Mechanism-based targeting of unique survival signaling in residual tumors

项目摘要/摘要 癌基因靶向治疗的临床活性受到以下事实的限制：残留癌的一部分 细胞通常在治疗中存活下来，最终导致非常难以治疗的渐进性、抗药性疾病。 到目前为止，人们对残留的疾病细胞知之甚少，部分原因是获得和分析肿瘤 在这个阶段，标本在后勤方面一直是一个挑战。我们最近发现存活的残存细胞 不同的、癌基因匹配的靶向治疗显示DNA双链断裂(DSB)和 随之而来的是依赖ATM的DSB修复。在对EGFR突变的非小细胞进行的机制研究中 肺癌(NSCLC)，这种DNA损伤被观察到是由违反直觉的“亚致命性”驱动的 刽子手caspase3和7的激活，它们通过直接激活caspase3和caspase7来驱动DNA损伤 半胱氨酸氨基转移酶激活的DNA酶(CAD)。其结果是，残留的癌细胞存活在早期的EGFR抑制剂 治疗需要ATM活性来分解DSB，联合使用EGFR抑制剂和ATM抑制剂可以根除 残留细胞，在细胞和动物模型中导致高度渗透和持久的治疗反应。 这些发现进一步得到了我们的临床观察的支持，即残留的EGFR突变的肺癌 显示ATM活性显著上调，罕见的非小细胞肺癌患者其肿瘤存在- 在接受EGFR抑制剂治疗的患者中，ATM的功能突变显示无进展存活率增加。在这 建议，我们描述了研究以确定在残留肿瘤中驱动亚致死性caspase激活的机制。 细胞及其随之而来的依赖ATM的生存。此外，我们建议定义广义的、功能性的 亚致死性caspase和ATM激活在残留肿瘤细胞中的意义，揭示了随后的机制 残留肿瘤的脆弱性。最后，我们描述了将细胞、患者来源的异种移植、 基因工程小鼠模型，具有高度认证的、纵向采样的临床样本 目的：评价残余肿瘤细胞存活的治疗靶向性。总之，这些研究将定义关键， 区分残留肿瘤细胞的特征，促进我们对这一至关重要的但 对肿瘤生物学知之甚少，同时定义了一类新的基于机制的策略 将残留病降至最低的可能性。

Project Summary/Abstract The clinical activities of oncogene targeted therapies are limited by the fact that a subset of residual cancer cells often survive treatment, eventually giving rise to progressive, resistant disease that is very difficult to treat. To date, relatively little is known about residual disease cells, in part because obtaining and analyzing tumor specimens at this stage has been logistically challenging. We recently discovered that residual cells surviving treatment with diverse, oncogene-matched targeted therapies exhibit DNA double strand breaks (DSBs) and consequent, ATM-dependent DSB repair. In mechanistic studies performed in EGFR mutant non-small cell lung cancer (NSCLC), this DNA damage was observed to be driven by the counterintuitive “sublethal” activation of executioner caspases 3 and 7, which drive DNA damage through their direct activation of caspase-activated DNase (CAD). As a consequence, residual cancer cells that survive upfront EGFR inhibitor treatment require ATM activity to resolve DSBs, and combining EGFR inhibitors with ATM inhibitors eradicates residual cells, leading to highly penetrant and durable therapeutic responses in cellular and animal models. These findings are further supported by our clinical observations that residual EGFR mutant lung tumors display marked upregulation of ATM activity and that rare NSCLC patients whose tumors harbor loss-of- function mutations in ATM exhibit increased progression-free survival on EGFR inhibitor therapy. In this proposal, we describe studies to define the mechanisms driving sublethal caspase activation in residual tumor cells and their consequent, ATM-dependent survival. Further, we propose to define the broad, functional implications of sublethal caspase and ATM activation in residual tumor cells, revealing consequent mechanistic vulnerabilities of residual tumors. Finally, we describe studies that integrate cellular, patient-derived xenograft, and genetically engineered mouse models with highly credentialed, longitudinally sampled clinical specimens to evaluate the therapeutic targeting of residual tumor cell survival. Together, these studies will define key, distinguishing features of residual tumor cells, advancing our basic understanding of this critically important but poorly understood aspect of tumor biology while defining a new class of mechanism-based strategies with the potential to minimize residual disease.