Cancer immunology research最新文献

Traditional anti-cancer therapies induce tumor cell death and subsequent release of Damage Associated Molecular Patterns (DAMPs) that activate the innate inflammatory response. Paradoxically, after treatment, macrophages often adopt a pro-wound healing, rather than pro-inflammatory, phenotype and contribute to cancer progression. We found that in areas proximal to DAMP release, tumor cells upregulate the expression of Pros1. Tumor-secreted Pros1 binds to the macrophage Mer receptor, consequently limiting responsiveness to DAMPs by preventing Toll Like Receptor (TLR) signal transduction. Pharmacological inhibition of PTP1b signaling downstream of Mer rescued the pro-inflammatory response, even in the presence of Pros1. Combining PTP inhibition with traditional therapeutics, like chemo- or radiotherapy, rescued the innate immune response to DAMPs, increased immune infiltration, and resulted in a 40-90% reduction in tumor growth in multiple treatment refractory preclinical models. Our findings suggest using PTP1b inhibitors may be a tumor agnostic means of improving the efficacy of some of the most widely used anti-cancer therapeutic agents.

Ovarian cancer accounts for more deaths than any other cancer of the female reproductive system. Patients who have ovarian tumors infiltrated with high frequencies of T cells are associated with a greater survival probability. However, therapies to revitalize tumor-associated T cells, such as PD-L1/PD-1 or CTLA4 blockade, are ineffective for the treatment of ovarian cancer. In this study, we demonstrate that for ovarian cancer, Toll-Like Receptor 5 (TLR5) signaling, for which the only known ligand is bacterial flagellin, governed failure of PD-L1 and CTLA4 blockade. Mechanistically, chronic TLR5 signaling on CD11c+ cells in vivo and in vitro impaired the differentiation of functional IL-12-producing XCR1+CD103+ conventional type 1 dendritic cells (cDC1), biasing CD11c+ precursor cells toward myeloid subsets expressing high levels of PD-L1. This culminated in impaired activation of CD8+ T cells, reducing CD8+ T-cell function and ability to persist within the ovarian tumor microenvironment. Expansion of cDC1s in situ using FLT3L in combination with PD-L1 blockade achieved significant survival benefit in TLR5 knockout mice bearing ovarian tumors, whereas no benefit was observed in the presence of TLR5 signaling. Thus, we have identified a host-intrinsic mechanism leading to the failure of PD-L1 blockade for ovarian cancer, demonstrating that chronic TLR5 signaling on CD11c+ cells is a barrier limiting the efficacy of checkpoint therapy.

The tumor microenvironment (TME) in solid tumors contains myeloid cells that modulate local immune activity. STING signaling activation in these myeloid cells enhances local type I interferon (IFN) production, inducing an innate immune response that mobilizes adaptive immunity and reprograms immunosuppressive myeloid populations to drive antitumor immunity. Here, we generated TAK-500, an immune cell directed antibody drug conjugate (iADC), to deliver a STING agonist to CCR2+ human cells and drive enhanced antitumor activity relative to non-targeted STING agonists. Preclinically, TAK-500 triggered dose-dependent innate immune activation in vitro. In addition, a murine TAK-500 iADC surrogate enhanced innate and adaptive immune responses both in vitro and in murine tumor models. Spatially resolved analysis of CCR2 and immune cell markers in the TME of >1,000 primary human tumors showed the CCR2 protein was predominantly expressed in intratumoral myeloid cells. Collectively, these data highlight the clinical potential of delivering a STING agonist to CCR2+ cells.

