Literatura académica sobre el tema "Immune checkpoint blocker"

To direct checkpoint inhibition to the tumor microenvironment, while avoiding systemic immune activation, we have synthesized a bispecific antibody [norleucine4, d-Phe7]-melanocyte stimulating hormone (NDP-MSH)-antiprogrammed cell death-ligand 1 antibody (αPD-L1) by conjugating a melanocyte stimulating hormone (α-MSH) analog to the antiprogrammed cell death-ligand 1 to (αPD-L1) antibody avelumab. This bispecific antibody can bind to both the melanocortin-1 receptor (MC1R) and to PD-L1 expressed on melanoma cells and shows enhanced specific antitumor efficacy in a syngeneic B16-SIY melanoma mouse model compared with the parental antibody at a 5 mg/kg dose. Moreover, the bispecific antibody showed increased infiltrated T cells in the tumor microenvironment. These results suggest that a tumor-targeted PD-L1-blocking bispecific antibody could have a therapeutic advantage in vivo, especially when used in combination with other checkpoint inhibitors.

Immune checkpoint blockers (ICBs) have shown great promise at harnessing immune system to combat cancer. However, only a fraction of patients can directly benefit from the anti–programmed cell death protein 1 (aPD1) therapy, and the treatment often leads to immune-related adverse effects. In this context, we developed a prodrug hydrogelator for local delivery of ICBs to boost the host’s immune system against tumor. We found that this carrier-free therapeutic system can serve as a reservoir for extended tumoral release of camptothecin and aPD1 antibody, resulting in an immune-stimulating tumor microenvironment for boosted PD-1 blockade immune response. Our in vivo results revealed that this combination chemoimmunotherapy elicits robust and durable systemic anticancer immunity, inducing tumor regression and inhibiting tumor recurrence and metastasis. This work sheds important light into the use of small-molecule prodrugs as both chemotherapeutic and carrier to awaken and enhance antitumor immune system for improved ICBs therapy.

9570 Background: Tumor infiltrating lymphocytes (TIL) play a crucial role in the therapeutic impact of immune checkpoint blockers. Methods: We investigated metastases from 56 melanoma patients before and during treatment with immune checkpoint blockers (i) immunohistochemically, (ii) with TCR repertoire profiling and (iii) analysis of the transcriptome. The patients were treated with ipilimumab (n = 25) or pembrolizumab (n = 23) or ipilimumab/nivolumab (n = 7); half of them had a disease control, the other half progressed as best response to treatment. Results: In contrast to previous reports immunohistochemical analysis of the immune infiltrate revealed no significant difference in the number of CD8+ TILs in pretreatment samples of responders and non-responders. Instead, the number of CD4 + TILs including regulatory T cells (Treg) and the number of PD-1 + cells was higher in responders especially when receiving pembrolizumab. Samples taken at least 6 weeks after start of the immune checkpoint blocker showed a significant higher number of immune cells in responders through all T cell subsets (CD3,4,8,FoxP3, PD-1), B cells (CD20) as well as macrophages (CD68, CD163). TCR repertoire profiling by deep TCR sequencing demonstrated that responders develop a more diverse repertoire under treatment (p = 0.05). Pretreatment samples as well as the size of the top 10 TCR clones posttreatment did not differ significantly in responders and non-responders. By RNA sequencing no differential expression profiles between responders and non-responders was found pretreatment. Posttreatment samples expressed different genes compared to pretreatment samples in responders including MHC molecules, CDK2/4, Myc, TNF family members and different apoptosis-inducing genes. There was no differential gene expression in non-responders pre- and posttreatment. Conclusions: Pretreatment metastases from responders and non-responders do not differ much. With treatment responding patients have significant higher numbers of immune cells including T- and B- cells as well as macrophages and develop a more diverse TCR repertoire. RNA sequencing revealed a differential expression pre- versus posttreatment only in responding patients.

Melanoma is becoming increasingly common worldwide, with high rates of transformation into malignancy compared to other skin lesions. The prognosis of patients with melanoma at an advanced stage is highly unsatisfying despite the development of immunotherapy, target therapy, or combinative therapy. The major barrier to exploiting immune checkpoint therapies and achieving the best benefits clinically is resistance that can easily develop if regimens are not selected appropriately. In this study, we investigated the possibility of using immune-related genes to predict patient survival and their responses to immune checkpoint blocker therapies with the expression profiles available at The Cancer Genome Atlas (TCGA) Program plus expression data from the Gene Expression Omnibus (GEO) for validation. A five gene signature that is highly correlated with the local infiltration of cytotoxic lymphocytes in the tumor microenvironment was identified, and a scoring model was developed with stepwise regression after multivariate Cox analyses. The score calculated strongly correlates with Breslow depth, and this model effectively predicts the prognosis of patients with melanoma, whether primary or metastasized. It also depicts the heterogenous immune-related nature of melanoma by revealing different predicted responses to immune checkpoint blocker therapies through its correlation to tumor immune dysfunction and exclusion (TIDE) score.

