Oncoimmunology最新文献

Most exhaustion studies have focused on CD8⁺ T cells. Here, we demonstrated reciprocal growth inhibition of CD4⁺ T cells and colorectal cancer cells, which induced the expression of PD-1, PD-L1, and PD-L2 in CD4⁺ T cells. The accelerated exhaustion of CD4⁺ T cells was evidenced by the reduced secretion of several cytokines, including IL-2, IFN-γ, or TNFα, and elevated secretion of CXCL family chemokines. Progressive expression of PD-L1, CTLA4, and IDO1 exhaustion markers occurred concomitantly with tumor growth in vivo in a mouse model. The pattern of CD4⁺ T cell exhaustion was analogous to that observed in CD8⁺ T cells, although with altered dynamics. The PD-L1-high phenotype can be induced by co-culture with tumor cells and is mediated by secreted factors in addition to cell contact. Our findings revealed that IFN-γ receptor knockout T cells exhibited PD-L1 protein expression when cultured with tumor cells, suggesting that PD-L1 expression is not fully dependent on IFN-γ. The TIL population undergoing exhaustion due to persistent antigen stimulation in the presence of cancer cells gradually acquires an immunosuppressive phenotype. The accumulation of inhibitory signals exerted by both cancer cells and T cells, which had converted to a suppressive phenotype, accelerated T cell exhaustion.

Over the last decade, the annual Immunorad Conference, held under the joint auspicies of Gustave Roussy (Villejuif, France) and the Weill Cornell Medical College (New-York, USA) has aimed at exploring the latest advancements in the fields of tumor immunology and radiotherapy-immunotherapy combinations for the treatment of cancer. Gathering medical oncologists, radiation oncologists, physicians and researchers with esteemed expertise in these fields, the Immunorad Conference bridges the gap between preclinical outcomes and clinical opportunities. Thus, it paves a promising way toward optimizing radiotherapy-immunotherapy combinations and, from a broader perspective, improving therapeutic strategies for patients with cancer. Herein, we report on the topics developed by key-opinion leaders during the 7^th Immunorad Conference held in Paris-Les Cordeliers (France) from September 27th to 29th 2023, and set the stage for the 8^th edition of Immunorad which will be held at Weill Cornell Medical College (New-York, USA) in October 2024.

Tumor-resident immune cells play a crucial role in eliciting anti-tumor immunity and immunomodulatory drug responses, yet these functions have been difficult to study without tractable models of the tumor immune microenvironment (TIME). Patient-derived ex vivo models contain authentic resident immune cells and therefore, could provide new mechanistic insights into how the TIME responds to tumor or immune cell-directed therapies. Here, we assessed the reproducibility and robustness of immunomodulatory drug responses across two different ex vivo models of breast cancer TIME and one of renal cell carcinoma. These independently developed TIME models were treated with a panel of clinically relevant immunomodulators, revealing remarkably similar changes in gene expression and cytokine profiles among the three models in response to T cell activation and STING-agonism, while still preserving individual patient-specific response patterns. Moreover, we found two common core signatures of adaptive or innate immune responses present across all three models and both types of cancer, potentially serving as benchmarks for drug-induced immune activation in ex vivo models of the TIME. The robust reproducibility of immunomodulatory drug responses observed across diverse ex vivo models of the TIME underscores the significance of human patient-derived models in elucidating the complexities of anti-tumor immunity and therapeutic interventions.

T cells that recognize tumor-specific mutations are crucial for cancer immunosurveillance and in adoptive transfer of TILs or transgenic-TCR T cell products. However, their challenging identification and isolation limits their use in clinical practice. Therefore, novel approaches to isolate tumor-specific T cells are needed. Here, we report the isolation of neoantigen-specific CD8⁺ T cells from a vaccination site of a metastatic breast cancer patient who received a personalized vaccine. Based on the somatic mutations, potential MHC binding epitopes were predicted, of which 17 were selected to generate a peptide vaccine. Cutaneous biopsies were processed after the fifth vaccination cycle to obtain infiltrating lymphocytes from the vaccination site (VILs). IFNγ ELISpot revealed reactivity to four peptides used in the vaccine. Reactive T cells from VILs were non-overlapping with those detected in the blood and the tumor-microenvironment. ScTCR Seq analysis revealed the presence of a clonotype in VILs that further expanded after a round of in vitro stimulation and validated to be specific against a private mutation, namely NCOR1^L1475R, presented in the context of HLA-B * 07:02, with no reactivity to the wild-type peptide. Our study shows, for the first time, that tumor mutation - specific T cells are generated at high frequencies in the vaccination site and can be isolated with standard methods for TCR screening. The easy and safe accessibility of skin biopsies overcomes the major hurdles of current TCR screening approaches and present exciting opportunities for the development of innovative immunotherapeutic strategies.

