properties of wild-type (WT) TP53. APR-246 is one such molecule, and it is referred to as a mutant TP53 reactivator. To understand the potential of APR-246 to sensitize PDAC cells to chemotherapy, we introduced a vector encoding WT-TP53 into two PDAC cell lines, one lacking the expression of TP53 (PANC-28) and one with a gain-of-function (GOF) mutant TP53 (MIA-PaCa-2). APR-246 increased drug sensitivity in the cells containing either a WT or mutant TP53 protein with GOF activity, but not in cells that lacked TP53. The introduction of WT-T53 into PANC-28 cells increased their sensitivity to the TP53 reactivator, chemotherapeutic drugs, and signal transduction inhibitors. The addition of WT-TP53 to PDAC cells with GOF TP53 also increased their sensitivity to the drugs and therapeutics, indicating that APR-246 could function in cells with WT-TP53 and GOF TP53. These results highlight the importance of knowledge of the type of TP53 mutation that is present in cancer patients before the administration of drugs which function through the reactivation of TP53.

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Deben, Christophe, Vanessa Deschoolmeester, Jorrit De Waele, Julie Jacobs, Jolien Van den Bossche, An Wouters, Marc Peeters, et al. "Hypoxia-Induced Cisplatin Resistance in Non-Small Cell Lung Cancer Cells Is Mediated by HIF-1α and Mutant p53 and Can Be Overcome by Induction of Oxidative Stress." Cancers 10, no. 4 (April 21, 2018): 126. http://dx.doi.org/10.3390/cancers10040126.

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The compound APR-246 (PRIMA-1MET) is a known reactivator of (mutant) p53 and inducer of oxidative stress which can sensitize cancer cells to platinum-based chemotherapeutics. However, the effect of a hypoxic tumor environment has been largely overlooked in this interaction. This study focusses on the role of hypoxia-inducible factor-1α (HIF-1α) and the p53 tumor suppressor protein in hypoxia-induced cisplatin resistance in non-small cell lung cancer (NSCLC) cells and the potential of APR-246 to overcome this resistance. We observed that hypoxia-induced cisplatin resistance only occurred in the p53 mutant NCI-H2228Q331* cell line, and not in the wild type A549 and mutant NCI-H1975R273H cell lines. Cisplatin reduced HIF-1α protein levels in NCI-H2228Q331* cells, leading to a shift in expression from HIF-1α-dependent to p53-dependent transcription targets under hypoxia. APR-246 was able to overcome hypoxia-induced cisplatin resistance in NCI-H2228Q331* cells in a synergistic manner without affecting mutant p53Q331* transcriptional activity, but significantly depleting total glutathione levels more efficiently under hypoxic conditions. Synergism was dependent on the presence of mutant p53Q331* and the induction of reactive oxygen species, with depletion of one or the other leading to loss of synergism. Our data further support the rationale of combining APR-246 with cisplatin in NSCLC, since their synergistic interaction is retained or enforced under hypoxic conditions in the presence of mutant p53.

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Thompson, Meghan C., Matthew S. Davids, Nitin Jain, Jacob D. Soumerai, Praveen Ramakrishnan Geethakumari, Amy Gubits, Denice Hickman, et al. "Phase 1 and Dose Expansion Study of APR-246 in Combination with Ibrutinib or Venetoclax-Based Therapy in Subjects with TP53-Mutant Relapsed and/or Refractory Non-Hodgkin Lymphomas (NHL) Including Chronic Lymphocytic Leukemia (CLL) and Mantle Cell Lymphoma (MCL)." Blood 136, Supplement 1 (November 5, 2020): 15–16. http://dx.doi.org/10.1182/blood-2020-139022.

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Background: Outcomes for CLL pts with TP53 aberrancy including deletion of 17p (del17p) or TP53 mutations treated with chemo+/-immunotherapy (CIT) have been historically poor. Despite improvements, pts with TP53 aberrancy treated with novel agent-based regimens such as ibrutinib (ibr), acalabrutinib and venetoclax (ven), still have inferior outcomes as compared to pts with intact TP53. In 5 year follow-up data from relapsed/refractory (R/R) CLL pts treated with ibr, pts with del17p had a shorter median progression free survival (PFS) and overall survival (OS) (26 and 57 months) vs. the overall cohort (median PFS 51 months, OS not reached, O'Brien et al Blood 2018). Additionally, for R/R CLL pts treated with 24 months of ven and rituximab (VR), del17p and/or a TP53 mutation was associated with an increased risk of CLL progression after stopping ven (p=0.01, Kater et al JCO 2019). In addition, pts with mantle cell lymphoma (MCL) with TP53 mutations have a poor response to CIT and autologous stem cell transplantation. In a series of MCL pts who discontinued ibr, 75% who discontinued for progression harbored TP53 alterations (Jain et al Br J Haematol 2018). These studies highlight an unmet need for improved treatments for CLL and MCL pts with TP53 mutations. APR-246 is a novel small molecule that is converted to methylene quinuclidinone (MQ), a reactive electrophile that forms a covalent bond with the p53 core domain to reactivate mutant p53 and restore wild type p53 function and apoptotic activity (Zhang et al Cell Death Disease 2018). Additionally, APR-246 has been shown to deplete glutathione and induce reactive oxygen species (Liu et al Nat Commun 2017). Clinical activity has been demonstrated in phase II studies of APR-246 + azacitadine in TP53 mutant MDS (ORR 88%, CR 61%, Sallman et al ASH 2019; ORR 75%, CR 57%, Cluzeau T et al EHA 2020). A phase I trial of APR-246 in combination with venetoclax is ongoing in AML (NCT04214860). APR-246 induces apoptosis in TP53 mutated CLL cells (Jaskova et al, Leuk Res 2020) and single agent activity in CLL has been described in the APR-246 first-in-human clinical trial (Lehmann S et al JCO 2012; Deneberg S et al Blood Canc J 2016). Study Design and Methods: This is a phase 1, open-label, 3+3 dose de-escalation and dose expansion study investigating APR-246 in combination with (cohort 1) ibrutinib or (cohort 2) VR in pts with R/R TP53 mutant CLL or MCL (Figure 1). The safety lead-in portion of the study includes two safety cohorts of CLL pts with TP53 mutations: APR-246 in combination with (1) ibrutinib (ibr), n~28 pts or (2) APR-246 in combination with VR, n=~28 pts. Treatment will be administered according to Figure 2. Eligible pts must have a TP53 mutation. Based on the results of an integrated assessment of the safety, tolerability and preliminary clinical activity in the safety lead-in cohorts, ibr and/or VR will be selected for further study in combination with APR-246 in a dose expansion portion of the study which will include pts with TP53-mutant (1) R/R CLL (n≤20) and (2) R/R MCL (≤40). The primary study endpoints will be (1) the occurrence of DLTs according to the NCI CTCAE, version 5.0, (2) the frequency of treated-emergent adverse events (AE) and SAE, and (3) the recommended phase 2 dose (RP2D) of APR-246 in combination with ibr or VR. Secondary study endpoints include pharmacokinetic parameters, the complete response rate, objective response rate, duration of response and PFS for APR-246 in combination with ibr or VR. Correlative studies are planned to examine the effect of APR-246 combinations on the p53 pathway and examine genome and transcriptome correlates of response and resistance. Patient samples will be collected at multiple timepoints to measure p53 protein expression by immunoblot of protein lysates from mononuclear cells. Specifically, p53, BCL2, BAX, NOXA and PUMA levels will be examined to assess the effect of APR-246 + ibr or VR on the p53 pathway. These studies will be complemented by BH3 profiling, a functional technique to assess the propensity of the tumor cells to undergo apoptosis and their dependence on specific anti-apoptotic proteins. Additionally, intracellular flow cytometry will evaluate the effect of the combinations on key markers within the p53 pathway. DNA and RNA sequencing will be performed to identify potential biomarkers of response. This study is planned to be open for enrollment by September 2020 at the first study site and is planned to open at up to 10 study sites. Disclosures Davids: Bristol Myers Squibb: Research Funding; Pharmacyclics: Consultancy, Research Funding; Surface Oncology: Research Funding; Merck: Consultancy; TG Therapeutics: Consultancy, Research Funding; Verastem: Consultancy, Research Funding; Syros Pharmaceuticals: Consultancy; Research to Practice: Honoraria; Zentalis: Consultancy; Genentech: Consultancy, Research Funding; Eli Lilly: Consultancy; Celgene: Consultancy; AstraZeneca: Consultancy, Research Funding; BeiGene: Consultancy; AbbVie: Consultancy; Adaptive Biotechnologies: Consultancy; Ascentage Pharma: Consultancy, Research Funding; Janssen: Consultancy; MEI Pharma: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Gilead Sciences: Consultancy; Sunesis: Consultancy. Jain:Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Aprea Therapeutics: Research Funding; Precision Bioscienes: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Research Funding; Fate Therapeutics: Research Funding; BMS: Research Funding; BeiGene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; ADC Therapeutics: Research Funding; TG Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Verastem: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Cellectis: Research Funding; AstraZeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Research Funding; Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Soumerai:AstraZeneca: Consultancy; AbbVie: Consultancy; TG Therapeutics: Research Funding; Beigene: Consultancy, Research Funding; BostonGene: Research Funding; Genentech/Roche: Research Funding; GlaxoSmithKine: Research Funding; Verastem: Consultancy. Gubits:Aprea Therapeutics: Current Employment. Hickman:Aprea Therapeutics: Current Employment. Wennborg:Aprea Therapeutics: Current Employment, Current equity holder in publicly-traded company. Attar:Aprea Therapeutics: Current Employment. Abdel-Wahab:Merck: Consultancy; Envisagenics Inc.: Current equity holder in private company; H3 Biomedicine Inc.: Consultancy, Research Funding; Janssen: Consultancy. Mato:TG Therapeutics: Consultancy, Other: DSMB, Research Funding; Adaptive: Consultancy, Research Funding; BeiGene: Consultancy; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; LOXO: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding.