SummaryImmune checkpoint inhibitors (ICI) have improved survival of patients with metastatic melanoma but can induce autoimmunologic side effects. Ye et al. report a retrospective analysis that further supports the finding that these are biomarkers for patients’ clinical benefit. Thereby, patients with immune-related adverse events show a differential gene expression in chemokine-mediated signalling.

Le cancer est une pathologie souvent associée au vieillissement. Plusieurs phénomènes liés à l’inflammaging (inflammation chronique associée à l'âge) sont des marqueurs de sénescence, tels que l’immunosénescence et l’hématopoïèse clonale. Cette inflammation chronique favorise le développement de nombreuses pathologies, telles que les comorbidités cardiovasculaires, tout en réduisant la capacité de réponse immunitaire avec l'âge. L’immunosénescence se caractérise notamment par la diminution du nombre et de la fréquence des lymphocytes T naïfs dans le sang, en raison de leur conversion en lymphocytes T mémoires suite à une exposition naturelle aux pathogènes, auto-antigènes et néo-antigènes. En parallèle, l’involution thymique liée à l'âge réduit la production de nouveaux lymphocytes T naïfs au cours de la vie. Les infections virales chroniques, telles les virus appartenant à la famille des Herpesviridae comme le CMV, contribuent également à l'augmentation des lymphocytes T mémoires en différenciation terminale et à la sénéscence lymphocytaire. Parallèlement à la sénescence immunitaire, on observe l’émergence, avec l'âge et sous l'influence de divers facteurs, d'une hématopoïèse clonale (CH). Elle repose sur la détection de mutations somatiques dans les cellules hématopoïétiques chez des patients sans maladie hématologique avérée. Ces mutations, identifiées grâce au séquençage de nouvelle génération (NGS) dans le sang périphérique, affectent des gènes associés à des pathologies telles que les leucémies myéloïdes aiguës ou les syndromes myélodysplasiques (comme DNMT3A, TET2,ASXL1). Le vieillissement est un facteur de risque majeur de la CH, avec une prévalence supérieure à 10 % après 70 ans, qui augmente progressivement avec l'âge. La CH est également plus fréquente chez les patients atteints de cancer, sous l'effet des traitements ou de facteurs environnementaux (comme le tabac, la radiothérapie et la chimiothérapie). Cependant, son impact pronostique chez les patients atteints de tumeurs solides reste encore peu connu. D’un point de vue thérapeutique, de nombreux progrès ont été réalisés ces dernières années en oncologie solide avec l’avènement des thérapies ciblées et de l’immunothérapie. L’approche antitumorale de l’immunothérapie repose sur un nouveau paradigme: mobiliser le système immunitaire du patient à des fins thérapeutiques. De nombreuses classes de traitements sont en cours de développement, mais les inhibiteurs des points de contrôle immunitaire restent les plus avancés. Ils sont approuvés dans de nombreuses indications, en monothérapie ou en combinaison. La recherche de biomarqueurs a permis de mieux définir les populations candidates à ces traitements. Plusieurs biomarqueurs prédictifs et pronostiques sont désormais disponibles, principalement liés à la tumeur ou à son micro-environnement. Certains biomarqueurs pourraient également être liés au profil immunitaire du patient. L’objectif de cette thèse est d’analyser l’influence de l’hématopoïèse clonale, de l’immuno- sénescence et de l’inflammaging sur l’efficacité des traitements antitumoraux chez des patients atteints de cancers solides
Cancer is a pathology often associated with aging. Several phenomena related to inflammaging (chronic age-related inflammation) are markers of senescence, such as immunosenescence and clonal hematopoiesis. This chronic inflammation promotes the development of many diseases, such as cardiovascular comorbidities, while reducing the capacity for an efficient immune response with age. Immunosenescence is notably characterized by a decrease in the number and frequency of naïve T lymphocytes in the blood, due to their conversion into memory T lymphocytes following natural exposure to pathogens, autoantigens, and neoantigens. In parallel, thymic involution associated with aging reduces the production of new naïve T lymphocytes throughout life. Chronic viral infections, such as those caused by viruses in the Herpesviridae family, including CMV, also contribute to the increase in terminally differentiated memory T lymphocytes and lymphocyte senescence. Alongside immune senescence, the emergence of clonal hematopoiesis (CH) is observed with aging, influenced by various factors. CH is characterized by the detection of somatic mutations in hematopoietic cells in patients without hematologic disease. These mutations, identified through next-generation sequencing (NGS) in peripheral blood, affect genes associated with conditions such as acute myeloid leukemia or myelodysplastic syndromes (e.g., DNMT3A, TET2, ASXL1). Aging is a major risk factor for CH, with a prevalence of over 10% after the age of 70, and it increases progressively with age. CH is also more frequent in cancer patients, influenced by treatments or environmental factors (such as smoking, radiotherapy, and chemotherapy). However, its prognostic impact in patients with solid tumors remains largely unknown. From a therapeutic perspective, significant progress has been made in solid oncology in recent years with the advent of targeted therapies and immunotherapy. The antitumor approach of immunotherapy is based on a new paradigm: mobilizing the patient’s immune system for therapeutic purposes. Several classes of treatments are under development, with immune checkpoint inhibitors leading the way. These inhibitors are approved in numerous indications, either as monotherapy or in combination. The search for biomarkers has refined the selection of candidate populations. Several predictive and prognostic biomarkers are now available, mainly related to the tumor or its microenvironment. Some biomarkers could also be related to the patient's immune profile. The objective of this thesis is to analyze the impact of clonal hematopoiesis, immunosenescence, and inflammaging on the effectiveness of antitumor treatments in patients with solid cancers

