Oncoimmunology最新文献

Among the plethora of cancer immune evasion mechanisms, T-cell-inhibiting factors within the tumor microenvironment impose a major challenge for the development of novel immunotherapies. Strategies to overcome immunosuppression and remodel the TME are therefore urgently needed. Therapeutic cancer vaccines based on engineered arenaviruses have been proven to generate potent tumor specific CD8+ T-cell responses in preclinical models and cancer patients. Despite signs of clinical activity as monotherapy, combination therapies are needed to further increase the therapeutic effect. To address this need, we evaluated the efficacy of recombinant vectors based on lymphocytic choriomeningitis virus encoding the T-cell stimulating cytokines IL-7, IL-12 and IL-15 with or without tumor-associated antigens. These vectors were tested in three different mouse tumor models (TC-1, MC-38 and B16.F10). Our results demonstrate that only IL-12 encoding vectors led to increased immunogenicity and efficacy, which, after systemic administration, was associated with adverse events. The safest and most potent regimen consisted of systemic vaccination with tumor antigen encoding vectors and local injection of IL-12-encoding vectors. A single round of this treatment regimen resulted in 86-100% tumor-free mice and warrants further investigation.

Sertraline and indatraline are two antidepressants that function as serotonin reuptake inhibitors and have demonstrated promising anticancer potential, although their precise mechanisms of action remain unclear. Both compounds trigger cholesterol accumulation within lysosomes followed by lysosomal membrane permeabilization, ultimately leading to the activation of immunogenic cell death (ICD). This, in turn, triggers a T cell-mediated adaptive immune response that facilitates significant tumor control.

BCMA-directed CAR-T therapies have shown promising results in multiple myeloma (MM). However, patients continue to relapse. T cell exhaustion with increased TIGIT expression is a resistance mechanism which was confirmed in CAR-T cells from ARI0002h trial, an academic CAR-T developed in our institution. We aimed to analyze the impact of blocking TIGIT on the efficacy of ARI0002h. We used three different strategies to block TIGIT: (1) Addition of an external blocking anti-TIGIT-antibody (Ab), (2) Modify ARI0002h into a 4^th generation CAR-T, named ARITIGIT, capable of secreting a soluble TIGIT-blocking scFv and (3) TIGIT knock-out in ARI0002h using CRISPR/Cas9. Each strategy was evaluated in vitro and in vivo. Adding a TIGIT-blocking Ab to ARI0002h improved in vitro cytotoxicity, but failed to enhance mice survival. The new 4^th generation CAR-T, ARITIGIT, was also unable to achieve better survival outcomes despite favoring the in vivo model by using a myeloma cell line with high expression of the TIGIT ligand PVR. Interestingly, when mice were challenged with a second infusion of tumor cells, mimicking a relapse model, a trend for improved survival with ARITIGIT was observed (p = 0.11). Finally, TIGIT-knock-out on ARI0002h (KO-ARI0002h) using CRISPR/Cas9 showed similar in vitro activity to ARI0002h. In an in vivo stress model, TIGIT KO-ARI0002h prolonged survival (p = 0.02). However, this improvement was not significant compared to ARI0002h (p = 0.07). This study failed to demonstrate a significant benefit of TIGIT-blockade on ARI0002h cells despite using three different approaches, suggesting that targeting a single immune checkpoint may be insufficient.

Adoptive cell therapy and the use of monoclonal antibodies are two therapeutic modalities implemented in the treatment of multiple myeloma (MM). In this study, we combined the anti-CD38 therapeutic mAb daratumumab with different types of NK cells, leveraging the antibody-dependent cell-mediated cytotoxicity (ADCC) performed by these immune cells. Daratumumab was initially combined with activated and expanded NK cells (eNK), resulting in significant cytotoxic activity against human MM cell lines. As an alternative model to minimize the variability among donors of NK cells, the NK92 cell line was used, which showed greater cytotoxic activity than eNK cells against MM cell lines. However, since NK92 cells lacked CD16 receptor expression, they could not be used in combination with mAbs. To circumvent this, we performed a CD16 transfection on NK92 cells, generating the stable NK92-CD16 cell line. These cells were tested in combination with daratumumab against human MM cell lines with excellent results under various conditions, such as 2D and 3D cultures, even at very low effector-to-target ratios. NK92-CD16 cells were then tested in the presence of daratumumab against plasma cells from MM patients, with anti-myeloma activity even against cells from relapsed patients. In vivo experiments using MM xenografts or intravenous injection of MM cells in NGS mice, followed by treatment with NK92-CD16 cells in the presence or absence of daratumumab showed tumor regressions, especially in the second model, with nearly complete elimination of the MM cells when NK92-CD16 cells were combined with daratumumab.

Adoptive cell therapy with tumor-infiltrating lymphocytes (TILs) has demonstrated consistent clinical efficacy in treating advanced melanoma and other "hot" tumors. However, it has shown limited success in "cold" tumors like glioblastoma. We present the successful treatment of a rapidly progressing glioblastoma patient with TILs expanded using a defined cytokine combination of IL-2, IL-15, and IL-21. The patient received lymphodepletion with cyclophosphamide one day pre-TIL infusion, followed by a single dose of IL-2 post-transfer. Complete tumor regression was observed after two TIL infusions administered two weeks apart. The TIL products were enriched for CD8⁺ T-cells and demonstrated specific lysis of the autologous tumor cell line. Transcriptomic analysis of tumor biopsies post-TIL infusion revealed increased expression of genes associated with immunological synapse formation and T-cell effector function, correlating with the patient's clinical outcome. T-cell receptor (TCR) next-generation sequencing of the infused TILs and post-treatment tumor biopsies confirmed the infiltration and expansion of TIL-derived clonotypes within the tumor microenvironment. CD8⁺ T-cell clonotypes exhibited robust tumor migration and expansion, while CD4⁺ T-cells showed limited tumor infiltration. In conclusion, TILs expanded with IL-2/IL-15/IL-21 represent a promising therapeutic approach for glioblastoma, overcoming traditional challenges posed by the tumor microenvironment and achieving significant clinical outcomes.

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.

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.