Targeting replication stress signaling to overcome immune evasion in small cell lung cancer

迫切需要新的治疗策略来改善小鼠的免疫检查点阻断(ICB)治疗 细胞肺癌(SCLC)。小细胞肺癌严重依赖复制应激反应(RSR)来缓解癌基因- 诱导复制应激。主要RSR组分在小细胞肺癌中高表达，是小分子靶标 临床开发中的抑制剂。我们证明了RSR抑制调节PD-L1的表达，刺激 调节1型干扰素免疫反应的cGAS/STIN/TBK1先天免疫途径-- 依附时尚。我们表明，用遗传或药物方法靶向RSR是可以被很好地耐受的。 并增强ICB对多只小鼠移植瘤和遗传性小细胞肺癌模型的抗肿瘤作用。我们的 目的是证明RSR抑制和免疫感觉通路之间的新的直接联系可以 改善免疫原性差的小细胞肺癌的ICB疗效。我们的长期目标是开发小说 可以很容易地转化为临床的免疫治疗方法。我们最重要的假设是RSR 抑制在增加PD-L1表达和恢复抗肿瘤的同时加强DNA损伤 免疫反应通过先天免疫信号的激活和由此产生的细胞毒性T细胞的渗透。 在目标1中，我们将确定RSR抑制对PD-L1表达的细胞内在影响，翻译后 通过(1)定义RSR恶化对AKT/GSK3β的影响，修改和稳定小细胞肺癌 (2)确定RSR抑制如何调节PD-L1的表达、糖基化和稳定。 人类和基因工程小鼠模型(GEMM)来源的细胞系和 (3)研究RSR抑制对小细胞肺癌患者样本PD-L1表达的影响。 并与临床结果相关。在目标2中，我们将确定RSR的免疫学后果 抑制：(1)cGAS/STING介导的天然免疫途径激活和T1干扰素应答； 免疫活性体内小细胞肺癌模型中的获得性免疫和免疫细胞亚群；以及(3)患者样本。 在目标3中，我们将开发一种治疗策略，将RSR抑制剂与当前的护理标准(抗- PD-L1+化疗)，通过(1)检测小分子RSR抑制剂对小细胞肺癌的抗肿瘤作用。 联合化疗免疫治疗原发小细胞肺癌；(2)进展 预测RSR抑制联合抗PD-L1和抗PD-L1治疗效果的生物标志物 化疗。在这个目标中，我们将在单个细胞分辨率下剖析免疫变化。 我在研究小细胞肺癌和遥感生物学方面有着卓有成效的记录，并建立了一个多学科的 拥有免疫学、单细胞技术、生物信息学和小鼠模型方面的专业知识的团队。建议数 研究将确定RSR信号、PD-L1表达和先天免疫之间的新联系。这个 结果将勾勒出一个新的治疗机会，使用RSR抑制剂来挽救ICB在小细胞肺癌中的疗效， 最具侵袭性的肺癌，这与NCI的使命高度相关。

New therapeutic strategies are urgently needed to improve immune checkpoint blockade (ICB) therapy in small cell lung cancer (SCLC). SCLCs rely heavily on the replication stress response (RSR) to mitigate oncogene- induced replication stress. Major RSR components are overexpressed in SCLC and are targets of small molecule inhibitors in clinical development. We demonstrated that RSR inhibition regulates PD-L1 expression, stimulates the cGAS/STING/TBK1 innate immune pathway to modulate immune responses in a type 1 interferon (T1IFN)- dependent fashion. We showed that targeting RSR with genetic or pharmacologic approaches is well-tolerated and potentiates the antitumor response with ICB in multiple mouse xenograft and genetic SCLC models. Our objective is to demonstrate that the novel direct link between RSR inhibition and immune sensing pathways can improve ICB efficacy in otherwise poorly immunogenic SCLCs. Our long-term goal is to develop novel immunotherapy approaches that can be readily translated into the clinic. Our overarching hypothesis is that RSR inhibition potentiates DNA damage while concurrently increasing PD-L1 expression and restoring antitumor immune responses through innate immune signaling activation and the resulting cytotoxic T-cell infiltration. In Aim 1, we will identify the cell-intrinsic effects of RSR inhibition on PD-L1 expression, post-translational modifications, and stabilization in SCLC by (1) defining the impact of RSR exacerbation on the AKT/GSK3β pathway; (2) identifying how RSR inhibition regulates PD-L1 expression, glycosylation, and stabilization in molecularly characterized human and genetically engineered mouse model (GEMM)-derived cell lines and in vivo models; and (3) investigating the effects of RSR inhibition on PD-L1 expression in SCLC patient samples and correlating with clinical outcomes. In Aim 2, we will determine the immunologic consequences of RSR inhibition on: (1) cGAS/STING-mediated innate immune pathway activation and the T1IFN response; (2) adaptive immunity and immune cell subsets in immunocompetent in vivo SCLC models; and (3) patient samples. In Aim 3, we will develop a therapeutic strategy combining RSR inhibitors with the current standard-of-care (anti- PD-L1+chemotherapy) in SCLC by (1) testing the antitumor efficacy of small molecule RSR inhibitors in combination with chemoimmunotherapy in autochthonous SCLC tumors in GEMMs; and (2) developing biomarkers that predict the therapeutic efficacy of RSR inhibition in combination with anti-PD-L1 and chemotherapy. In this aim we will dissect the immune changes, at a single cell resolution. I have a track record of productivity in studying SCLC and RS biology and have assembled a multidisciplinary team with expertise in immunology, single-cell technologies, bioinformatics, and mouse models. The proposed research will define a new connection between RSR signaling, PD-L1 expression, and innate immunity. The results will outline a novel therapeutic opportunity to use RSR inhibitors to rescue the efficacy of ICB in SCLC, the most aggressive form of lung cancer, which is highly relevant to the mission of the NCI.