The immunostimulatory ability of oligonucleotides containing CpG motif (CpG-ODN), agonists of TLR9, can be harnessed to promote antitumor immunity by their application at the tumor site to stimulate local activation of innate immunity; however, this is not always true for lung tumor where the immunosuppressive microenvironment, crucial to avoid tissue damage by inflammatory response to the continuous exposition to inhaled particles, limits the power of immunotherapy. Thus, the tumor microenvironment is a critical factor for successful use of these immunotherapeutics, and strategies to shift a tumor-supporting milieu to a host-friendly one might lead to improved anti-tumor activity of CpG-ODN. Since bronchial and bronchoalveolar tumors are accessible via the endobronchial space, inhalation of aerosolized immunotherapeutic agents might represent a convenient and simple approach to shape a tumor microenvironment more favorable to induce an immune response against lung primary cancer and/or metastases. Aim of this thesis is the evaluation of strategies to improve the antitumor activity of aerosolized TLR9 agonist in the lung. The thesis is divided in three tasks: 1) the evaluation of aerosol delivery CpG-ODN combined with Poly(I:C), a TLR3 agonist able to convert tumor-supporting macrophages to tumoricidal effectors, in the treatment of B16 melanoma lung metastases in C57BL/6 mice. 2) the investigation of the mechanism by which the two combined agonists could induce the activation of effector cells population. 3) the exploration of strategies to improve the therapeutic efficacy of TLR9/TLR3 agonists by including in the inhalant either an antibody directed to both Ly6G and Ly6C markers, to locally deplete myeloid-derived suppressive cells (MDSC), or IFNα, to directly activate innate immune cells in the lung. Aerosolization of CpG-ODN with Poly(I:C) into the bronchoalveolar space reduced the presence of M2-associated arginase- and IL-10-secreting macrophages in tumor-bearing lungs and increased the anti-tumor activity of aerosolized CpG-ODN alone against B16 lung metastases without apparent signs of toxicity or injury of the bronchial-bronchiolar structures and alveolar walls. Moreover, CpG-ODN/Poly(I:C) aerosol combined with dacarbazine, a therapeutic agent used in patients with inoperable metastatic melanoma able to exert immunostimulatory effects, led to a significant increase in anti-tumor activity as compared to treatments with aerosolized CpG-ODN/Poly(I:C) or dacarbazine alone. This effect was related to an enhanced recruitment and cytotoxic activity of tumor-infiltrating NK cells in the lung. Our in vitro and in vivo experiments to elucidate the mechanism of NK cells activation by TLR9/TLR3 stimulation revealed that the two agonists were able to directly induce IFN-γ secretion by NK cells, but the stimulation of their cytotoxic activity required the presence of alveolar macrophages. Interestingly, our experiments demonstrated that, reciprocally, NK cells were able to influence macrophages polarization, since alveolar macrophages incubated with activated NK cells from the lungs of melanoma metastases-bearing mice that were given aerosolized TLR9/TLR3 agonists, up-regulated M1- and down-regulated M2-related genes. Addition of nebulized anti-MDSC antibody RB6-8C5 to aerosolized CpG-ODN/Poly(I:C) resulted in reduced mRNA levels of immunosuppressive molecules (IL10, Arg-1 and Nos2), increased activation of resident NK cells and improved treatment outcome, with a significant reduction in established B16 melanoma lung metastases, compared to treatment with CpG-ODN/Poly(I:C) alone. Likewise, addition of aerosolized IFN-α led to increased mRNA levels of pro-inflammatory cytokines (IL15 and IFN-γ) in the lung and recruitment of highly activated NK cells, with no evident signs of toxicity and with a significantly improved anti-tumor effect, as compared with aerosolized CpG-ODN/Poly(I:C). Combining both IFN-α and RB6-8C5 with CpG-ODN/Poly(I:C) did not produce additive effects. In conclusion, the results of this thesis indicate that the pulmonary route is a feasible and non-invasive strategy to deliver immunodulatory molecules, including antibodies and cytokines, to reprogram the lung microenvironment shaping it more favorable to foster immune destruction of tumors.