Adoptive cell therapy including chimeric antigen receptor (CAR) T cells targeting CD19 has been approved by FDA to treat B cell-derived malignancies with remarkable success. The success has not yet been expanded to treating Acute Myeloid Leukemia (AML). We previously showed that a nanobody and single-chain fragment variable (scFv) CD13 (Nanobody)/TIM-3 (scFv) directed bispecific split CAR (bissCAR) T cells, while effective in eliminating AML in preclinical models, also caused substantial toxicity to human hematopoietic stem cells (HSCs) and other lineages. To maintain the bissCART specificity and efficacy, yet reduce toxicity to normal cells including HSCs, we generated new anti-TIM-3 nanobodies and constructed new cognate nanobodies-directed CD13/41BB and TIM3/CD3zeta nbiCARTs. The resultant nbiCARTs showed strong antitumor activity to CD13/TIM3 positive leukemic cells in vitro and in preclinical models. Importantly, the 3^rd generation of nbiCARTs had little toxicity to human bone marrow-derived colony forming progenitors ex vivo and the human HSCs in mice with a humanized immune system. Together, the current studies generated novel and 3^rd G CD13/TIM-3 nbiCARTs that displayed stronger antitumor activity yet minimal toxicity to normal tissues like HSCs that express a moderate level of CD13, paving the way to further evaluate the novel CD13/TIM-3CARTs in treating aggressive and refractory AML in clinical studies.

The 4662 KPC model is one of the most widely used mouse models of pancreatic cancer. It represents an excluded immune phenotype and closely recapitulates the pathophysiology of pancreatic cancer in humans. We set out to identify the endogenous neoepitopes present in 4662 cells. By combining whole-exome and RNA-sequencing and a bioinformatic neoantigen prediction pipeline, we have identified 15 potential candidate neoantigen epitopes. Ten more highly expressed were selected for validation in an in vivo vaccination study with 4662-tumor bearing mice. The Mrps35-derived neoantigen was found to be immunogenic as we have identified endogenous T-cells responding to this neoepitope, and the response was significantly increased upon vaccination with a synthetic peptide and upon PD1-IL2v therapy. Dextramers based on this peptide were validated and can be used to monitor endogenous tumor-specific CD8+ T-cells in response to immunotherapy. This will support the development of novel therapies for this highly unmet medical need indication.

Metabolic processes are crucial in immune regulation, yet the impact of metabolic heterogeneity on immunological functions remains unclear. Integrating metabolomics into immunology allows the exploration of the interactions of multilayered features in the biological system and the molecular regulatory mechanism of these features. To elucidate such insight in lung squamous cell carcinoma (LUSC), we analyzed 106 LUSC tumor tissues. We performed high-resolution matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) to obtain spatial metabolic profiles, and immunohistochemistry to detect tumor-infiltrating T lymphocytes (TILs). Unsupervised k-means clustering and Simpson's diversity index were employed to assess metabolic heterogeneity, identifying five distinct metabolic tumor subpopulations. Our findings revealed that TILs are specifically associated with metabolite distributions, not randomly distributed. Integrating a validation cohort, we found that heterogeneity-correlated metabolites interact with CD8+ TIL-associated genes, affecting survival. High metabolic heterogeneity was linked to worse survival and lower TIL levels. Pathway enrichment analyses highlighted distinct metabolic pathways in each subpopulation and their potential responses to chemotherapy. This study uncovers the significant impact of metabolic heterogeneity on immune functions in LUSC, providing a foundation for tailoring therapeutic strategies.

