Academic literature on the topic 'Glioblastoma, cancer stem-like cells, EGFR and NF-kB'

Abstract The treatment options for Glioblastoma (GBM) are currently limited to resection and chemotherapy approaches, but resistance to chemotherapy is common in patients. There is an urgent need for further understanding of the underlying biology of tumorigenesis in order to develop new treatment options. Previous genomic work on GBMs has shown that the epidermal growth factor receptor (EGFR) is frequently amplified and constitutively active in GBM tumors. To discover new factors that contribute to progression of EGFR-driven GBMs, we used our Drosophila GBM model in which GBM-like glial neoplasia can be induced by glial-specific overexpression of constitutively active forms of EGFR and dp110, a subunit of Phosphoinositide 3-kinase (PI3K), using the UAS-GAL4 gene expression system. Using our Drosophila GBM model system, we performed a modifier screen in which we searched for genes and pathways that worsened or ‘enhanced’ glial neoplasia when specifically overexpressed or activated in neoplastic glia. From our screen, we identified the Toll pathway, which in Drosophila activates an NF-κB signaling pathway. Furthermore, the Toll pathway normally functions in innate immune and injury responses as well as in development and cell proliferation. Using our Drosophila GBM model, we are studying how the Toll signaling pathway and its effectors, including NF-κB, contribute to enhanced growth of neoplastic glial cells. Furthermore, using well-defined mouse genetic models and human patient-derived GBM models, we are examining whether Toll pathway regulatory and signaling mechanisms that we have uncovered in Drosophila function in EGFR-mutant GBM tumor stem cells to promote GBM progression and chemotherapy resistance.

1012 Background: While effective, target-directed therapies are available for ER-positive and HER2-amplified breast cancer, adjuvant therapeutic options for triple-negative breast cancer (TNBC) are limited in the absence of well-defined molecular targets. Constitutive activation of oncogenic nuclear factor kB (NFkB) has been associated with ER-negative or basal-like (BL) breast cancers, but the underlying mechanism of this activation remains undefined. We previously showed that deletion of the endogenous NFkB repressor gene NFKBIA associates with EGFR non-amplified glioblastoma multiforme and portends unfavorable clinical outcome (Bredel et al. NEJM 2011). Methods: We analyzed >5,000 human breast cancers for deletions, mutations and/or expression of NFKBIA. We studied tumor suppressor activity of NFKBIA and the effect of targeted NFkB inhibition in cell culture with various NFKBIA genotypes. We compared molecular results with outcomes of affected persons. Results: NFKBIA is often (10.8%) deleted but not mutated in breast cancer. NFKBIA deletions are significantly associated with TNBC (32.8%) and particularly frequent in the BL subtype (36.7%). Loss of NFKBIA exerts a haploinsufficient effect on NFKBIA expression and the transactivation of several NF-kB target genes with important roles in breast carcinogenesis. Restoration of NFKBIA expression or pharmacologic NFkB inhibition attenuates the malignant phenotype of cells cultured from TNBC with NFKBIA deletion. Deletion and low expression of NFKBIA are highly associated with unfavorable overall survival, independent of patient age, tumor stage, nodal status, and tumor subtype. Loss of NFKBIA expression portends significantly poorer disease-specific survival, recurrence-free survival, and distant metastasis-free survival. Moreover, NFKBIA expression is significantly associated with duration of metastasis-free survival in subgroups of patients with brain or lung metastases from breast cancer. Conclusions: NFKBIA is a new, prognostically relevant, molecular target in TNBC, which remains a clinically challenging subtype of breast cancer with limited treatment options.