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Ghosh, Arnab, Judith Michel, Divya Venkatesh, Riccardo Mezzadra, Lauren Dong, Fadi Samaan, Ricardo Gomez, et al. "Abstract 250: Activating canonical p53 functions in tumor-associated macrophages improves immune checkpoint blockade efficacy." Cancer Research 82, no. 12_Supplement (June 15, 2022): 250. http://dx.doi.org/10.1158/1538-7445.am2022-250.

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Abstract Canonical p53-activated pathways can influence a microenvironment that promotes antitumor immune surveillance via tumor-associated macrophages (TAMs). We examined whether p53 activity in the tumor microenvironment (TME) influences antitumor immunity and show that p53 signaling induced pharmacologically with APR-246 (eprenetapopt) can augment the efficacy of immune checkpoint blockade (ICB) in preclinical models, a strategy that is also being tested in patients (NCT04383938). We first investigated the effects of combining APR-246 with ICB in wildtype C57BL6 (B6) mice bearing syngeneic p53 wildtype MC38 colon cancer and B16 melanoma tumors. The combination of an anti-PD-1 antibody (RMP1-14) with APR-246 in mice significantly delayed tumor growth (p < 0.001) and improved survival of tumor-bearing mice, compared to monotherapies (p < 0.01). To further dissect the effects of APR-246 on myeloid and T cells in the TME, we used a conditional knockout of p53 in CSF1R+myeloid cells (CSF1Rcre/p53fl mice), or T cells (CD8cre/p53fl mice). CSF1Rcre/p53fl had loss of tumor control and worse survival with APR-246+anti-PD-1. CD8cre/p53fl had intact tumor control. To study enhanced p53 activity in the TME, we performed flow cytometry, cytokine multiplex and global transcriptional profiling by RNA seq. We found enhanced p53-activity led to increased infiltration of T cells, increased MHC-II expression in TAMs and downregulation of M2-associated cytokines. This was associated with cellular senescence in TAMs and induction of canonical p53-induced senescence-associated secretory phenotype (SASP). Our preclinical findings informed the development of a phase I/II clinical trial using APR-246 with pembrolizumab for patients with advanced solid tumors (NCT04383938). We studied peripheral blood samples from two of the patients with tumor regression and two patients in whom tumors progressed on therapy. We analyzed peripheral blood mononuclear cells (PBMCs) and serum prior to therapy, and at the beginning of cycle 2 and 5 for the patients with tumor control, and at the end of therapy for patients who had progression. Single cell RNA-seq of PBMCs demonstrated a signature consistent with T cell activation and proliferation, and SASP-associated changes in the myeloid compartment as seen in mice. T cell profiling of PBMCs by flow cytometry demonstrated strong proliferation of T cells in patients with tumor control. Serum cytokine analysis demonstrated robust in IL-12, IFN-gamma and Eotaxin-1 in the two responders, which was not seen in the patients whose tumors progressed. Our study illustrates p53-induced SASP in TAMs as a mechanism to reprogram the TME and augment responses to ICB. Ongoing studies will help determine biomarkers that are predictive of response to APR-246+ICB therapy. Citation Format: Arnab Ghosh, Judith Michel, Divya Venkatesh, Riccardo Mezzadra, Lauren Dong, Fadi Samaan, Ricardo Gomez, Nathan Suek, Aliya Holland, Yu-Jui Ho, Mohsen Abu-Akeel, Luis Felipe Campesato, Levi Mark Bala Mangarin, Cailian Liu, Hong Zhong, Sadna Budhu, Andrew Chow, Roberta Zappasodi, Marcus Ruscetti, Scott W. Lowe, Taha Merghoub, Jedd D. Wolchok. Activating canonical p53 functions in tumor-associated macrophages improves immune checkpoint blockade efficacy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 250.

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Lehmann, Sören, Vladimir J. N. Bykov, Dina Ali, Ove Andrén, Honar Cherif, Ulf Tidefelt, Bertil Uggla, et al. "Targeting p53 in Vivo: A First-in-Human Study With p53-Targeting Compound APR-246 in Refractory Hematologic Malignancies and Prostate Cancer." Journal of Clinical Oncology 30, no. 29 (October 10, 2012): 3633–39. http://dx.doi.org/10.1200/jco.2011.40.7783.

