Advances In Cancer Immunotherapy Research Articles

Recent advancements at ASCO 2024 in PD-L1 and PD-1 bispecific antibodies.

Recent advancements in cancer immunotherapy have spotlighted the PD-1/PD-L1 pathway, crucial for its role in immune checkpoint regulation. Traditional inhibitors, though successful, face challenges like resistance and adverse effects. Bispecific antibodies targeting PD-1 and PD-L1 present a ground-breaking solution by simultaneously engaging multiple immune regulatory molecules. Developments in PD-1/PD-L1 bispecific antibodies up to now have been summarized, and the latest findings from the 2024 ASCO conference are presented, revealing that bispecific antibodies exhibit robust efficacy in treating various types of cancers, marking a significant step forward in cancer treatment.

Immune microenvironment of cancer bone metastasis.

Bone is a common and frequent site of metastasis in cancer patients, leading to a significant reduction in quality of life and increased mortality. Bone marrow, the primary site of hematopoiesis, also serves as both a primary and secondary lymphoid organ. It harbors and supports a diverse array of immune cells, thereby creating a distinct immune microenvironment. These immune cells engage in a range of activities, including anti-tumor, pro-tumor, or a combination of both, which influence the development and progression of bone metastases. Rapid advances in cancer immunotherapy have underscored its potential to eradicate bone metastases. However, clinical outcomes have not yet met expectations. To improve the efficacy of immunotherapy, it is crucial to gain a comprehensive and in-depth understanding of the immune microenvironment within bone metastases. This review provides an overview of the current understanding of the role of different immune cells, their anti-tumor and pro-tumor activities, and their overall contribution to bone metastasis.

Advances in Cancer Immunotherapy: Enhancing the Immune Response and Addressing Therapeutic Challenges

Cancer is the top cause of death around the world. In 2022, nearly 20 million people were diagnosed with cancer, and about 9.7 million died from it. In China, almost 5 million new cancer cases were reported, with over 2.5 million fatalities. Immunotherapy is a new way to treat cancer. It boosts the body’s immune system to fight cancer cells. This method is less harmful to patients and more precise than older treatments like chemotherapy and radiation. There are different kinds of immunotherapy, including vaccines, treatments with substances that boost the immune system, transferring cells, and blocking proteins that stop the immune system from working. Even though immunotherapy is helpful, it can have side effects and tumors can become resistant to it. Each person’s tumor is unique, which makes treatment tricky. Sometimes, tumors can change and resist the therapy. We also don’t have enough markers to tailor treatments to each person’s needs. This review discusses the response of immune system, and how immunotherapy can be used to treat cancer.

Antibody blockade of the PSGL-1 immune checkpoint enhances T-cell responses to B-cell lymphoma.

Despite advancements in cancer immunotherapy, most lymphomas remain unresponsive to checkpoint inhibitors. P-selectin glycoprotein ligand-1 (PSGL-1), recently identified as a promoter of T-cell exhaustion in murine melanoma models, has emerged as a novel immune checkpoint protein and promising immunotherapeutic target. In this study, we investigated the potential of PSGL-1 antibody targeting in B-cell lymphoma. Using allogeneic co-culture systems, we demonstrated that targeted antibody interventions against human PSGL-1 enhanced T-cell activation and effector cytokine production in response to lymphoma cells. Moreover, in vitro treatment of primary lymphoma cell suspensions with PSGL-1 antibody resulted in increased activation of autologous lymphoma-infiltrating T cells. Using the A20 syngeneic B-cell lymphoma mouse model, we found that PSGL-1 antibody treatment significantly slowed tumor development and reduced the endpoint tumor burden. This antitumoral effect was accompanied by augmented tumor infiltration of CD4+ and CD8+ T cells and reduced infiltration of regulatory T cells. Finally, anti-PSGL-1 administration enhanced the expansion of CAR T cells previously transferred to mice bearing the aggressive Eμ-Myc lymphoma cells and improved disease control. These results demonstrate that PSGL-1 antibody blockade bolsters T-cell activity against B-cell lymphoma, suggesting a potential novel immunotherapeutic approach for treating these malignancies.