De nombreuses données suggèrent que le succès thérapeutique de certaines chimiothérapies conventionnelles, radiothérapies, ainsi que des thérapies ciblées est dû à leur capacité a induire la mort cellulaire immunogène (ICD), ce qui stimule la libération ou l'exposition des motifs moléculaires associés à un dommage (DAMPs) conduisant à leur reconnaissance par le système immunitaire, rétablissant ainsi l'immunosurveillance. En utilisant un criblage non polarisé, le crizotinib a été identifié en tant qu'inhibiteur de tyrosine-kinase ayant la capacité de stimuler la libération de caractéristiques distinctives de l’ICD. Des expériences faites par la suite ont montréque le crizotinib induit l'exposition de la calreticulin, la sécrétion d'ATP et la libération d’HMGB1, ainsi que le stress du réticulum endoplasmique dans les lignées cellulaires cancéreuses murines et humaines, notamment en combinaison avec les agents non immunogènes tel que le cisplatine. L’ICD causée par la combinaison du crizotinib avec la chimiothérapie a aussi été observée dans les cellules du cancer bronchique non à petites cellules (NSCLC), cellules ne possédant pas de mutations activatrices d’ALK ou ROS1 ; cela suggère un mode d'action hors-cible. Des études comparatives ont montré que seule la conformation utilisée en clinique, l’isoforme (R)-crizotinib, a la capacité de stimuler l’ICD ; le (S)-énantiomère ne possède pas ces caractéristiques. Combinées au cisplatine, les cellules fibrosarcome MCA205 et les cellules cancéreuses du poumon TC-1 traitées avec le crizotinib ont vacciné efficacement les souris immunocompétentes syngéniques contre la croissance des cellules vivantes de même type. Le crizotinib a amélioré l'efficacité de la chimiothérapie dans trois modèles de cancer du poumon orthotopiques : transplantable, induit par des carcinogènes et induites par les oncogènes. De façon remarquable, l’effet du crizotinib est aboli si un des signaux de l’ICD est bloqué. L'efficacité anticancéreuse dans chaque modèle s’est révélé être lié à l'infiltration de lymphocytes T, montrant l’implication d’une réaction immunitaire. Cela a été confirmé par des expériences chez des souris immunodéficientes (nu/nu, déficientes en thymodépendantes lymphocytes T) et dans des souris immunocompétentes dans lesquelles l’interféron gamma a été neutralisé à l’aide d’un anticorps ; l’effet du crizotinib était aboli dans les deux modèles. La combinaison du crizotinib avec le cisplatine a entraîné un accroissement de l'expression de PD-1, PDL-1 et CTLA-4 dans la tumeur, s’accompagnant par conséquent d'une sensibilisation importante des NSCLC à l'immunothérapie avec des anticorps anti-PD-1 et CTLA-4. Ainsi, la combinaison du crizotinib avec la chimiothérapie conventionnelle et les inhibiteurs des points de contrôle immunitaire peuvent être actifs contre le NSCLC. Les données présentées dans cette thèse pourraient faciliter la conception d’essais cliniques afin d’établir de nouvelles stratégies combinatoires pour le traitement des NSCLC
Accumulating evidence suggests that certain conventional chemotherapies, radiotherapies, as well as targeted therapies mediate their long-term therapeutic success by inducing immunogenic cell death (ICD), which stimulate the release or exposure of danger-associated molecular patterns from or on cancer cells, causing their recognition by the immune system, thus reinstating immunosurveillance. An unbiased screen identified crizotinib as a tyrosine kinase inhibitor that is potent in provoking hallmarks of ICD. In subsequent low-throughput validation experiments, crizotinib promoted Calreticulin exposure, ATP secretion, HMGB1 release, as well as ER stress in both human and murine cancer cells, especially if it is combined with normally non-ICD inducing chemotherapeutics such as cisplatin. ICD induced by the combination of chemotherapy and crizotinib was also observed in non-small cell lung carcinoma (NSCLC) cells lacking activating mutations of the crizotinib targets ALK and ROS1, suggesting an off-target-mediated mode of action. Comparative studies indicated that exclusively the clinically used (R) isoform of crizotinib was efficient in inducing cell death and stimulating ICD hallmarks whereas the (S) enantiomer lacked those characteristics. When combined with cisplatin, crizotinib-killed fibrosarcoma MCA205 cells as well as lung cancer TC-1 cells efficiently vaccinated syngeneic immunocompetent mice against a re-challenge with live cancer cells of the same types. Crizotinib improved the efficacy of chemotherapy with non-ICD inducers (such as cisplatin and mitomycin C) on three distinct (transplantable, carcinogen- or oncogene induced) orthotopic NSCLC models, none of which relied on the activation of ALK or ROS1. Of note these anticancer effects were completely lost if any of the ICD signals was blocked. These anticancer efficacies in different models were linked to an increased T lymphocyte infiltration as a sign of an immune response and were lost if such tumors grew on immunodeficient (nu/nu) mice that are athymic and hence lack thymus-dependent T lymphocytes, or on immunocompetent mice with a neutralization of interferon-. The combination of cisplatin and crizotinib led to an increase in the expression of CTLA-4, PD-1 and PD-L1 in tumors, coupled to a strong sensitization of NSCLC to immunotherapy with antibodies blocking CTLA-4 and PD-1. Hence, a combination of crizotinib, conventional chemotherapy and immune checkpoint blockade may be active against NSCLC, and these data might facilitate the design of clinical trials to evaluated novel combination regiments for the treatment of NSCLC