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Purpose APR-246 (PRIMA-1MET) is a novel drug that restores transcriptional activity of unfolded wild-type or mutant p53. The main aims of this first-in-human trial were to determine maximum-tolerated dose (MTD), safety, dose-limiting toxicities (DLTs), and pharmacokinetics (PK) of APR-246. Patients and Methods APR-246 was administered as a 2-hour intravenous infusion once per day for 4 consecutive days in 22 patients with hematologic malignancies and prostate cancer. Acute myeloid leukemia (AML; n = 7) and prostate cancer (n = 7) were the most frequent diagnoses. Starting dose was 2 mg/kg with dose escalations up to 90 mg/kg. Results MTD was defined as 60 mg/kg. The drug was well tolerated, and the most common adverse effects were fatigue, dizziness, headache, and confusion. DLTs were increased ALT/AST (n = 1), dizziness, confusion, and sensory disturbances (n = 2). PK showed little interindividual variation and were neither dose nor time dependent; terminal half-life was 4 to 5 hours. Tumor cells showed cell cycle arrest, increased apoptosis, and upregulation of p53 target genes in several patients. Global gene expression analysis revealed changes in genes regulating proliferation and cell death. One patient with AML who had a p53 core domain mutation showed a reduction of blast percentage from 46% to 26% in the bone marrow, and one patient with non-Hodgkin's lymphoma with a p53 splice site mutation showed a minor response. Conclusion We conclude that APR-246 is safe at predicted therapeutic plasma levels, shows a favorable pharmacokinetic profile, and can induce p53-dependent biologic effects in tumor cells in vivo.

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Nikolaev, Anatoly, John B. Fiveash, and Eddy S. Yang. "Combined Targeting of Mutant p53 and Jumonji Family Histone Demethylase Augments Therapeutic Efficacy of Radiation in H3K27M DIPG." International Journal of Molecular Sciences 21, no. 2 (January 13, 2020): 490. http://dx.doi.org/10.3390/ijms21020490.

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Diffuse intrinsic pontine glioma (DIPG) is an aggressive pediatric brainstem tumor with a 5-year survival of <1%. Up to 80% of the DIPG tumors contain a specific K27M mutation in one of the two genes encoding histone H3 (H3K27M). Furthermore, p53 mutations found in >70–80% of H3K27M DIPG, and mutant p53 status is associated with a decreased response to radiation treatment and worse overall prognosis. Recent evidence indicates that H3K27M mutation disrupts tri-methylation at H3K27 leading to aberrant gene expression. Jumonji family histone demethylases collaborates with H3K27 mutation in DIPG by erasing H3K27 trimethylation and thus contributing to derepression of genes involved in tumorigenesis. Since the first line of treatment for pediatric DIPG is fractionated radiation, we investigated the effects of Jumonji demethylase inhibition with GSK-J4, and mutant p53 targeting/oxidative stress induction with APR-246, on radio-sensitization of human H3K27M DIPG cells. Both APR-246 and GSK-J4 displayed growth inhibitory effects as single agents in H3K27M DIPG cells. Furthermore, both of these agents elicited mild radiosensitizing effects in human DIPG cells (sensitizer enhancement ratios (SERs) of 1.12 and 1.35, respectively; p < 0.05). Strikingly, a combination of APR-246 and GSK-J4 displayed a significant enhancement of radiosensitization, with SER of 1.50 (p < 0.05) at sub-micro-molar concentrations of the drugs (0.5 μM). The molecular mechanism of the observed radiosensitization appears to involve DNA damage repair deficiency triggered by APR-246/GSK-J4, leading to the induction of apoptotic cell death. Thus, a therapeutic approach of combined targeting of mutant p53, oxidative stress induction, and Jumonji demethylase inhibition with radiation in DIPG warrants further investigation.

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Sallman, David A., Amy E. DeZern, Guillermo Garcia-Manero, David P. Steensma, Gail J. Roboz, Mikkael A. Sekeres, Thomas Cluzeau, et al. "Eprenetapopt (APR-246) and Azacitidine in TP53-Mutant Myelodysplastic Syndromes." Journal of Clinical Oncology 39, no. 14 (May 10, 2021): 1584–94. http://dx.doi.org/10.1200/jco.20.02341.

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PURPOSE Approximately 20% of patients with TP53-mutant myelodysplastic syndromes (MDS) achieve complete remission (CR) with hypomethylating agents. Eprenetapopt (APR-246) is a novel, first-in-class, small molecule that restores wild-type p53 functions in TP53-mutant cells. METHODS This was a phase Ib/II study to determine the safety, recommended phase II dose, and efficacy of eprenetapopt administered in combination with azacitidine in patients with TP53-mutant MDS or acute myeloid leukemia (AML) with 20%-30% marrow blasts (ClinicalTrials.gov identifier: NCT03072043 ). RESULTS Fifty-five patients (40 MDS, 11 AML, and four MDS/myeloproliferative neoplasms) with at least one TP53 mutation were treated. The overall response rate was 71% with 44% achieving CR. Of patients with MDS, 73% (n = 29) responded with 50% (n = 20) achieving CR and 58% (23/40) a cytogenetic response. The overall response rate and CR rate for patients with AML was 64% (n = 7) and 36% (n = 4), respectively. Patients with only TP53 mutations by next-generation sequencing had higher rates of CR (69% v 25%; P = .006). Responding patients had significant reductions in TP53 variant allele frequency and p53 expression by immunohistochemistry, with 21 (38%) achieving complete molecular remission (variant allele frequency < 5%). Median overall survival was 10.8 months with significant improvement in responding versus nonresponding patients by landmark analysis (14.6 v 7.5 months; P = .0005). Overall, 19/55 (35%) patients underwent allogeneic hematopoietic stem-cell transplant, with a median overall survival of 14.7 months. Adverse events were similar to those reported for azacitidine or eprenetapopt monotherapy, with the most common grade ≥ 3 adverse events being febrile neutropenia (33%), leukopenia (29%), and neutropenia (29%). CONCLUSION Combination treatment with eprenetapopt and azacitidine is well-tolerated yielding high rates of clinical response and molecular remissions in patients with TP53-mutant MDS and oligoblastic AML.

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Byskata, Karin, Monika Lukoseviciute, Filippo Tuti, Mark Zupancic, Ourania N. Kostopoulou, Stefan Holzhauser, and Tina Dalianis. "Targeted Therapy with PI3K, PARP, and WEE1 Inhibitors and Radiotherapy in HPV Positive and Negative Tonsillar Squamous Cell Carcinoma Cell Lines Reveals Synergy while Effects with APR-246 Are Limited." Cancers 15, no. 1 (December 23, 2022): 93. http://dx.doi.org/10.3390/cancers15010093.