A microphysiological assay for studying T-cell chemotaxis, trafficking and tumor killing

Tumors in patients non-responsive to immunotherapy harbor a series of barriers that impede the efficacy of effector T-cells. Consequently, therapeutically modulating the chemotaxis machinery to enable effector T cell infiltration and function in the tumor could result in more successful therapeutic outcomes. Complexin-vitromodels allow re-creation ofin-vivotumor complexities in anin-vitrosetting, allowing improved translatability to patient biology at the laboratory scale. We identified a gap in available industrial scale microphysiological (MPS) assays for faster validation of targets and strategies that enable T-cell chemotaxis and effector function within tumor microenvironments. Using a commercially available, 96-chip 2-lane microfluidic assay system, we present a novel, scalable, complexin vitroMPS assay to study 3D T-cell chemotaxis and function within native, extracellular matrix (ECM)-rich multicellular tumor environments. Activated or naïve CD3+ T-cells stained with far-red nuclear stain responded to the chemokine gradients generated within the matrigel-collagen ECM by migrating into the microfluidic channel (∼5 mm horizontal window), in a concentration- and cell type-dependent manner. Furthermore, we observed and tracked chemotaxis and cancer cell killing function of antigen-specific CD4.CD8. chimeric antigen receptor (CAR)-T cells that responded to CXCR3 agonist gradient built through the expansive 5 mm of cancer cell colony containing stroma. The 2-lane assay system yielded useful information regarding donor and dose-dependent differences in CAR-T cell chemotaxis and tumor killing. The scalable assay system allows a granular window into immune cell migration and function in tissue spaces beyond endothelium, addressing a missing gap in studying tissue-specific immune cell chemotaxis and function to bring forward advancements in cancer immunotherapy.

The relevance of tumor target expression levels on IgA-mediated cytotoxicity in cancer immunotherapy

Recent advances in cancer immunotherapy, particularly the success of immune checkpoint inhibitors, have reignited interest in targeted monoclonal antibodies for immunotherapy. Antibody therapies aim to minimize on-target, off-tumor toxicity by targeting antigens overexpressed on tumor cells but not on healthy cells. Despite considerable efforts, some therapeutic antibodies have been linked to dose-limiting side effects. Our hypothesis suggests that the efficacy of IgG leads to a lower target expression threshold for tumor cell killing, contributing to these side effects. Earlier, therapeutic IgG antibodies were reformatted into the IgA isotype. Unlike IgG, which primarily engages Fc gamma receptors (FcγR) to induce antibody-dependent cellular cytotoxicity (ADCC) by NK cells and antibody-dependent cellular phagocytosis (ADCP) by monocytes/macrophages, IgA antibodies activate neutrophils through the Fc alpha receptor I (CD89, FcαRI). In previous studies, it appeared that IgA may require a higher target expression threshold for effective killing, and we aimed to investigate this in our current study. Moreover, we investigated how blocking the myeloid checkpoint CD47/SIRPα axis affect the target expression threshold. Using a tetracycline-inducible expression system, we regulated target expression in different cell lines. Our findings from ADCC assays indicate that IgA-mediated PMN ADCC requires a higher antigen expression level than IgG-mediated PBMC ADCC. Furthermore, blocking CD47 enhanced IgA-mediated ADCC, lowering the antigen threshold. Validated in two in vivo models, our results show that IgA significantly reduces tumor growth in high-antigen-expressing tumors without affecting low-antigen-expressing healthy tissues. This suggests IgA-based immunotherapy could potentially minimize on-target, off-tumor side effects, improving treatment efficacy and patient safety.

