Targeting the DNA damage response in combination with radiation to induce innate immunity and improve immunotherapy efficacy in pancreatic cancer

摘要 需要治疗策略来提高免疫检查点阻断(ICB)治疗的疗效 胰腺导管腺癌(PDAC)。PDAC对DNA损伤反应的依赖程度增加 (DDR)用于减轻癌基因诱导的复制应激，DDR通过调节调节天然免疫 CGAS/STIN/TBK1介导的癌症DNA检测。ATM是DDR中的顶端蛋白，也是靶点 小分子抑制剂在临床开发中的应用。此外，电离辐射会刺激 调节1型干扰素免疫反应的cGAS/STIN/TBK1天然免疫途径-- 辐射与ICB的协同作用所需的依赖方式。因此，中心假说 这一建议的一个新的直接联系ATM和先天免疫感应通路可以是 利用治疗与放射相结合的方法增强肿瘤的T1干扰素途径和 改善免疫原性差的PDAC的ICB疗效。这一假设将在三年内得到检验 具体目标：目标1将定义ATM抑制的免疫学后果 辐射和ATM影响PDAC先天免疫的机制。在这个目标中，我们将评估 胞质DNA(1A)、ATM底物(1B)和模式识别受体途径的作用 免疫终点的信号(1C)，如T1IFN介导的信号、PD-L1表达和T细胞介导的 杀戮(1D)。目的2将研究免疫对ATM耗竭的PDAC敏感性的贡献 肿瘤以放疗和PD-L1联合治疗为主。我们的初步数据显示，ATM机既有这两种功能 影响肿瘤敏感性的肿瘤和宿主免疫依赖机制(即分泌T1干扰素) 联合抗PD-L1和放射治疗。我们将确定肿瘤和宿主T1干扰素信号对 ATM缺陷肿瘤对抗PD-L1联合放射治疗的敏感性及免疫效应 后果(2B)。我们假设ATM缺乏的治疗优势将在 T1IFNR缺陷的肿瘤细胞和宿主，因为肿瘤产生的T1干扰素可能增加肿瘤 通过肿瘤和宿主依赖机制进行免疫监测。在目标3中，我们将开发一种 ATM抑制剂和放疗联合抗PD-L1治疗PDAC的策略。我们的预赛 数据显示，药物ATM抑制激活了免疫途径。我们将确定其疗效。 临床候选ATM抑制剂AZD0156联合抗PD-L1及最佳放射治疗 同基因PDAC肿瘤和自体PDAC肿瘤的剂量/分割方案 转基因小鼠模型(3A)。我们还将开发药效学生物标志物，以预测 ATM抑制加放疗联合抗PD-L1(3B)治疗效果观察完成这些工作 AIMS将定义ATM、辐射和先天免疫之间的新联系，这将被利用 在治疗方面，将ICB的疗效扩展到PDAC，这与NIH的使命高度相关。

ABSTRACT Therapeutic strategies are needed to improve the efficacy of immune checkpoint blockade (ICB) therapy in pancreatic ductal adenocarcinomas (PDAC). PDACs have an increased reliance on the DNA damage response (DDR) for mitigating oncogene-induced replication stress and, the DDR regulates innate immunity via regulation of cGAS/STING/TBK1-mediated detection of cancer DNA. ATM is the apical kinase in the DDR and the target of small molecule inhibitors in clinical development. Furthermore, ionizing radiation stimulates the cGAS/STING/TBK1 innate immune pathway to modulate immune responses in a type 1 interferon (T1IFN)- dependent fashion that are required for the synergy of radiation with ICB. Therefore, the central hypothesis of this proposal is that a novel direct link between ATM and innate immune sensing pathways can be leveraged therapeutically in combination with radiation to enhance the tumoral T1IFN pathway and improve ICB efficacy in otherwise poorly immunogenic PDACs. This hypothesis will be tested in three specific aims: Aim 1 will define the immunologic consequences of ATM inhibition in combination with radiation and the mechanisms by which ATM affects innate immunity in PDAC. In this aim we will assess the contributions of cytoplasmic DNA (1A), ATM substrates (1B), and pattern recognition receptor pathway signaling (1C) to immune endpoints such as T1IFN-mediated signaling, PD-L1 expression, and T cell-mediated killing (1D). Aim 2 will investigate the immune contribution to the sensitivity of ATM depleted PDAC tumors to the combination of radiation and PD-L1 therapy. Our preliminary data suggest that ATM has both tumor and host immune-dependent mechanisms (i.e. T1IFN secretion) that influence the sensitivity of tumors to combined anti-PD-L1 and radiation. We will determine the contribution of tumoral and host T1IFN signaling to the sensitivity of ATM-deficient tumors to combined anti-PD-L1 and radiation therapy (2A) as well as the immune consequences (2B). We hypothesize that the therapeutic advantages of ATM deficiency will be diminished in T1IFNR deficient tumor cells and hosts since tumoral T1IFN production likely increases tumor immunosurveillance through both tumor and host-dependent mechanisms. In Aim 3 we will develop a therapeutic strategy combining ATM inhibitors and radiation with anti-PD-L1 in PDAC. Our preliminary data show that pharmacologic ATM inhibition activates the immune pathway. We will determine the efficacy of the clinical candidate ATM inhibitor AZD0156 in combination with anti-PD-L1 and the optimal radiation dose/fractionation schema in syngeneic PDAC tumors and autochthonous PDAC tumors in genetically engineered mouse models (3A). We will also develop pharmacodynamic biomarkers that will be predictive of the therapeutic efficacy of ATM inhibition and radiation in combination with anti-PD-L1 (3B). Completion of these aims will define a new connection between ATM, radiation and innate immunity that will be leveraged therapeutically to extend the efficacy of ICB to PDAC which is highly relevant to the mission of the NIH.