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Human papillomavirus positive (HPV+) tonsillar and base of tongue cancer (TSCC/BOTSCC) is rising in incidence, but chemoradiotherapy is not curative for all. Therefore, targeted therapy with PI3K (BYL719), PARP (BMN-673), and WEE1 (MK-1775) inhibitors alone or combined was pursued with or without 10 Gy and their effects were analyzed by viability, proliferation, and cytotoxicity assays on the TSCC/BOTSCC cell lines HPV+ UPCI-SCC-154 and HPV− UT-SCC-60A. Effective single drug/10 Gy combinations were validated on additional TSCC lines. Finally, APR-246 was assessed on several TSCC/BOTSCC cell lines. BYL719, BMN-673, and MK-1775 treatments induced dose dependent responses in HPV+ UPCI-SCC-154 and HPV− UT-SCC-60A and when combined with 10 Gy, synergistic effects were disclosed, as was also the case upon validation. Using BYL719/BMN-673, BYL719/MK-1775, or BMN-673/MK-1775 combinations on HPV+ UPCI-SCC-154 and HPV− UT-SCC-60A also induced synergy compared to single drug administrations, but adding 10 Gy to these synergistic drug combinations had no further major effects. Low APR-246 concentrations had limited usefulness. To conclude, synergistic effects were disclosed when complementing single BYL719 BMN-673 and MK-1775 administrations with 10 Gy or when combining the inhibitors, while adding 10 Gy to the latter did not further enhance their already additive/synergistic effects. APR-246 was suboptimal in the present context.

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Sallman, David A., Amy E. DeZern, David P. Steensma, Kendra L. Sweet, Thomas Cluzeau, Mikkael A. Sekeres, Guillermo Garcia-Manero, et al. "Phase 1b/2 Combination Study of APR-246 and Azacitidine (AZA) in Patients with TP53 mutant Myelodysplastic Syndromes (MDS) and Acute Myeloid Leukemia (AML)." Blood 132, Supplement 1 (November 29, 2018): 3091. http://dx.doi.org/10.1182/blood-2018-99-119990.

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Abstract Introduction: TP53 mutant (mTP53) MDS and AML, accounting for 5-10% of de novo MDS and 25-30% of therapy related MDS (t-MDS), represent a distinct molecular cohort with inferior outcomes. Hypomethylating agents (HMA) are preferred treatments for patients (pts) with these mutations, although with CR rates of only 20-30% and median OS of 6-12 months. APR-246 is a novel, first-in-class small molecule that selectively induces apoptosis in mTP53 cancer cells through mutant p53 protein re-activation by restoring the wild-type conformation, with single agent activity in mTP53 AML. We report the planned, completed Phase 1b results of APR-246+ azacitidine (AZA) in mTP53 MDS/AML. Methods: This is a multicenter Phase 1b/2 trial of APR-246+AZA in HMA naïve mTP53 MDS and oligoblastic AML (≤ 30% blasts) pts ≥ 18 years of age. Pts received APR-246 in a 3+3 dose escalation design (50, 75, 100 mg/kg lean body weight (equivalent to 4500mg fixed dose based on PK studies)) IV daily over 4 days in a lead-in phase (days -14 to -10) followed by the same dose of APR-246 (days 1-4) + AZA 75 mg/m2 SC/IV over 7 days (days 4-10 or 4-5 and 8-12) in 28 day cycles. The primary objective was to define safety and the recommended Phase 2 dose (RP2D), with AEs graded by CTCAE v4.03 and DLT assessment over 6 weeks. Secondary objectives included response by IWG 2006 criteria as well as serial next generation sequencing (NGS) and p53 IHC for evaluation of clonal suppression and remission depth as predictors of outcomes. For minimal residual disease (MRD) analysis, a custom target-capture NGS assay was developed using unique molecular Identifiers for error correction with a limit of detection of 0.1% with results validated by pt specific digital droplet PCR (ddPCR). Nanostring nCounter RNA expression analysis was conducted on a panel of 770 genes after the lead-in phase to assess transcriptional effects induced by APR-246. Results: As of July 30, 2018, 12 pts (42% male; median age 66 years (39-73)) were enrolled. Three pts had AML-MRC and 9 had MDS; all pts had poor risk cytogenetics (17% poor, 83% very poor) and higher risk disease by IPSS-R (25% high, 75% very high). T-MDS occurred in 5 pts (42%) and 7 pts (58%) were transfusion-dependent at baseline. Median BM blasts were 9% (4-30). Eleven of 12 pts (92%) had a TP53 missense mutation in the DNA binding domain with multiple mutations in 4/12 pts (33%). For 9/12 pts (75%), TP53 was the sole mutation. Median time on study is 176 days (41-298) with 7 pts ongoing. Treatment (Tx) related AEs during the lead-in phase (all G1) included nausea (n=5), neuropathy (n=5), decreased appetite (n=2), and dizziness (n=2) which were all transient. Tx related AEs occurring in > 1 pt in the combination phase included nausea/vomiting (n=6), dizziness (n=3), headache (n=3), neuropathy (n=3), fall (n=2), pruritus (n=2), thrombocytopenia (n=6), neutropenia (n=5), and leukopenia (n=4); all G1/G2 except cytopenias (G3/G4). No DLTs have occurred to date. Eleven of twelve pts were response evaluable with 1 pt discontinuing tx prior to 1st disease assessment (Fig 1A). ORR by IWG was 100% (11/11) with 9 CR (82%) and 2 marrow CR (mCR; 18%). Median time to first response was 70 days (4-91) and one CR patient achieved mCR and partial cytogenetic response after APR-246 lead-in prior to combination therapy. All CR pts had high p53 positivity by IHC at baseline (25-80%) which normalized on serial assessment with the 2mCR pts having <5% p53+ at baseline. Serial NGS with a variant allele frequency (VAF) cutoff of 5% was negative in 73% of patients (8/11). In NGS negative pts, MRD analysis, validated by ddPCR, was performed with a median VAF of 0.3% (0.1%-3.1%) at best molecular response. Enriched pathway analysis via Reactome following APR-246 lead-in phase showed transcriptional activation of p53 targets (FDR = 9.16E-09), including pathways involved in cell cycle arrest, apoptosis, DNA repair, and regulation of TP53 activity. At a median follow up of 7 months, the median OS or PFS has not been reached. In comparison to a internal historical cohort of 51 mTP53 MDS/AML treated with AZA alone, APR-246+AZA had a trend for improved OS (NR vs 7.6months; HR 0.30, P=0.07; Fig 1B). Conclusions: APR-246+AZA combination is well tolerated in mTP53 MDS/AML. Responses have been achieved in all evaluable pts (82% CR) accompanied by deep molecular and durable remissions. The RP2D of APR-246 is a fixed dose of 4500mg days 1-4 in combination with AZA and phase 2 accrual has begun. Disclosures Sallman: Celgene: Research Funding, Speakers Bureau. Sweet:Agios: Consultancy; Phizer: Consultancy; Agios: Consultancy; BMS: Honoraria; Celgene: Honoraria, Speakers Bureau; Jazz: Speakers Bureau; Celgene: Honoraria, Speakers Bureau; BMS: Honoraria; Phizer: Consultancy; Novartis: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Astellas: Consultancy; Jazz: Speakers Bureau; Astellas: Consultancy. Cluzeau:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Speakers Bureau; Sanofi: Speakers Bureau; Menarini: Consultancy; Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Sekeres:Opsona: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Opsona: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Roboz:Orsenix: Consultancy; Cellectis: Research Funding; Eisai: Consultancy; Astex Pharmaceuticals: Consultancy; Argenx: Consultancy; Pfizer: Consultancy; Bayer: Consultancy; Eisai: Consultancy; Sandoz: Consultancy; Jazz Pharmaceuticals: Consultancy; Jazz Pharmaceuticals: Consultancy; Novartis: Consultancy; Pfizer: Consultancy; Otsuka: Consultancy; Bayer: Consultancy; Aphivena Therapeutics: Consultancy; Celltrion: Consultancy; Argenx: Consultancy; Celgene Corporation: Consultancy; Daiichi Sankyo: Consultancy; Celltrion: Consultancy; Sandoz: Consultancy; Astex Pharmaceuticals: Consultancy; Aphivena Therapeutics: Consultancy; Orsenix: Consultancy; Otsuka: Consultancy; Roche/Genentech: Consultancy; Roche/Genentech: Consultancy; Janssen Pharmaceuticals: Consultancy; Daiichi Sankyo: Consultancy; Novartis: Consultancy; AbbVie: Consultancy; Janssen Pharmaceuticals: Consultancy; Celgene Corporation: Consultancy; AbbVie: Consultancy; Cellectis: Research Funding. Bhagat:Genoptix: Employment. Tell:Aprea Therapeutics: Employment. Fenaux:Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Jazz: Honoraria, Research Funding; Otsuka: Honoraria, Research Funding; Roche: Honoraria. List:Celgene: Research Funding. Komrokji:Novartis: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau.

