Mechanism-based targeting of unique survival signaling in residual tumors

项目概要/摘要 癌基因靶向治疗的临床活性受到以下事实的限制： 细胞通常在治疗中存活，最终导致进行性的、耐药的疾病，这是非常难以治疗的。 到目前为止，对残留的疾病细胞知之甚少，部分原因是获得和分析肿瘤细胞， 现阶段的标本在后勤方面具有挑战性。我们最近发现残存的细胞 用不同的癌基因匹配的靶向疗法治疗显示出DNA双链断裂（DSB）， 随后，ATM依赖性DSB修复。在EGFR突变型非小细胞肺癌中进行的机制研究中， 肺癌（NSCLC），观察到这种DNA损伤是由违反直觉的“亚致死” 激活刽子手半胱天冬酶3和7，通过直接激活 半胱天冬酶激活的DNA酶（CAD）。因此，在EGFR抑制剂之前存活的残余癌细胞 治疗需要ATM活性来解决DSB，并且EGFR抑制剂与ATM抑制剂的组合根除了DSB。 残余细胞，导致细胞和动物模型中的高度渗透和持久的治疗反应。 我们的临床观察结果进一步支持了这些发现， 显示出ATM活性的显著上调，并且罕见的肿瘤具有ATM活性缺失的NSCLC患者， ATM中的功能突变在EGFR抑制剂治疗中表现出增加的无进展生存期。在这 建议，我们描述的研究，以确定机制驱动亚致死半胱天冬酶激活残留肿瘤 细胞及其随后的ATM依赖性存活。此外，我们建议界定广泛的、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 残余肿瘤的脆弱性。最后，我们描述了整合细胞，患者来源的异种移植物， 和基因工程小鼠模型， 以评估残余肿瘤细胞存活的治疗靶向。总之，这些研究将确定关键， 残留肿瘤细胞的区别特征，推进我们对这一至关重要但 肿瘤生物学知之甚少的方面，同时定义了一类新的基于机制的策略， 尽可能减少残留疾病。

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.