Tese no âmbito do doutoramento em Química, ramo de Química Médica, apresentada ao Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade de Coimbra.
Photodynamic therapy (PDT) relies on the administration of a photosensitizer (PS) that is activated on the target tissue after the irradiation with light of a specific wavelength absorbed by the PS. Redaporfin is a recently developed photosensitizer for PDT that is currently in phase 2 clinical trials (NCT02070432). Redaporfin is a photostable bacteriochlorin with intense infrared absorption, high yield of ROS generation, high phototoxicity, low skin photosensitivity and favorable pharmacokinetics. A vascular protocol of redaporfin-PDT with mice bearing CT26.WT tumors not only destroys the primary tumor but also reduces the development of metastasis, thus suggesting antitumor immunity. This work characterizes the immune response triggered by this vascular-PDT protocol. At different timepoints after tumor irradiation, blood samples were collected, and distinct immune cell populations and cytokines were quantified. Redaporfin-PDT leads to a strong neutrophilia, with systemic increase of IL-6, increased percentage of CD4+ and CD8+ T cells producing IFN-γ or CD69+ and increased CD4+/CD8+ T cell ratio. We also showed that at the tumor bed, T cell tumor infiltration disappeared after PDT but reappeared with a much higher incidence one day later. The depletion of specific immune populations suggested that neutrophils and cytotoxic T cells have a major role in the development of the antitumor immune response elicited by redaporfin-PDT, while helper T cells may just have a supportive role. Regarding this, we hypothesize that the combination of redaporfin-PDT with an immune therapy may potentiate the efficacy of both therapies, namely by increasing the response rates of immunotherapies and strengthening the systemic effects of PDT, especially in difficult tumors to treat. The tumor models were selected taking in consideration that redaporfin-PDT is capable of eliciting immunogenic cell death (ICD) and may be able to enhance the immunogenicity of tumor cells. Melanoma and mammary carcinoma tumors are recognized to be more aggressive and difficult to treat than most mouse tumor models, namely colon carcinoma. The response to redaporfin-PDT was evaluated in mouse mammary carcinoma expressing luciferase (4T1-luc2) and in mouse skin melanoma (B16F10) tumor models, and PDT parameters were optimized to maximize the impact on tumors while minimizing treatment lethality. A significant edema that later progressed to necrosis was observed in both tumor models. However, cures were only achieved with the B16F10 tumor model. Imaging with photoacoustic tomography suggested that the lower content of redaporfin in 4T1 tumors is the main reason for the challenging behavior of this orthotopic 4T1 model. The antitumor effect elicited by PDT is in some cases opposed by the immunosuppressive mechanisms elicited by tumor cells which makes the treatment ineffective. Thus, immunotherapies that have as major goal the alleviation of this immunosuppressive tumor environment are interesting for combination therapies, increasing the efficacy with better antitumoral and antimetastatic effects. We reported a combination of redaporfin-PDT with immunotherapies using CTLA-4 and PD-1 in three different tumor models. Treatment outcomes were evaluated by survival, tumor growth kinetics and, for the carcinoma model, observation of metastasis development by bioluminescent imaging. Furthermore, we evaluated the changes on expression of several immune checkpoint molecules triggered by redaporfin-PDT in vitro. Combination of redaporfin-PDT with CTLA-4 immunotherapy, but not with PD-1, led to a significant improvement of survival and a higher cure rate in the colon carcinoma animal model. However, the same was not achieved with the melanoma and breast carcinoma animal models. Expression of immune checkpoint molecules was induced in tumor cells treated in vitro with redaporfin-PDT. The most notable changes were observed for CD80 and PD-L1. These results demonstrate that the combination of photodynamic therapy with immunotherapy may improve the treatment of malignant diseases that represent a challenge to immunotherapies alone and highlights the fact that a global therapeutic strategy may not be ideal for every tumor model. Combinatorial approaches are not universal and have to be tailored to the specificities of each clinical case.