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Mohell, N., J. Alfredsson, Å. Fransson, M. Uustalu, S. Byström, J. Gullbo, A. Hallberg, V. J. N. Bykov, U. Björklund, and K. G. Wiman. "APR-246 overcomes resistance to cisplatin and doxorubicin in ovarian cancer cells." Cell Death & Disease 6, no. 6 (June 2015): e1794-e1794. http://dx.doi.org/10.1038/cddis.2015.143.

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Li, Jing, Cheng Li, Guoliang Wang, Zhen Liu, Pei Chen, Qichen Yang, Nuo Dong, Huping Wu, Zuguo Liu, and Wei Li. "APR-246/PRIMA-1MetInhibits and Reverses Squamous Metaplasia in Human Conjunctival Epithelium." Investigative Opthalmology & Visual Science 57, no. 2 (February 11, 2016): 444. http://dx.doi.org/10.1167/iovs.15-17519.

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Aryee, D. N. T., S. Niedan, J. Ban, R. Schwentner, K. Muehlbacher, M. Kauer, R. Kofler, and H. Kovar. "Variability in functional p53 reactivation by PRIMA-1Met/APR-246 in Ewing sarcoma." British Journal of Cancer 109, no. 10 (October 15, 2013): 2696–704. http://dx.doi.org/10.1038/bjc.2013.635.

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Krayem, Mohammad, Fabrice Journe, Murielle Wiedig, Renato Morandini, Ahmad Najem, François Salès, Leon C. van Kempen, et al. "p53 Reactivation by PRIMA-1Met (APR-246) sensitises V600E/KBRAF melanoma to vemurafenib." European Journal of Cancer 55 (March 2016): 98–110. http://dx.doi.org/10.1016/j.ejca.2015.12.002.

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Synnott, Naoise C., Patricia M. McGowan, Aisling Pierce, Maeve Kiely, Norma O'Donovan, John Crown, Patrick A. Kiely, and Michael J. Duffy. "PRIMA-1MET (APR-246): A novel targeted therapy for triple negative breast cancer?" Journal of Clinical Oncology 33, no. 15_suppl (May 20, 2015): e12072-e12072. http://dx.doi.org/10.1200/jco.2015.33.15_suppl.e12072.

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Liljebris, C., N. Mohell, E. Olaisson, T. Uhlin, K. G. Wiman, and S. Lehmann. "APR-246, a new class anticancer compound in phase l/lla clinical trials." Journal of Clinical Oncology 28, no. 15_suppl (May 20, 2010): TPS183. http://dx.doi.org/10.1200/jco.2010.28.15_suppl.tps183.

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Magri, Jolanda, Alessandro Gasparetto, Laura Conti, Enzo Calautti, Chiara Cossu, Roberto Ruiu, Giuseppina Barutello, and Federica Cavallo. "Tumor-Associated Antigen xCT and Mutant-p53 as Molecular Targets for New Combinatorial Antitumor Strategies." Cells 10, no. 1 (January 8, 2021): 108. http://dx.doi.org/10.3390/cells10010108.

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The cystine/glutamate antiporter xCT is a tumor-associated antigen that has been newly identified in many cancer types. By participating in glutathione biosynthesis, xCT protects cancer cells from oxidative stress conditions and ferroptosis, and contributes to metabolic reprogramming, thus promoting tumor progression and chemoresistance. Moreover, xCT is overexpressed in cancer stem cells. These features render xCT a promising target for cancer therapy, as has been widely reported in the literature and in our work on its immunotargeting. Interestingly, studies on the TP53 gene have revealed that both wild-type and mutant p53 induce the post-transcriptional down modulation of xCT, contributing to ferroptosis. Moreover, APR-246, a small molecule drug that can restore wild-type p53 function in cancer cells, has been described as an indirect modulator of xCT expression in tumors with mutant p53 accumulation, and is thus a promising drug to use in combination with xCT inhibition. This review summarizes the current knowledge of xCT and its regulation by p53, with a focus on the crosstalk of these two molecules in ferroptosis, and also considers some possible combinatorial strategies that can make use of APR-246 treatment in combination with anti-xCT immunotargeting.

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Magri, Jolanda, Alessandro Gasparetto, Laura Conti, Enzo Calautti, Chiara Cossu, Roberto Ruiu, Giuseppina Barutello, and Federica Cavallo. "Tumor-Associated Antigen xCT and Mutant-p53 as Molecular Targets for New Combinatorial Antitumor Strategies." Cells 10, no. 1 (January 8, 2021): 108. http://dx.doi.org/10.3390/cells10010108.

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The cystine/glutamate antiporter xCT is a tumor-associated antigen that has been newly identified in many cancer types. By participating in glutathione biosynthesis, xCT protects cancer cells from oxidative stress conditions and ferroptosis, and contributes to metabolic reprogramming, thus promoting tumor progression and chemoresistance. Moreover, xCT is overexpressed in cancer stem cells. These features render xCT a promising target for cancer therapy, as has been widely reported in the literature and in our work on its immunotargeting. Interestingly, studies on the TP53 gene have revealed that both wild-type and mutant p53 induce the post-transcriptional down modulation of xCT, contributing to ferroptosis. Moreover, APR-246, a small molecule drug that can restore wild-type p53 function in cancer cells, has been described as an indirect modulator of xCT expression in tumors with mutant p53 accumulation, and is thus a promising drug to use in combination with xCT inhibition. This review summarizes the current knowledge of xCT and its regulation by p53, with a focus on the crosstalk of these two molecules in ferroptosis, and also considers some possible combinatorial strategies that can make use of APR-246 treatment in combination with anti-xCT immunotargeting.