Abstract INTRODUCTION In 2021, the World Health Organization (WHO) reclassified glioblastoma, the most common form of adult brain cancer, into isocitrate dehydrogenase (IDH) wild-type glioblastomas and grade IV IDH mutant (G4 IDHm) astrocytomas. For both tumor types, intra-tumoral heterogeneity is a key contributor to therapeutic failure. METHODS we applied integrated genome-wide chromatin accessibility (snATACseq) and transcription (snRNAseq) profiles to clinical specimens derived IDHwt glioblastomas and G4 IDHm) astrocytomas, with goal of therapeutic target discovery. RESULTS The integrated analysis achieved resolution of intra-tumoral heterogeneity not previously possible, providing a molecular landscape of extensive regional and cellular variability. snATACseq delineated focal amplification down to an ~40 KB resolution. The snRNA analysis elucidated distinct cell types and cell states (neural progenitor/oligodendrocyte cell-like or astrocyte/mesenchymal cell-like) that were superimposable onto the snATACseq landscape. Paired-seq (parallel snATACseq and snRNAseq using the same clinical sample) provided high resolution delineation of extrachromosomal circular DNA (ecDNA), harboring oncogenes including CCND1 and EGFR. Importantly, the copy number of ecDNA genes correlated closely with the level of RNA expression. Integrated analysis across all specimens profiled suggests that IDHm grade 4 astrocytoma and IDHwt glioblastoma cells shared a common chromatin structure defined by open regions enriched for Nuclear Factor 1 transcription factors (NFIA and NFIB). Silencing of NF1A or NF1B suppressed in vitro and in vivo growth of patient-derived IDHwt glioblastomas and G4 IDHm astrocytoma models that mimic distinct glioblastoma cell states. CONCLUSION Our findings suggest despite distinct genotypes and cell states, glablastoma/G4 astrocytoma cells share dependency on core transcriptional programs, yielding an attractive platform for addressing therapeutic challenges associated with intra-tumoral heterogeneity.

Abstract Glioblastoma (GBM) is a dismal disease and despite optimal treatment, long-term survival remains uncommon. Molecular classification revealed three distinct GBM subgroups and has helped to shine light on the tumor’s inter/intratumoral heterogeneity. Interestingly, recent evidence shows plasticity between these subtypes in which the proneural (PN) glioma stem-like cells undergo transition into the more aggressive mesenchymal (MES) subtype leading to therapeutic resistance. Extracellular vesicles (EVs) are considered a heterogeneous group of membrane-limited vesicles secreted by nearly every cell. In the context of GBM, these biological nanoparticles act as multifunctional signaling complexes and play an important role in intercellular communication allowing cancer cells to exchange information with each other, the tumor microenvironment, and distant cells. We show that MES cells derived EVs modulate PN cells to increase migratory potential, stemness, invasiveness, aggressiveness, and therapeutic resistance by inducing mesenchymal transition through NF-KB/STAT3 signaling. Furthermore, we shine light on the role of EVs derived from irradiated GBM cells and their potential impact on microglia and resulting treatment resistance.

Cancer stem cells (CSCs) are crucial mediators of tumor growth, metastasis, therapy resistance, and recurrence in a broad variety of human cancers. Although their biology is increasingly investigated within the distinct types of cancer, direct comparisons of CSCs from different tumor types allowing comprehensive mechanistic insights are rarely assessed. In the present study, we isolated CSCs from endometrioid carcinomas, glioblastoma multiforme as well as adenocarcinomas of lung and prostate and assessed their global transcriptomes using full-length cDNA nanopore sequencing. Despite the expression of common CSC markers, principal component analysis showed a distinct separation of the CSC populations into three clusters independent of the specific type of tumor. However, GO-term and KEGG pathway enrichment analysis revealed upregulated genes related to ribosomal biosynthesis, the mitochondrion, oxidative phosphorylation, and glycolytic pathways, as well as the proteasome, suggesting a great extent of metabolic flexibility in CSCs. Interestingly, the GO term “NF-kB binding” was likewise found to be elevated in all investigated CSC populations. In summary, we here provide evidence for high global transcriptional similarities between CSCs from various tumors, which particularly share upregulated gene expression associated with mitochondrial and ribosomal activity. Our findings may build the basis for identifying novel therapeutic strategies targeting CSCs.