Regulatory T (Treg) cells play key roles in cancer immunity by suppressing a range of antitumor immune responses and contributing to resistance to PD-1 blockade therapy. Given their critical roles in self-tolerance, local control of immunosuppression by Treg cells, such as in the tumor microenvironment, has been intensively studied. Inhibition of HSP90, a chaperone with vital roles in regulating proteostasis in cancer cells, impedes cancer progression by interrupting oncogenic signaling pathways and potentially modulating antitumor immunity, but we have very little mechanistic insight into these immune modulatory effects. In this study, we show that the number of Treg cells is selectively reduced by the HSP90 inhibitor pimitespib in animal models and patients with gastric cancer in a clinical trial (EPOC1704). Pimitespib reduced the highly immunosuppressive human FOXP3high effector Treg cells by inhibiting their proliferation and decreasing their expression of effector molecules, which improved the priming and activation of antigen-specific CD8+ T cells. Mechanistic studies revealed that pimitespib selectively degraded STAT5, a key transducer of the IL2 signaling pathway, which is essential for Treg cell development and maintenance, and consequently compromised FOXP3 expression, leading to selective impairment of immunosuppression in the tumor microenvironment by Treg cells. Thus, pimitespib treatment combined with PD-1 blockade exhibited a far stronger antitumor effect than either treatment alone in animal models. Through these data, we propose that HSP90 inhibition is a promising therapeutic option for Treg cell-targeted cancer immunotherapy.

Tumor-reactive CD4+ T cells often accumulate in the tumor microenvironment (TME) in human cancer, but their functions and roles in antitumor responses remain elusive. Here, we investigated the immunopeptidome of HLA class II-positive (HLA-II+) endometrial cancer with an inflamed TME using a proteogenomic approach. We identified HLA-II neoantigens, one of which induced polyclonal CD4+ tumor-infiltrating lymphocyte responses. We then experimentally demonstrated that neoantigen-specific CD4+ tumor-infiltrating lymphocytes lyse target cells in an HLA-II-dependent manner. Single-cell transcriptomic analysis of the TME coupled with T-cell receptor sequencing revealed the presence of CD4+ T-cell clusters characterized by CXCL13 expression. The CXCL13+ clusters contained two subclusters with distinct cytotoxic gene expression patterns. The identified neoantigen-specific CD4+ T cells were found exclusively in one of the CXCL13+ subclusters characterized by granzyme B and CCL5 expression. These results demonstrate the involvement of tumor-reactive CD4+ T cells with cytotoxic function in immune surveillance of endometrial cancer and reveal their transcriptomic signature.

Novel therapeutic strategies are needed to improve the efficacy of chimeric antigen receptor (CAR) T cells as a treatment of solid tumors. Multiple tumor microenvironmental factors are thought to contribute to resistance to CAR T-cell therapy in solid tumors, and appropriate model systems to identify and examine these factors using clinically relevant biospecimens are limited. In this study, we examined the activity of B7-H3-directed CAR T cells (B7-H3.CAR-T) using 3D microfluidic cultures of patient-derived organotypic tumor spheroids (PDOTS) and then confirmed the activity of B7-H3.CAR T cells in PDOTS. Although B7-H3 expression in PDOTS was associated with B7-H3.CAR-T sensitivity, mechanistic studies revealed dynamic upregulation of co-inhibitory receptors on CAR T-cells following target cell encounter that led to CAR T-cell dysfunction and limited efficacy against B7-H3-expressing tumors. PD-1 blockade restored CAR T-cell activity in monotypic and organotypic tumor spheroids with improved tumor control and upregulation of effector cytokines. Given the emerging role of TANK-binding kinase 1 (TBK1) as an immune evasion gene, we examined the effect of TBK1 inhibition on CAR T-cell efficacy. Similar to PD-1 blockade, TBK1 inhibition restored CAR T-cell activity in monotypic and organotypic tumor spheroids, prevented CAR T-cell dysfunction, and enhanced CAR T-cell proliferation. Inhibition or deletion of TBK1 also enhanced the sensitivity of cancer cells to immune-mediated killing. Taken together, our results demonstrate the feasibility and utility of ex vivo profiling of CAR T cells using PDOTS and suggest that targeting TBK1 could be used to enhance CAR T-cell efficacy by overcoming tumor-intrinsic and -extrinsic resistance mechanisms.