A terapia fotodinâmica (PDT, do inglês, photodynamic therapy) consiste na administração de um fotossensibilizador (PS, do inglês, photosensitizer) que é ativado no tecido alvo após a irradiação com luz com um comprimento de onda absorvido pelo PS. A redaporfin é um fotossensibilizador desenvolvido recentemente para a PDT e que está atualmente em ensaios clínicos fase 2 (NCT02070432). A redaporfin é uma bacterioclorina fotoestável com intensa absorção no infravermelho próximo, elevado rendimento de formação de espécies reativas de oxigénio (ROS, do inglês, reactive oxygen species), elevada fototoxicidade, baixa fotossensibilidade da pele e uma farmacocinética favorável. A aplicação de um protocolo de PDT vascular com redaporfin em murganhos com tumores de carcinoma do cólon (CT26.WT) não só destrói o tumor primário como também reduz o desenvolvimento de metástases, sugerindo assim o aparecimento de imunidade anti-tumoral. Este trabalho caracteriza a resposta imunitária desencadeada através deste protocolo de PDT vascular. Em tempos pré-determinados após a irradiação do tumor foram feitas colheitas de sangue e foram quantificadas as diferentes populações de células imunes e citocinas envolvidas na resposta imunitária. A PDT com a redaporfin provoca uma forte neutrófilia, um aumento sistémico da IL-6, um aumento da percentagem de células CD4+ e CD8+ T que produtoras de IFN-γ ou CD69+ e um aumento do rácio de células T CD4+/CD8+. Ao nível do leito tumoral, a infiltração de linfócitos T desaparece após a PDT, mas reaparece com muito maior incidência 24 h mais tarde. A depleção de populações de células imunes específicas demonstrou que os neutrófilos e as células T citotóxicas desempenham um papel importante no desenvolvimento da resposta imune anti-tumoral desencadeada pela PDT com redaporfin, enquanto que as células T auxiliares parecem desempenhar apenas um papel de suporte. Tendo isto em consideração, propomos que a combinação da PDT com a redaporfin e a imunoterapia pode potenciar a eficácia de ambos os tratamentos, nomeadamente através do aumento da taxa de resposta às imunoterapias bem como o reforço do efeito sistémico da PDT, especialmente em tumores difíceis de tratar. Os modelos tumorais utilizados nestes estudos foram selecionados tendo em conta que a PDT com a redaporfin é capaz de gerar morte celular imunogénica e aumentar a imunogenicidade das células tumorais tratadas. Os melanomas e carcinomas mamários são reconhecidos por serem bastante mais agressivos e difíceis de tratar do que a maioria dos modelos tumorais de murganho usados, como o carcinoma do cólon. A resposta à PDT com redaporfin foi avaliada em murganhos com modelos tumorais de carcinoma mamário que expressa luciferase (4T1-luc2) e de melanoma da pele (B16F10). Os parâmetros da PDT foram otimizados para maximizar o impacto no tumor primário e minimizar a letalidade do tratamento. Em ambos os modelos foi observado edema que posteriormente evoluiu para necrose, contudo, apenas foram obtidas curas no modelo de melanoma. Recorrendo a tomografia fotoacústica verificou-se que o baixo conteúdo de redaporfin que consegue aceder ao tumor pode ser a principal razão para a falta de eficácia no modelo ortotópico de 4T1. A resposta anti-tumoral desencadeada pela PDT é por vezes neutralizada por mecanismos imunossupressores desencadeados pelas células tumorais que diminuem a eficácia do tratamento. Deste modo, as imunoterapias que têm como função atenuar o ambiente tumoral imunossupressor aparentam ser promissoras em terapias combinatórias que ambicionam aumentar a eficácia dos efeitos anti-tumorais e anti-metastáticos. Neste estudo, reportamos a combinação da PDT com redaporfin e as imunoterapias usando a CTLA-4 e a PD-1 em três modelos tumorais diferentes. Os resultados dos tratamentos foram avaliados através do tempo de sobrevida, da cinética de crescimento tumoral e, para o caso do modelo do carcinoma mamário, do desenvolvimento das metástases analisado através de imagiologia de bioluminescência. Posteriormente, as alterações da expressão de diferentes moléculas dos checkpoints imunitários em células tumorais foram avaliadas após a PDT in vitro. A combinação da PDT com a redaporfin e a imunoterapia com CTLA-4, mas não com a PD-1, originou uma melhoria significativa da sobrevida e um aumento da taxa de curas no modelo de carcinoma do cólon de murganhos. Contudo, o mesmo não se verificou para os modelos de melanoma e de carcinoma mamário. O aumento da expressão de moléculas dos checkpoints imunitários foi induzido de forma significativa nas células tumorais após o tratamento de PDT in vitro. As alterações mais notáveis foram observadas para CD80 e PD-L1. Os resultados sugerem que a combinação de PDT com imunoterapia pode ser eficaz no tratamento de tumores que são um maior desafio para a imunoterapia como tratamento isolado. Isto salienta a ideia de que uma estratégia terapêutica global pode não ser a ideal para todos os modelos tumorais. As estratégias combinatórias não são universais e necessitam de ser adaptadas às especificações de cada caso clínico.
Luzitin S.A.

