Targeting the cytokine circuitry of KRAS-driven lung cancer

本研究项目提案的目标是在KRAS中增选功能失调的先天免疫信号传导， 导致肺癌的治疗弱点。具体来说，我的实验室多年来一直专注于 靶向TBK 1以抑制细胞因子和趋化因子如IL-6和CCL 5的产生， 致瘤性和免疫抑制。例如，TBK 1抑制也使肿瘤对MEK抑制敏感， 作为PD-1阻断剂在过去的几年里，越来越明显的是， RIG-I/MAVS或cGAS/STING等通路在重定向TBK 1以激活IRF 3/STAT 1中起关键作用 并启动细胞毒性抗病毒反应。KRAS如何突变肺癌，尤其是STK 11/LKB 1 共突变，避免这种反应，并优先激活NF-κB/STAT 3生存信号转导仍然存在 不清楚 在开发三联疗法以抑制TBK 1/MEK信号传导和抑制适应性细胞凋亡的同时， 转录反馈，我们偶然观察到KRAS-LKB 1（KL）突变型肺癌 表观遗传沉默刺痛。对KL细胞的详细研究揭示了增强的 DNMT 1活性和避免检测线粒体DNA的需要，线粒体DNA由于受损而积累。 线粒体重新激活KL细胞中的STING表达导致细胞毒性和增强的细胞毒性。 免疫原性，特别是当与STING激动剂组合时。因此，不是抑制多种信号传导， 这些研究揭示了一个简单的脆弱性， 在治疗上被吸收了 因此，这项建议的广泛的长期目标是表征表观遗传机制， STING沉默并将这种状态纳入肿瘤脆弱性。迫使细胞去处理 STING再表达的增加，在通过DNA损伤或直接STING激动作用驱动其活性的同时， KRAS驱动的肺癌这一主要亚群的治疗潜力。鉴于目前尚不清楚的 靶向三个或更多个KRAS下游通路，这是动物长期持久应答所需的 模型，这种更简单的策略，也可以重新参与抗肿瘤免疫，具有显着的潜力。此外，委员会认为， 除了我们提出的体内研究之外，我们的新模型系统使用患者来源的异种移植物和直接移植物。 患者来源的器官型肿瘤球体（XDOTS和PDOTS）在实际移植中提供了快速验证 肿瘤的具体目标是：1）优化逆转KL肿瘤中STING的表观遗传沉默的策略，2） 开发具有促进有丝分裂滑移的特定药剂的联合治疗策略，以及3）利用 免疫活性模型来探索STING引发对适应性T细胞应答的直接作用。通过 这些补充研究的目标是重新连接KRAS驱动的肺癌的细胞因子回路， 这种细胞毒性抗病毒信号传导机制，并最终克服对免疫检查点的内在抗性 抑制剂疗法

The goal of this research project proposal is to co-opt dysfunctional innate immune signaling in KRAS- driven lung cancers as a therapeutic vulnerability. Specifically, my laboratory has focused for many years on targeting TBK1 to inhibit the production of cytokines and chemokines such as IL-6 and CCL5 that are pro- tumorigenic and immune suppressive. For example, TBK1 inhibition sensitizes tumors to MEK inhibition, as well as PD-1 blockade. Over the past several years it has also become increasingly apparent that viral sensing pathways, such as RIG-I/MAVS or cGAS/STING play a key role in re-directing TBK1 to activate IRF3/STAT1 and initiate a cytotoxic anti-viral response. How KRAS mutant lung cancers, especially those with STK11/LKB1 co-mutation, avoid this response and preferentially activate NF-κB/STAT3 survival signaling has remained unclear. While developing triple combination therapies to inhibit TBK1/MEK signaling and suppress adaptive transcriptional feedback, we made the serendipitous observation that KRAS-LKB1 (KL) mutant lung cancers epigenetically silence STING. Detailed studies in KL cells unveiled a mechanistic connection between enhanced DNMT1 activity and the need to avoid detection of mitochondrial DNA, which accumulates due to damaged mitochondria. Re-activating STING expression in KL cells results in cellular cytotoxicity and enhanced immunogenicity, especially when combined with STING agonism. Thus, instead of inhibiting multiple signaling pathways downstream KRAS, these studies uncover a straightforward vulnerability that could be more readily co-opted therapeutically. The broad, long term objective of this proposal is therefore to characterize the epigenetic mechanism of STING silencing and to co-opt this state into a tumor vulnerability. Forcing cells to deal with the consequences of STING re-expression, while driving its activity via DNA damage or direct STING agonism, has important therapeutic potential for this major subset of KRAS-driven lung cancer. Given the unclear therapeutic window of targeting three or more KRAS downstream pathways, which is required for long-term durable response in animal models, this simpler strategy, which can also re-engage anti-tumor immunity, has significant potential. Moreover, in addition to the in vivo studies we propose, our novel model system using patient-derived xenograft and direct patient-derived organotypic tumor spheroids (XDOTS and PDOTS) provides rapid validation in actual explanted tumors. Specific aims are to: 1) Optimize strategies to reverse epigenetic silencing of STING in KL tumors, 2) Develop combination therapy strategies with specific agents that promote mitotic slippage, and 3) Utilize immune-competent models to explore the direct role of STING priming on adaptive T cell responses. Through these complementary studies, the goal is to rewire the cytokine circuitry of KRAS-driven lung cancer to engage this cytotoxic anti-viral signaling machinery and ultimately to overcome intrinsic resistance to immune checkpoint inhibitor therapy.