Pleural mesothelioma is a fatal disease with limited treatment options. Recently, pleural mesothelioma management has improved with the development of immune checkpoint inhibitors (ICI). In first-line therapy, dual PD-1 and CTLA-4 blockade enhances tumor control and patient survival compared with chemotherapy. Unfortunately, only a fraction of patients is responsive to immunotherapy, and approaches to reshape the tumor immune microenvironment and make ICIs more effective are urgently required. In this study, we evaluated the effect of hyperthermic intrathoracic chemotherapy (HITOC), a treatment that combines fever-range hyperthermia with local intrapleural cisplatin chemotherapy, on the tumor immune microenvironment and response to ICIs. To do this, we developed a murine pleural mesothelioma model of HITOC. We found that HITOC significantly improved tumor control and animal survival through a mechanism involving the development of a cytotoxic immune response. Additionally, HITOC enhanced immune checkpoint expression by T lymphocytes and synergized with dual PD-1 and CTLA-4 inhibition, leading to further improvement in animal survival. Finally, the analysis of peritoneal mesothelioma patient samples treated by pressurized intraperitoneal aerosol chemotherapy revealed a similar immunomodulation. In conclusion, HITOC remodels the tumor immune microenvironment of pleural mesothelioma by promoting T-cell infiltration into the tumor and could be considered in combination with ICIs in the context of a clinical trial.

Epithelial ovarian cancer is the most common type of ovarian cancer with a low rate of response to immunotherapy such as immune checkpoint blockade therapy. In this study, we report that nucleus accumbens-associated protein 1 (NAC1), a putative driver of epithelial ovarian cancer, has a critical role in immune evasion. We showed in murine ovarian cancer models that depleting or inhibiting tumoral NAC1 reduced the recruitment and immunosuppressive function of myeloid-derived suppressor cells (MDSC) in the tumor microenvironment, led to significant increases of cytotoxic tumor-infiltrating CD8+ T cells, and promoted antitumor immunity and suppressed tumor progression. We further showed that tumoral NAC1 directly enhanced the transcription of CXCL16 by binding to CXCR6, thereby promoting MDSC recruitment to the tumor. Moreover, lipid C20:1T produced by NAC1-expressing tumor cells fueled oxidative metabolism of MDSCs and promoted their immune-suppressive function. We also showed that NIC3, a small-molecule inhibitor of NAC1, was able to sensitize mice bearing NAC1-expressing ovarian tumors to anti-PD-1 therapy. Our study reveals a critical role for NAC1 in controlling tumor infiltration of MDSCs and in modulating the efficacy of immune checkpoint blockade therapy. Thus, targeting of NAC1 may be exploited to sensitize ovarian cancer to immunotherapy.

Anti-PD-1, trastuzumab, and chemotherapy are used in the treatment of patients with advanced HER2-positive esophagogastric adenocarcinoma, but long-term survival remains limited. In this study, we report extended follow-up data from the INTEGA trial (NCT03409848), which investigated the efficacy of the anti-PD-1 nivolumab, trastuzumab, and FOLFOX chemotherapy (FOLFOX arm) in comparison with a chemotherapy-free regimen involving nivolumab, trastuzumab, and the anti-CTLA-4 ipilimumab (Ipi arm) in the first-line setting for advanced disease. The 12-month overall survival (OS) showed no statistical difference between the arms, with 57% OS (95% confidence interval, 41%-71%) in the Ipi arm and 70% OS (95% confidence interval, 54%-82%) in the FOLFOX arm. Crossing of the survival curves indicated a potential long-term benefit for some patients within the Ipi arm, but early progressors in the Ipi arm underlined the need for biomarker-guided strategies to optimize treatment selection. To this end, metabolomic and cytokine analyses demonstrated elevated levels of normetanephrine, cortisol, and IL6 in immunotherapy-unresponsive patients in the Ipi arm, suggesting a role for systemic inflammatory stress in modulating antitumor immune responses. Patients with this signature also showed an increased neutrophil to lymphocyte ratio that persisted in the Ipi arm, but not in the FOLFOX arm, and strongly correlated with survival. Furthermore, a low neutrophil to lymphocyte ratio characterized patients benefiting from immunotherapy and targeted therapy without the need for additional chemotherapy. These data suggest that patient selection based on inflammatory stress-driven immune changes could help customize first-line treatment in patients with advanced HER2-positive esophagogastric adenocarcinoma to potentially improve long-term survival.