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

目前迫切需要新的治疗策略来改善小细胞肺癌的免疫检查点阻断（ICB）治疗。 细胞肺癌（SCLC）。SCLC严重依赖于复制应激反应（RSR）来减轻癌基因- 诱导复制应激。主要的RSR组分在SCLC中过表达，并且是小分子药物的靶点。 临床开发中的抑制剂。我们证明RSR抑制调节PD-L1表达，刺激PD-L1表达， cGAS/STING/TBK 1先天免疫途径调节1型干扰素（T1 IFN）中的免疫应答- 依赖的方式。我们发现用遗传学或药理学方法靶向RSR是耐受性良好的 并在多个小鼠异种移植和遗传SCLC模型中增强ICB的抗肿瘤反应。我们 目的是证明RSR抑制和免疫传感途径之间的新的直接联系， 在免疫原性差的SCLC中提高ICB功效。我们的长期目标是开发新颖的 免疫治疗方法，可以很容易地转化为临床。我们的首要假设是RSR 抑制增强DNA损伤，同时增加PD-L1表达并恢复抗肿瘤活性 通过先天免疫信号传导激活和产生的细胞毒性T细胞浸润的免疫应答。 在目的1中，我们将确定RSR抑制对PD-L1表达、翻译后表达和细胞内的影响。 通过（1）定义RSR恶化对AKT/GSK 3 β的影响， （2）确定RSR抑制如何调节PD-L1表达，糖基化和稳定性， 分子表征的人和基因工程小鼠模型（GEMM）衍生的细胞系， 体内模型;和（3）研究RSR抑制对SCLC患者样品中PD-L1表达的影响 并与临床结果相关联。在目标2中，我们将确定RSR的免疫学后果 抑制：（1）cGAS/STING介导的先天免疫途径活化和T1 IFN应答;（2） 免疫活性体内SCLC模型中的适应性免疫和免疫细胞亚群;和（3）患者样品。 在目标3中，我们将开发一种将RSR抑制剂与目前的标准治疗（抗- 通过（1）测试小分子RSR抑制剂在SCLC中的抗肿瘤疗效， 在GEMM中的自体SCLC肿瘤中与化学免疫疗法组合;以及（2）开发 预测RSR抑制与抗PD-L1联合治疗疗效的生物标志物， 化疗在这个目标中，我们将解剖免疫变化，在单细胞分辨率。 我在学习SCLC和RS生物学方面的生产力记录，并组装了一个多学科的 该团队拥有免疫学、单细胞技术、生物信息学和小鼠模型方面的专业知识。拟议 研究将确定RSR信号传导，PD-L1表达和先天免疫之间的新联系。的 结果将概述使用RSR抑制剂挽救ICB在SCLC中的功效的新的治疗机会， 这是最具侵袭性的肺癌，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.