Nanobubble‐Based Acoustical Bursting of Nuclear Membrane for Interleukin‐33 Release Induces Eosinophil‐Mediated Cancer Immunotherapy

AbstractDespite noteworthy advances in cancer immunotherapy, the understanding of effective strategies to harness eosinophils in anti‐cancer immunity, which is critical for cytotoxic T‐cell recruitment, remains limited. In particular, interleukin‐33, which is essential for eosinophil activation, is chromatin‐bound and lacks efficient extracellular release mechanisms for its intact form. Here, a nanobubble‐based acoustical cancer cell‐bursting strategy (NanoBurst) is reported to elicit eosinophil‐mediated cancer immunity by releasing damage‐associated molecular patterns (DAMPs). NanoBurst consists of polymeric nanoparticles encapsulating a gas precursor, designed to effectively disrupt cancer cell membranes upon exposure to ultrasound. This process triggers the efficient release of both nucleus‐derived (e.g., high‐mobility group nucleosome‐binding domain‐1, gasdermin E, interleukin‐33) and cytoplasm‐derived DAMPs, initiating the eosinophil‐mediated immune cascade. Consequently, NanoBurst induces direct tumoricidal effects by activating eosinophils and enhances anti‐cancer immunity by recruiting NK cells and cytotoxic T‐cells in vivo. When combined with a dipeptidyl peptidase‐4 (DPP4) inhibitor, an inducer of eosinophil‐mediated chemotaxis, NanoBurst effectively inhibits the growth of primary tumors and the metastasis to the lung in a CT26 tumor‐bearing mouse model. Notably, boosting eosinophil‐mediated anti‐cancer immunity with NanoBurst‐DPP4 inhibitor shows superior efficacy for tumor suppression compared to immune checkpoint inhibitors.

Exosomes of immune cell origin and their therapeutic potential for tumors

AbstractExosomes are nanoscale membrane vesicles identified by electron microscopy in 1946. They are approximately 30–150 nm in size. Originally, exosomes were thought to be used to eliminate excess components from cells to maintain their normal physiology. Later, it was found that the function and targeting of specific cellular components in exosomes have important implications for the regulation of cellular communication. In the last few years, exosomes have been linked to tumors, infections, and other diseases. New advances in cancer immunotherapy have occurred as a result of the identification of exosomes of immune cell origin, expanding the existing anticancer immune response. This article details exosomes derived from dendritic cells, T lymphocytes (CD4+ T cells, CD8+ T cells, and CAR‐T cells), natural killer cells, and their promising applications in tumor therapy.

Lessons from Post-Immunotherapy Tumor Tissues in Clinical Trials: How Can We Fuel the Tumor Microenvironment in Gliomas?

Despite recent advancements in cancer immunotherapy, many patients with gliomas and glioblastomas have yet to experience substantial therapeutic benefits. Modulating the tumor microenvironment (TME) of gliomas, which is typically "cold", is crucial for improving treatment outcomes. Clinical tumor specimens obtained post-immunotherapy provide invaluable insights. However, access to such post-immunotherapy samples remains limited, even in clinical trials, as tumor tissues are often collected only at tumor relapse. Recent studies of neoadjuvant immunotherapy provided important insights by incorporating surgical resections of post-treatment tumors. Moreover, pre-surgical immunotherapies are increasingly integrated into clinical trial designs to evaluate treatment efficacy. These investigations reveal critical information, particularly regarding the delivery success of therapeutic agents, the expansion and persistence of immune products, and the cellular and molecular changes induced in the TME. In this review, we assess the findings on post-treatment tumor specimens obtained from recent immunotherapy clinical trials on gliomas, highlight the importance of these samples for understanding therapeutic impacts, and discuss proactive investigation approaches for future clinical trials.

Protein O-fucosyltransferase 1 promotes PD-L1 stability to drive immune evasion and directs liver cancer to immunotherapy

Background and aimsThe immunosuppressive tumor microenvironment (TME) plays an essential role in cancer progression and immunotherapy response. Despite the considerable advancements in cancer immunotherapy, the limited response to immune checkpoint...