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Rökaeus, N., J. Shen, I. Eckhardt, V. J. N. Bykov, K. G. Wiman, and M. T. Wilhelm. "PRIMA-1MET/APR-246 targets mutant forms of p53 family members p63 and p73." Oncogene 29, no. 49 (September 6, 2010): 6442–51. http://dx.doi.org/10.1038/onc.2010.382.

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Deneberg, S., H. Cherif, V. Lazarevic, P.-O. Andersson, M. von Euler, G. Juliusson, and S. Lehmann. "An open-label phase I dose-finding study of APR-246 in hematological malignancies." Blood Cancer Journal 6, no. 7 (July 2016): e447-e447. http://dx.doi.org/10.1038/bcj.2016.60.

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Cluzeau, Thomas, Marie Sebert, Ramy Rahmé, Stefania Cuzzubbo, Anouk Walter-petrich, Jacqueline Lehmann che, Pierre Peterlin, et al. "APR-246 Combined with Azacitidine (AZA) in TP53 Mutated Myelodysplastic Syndrome (MDS) and Acute Myeloid Leukemia (AML). a Phase 2 Study By the Groupe Francophone Des Myélodysplasies (GFM)." Blood 134, Supplement_1 (November 13, 2019): 677. http://dx.doi.org/10.1182/blood-2019-125579.

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Introduction : TP53 mutated (TP53m) MDS and AML have very poor outcome irrespective of the treatment received, including 40% responses (20% CR) with azacitidine (AZA) with short response duration and a median overall survival (OS) of about 8 months (Bejar, Blood 2014). APR-246 is a prodrug spontaneously converted to methylene quinuclidinone (MQ), a Michael acceptor that binds covalently to cysteines in mutant p53, leading to protein reconformation that reactivates its pro apoptotic and cell cycle arrest functions. The combination of AZA and APR 246 showed promising results in a phase Ib study in TP53m MDS (Sallman, ASH 2018). We report interim results of a GFM phase 2 study of AZA+ APR-246 in TP53m MDS and AML, conducted in parallel with a similar US MDS consortium study. Patients and Methods : The study included hypomethylating agent (HMA) naïve and not previously allografted intermediate, high or very high IPSS-R TP53m MDS and AML adult patients. Patients received APR-246 4500 mg IV /d (6 hour infusions) (days 1-4) followed by AZA 75 mg/m²/d (days 4-10) in 28 day cycles. Response (primary endpoint, assessed by IWG 2006 for MDS and ELN criteria for AML) was evaluated after 3 and 6 cycles in the intent to treat (ITT) population, ie all patients who had received any protocol treatment, and in patients who had at least a blood and bone marrow evaluation after cycle 3 (evaluable population). Allo-SCT, when possible, was proposed after 3 to 6 cycles, and treatment with reduced APR 246 and AZA doses could be continued after allo-SCT. Results : 53 patients were enrolled between Sept 2018 and July 2019 in 7 GFM centers, with a median age of 73 years (range 44-87), and M/F: 28/25. 34 patients had MDS (including 74% very high IPSS-R) and 19 had AML. IPSS-R cytogenetic risk was very poor in 30/34 MDS, and unfavorable in 18/19 AML, complex in 89% of the patients. Median baseline mutated TP53 VAF was 21% (range 3-76). Nineteen of the 53 patients had been included at least 7 months before date of analysis (25 July 2019), had received protocol treatment and were thus potentially evaluable for response after 6 treatment cycles (ITT population). One of them died after only one cycle from an unrelated cause (cerebral ischemic stroke), and 2 during the third cycle (from bleeding and sepsis, respectively). In the remaining 16 patients (evaluable population per protocol), the response rate was 75% including 9 (56%) CR, 3 (19%) marrow CR or stable disease with hematological improvement (HI), and 4 treatment resistance. In the ITT population, the response rate was 63%, including 47% CR, and 16% stable or marrow CR+ HI. Among CR patients, complete cytogenetic CR and negative NGS for TP53 mutation (VAF cutoff of 2%) were achieved in 7/9 (78%) and 8/8 (100%), respectively. So far, 1 patient has undergone allo-SCT. All 53 patients had received at least one treatment cycle, and no increased myelosuppression, compared with AZA alone, was apparent. Treatment related AEs observed in ≥ 20% of patients were febrile neutropenia in 19 (36%) and neurological AEs in 21 (40%) of the patients. The latter, reviewed with a neurological team, were mainly grade 1 or 2 and consisted of ataxia (n=13), sometimes associated with cognitive impairment (n=4), suggesting a cerebellar origin. Other patients experienced acute confusion (n=4), isolated dizziness (n=3) and facial paresthesia (n=1). Neurological AEs reached grade III in 3 cases (1 acute confusion, 2 ataxia). Occurrence of neurological AEs was correlated with lower glomerular filtration rate at treatment onset (p<0.01) and higher age (p=0.05). Neurological symptoms spontaneously regressed within 5 days of drug discontinuation (after a median of 1 day). They did not recur in the following cycles after per protocol APR 246 dose reductions. Conclusion : In this very high-risk elderly population of TP53m MDS and AML, generally with complex karyotype, a promising 56% CR rate at 6 cycles was reached in the evaluable population with AZA+ APR 246 combination, with deep molecular remission in all CR patients. We observed manageable neurologic AEs, mainly in elderly patients with reduced renal function, who therefore require close monitoring and dose reduction if necessary. An update regarding safety and efficacy in the 53 patients, including survival data, will be available at the meeting. A phase III international trial comparing AZA alone and AZA+ APR 246 in TP53m MDS is ongoing. Disclosures Cluzeau: Abbvie: Consultancy; Jazz Pharma: Consultancy; Menarini: Consultancy. Peterlin:AbbVie Inc: Consultancy; Astellas: Consultancy; Jazz Pharma: Consultancy; Daiichi-Sankyo: Consultancy. Recher:Daiichi-Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; chugai: Research Funding; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Agios: Research Funding; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Astellas Pharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz Pharmaceuticals: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Stamatoullas:Celgene: Honoraria; Takeda: Consultancy. Berthon:JAZZPHARMACEUTICAL: Other: DISCLOSURE BOARD; CELGEN: Other: DISCLOSURE BOARD; PFIZER: Other: DISCLOSURE BOARD. Sallman:Celyad: Membership on an entity's Board of Directors or advisory committees. Ades:Amgen: Research Funding; Astellas: Membership on an entity's Board of Directors or advisory committees; Silence Therapeutics: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Helsinn Healthcare: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Fenaux:Celgene Corporation: Honoraria, Research Funding; Astex: Honoraria, Research Funding; Jazz: Honoraria, Research Funding; Aprea: Research Funding.