Immunotherapy has emerged as a ground breaking approach in the treatment of various cancers and autoimmune diseases, utilizing the body’s immune system to combat disease. This article reviews the mechanisms of action of different types of immunotherapy, including checkpoint inhibitors, monoclonal antibodies, and adaptive cell transfer. Checkpoint inhibitors such as PD-1/PD-L1 and CTLA-4 blockers enhance immune responses by releasing brakes on T cells, thereby promoting anti-tumor immunity. Monoclonal antibodies target specific antigens on cancer cells or immune cells, facilitating targeted destruction. Adaptive cell transfer involves modifying and re-infusing patient-derived immune cells to enhance their tumor-fighting capabilities. Despite their promise, immunotherapies can elicit immune-related adverse events ranging from mild to severe, affecting various organ systems. Common side effects include fatigue, rash, and gastrointestinal disturbances, while severe reactions may involve pneumonitis, colitis, or endocrinopathies. Understanding these mechanisms and side effects is crucial for optimizing patient care and expanding the therapeutic potential of immunotherapy.

Immunotherapy, a transformative cancer treatment, harnesses the immune system’s inherent ability to combat neoplastic cells. Ancient medicine hinted at immunological principles, recognizing natural disease resistance and the body’s defensive capabilities. Over time, the understanding of the immune system evolved, with key contributions from early thinkers like Ibn Sina and later scientific pioneers like Ilya Mechnikov. The immune system, comprising innate and adaptive components, is vital in defending against pathogens and regulating cell proliferation, including cancerous cells. The concept of immune surveillance highlights the immune system’s role in preventing cancer development. Modern immunotherapy includes several approaches: monoclonal antibodies target specific proteins on cancer cells to mark them for destruction; cancer vaccines prevent virus-related cancers like HPV and hepatitis B; adoptive cell therapy, including CAR T-cell and TIL therapies, enhances patients’ immune cells to fight cancer; checkpoint inhibitors block proteins that allow cancer cells to evade the immune response; and oncolytic virotherapy uses engineered viruses to destroy cancer cells and stimulate the immune response. These therapies, based on profound immunological insights, represent a significant advancement in oncology, offering new hope for patients by leveraging the immune system’s power to combat cancer.

AbstractUntil recently, radiotherapy was viewed solely from a tumour cell-autonomous perspective, whereby successful therapy resulted from inflicting breaks in nuclear DNA above an unspecified threshold that exceeded the tumour cell’s capacity for repair. Greater understanding of the importance of non-tumour cell-autonomous, immunological aspects of radiation-induced cell death in the context of the tumour micro-environment (TME) has altered this rather narrow perception. We now know that clinical responses to radiotherapy are inextricably linked to the immune system: loco-regional radiotherapy can trigger abscopal, immune-mediated responses at distant unirradiated sites (albeit rarely), while patients who are pathologically or iatrogenically immunosuppressed may derive less benefit from radiotherapy. The intrinsic biology of individual tumours, their associated microenvironments, and the physical characteristics of the delivered radiation, can all influence the immunogenicity of radiotherapy. By understanding and modulating cross-talk between molecular responses to radiation-induced DNA damage, associated mechanisms of cell death and subsequent innate and adaptive immune responses, we may be able to improve clinical outcomes of radiotherapy.In this chapter, the focus will be on mechanisms of DNA damage repair and how tumours exploit alterations in these to enhance their survival. However, tumour cell-intrinsic aberrations in DNA repair can render tumour cells vulnerable to the effects of radiotherapy and this may be enhanced further by rational use of targeted DNA damage-response inhibitors. In particular, we will focus on how disordered DNA repair and its pharmacological modulation through ataxia telangiectasia and Rad3-related kinase inhibition can lead to radiation-induced immunostimulation and how this can be exploited further in the clinic through the use of specific immunotherapies, such as immune checkpoint blockers. As part of the discussion, specific mechanisms of radiation-induced cell death will be discussed, with emphasis on mechanisms of triggering immunologically visible, pro-inflammatory modes of cell death.