Effect of cancer immunotherapy with CD39/PD-L1 bispecific antibody OriA631-b.

e14508 Background: Despite significant advancements in cancer immunotherapy through the use of immune checkpoint inhibitors, there remains a need for more robust strategies to enhance anti-tumor immune responses. This study introduces and characterizes OriA631-B, an innovative CD39/PD-L1 bispecific antibody. By simultaneously targeting the metabolic checkpoint CD39 and the immune checkpoint PD-L1, this novel antibody has the potential to significantly augment anti-tumor efficacy, particularly in cold tumors characterized by a scarcity of infiltrating immune cells. The development of OriA631-B marks a breakthrough in concurrently addressing two crucial immunosuppressive pathways. Methods: The creation of OriA631-B involved cutting-edge antibody engineering methodologies to guarantee optimal binding affinity and specificity for its target antigens, CD39 and PD-L1. With meticulous design and refinement, OriA631-B was developed to exhibit robust binding capabilities to both CD39 and PD-L1, enabling simultaneous and precise recognition. Leveraging advanced antibody engineering techniques was instrumental in crafting OriA631-B as a potent tool with heightened binding properties, broadening its potential applications across diverse therapeutic contexts. Results: In vitro investigations revealed the efficacy of OriA631-B, derived from the foundation of a clinically validated in-house generated PD-L1 antibody (YN035). This innovative antibody effectively thwarted CD39-mediated adenosine production, resulting in heightened effector T cell function and proliferation. In vivo efficacy assessments conducted on syngeneic hot tumor models MC38 and Hepa1-6 underscored the remarkable effectiveness of OriA631, the CD39 monoclonal antibody (mAb), in controlling tumor growth. Notably, OriA631-B, the CD39/PD-L1 bispecific antibody, exhibited even more profound impacts, significantly restraining tumor growth beyond the effects observed with single-target treatments in the hot tumor model or combination therapies in both the hot tumor model MC38 and the cold tumor model CT26. These findings underscore the potent therapeutic potential of OriA631-B and its capacity to exert robust anti-tumor activity by concurrently targeting CD39 and PD-L1. Additionally, safety profiling revealed an acceptable toxicity profile for OriA631-B, with no significant adverse events observed during the study. Conclusions: In summary, OriA631-B demonstrates potential as an innovative immunotherapeutic strategy for cancer treatment by concurrently targeting CD39-mediated immune suppression and PD-L1-mediated T cell exhaustion. Further exploration, including clinical trials, is imperative to fully uncover the therapeutic capabilities of this groundbreaking bispecific antibody in cancer immunotherapy.

Recent Advances in Cancer Immunotherapy: Clinical Implications and Future Directions

Cancer immunotherapy has transformed cancer treatment by harnessing the immune system to recognize and eliminate cancer cells. Recent years have witnessed significant advancements in this field, including the development of immune checkpoint inhibitors, chimeric antigen receptor (CAR) T-cell therapy, cancer vaccines, and adoptive cell therapy. These approaches have shown promising results in clinical trials, leading to improved outcomes for cancer patients. This paper provides an in-depth overview of recent advances in cancer immunotherapy, their clinical implications, challenges, and future directions.

The immunosuppressive landscape in tumor microenvironment.

Recent advances in cancer immunotherapy, especially immune checkpoint inhibitors (ICIs), have revolutionized the clinical outcome of many cancer patients. Despite the fact that impressive progress has been made in recent decades, the response rate remains unsatisfactory, and many patients do not benefit from ICIs. Herein, we summarized advanced studies and the latest insights on immune inhibitory factors in the tumor microenvironment. Our in-depth discussion and updated landscape of tumor immunosuppressive microenvironment may provide new strategies for reversing tumor immune evasion, enhancing the efficacy of ICIs therapy, and ultimately achieving a better clinical outcome.

T-Cell Engagers-The Structure and Functional Principle and Application in Hematological Malignancies.