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Nagourney, Adam Jeremiah, Steven Scott Evans, Max Serge Duesberg, Paulo D'Amora, Paula J. Bernard, Eric Francisco, and Robert Alan Nagourney. "Drugging the undruggable-targeting P53: A comparative analysis of APR-246 and coti-2 in human tumor primary culture explants." Journal of Clinical Oncology 40, no. 16_suppl (June 1, 2022): e15092-e15092. http://dx.doi.org/10.1200/jco.2022.40.16_suppl.e15092.

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e15092 Background: The TP53 tumor suppressor is the most commonly mutated gene in human cancer. P53 protein comprised of 393 amino acids functions as a tetramer with the loss of function mutations concentrated in “hotspots” that often affect DNA binding domains. APR-246 and COTI-2 are novel small molecules that are under clinical investigation for the treatment of P53 mutated cancers. APR, a quinuclidine binds to P53 cysteine residues altering the functional conformation while COTI is a thio-semicarbazone, found active in P53 mutant tumors using a novel computational platform. As the mechanisms of action may differ we undertook a comparative analysis of these compounds in 3D human tumor explants derived from surgical specimens. Methods: Ex Vivo Analyses of Programmed Cell Death (EVA/PCD) (D’Amora, P et al Gyn. Oncol. 2021) was applied to 236 human tumor primary culture explants isolated from surgical specimens. After disaggregation, micro-spheroids, isolated by precise density centrifugation were exposed to APR, COTI and other agents for 72-96 hours. Drug-induced cell death was measured by delayed-loss-of-membrane integrity and ATP content (luciferase). Dose response curves were interpolated to LC50 values. Synergy analysis used the method of Chou & Talalay. Correlation coefficients used Pearson moment. Results: APR and COTI reveal the highest activity in hematologic neoplasms. Solid tumor activity patterns diverged with COTI active in gynecologic malignancies and NSCLC and moderately active in breast and colorectal while APR is active in colorectal but less active in breast and NSCLC. Pearson moments for COTI vs APR revealed an R value = 0.146 (NS). COTI activity correlated with Nitrogen Mustard and Alpelisib (PIK3CA) while APR activity correlated with Doxorubicin and Everolimus. COTI combinations focused upon ovarian cancers identified synergy in 25% and antagonism in 18%. Conclusions: P53’s function as the “guardian of the genome” is consistent with our findings that many cytotoxic and targeted agents that induce cell death reveal correlations with APR and COTI. While APR affects the structural conformation of P53, COTI may function downstream via oxidative, metabolic or other stress responses. The correlation coefficient for APR vs COTI at 0.146 (NS) suggests distinct mechanisms of action. This is supported by different disease-specific-profiles and correlations with other drugs. COTI synergy in ovarian cancers, the target of current clinical trials at 25% is below expectations. With differing disease specificities, selecting between these and related agents to optimize clinical outcomes may require a more granular examination of cellular mechanisms of response and resistance. Primary culture analyses offer insights into drug mechanisms of action, combinatorial potential and have the capacity to improve patient selection.

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38

Nagourney, Adam Jeremiah, Steven Scott Evans, Max Serge Duesberg, Paulo D'Amora, Paula J. Bernard, Eric Francisco, and Robert Alan Nagourney. "Drugging the undruggable-targeting P53: A comparative analysis of APR-246 and coti-2 in human tumor primary culture explants." Journal of Clinical Oncology 40, no. 16_suppl (June 1, 2022): e15092-e15092. http://dx.doi.org/10.1200/jco.2022.40.16_suppl.e15092.

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e15092 Background: The TP53 tumor suppressor is the most commonly mutated gene in human cancer. P53 protein comprised of 393 amino acids functions as a tetramer with the loss of function mutations concentrated in “hotspots” that often affect DNA binding domains. APR-246 and COTI-2 are novel small molecules that are under clinical investigation for the treatment of P53 mutated cancers. APR, a quinuclidine binds to P53 cysteine residues altering the functional conformation while COTI is a thio-semicarbazone, found active in P53 mutant tumors using a novel computational platform. As the mechanisms of action may differ we undertook a comparative analysis of these compounds in 3D human tumor explants derived from surgical specimens. Methods: Ex Vivo Analyses of Programmed Cell Death (EVA/PCD) (D’Amora, P et al Gyn. Oncol. 2021) was applied to 236 human tumor primary culture explants isolated from surgical specimens. After disaggregation, micro-spheroids, isolated by precise density centrifugation were exposed to APR, COTI and other agents for 72-96 hours. Drug-induced cell death was measured by delayed-loss-of-membrane integrity and ATP content (luciferase). Dose response curves were interpolated to LC50 values. Synergy analysis used the method of Chou & Talalay. Correlation coefficients used Pearson moment. Results: APR and COTI reveal the highest activity in hematologic neoplasms. Solid tumor activity patterns diverged with COTI active in gynecologic malignancies and NSCLC and moderately active in breast and colorectal while APR is active in colorectal but less active in breast and NSCLC. Pearson moments for COTI vs APR revealed an R value = 0.146 (NS). COTI activity correlated with Nitrogen Mustard and Alpelisib (PIK3CA) while APR activity correlated with Doxorubicin and Everolimus. COTI combinations focused upon ovarian cancers identified synergy in 25% and antagonism in 18%. Conclusions: P53’s function as the “guardian of the genome” is consistent with our findings that many cytotoxic and targeted agents that induce cell death reveal correlations with APR and COTI. While APR affects the structural conformation of P53, COTI may function downstream via oxidative, metabolic or other stress responses. The correlation coefficient for APR vs COTI at 0.146 (NS) suggests distinct mechanisms of action. This is supported by different disease-specific-profiles and correlations with other drugs. COTI synergy in ovarian cancers, the target of current clinical trials at 25% is below expectations. With differing disease specificities, selecting between these and related agents to optimize clinical outcomes may require a more granular examination of cellular mechanisms of response and resistance. Primary culture analyses offer insights into drug mechanisms of action, combinatorial potential and have the capacity to improve patient selection.

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39

Fang, Y., and C. K. Chang. "PB1913: SYNERGISTIC EFFECTS OF DECITABINE AND APR-246 IN TP53 P.248Q-MUTATED MYELODYSPLASTIC SYNDROME." HemaSphere 6 (June 2022): 1792–93. http://dx.doi.org/10.1097/01.hs9.0000850504.79008.eb.

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40

Hang, Wei, Zhi-Xian Yin, Gang Liu, Qinghua Zeng, Xiang-Feng Shen, Qian-Hui Sun, Dong-Dong Li, et al. "Piperlongumine and p53-reactivator APR-246 selectively induce cell death in HNSCC by targeting GSTP1." Oncogene 37, no. 25 (January 18, 2018): 3384–98. http://dx.doi.org/10.1038/s41388-017-0110-2.