The rational design of immunotherapeutic agents has advanced with a fundamental understanding that both innate and adaptive immunity play important roles in cancer surveillance and tumor destruction; given that oncogenesis occurs and cancer progresses through the growth of tumor cells with low immunogenicity in an increasingly immunosuppressive tumor microenvironment. Checkpoint inhibitors in the form of monoclonal antibodies that block cancer’s ability to deactivate and evade the immune system have been widely indicated for a variety of tumor types. Through targeting the biological mechanisms and pathways that cancer cells use to interact with and suppress the immune system, immunotherapeutic agents have achieved success in inhibiting tumor growth while eliciting lesser toxicities, compared to treatments with standard chemotherapy. Development of “precise” bio-active tumor-targeted gene vectors, biotechnologies, and reagents has also advanced. This chapter presents ongoing clinical research involving immune checkpoint inhibitors, while addressing the clinical potential for tumor-targeted gene blockade in combination with tumor-targeted cytokine delivery, in patients with advanced metastatic disease, providing strategic clinical approaches to precision cancer immunotherapy.

This chapter discusses the principle of cancer immunotherapy in children and adolescents, starting with the most common form of cellular immunotherapy: allogeneic haematopoietic stem-cell transplantation (HSCT). It then discusses specific immunotherapy strategies based on the administration of classic monoclonal antibodies (mAbs) targeting tumour-associated antigens, novel bispecific antibodies that simultaneously target tumour-associated antigens and activate CD3⁺ T lymphocytes, and mAbs that block key inhibitory molecules of the immune system (checkpoint blockade). Finally, the chapter describes specific cellular immunotherapy approaches, such as tumour vaccine and adoptive transfer of immune cells. Although only a few immunotherapies have so far been incorporated into the standard practice for paediatric cancers, their role is enjoying a new revival, after the promising results obtained in recent clinical trials.

Immunopharmacology, the study of drugs that influence the immune system, is a critical field in both understanding and manipulating immune responses for therapeutic benefit. This branch of pharmacology encompasses a wide range of substances, including immunosuppressants, immunostimulants, and immunomodulators, each playing a pivotal role in treating various diseases. Immunosuppressants, such as corticosteroids, calcineurin inhibitors, and monoclonal antibodies, are essential in preventing organ transplant rejection and treating autoimmune diseases by dampening overactive immune responses. On the other hand, immunostimulants like vaccines and adjuvants boost the immune system’s ability to fight infections and certain cancers by enhancing antigen-specific responses.The advent of biologics, such as monoclonal antibodies and cytokine inhibitors, has revolutionized the treatment of autoimmune diseases, providing targeted approaches that minimize broad immunosuppression. For example, drugs like infliximab and etanercept inhibit tumor necrosis factor-alpha (TNF-α), a key cytokine in inflammatory processes, offering significant relief in conditions like rheumatoid arthritis and Crohn’s disease. Additionally, checkpoint inhibitors, a class of immunomodulatory drugs, have shown remarkable success in oncology by unleashing the immune system to target cancer cells more effectively. Agents like pembrolizumab and nivolumab block inhibitory pathways, such as PD-1/PD-L1, enhancing T-cell activity against tumors. Immunopharmacology also addresses the challenge of balancing efficacy and safety. Immunosuppressive therapies, while crucial for preventing transplant rejection, can increase susceptibility to infections and malignancies. Similarly, immunostimulatory therapies must be carefully managed to avoid triggering excessive inflammation or autoimmunity. Advances in precision medicine and biomarker research are enabling more personalized approaches, tailoring immunotherapies to individual patient profiles for optimized outcomes. The integration of immunopharmacology with other fields, such as genomics and bioinformatics, continues to drive innovation, paving the way for new treatments that harness the power of the immune system with unprecedented specificity and control.