Recent advancements in cancer immunotherapy have made directing the cellular immune response onto cancer cells a promising strategy for the treatment of hematological malignancies. The introduction of monoclonal antibody-based (mAbs) targeted therapy has significantly improved the prognosis for hematological patients. Facing the issues of mAb-based therapies, a novel bispecific antibody (BsAb) format was developed. T-cell engagers (TCEs) are BsAbs, which simultaneously target tumor-associated antigens on tumor cells and CD3 molecules present on T-cells. This mechanism allows for the direct activation of T-cells and their anti-tumor features, ultimately resulting in the lysis of tumor cells. In 2014, the FDA approved blinatumomab, a TCE directed to CD3 and CD19 for treatment of acute lymphoblastic leukemia. Since then, numerous TCEs have been developed, allowing for treating different hematological malignancies such as acute myeloid leukemia, multiple myeloma, and non-Hodgkin lymphoma and Hodgkin lymphoma. As of November 2023, seven clinically approved TCE therapies are on the market. TCE-based therapies still have their limitations; however, improving the properties of TCEs, as well as combining TCE-based therapies with other forms of treatment, give hope to find the cures for currently terminal diseases. In this paper, we summarized the technical basis of the TCE technology, its application in hematology, and its current issues and prospects.

Pancreatic cancer-associated fibroblasts modulate macrophage differentiation via sialic acid-Siglec interactions

Despite recent advances in cancer immunotherapy, pancreatic ductal adenocarcinoma (PDAC) remains unresponsive due to an immunosuppressive tumor microenvironment, which is characterized by the abundance of cancer-associated fibroblasts (CAFs). Once identified, CAF-mediated immune inhibitory mechanisms could be exploited for cancer immunotherapy. Siglec receptors are increasingly recognized as immune checkpoints, and their ligands, sialic acids, are known to be overexpressed by cancer cells. Here, we unveil a previously unrecognized role of sialic acid-containing glycans on PDAC CAFs as crucial modulators of myeloid cells. Using multiplex immunohistochemistry and transcriptomics, we show that PDAC stroma is enriched in sialic acid-containing glycans compared to tumor cells and normal fibroblasts, and characterized by ST3GAL4 expression. We demonstrate that sialic acids on CAF cell lines serve as ligands for Siglec-7, -9, -10 and -15, distinct from the ligands on tumor cells, and that these receptors are found on myeloid cells in the stroma of PDAC biopsies. Furthermore, we show that CAFs drive the differentiation of monocytes to immunosuppressive tumor-associated macrophages in vitro, and that CAF sialylation plays a dominant role in this process compared to tumor cell sialylation. Collectively, our findings unravel sialic acids as a mechanism of CAF-mediated immunomodulation, which may provide targets for immunotherapy in PDAC.

Integrating Reinforcement Learning and Monte Carlo Tree Search for enhanced neoantigen vaccine design.

Recent advances in cancer immunotherapy have highlighted the potential of neoantigen-based vaccines. However, the design of such vaccines is hindered by the possibility of weak binding affinity between the peptides and the patient's specific human leukocyte antigen (HLA) alleles, which may not elicit a robust adaptive immune response. Triggering cross-immunity by utilizing peptide mutations that have enhanced binding affinity to target HLA molecules, while preserving their homology with the original one, can be a promising avenue for neoantigen vaccine design. In this study, we introduced UltraMutate, a novel algorithm that combines Reinforcement Learning and Monte Carlo Tree Search, which identifies peptide mutations that not only exhibit enhanced binding affinities to target HLA molecules but also retains a high degree of homology with the original neoantigen. UltraMutate outperformed existing state-of-the-art methods in identifying affinity-enhancing mutations in an independent test set consisting of 3660 peptide-HLA pairs. UltraMutate further showed its applicability in the design of peptide vaccines for Human Papillomavirus and Human Cytomegalovirus, demonstrating its potential as a promising tool in the advancement of personalized immunotherapy.