Glycyrrhizic acid (GA), a natural compound isolated from licorice (Glycyrrhiza glabra), has exhibited anti-inflammatory and anti-tumor effects in vitro. Dipotassium glycyrrhizinate (DPG), a dipotassium salt of GA, also has shown an anti-tumor effect on glioblastoma cell lines, U87MG and T98G. The study investigated the DPG effects in the melanoma cell line (SK-MEL-28). MTT assay demonstrated that the viability of the cells was significantly decreased in a time- and dose-dependent manner after DPG (IC50 = 36 mM; 24 h). DNA fragmentation suggested that DPG (IC50) induced cellular apoptosis, which was confirmed by a significant number of TUNEL-positive cells (p-value = 0.048) and by PARP-1 [0.55 vs. 1.02 arbitrary units (AUs), p-value = 0.001], BAX (1.91 vs. 1.05 AUs, p-value = 0.09), and BCL-2 (0.51 vs. 1.07 AUs, p-value = 0.0018) mRNA compared to control cells. The proliferation and wound-healing assays showed an anti-proliferative effect on DPG-IC50-treated cells, also indicating an inhibitory effect on cell migration (p-values < 0.001). Moreover, it was observed that DPG promoted a 100% reduction in melanospheres formation (p-value = 0.008). Our previous microRNAs (miRs) global analysis has revealed that DPG might increase miR-4443 and miR-3620 expression levels. Thus, qPCR showed that after DPG treatment, SK-MEL-28 cells presented significantly high miR-4443 (1.77 vs. 1.04 AUs, p-value = 0.02) and miR-3620 (2.30 vs. 1.00 AUs, p-value = 0.01) expression compared to control cells, which are predicted to target the NF-kB, CD209 and TNC genes, respectively. Both genes are responsible for cell attachment and migration, and qPCR revealed significantly decreased CD209 (1.01 vs. 0.54 AUs, p-value = 0.018) and TNC (1.00 vs. 0.31 AUs, p-value = 2.38 × 10−6) mRNA expression levels after DPG compared to untreated cells. Furthermore, the migration of SK-MEL-28 cells stimulated by 12-O-tetradecanoylphorbol-13-acetate (TPA) was attenuated by adding DPG by wound-healing assay (48 h: p-value = 0.004; 72 h: p-value = 7.0 × 10−4). In addition, the MMP-9 expression level was inhibited by DPG in melanoma cells stimulated by TPA and compared to TPA-treated cells (3.56 vs. 0.99 AUs, p-value = 0.0016) after 24 h of treatment. Our results suggested that DPG has an apoptotic, anti-proliferative, and anti-migratory effect on SK-MEL-28 cells. DPG was also able to inhibit cancer stem-like cells that may cause cerebral tumor formation.

In the past years it was made a very huge effort to understand the genetic and molecular signatures of glioblastoma in order to improve targeted molecular therapy: but to date several things remain still unclear and new markers or new relationships have to been disclosed. Our aim is, therefore, to better clarify genetic signatures and pathways’ cross-talks in our glioblastoma-stem like cells model: actually we believe that these cells represent a real reservoir for the tumor of cells, which are able alone to maintain tumor growth, to give raise to a relapse and to determine radio- and chemo-resistance. First we presented a paper published in collaboration with our laboratory in 2012: in this study we found that the expression of MET oncogene was associated with a mesenchymal signature in our glioblastoma stem-like cells model and this expression is mutually exclusive with EGFR amplification; these cells also displayed different growth requirements in vitro and generated tumors with distinctive features in vivo; this suggested that MET could be a new target for therapy of a specific subset of GBMs (De Bacco et al 2012). Then we tried to better understand the possible cross-talk between EGFR and NF-kB signalling through a specific genetic signature disclosed in a precedent paper (Bredel et al 2011): a heterozygous deletion of NFKBIA gene, mutually exclusive with EGFR amplification. Surprisingly we found that this signature is a rare event in the primary tumor, but it is very frequent in our glioblastoma stem-like cells model in vitro and has also clear functional consequences. Our results raise the possibility that this deletion may be amplified in vitro, favored by the presence of EGF, mostly in that lines in which EGFR pathway is predominant; furthermore in these cells seems to be favored the constitutive active mutant of EGFR gene, EGFRvIII, probably in order to preserve EGFR-NF-kB axis. All these data suggest that our model is a much better system than serum-dependent cultures to study GBMs biology, bu at the same time various GSCs subgroups can be defined, that require both different factors to grow and also display different behaviours based on their genetic and molecular signatures.