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41

Synnott, Naoise C., Stephen F. Madden, Vladimir J. N. Bykov, John Crown, Klas G. Wiman, and Michael J. Duffy. "The Mutant p53-Targeting Compound APR-246 Induces ROS-Modulating Genes in Breast Cancer Cells." Translational Oncology 11, no. 6 (December 2018): 1343–49. http://dx.doi.org/10.1016/j.tranon.2018.08.009.

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42

Liu, David S. H., Matthew Read, Carleen Cullinane, Walid J. Azar, Christina M. Fennell, Karen G. Montgomery, Sue Haupt, et al. "APR-246 potently inhibits tumour growth and overcomes chemoresistance in preclinical models of oesophageal adenocarcinoma." Gut 64, no. 10 (July 17, 2015): 1506–16. http://dx.doi.org/10.1136/gutjnl-2015-309770.

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43

Roszkowska, Katarzyna A., Aleksandra Piecuch, Maria Sady, Zdzisław Gajewski, and Sylwia Flis. "Gain of Function (GOF) Mutant p53 in Cancer—Current Therapeutic Approaches." International Journal of Molecular Sciences 23, no. 21 (October 31, 2022): 13287. http://dx.doi.org/10.3390/ijms232113287.

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Continuous development of personalized treatments is undoubtedly beneficial for oncogenic patients’ comfort and survival rate. Mutant TP53 is associated with a worse prognosis due to the occurrence of metastases, increased chemoresistance, and tumor growth. Currently, numerous compounds capable of p53 reactivation or the destabilization of mutant p53 are being investigated. Several of them, APR-246, COTI-2, SAHA, and PEITC, were approved for clinical trials. This review focuses on these novel therapeutic opportunities, their mechanisms of action, and their significance for potential medical application.

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Peng, X., M.-Q.-Z. Zhang, F. Conserva, G. Hosny, G. Selivanova, V. J. N. Bykov, E. S. J. Arnér, and K. G. Wiman. "APR-246/PRIMA-1MET inhibits thioredoxin reductase 1 and converts the enzyme to a dedicated NADPH oxidase." Cell Death & Disease 4, no. 10 (October 2013): e881-e881. http://dx.doi.org/10.1038/cddis.2013.417.

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Ali, Dina, Kerstin Jönsson-Videsäter, Stefan Deneberg, Sofia Bengtzén, Hareth Nahi, Christer Paul, and Sören Lehmann. "APR-246 exhibits anti-leukemic activity and synergism with conventional chemotherapeutic drugs in acute myeloid leukemia cells." European Journal of Haematology 86, no. 3 (January 11, 2011): 206–15. http://dx.doi.org/10.1111/j.1600-0609.2010.01557.x.

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46

Saha, Manujendra N., Hua Jiang, Yijun Yang, Donna Reece, and Hong Chang. "PRIMA-1Met/APR-246 Displays High Antitumor Activity in Multiple Myeloma By Induction of p73 and Noxa." Molecular Cancer Therapeutics 12, no. 11 (September 12, 2013): 2331–41. http://dx.doi.org/10.1158/1535-7163.mct-12-1166.

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47

Li, Xiao-Lan, Jianbiao Zhou, Zit-Liang Chan, Jing-Yuan Chooi, Zhi-Rong Chen, and Wee-Joo Chng. "PRIMA-1met (APR-246) inhibits growth of colorectal cancer cells with different p53 status through distinct mechanisms." Oncotarget 6, no. 34 (October 1, 2015): 36689–99. http://dx.doi.org/10.18632/oncotarget.5385.

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48

Lyle, MS, PA-C, Lindsey. "ASH Highlights and Commentary: Myeloid Malignancies." Journal of the Advanced Practitioner in Oncology 13, no. 2 (March 1, 2022): 15–23. http://dx.doi.org/10.6004/jadpro.2022.13.2.11.

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This supplement to JADPRO provides an overview of several abstracts that were presented at the 2021 ASH Annual Meeting, along with expert commentary that aims to contextualize the information presented at ASH for the advanced practitioner. Lindsey Lyle, MS, PA-C, of University of Colorado Anschutz Medical Campus, considers promising results in the myeloid malignancies space. Ms. Lyle highlights long-term data on the combination of eprenetapopt (APR-246) and azacitidine in patients with TP53-mutated acute myeloid leukemia/myelodysplastic syndromes, a new option for patients with paroxysmal nocturnal hemoglobinuria, and valuable insights into Black and non-Black patient preferences regarding their treatment and communication with their providers.

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Seipel, Katja, Basil Kopp, Ulrike Bacher, and Thomas Pabst. "BMI1-Inhibitor PTC596 in Combination with MCL1 Inhibitor S63845 or MEK Inhibitor Trametinib in the Treatment of Acute Leukemia." Cancers 13, no. 3 (February 2, 2021): 581. http://dx.doi.org/10.3390/cancers13030581.

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Purpose: Prognosis for acute myeloid leukemia (AML) patients is poor, particularly in TP53 mutated AML, secondary, relapsed, and refractory AML, and in patients unfit for intensive treatment, thus highlighting an unmet need for novel therapeutic approaches. The combined use of compounds targeting the stem cell oncoprotein BMI1 and activating the tumor suppressor protein p53 may represent a promising novel treatment option for poor risk AML patients. Experimental Design: The BMI1 inhibitor PTC596, MCL1 inhibitor S63845, and MEK inhibitor trametinib, as well as the p53 activator APR-246 were assessed as single agents and in combination for their ability to induce apoptosis and cell death in leukemic cells. AML cells represented all major morphologic and molecular subtypes including FLT3-ITD and FLT3 wild type, NPM1 mutant and wild type, as well as TP53 mutant and wild type AML cell lines and a variety of patient derived AML cells. Results: AML cell lines were variably susceptible to PTC596 and to combination treatments with PTC596 and MCL1 inhibitor S63845, MEK inhibitor trametinib, or TP53 activator APR-246, independent of TP53 mutational status. Susceptibility of patient samples for PTC596 in combination with S63845 or trametinib was significant for the majority of adverse risk primary and secondary AML with minimal efficacy in favorable risk AML, and correlated significantly with CD34 positivity of the samples. BMI1 and MN1 gene expression, and MCL1 and MEK1 protein levels were identified as biomarkers for response to PTC596 combination treatments. Conclusions: The combination of PTC596 and S63845 may be an effective treatment in CD34+ adverse risk AML with elevated MN1 gene expression and MCL1 protein levels, while PTC596 and trametinib may be more effective in CD34+ adverse risk AML with elevated BMI1 gene expression and MEK protein levels.

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De La Rosa, Javier, Alejandro Urdiciain, María Zelaya, Idoya Zazpe, Bárbara Meléndez, Juan Rey, Miguel Idoate, et al. "APR-246 combined with 3-deazaneplanocin A, panobinostat or temozolomide reduces clonogenicity and induces apoptosis in glioblastoma cells." International Journal of Oncology 58, no. 3 (January 26, 2021): 312–30. http://dx.doi.org/10.3892/ijo.2021.5177.

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Journal articles on the topic 'APR-246'

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