Abstract 243: Organoid co-cultures with allogenic T cells to assess toxicity and efficacy of bispecific antibodies

Abstract Recent advances in cancer immunotherapy positively impacted the life expectancy of patients for an extensive range of clinical indications. With new treatment strategies, druggable targets and biomarkers being identified at an increasing pace, the number of patients eligible for cancer immunotherapy is expected to expand steadily. For example, the emerging Bispecific T cell Engagers (BiTEs) designed to simultaneously target CD3 and tumor-specific antigens and promote T cell cytotoxicity have seen recent clinical success. While BiTEs have been approved for the treatment of hematologic malignancies, promising therapeutic developments for solid tumors face hurdles in translating preclinical findings into therapy since conventional two-dimensional cancer models fail to recapitulate the immune cell interactions in the tumor microenvironment and therefore hold low clinical predictive value. We developed an innovative alternative, building on the discovery that adult stem cells proliferate and organize into three-dimensional organotypic structures that maintain complex characteristics of the original parental tissue, including molecular heterogeneity and morphological and functional traits. Here, we show the development of a patient-relevant preclinical platform for immunotherapy development in which colorectal (CRC) and non-small cell lung cancer (NSCLC) organoids are co-cultured with allogenic or autologous T cells to evaluate the activity and assess the cytotoxic potential of a BiTEs. The expression of tumor-specific BiTE target antigens is determined in patient-derived organoids (PDOs) by flow cytometry. Following this assessment, T cell-induced organoid death is quantified and characterized in real-time by image-based analysis of fluorescent live/dead dyes. Additionally, we measure cytokine secretion as a read-out of T cell activation and function. In our co-cultures, T cell-induced PDO death was increased upon BiTEs treatment. Similarly, IFNγ secretion correlated with expression levels of the targeted tumor antigen. In addition, PDO apoptosis and IFNγ secretion increased in a dose-dependent fashion in the presence of the TA-targeting TCB. In summary, our organoids and T cell co-cultures offer a powerful platform for developing and validating immunotherapies such as T cell-bispecific antibodies and will significantly contribute to our understanding of the critical factors determining successful immunotherapies. Citation Format: Cesar Oyarce, Virginia Bruno, Lorenzo Spagnuolo, Claudia Beaurivage, Javier Frias Aldeguer, Farzin Pourfarzad, Robert G. Vries, Sylvia F. Boj. Organoid co-cultures with allogenic T cells to assess toxicity and efficacy of bispecific antibodies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 243.

Abstract 4256: Autologous organoids and T cell co-cultures as a powerful personalized platform for immunotherapy development

Abstract Recent advances in cancer immunotherapy have had a positive impact on the life expectancy of patients for an extensive range of clinical indications. With new treatment strategies and druggable targets being identified at an increasing pace, the number of patients eligible for cancer immunotherapy is expected to expand steadily. However, promising therapeutic developments face hurdles in translating preclinical findings into therapy since conventional 2D cancer models hold low clinical predictive value. We developed an innovative alternative, building on the discovery that adult stem cells proliferate and organize into three-dimensional organotypic structures when they are embedded into extracellular matrix. Patient-derived organoids are generated from normal and malignant tissues and stored as high-quality biobanks that yield highly reproducible results. HUB Organoids® recapitulate complex characteristics of the parental tissue, including molecular heterogeneity, as well as morphological and functional traits. Since cancer progression and response to immunotherapy are governed by immune cell interactions in the tumor microenvironment, we developed an assay in which colorectal (CRC) and non-small cell lung cancer (NSCLC) tumor organoids are co-cultured with paired tumor infiltrating lymphocytes (TIL) that are simultaneously expanded as a source of tumor reactive cells. Paired resources allow for the screening of immune-modulatory therapies under physiologic conditions, not depending on peptide-pulsing and alloreactivity. We quantify tumor organoid killing and TILs reactivity by combining imaging-based analysis of apoptotic cells with flow cytometry to measure cytokine release by cytotoxic TILs. Here, we show that our system is robust and reproducible with an establishment rate of 75%, allowing for expansion of TILs that preserve T cell receptor repertoires. First line expansion of both PDO and TIL components can be used to effectively build coculture models and probe the tumor and immune components, respectively. Our system offers a powerful tool for the development and validation of cancer immunotherapy and can help to stratify cancer patients for susceptibility to various types of immunotherapies. We certify that the research use of each of the HBS marked above was conducted according to the expectations of each institution. Citation Format: Claudia Beaurivage, BanuPriya Sridharan, Sumeyra Mucuk, Kimberly Nadwodny, Derek Poore, Anna Schepers, Farzin Pourfarzad, Sylvia F. Boj. Autologous organoids and T cell co-cultures as a powerful personalized platform for immunotherapy development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4256.