Induction of endoplasmic reticulum (ER) stress is followed by exposure of calreticulin (CRT) on the cancer cell plasma membrane and elicits an anticancer immune response, referred to as immunogenic cell death (ICD). Smad7 is highly expressed by colorectal cancer (CRC) cells, and its knockdown with a specific antisense oligonucleotide (AS) induces ER stress. We hypothesized that, by preventing ER stress, high Smad7 in CRC cells can contribute to limiting ICD. This study aimed to investigate whether targeted inhibition of Smad7 in CRC cells promotes an anti-cancer immune response. Downregulation of Smad7 in the human HCT116 and DLD1 cells and murine CT26 cells promoted calreticulin translocation to the plasma membrane and this phenomenon was prevented by Tauro-urso-deoxycholic acid, an inhibitor of ER stress. Smad7-deficient cells secreted high levels of ATP and HMGB1, thereby promoting the activation of co-cultured dendritic cells. Mice engrafted with Smad7-deficient CT26 cells developed fewer and smaller tumors than wild-type CT26 cell-engrafted mice and exhibited a marked tumor infiltration with CD8⁺ cells and to a lesser extent CD4⁺ cells. Depletion of CD8⁺ T cells abrogated the inhibitory effect of Smad7 knockdown on the tumor volume. Finally, we showed that, in a vaccination model, implanted Smad7-deficient CT26 cells protected mice from the development of tumors induced by wild-type CT26 cells. These data show that Smad7 deficiency triggers ICD in CRC cells, thus reducing tumor development and growth, and suggest that Smad7 inhibitors could be developed as novel ICD inducers, providing a new concept for antitumor immunotherapy.

Medulloblastoma (MB) is a pediatric brain tumor that develops in the cerebellum, representing one of the most common malignant brain cancers in children. Standard treatments include surgery, chemotherapy, and radiation, but despite a 5-y survival rate of approximately 70%, these therapies often lead to significant neurological damage in the developing brain. This underscores the urgent need for less toxic, more effective therapeutic alternatives. Recent advancements in cancer immunotherapy, including immune checkpoint inhibitors and CAR-T cell therapy, have revolutionized cancer treatment. One promising avenue is the use of Gamma Delta (γδ)T cells, a unique T cell population with potential advantages, such as non-alloreactivity, potent tumor cell lysis, and broad antigen recognition. However, their capacity to recognize and target MB cells remains underexplored. To investigate the therapeutic potential of γδT cells against MB, we analyzed the proportion and status of MB-infiltrated γδT cells within patient datasets. We next investigated the expression of γδT cell ligands on MB cells and identified the EphA2 receptor and the phosphoantigen/Butyrophilin complex as key ligands, activating Vγ9 Vδ1 and Vγ9 Vδ2 T cells, respectively, leading to significant MB cell lysis in both monolayer and spheroid models. Importantly, preliminary safety data showed that γδT cells did not target differentiated neurons or neuroepithelial stem cells derived from induced pluripotent stem cells, underscoring the selectivity and safety of this approach. In conclusion, γδT cells trigger an efficient and specific killing of MB and would offer a promising novel therapeutic strategy.

Renal cell carcinoma (RCC) is recognized as an immunogenic tumor, yet tumor-infiltrating lymphocytes often exhibit diminished effector function. However, the mechanisms underlying reduced T and NK cell activity in RCC remain unclear. Here, we examined the immune contexture in RCC patients undergoing nephrectomy to identify immune-related biomarkers associated with disease progression. Immune cell phenotypes and secretion profiles were assessed using flow cytometry and Luminex multiplex analysis. Supervised multivariate analysis revealed several changes of which frequencies of T and NK cells expressing CCR5, CXCR3, and PD-1 were elevated within tumors compared with peripheral blood. In addition, higher levels of regulatory T cells, PD-1+, and CXCR3+ T and NK cells were observed in patients with relapse following nephrectomy. With regards to soluble factors, tumor-derived CXCL8 was associated with higher Fuhrman grade and increased frequency of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs). These biomarkers demonstrate potential relevance in the progression of RCC and merit further investigation in prospective studies.