Investigating the PD-L1:NLRP3 signaling axis as a tumor intrinsic mechanism of adaptive resistance to anti-PD-1 antibody immunotherapy

尽管检查点抑制免疫疗法对 肿瘤学方面，我们的大多数癌症患者对这种治疗策略没有反应。很明显 对这些驱动对检查点抑制剂产生耐药性的机制的更全面的理解 免疫治疗将导致开发更有效的免疫治疗方案，并 改进了针对特定疗法的患者选择。然而，我们对活动性肿瘤的理解-- 对药物靶向更敏感的介导耐药机制 可怜。髓系来源的抑制细胞(MDSCs)是一种免疫抑制细胞群 与检查点抑制剂治疗的不良反应有关。使用临床前 不同肿瘤类型的模型以及来自黑色素瘤患者的临床标本， 我们发现，对抗PD-1抗体(Ab)免疫治疗的抵抗力与 粒细胞MDSCs(PMN-MDSCs)在肿瘤床中的募集。后继机械论 研究是为了了解这种PMN积累的分子基础。 接受检查点抑制免疫治疗的肿瘤中的MDSCs注意到CXCR2- 依赖的趋化因子上调是对Wnt5a-YAP1信号轴的反应，这 途径是由肿瘤释放热休克蛋白-70(HSP70)来触发的 CD8T细胞活化。使用全基因组CRISPR筛查，我们已经确定了肿瘤 NLRP3炎症体是诱导这种信号级联和最终 PMN-MDSC在肿瘤床上的募集。基于这些累积数据，我们假设 PMN-MDSCs的适应性募集及其对效应性T细胞的抑制 抗PD-1ab免疫治疗的活性是通过激活肿瘤NLRP3介导的 炎症体通过肿瘤固有的PD-L1信号传导。我们进一步提出，药理学 抑制NLRP3炎症体将增强抗PD-1ab免疫治疗的疗效 在BRAFV600E黑色素瘤本土模型中以及影响这一点的基因突变中 通路可导致对检查点抑制免疫治疗的不同反应。除了……之外 在临床前黑色素瘤模型中模拟特定的功能获得NLRP3突变，我们将 还利用了一项正在进行的临床方案，该方案旨在从黑色素瘤组织中采集样本 患者，使NLRP3基因突变和表达水平相关联，PMN-MDSC 肿瘤浸润和临床对检查点抑制物免疫治疗的反应。总体而言，这 这项研究有望大大有助于我们理解对抗PD的适应性抵抗。 1ab免疫疗法在癌症中的应用。

Despite the positive impact that checkpoint inhibitor immunotherapy has had on the field of oncology, the majority of our cancer patients do not respond to this treatment strategy. It is clear that a more complete understanding of these mechanisms driving resistance to checkpoint inhibitor immunotherapy will lead to the development of more effective immunotherapy regimens and to improved patient selection for specific therapies. However, our understanding of active tumor- mediated resistance mechanisms that are more responsive to pharmacologic targeting remains poor. Myeloid-derived suppressor cells (MDSCs) are an immunosuppressive cell population that have been correlated with inferior responses to checkpoint inhibitor therapy. Using pre-clinical models of different tumor types as well as clinical specimens harvested from melanoma patients, we have found that resistance to anti-PD-1 antibody (ab) immunotherapy is associated with the recruitment of granulocytic MDSCs (PMN-MDSCs) into the tumor bed. Subsequent mechanistic studies were conducted to understand the molecular underpinnings for this accumulation of PMN- MDSCs in tumors undergoing checkpoint inhibitor immunotherapy which noted that CXCR2- dependent chemokines are upregulated in response to a Wnt5a-YAP1 signaling axis and that this pathway is triggered by the release of heat shock protein-70 (HSP70) by tumors in response to CD8+ T cell activation. Using a genome-wide CRISPR screen, we have determined that the tumor NLRP3 inflammasome is essential for the induction of this signaling cascade and the ultimate recruitment of PMN-MDSCs to the tumor bed. Based on this cumulative data, we hypothesize that the adaptive recruitment of PMN-MDSCs and its subsequent suppression of effector T cell activity in response to anti-PD-1 ab immunotherapy is mediated by activation of the tumor NLRP3 inflammasome via tumor intrinsic PD-L1 signaling. We further propose that the pharmacologic inhibition of the NLRP3 inflammasome will enhance the efficacy of anti-PD-1 ab immunotherapy in an autochthonous model of BRAFV600E melanoma and that genetic mutations impacting this pathway can lead to differential responses to checkpoint inhibitor immunotherapy. In addition to modeling specific gain-of-function NLRP3 mutations in pre-clinical melanoma models, we will also leverage an ongoing clinical protocol designed to harvest tissue specimens from melanoma patients, enabling the association of NLRP3 genetic mutations and expression levels, PMN-MDSC tumor infiltration, and clinical response to checkpoint inhibitor immunotherapy. Overall, this study promises to contribute significantly to our understanding of adaptive resistance to anti-PD- 1 ab immunotherapy in cancer.