Abstract 3611: A patient-derived organoid platform to assess the effectiveness of γδTCR cell therapy in solid tumors

Abstract Recent advances in cancer immunotherapy have positively impacted the life expectancy of patients for an extensive range of clinical indications. With new treatment strategies and druggable targets being identified at an increasing pace, the number of patients eligible for cancer immunotherapy is expected to expand steadily. However, promising therapeutic developments face hurdles in translating preclinical findings into therapy since conventional 2D cancer models hold low clinical predictive value. HUB developed an innovative alternative, building on the discovery that adult stem cells proliferate and organise into three-dimensional organotypic structures when embedded into the extracellular matrix. Patient-derived organoids are generated from healthy and malignant tissues, and they recapitulate complex characteristics of the original parental tissue, including molecular heterogeneity and morphological and functional traits. Cell therapies have achieved positive results in treating haematological cancers. Recently, the unique tumour-targeting properties of γδ T cell receptors have been leveraged to develop safer and more effective strategies. HUB and Gadeta joined efforts to explore the therapeutic potential of GDT002 - i.e. αβ T cells engineered with a Gadeta proprietary new γδTCR - to target solid cancers. A preclinical basket trial was performed using patient-derived organoids from several tumour types (colorectal, breast, head and neck, ovarian cancers) cocultured with GDT002. The results showed broad reactivity of GDT002 against solid tumor PDOs. Interestingly, GDT002 was particularly efficient at killing ovarian cancer-derived PDOs, allowing Gadeta to move GDT002 to clinical trials for this indication confidently. This study reveals that our tumor organoid co-culture with engineered T cells platform holds significant value for the preclinical development of cellular therapies. Citation Format: Andrea Bisso, Rene Overmeer, Sjoerd Baardman, Chris Coomans, Cesar Oyarce, Sylvia F. Boj. A patient-derived organoid platform to assess the effectiveness of γδTCR cell therapy in solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3611.

Challenges in the discovery of tumor-specific alternative splicing-derived cell-surface antigens in glioma

Despite advancements in cancer immunotherapy, solid tumors remain formidable challenges. In glioma, profound inter- and intra-tumoral heterogeneity of antigen landscape hampers therapeutic development. Therefore, it is critical to consider alternative sources to expand the repertoire of targetable (neo-)antigens and improve therapeutic outcomes. Accumulating evidence suggests that tumor-specific alternative splicing (AS) could be an untapped reservoir of antigens. In this study, we investigated tumor-specific AS events in glioma, focusing on those predicted to generate major histocompatibility complex (MHC)-presentation-independent, cell-surface antigens that could be targeted by antibodies and chimeric antigen receptor-T cells. We systematically analyzed bulk RNA-sequencing datasets comparing 429 tumor samples (from The Cancer Genome Atlas) and 9166 normal tissue samples (from the Genotype-Tissue Expression project), and identified 13 AS events in 7 genes predicted to be expressed in more than 10% of the patients, including PTPRZ1 and BCAN, which were corroborated by an external RNA-sequencing dataset. Subsequently, we validated our predictions and elucidated the complexity of the isoforms using full-length transcript amplicon sequencing on patient-derived glioblastoma cells. However, analyses of the RNA-sequencing datasets of spatially mapped and longitudinally collected clinical tumor samples unveiled remarkable spatiotemporal heterogeneity of the candidate AS events. Furthermore, proteomics analysis did not reveal any peptide spectra matching the putative antigens. Our investigation illustrated the diverse characteristics of the tumor-specific AS events and the challenges of antigen exploration due to their notable spatiotemporal heterogeneity and elusive nature at the protein levels. Redirecting future efforts toward intracellular, MHC-presented antigens could offer a more viable avenue.