(PQ7) Defining a new mode of RAS signaling in cancer from cytoplasmic protein granules

项目摘要 随着肿瘤发生和肿瘤进展的分子驱动因素的知识的增长，我们的能力也在增长 部署更有效和毒性更低的分子疗法。例如，针对癌症的治疗方法，如 肺癌中的ALK和EGFR抑制剂正在导致临床结果的改善。然而，并不是所有的患者 受益于这种新兴的精确医学方法，例如KRAS突变癌症患者，以及 那些最初确实从靶向治疗中受益的患者最终死于肿瘤进展，原因是 抗药性。更好地了解导致癌症的异常细胞信号调节 起始、进展和耐药性是扩大和改进分子治疗方案的关键 以延长患者的生存时间。该领域的一个主要空白是对潜在存在的了解很少 以及亚细胞结构的功能，这种结构可以癌症特异性的方式组织细胞信号以促进 癌症发病机制。通过研究对ALK靶向反应和抗性的分子决定因素 在ALK基因重排肺腺癌的治疗中，我们发现致癌的ALK基因 重排独特而精细地依赖于RAS-RAF-MEK-ERK(RAS/MAPK)信号 成长和生存。我们的研究表明，这种依赖的基础是这种致癌的碱性磷酸酶 激活细胞内的RAS，而不是来自脂膜的RAS 细胞。这是令人惊讶的，因为受体激酶，如天然的ALK和RAS都是典型的信号 完全来自脂膜隔室，如质膜。我们的发现促使 耐人寻味的假设是，RAS信号可以来自细胞质中的蛋白质颗粒，而不是脂质- 某些癌症中的膜室。我们提出了四个具体的目标，利用遗传、蛋白质组学、 生物物理学和细胞生物学研究来验证这一假说，目标是在 哺乳动物细胞，RAS信号可以从细胞质发出，在一个有组织的基于蛋白质的结构中 没有类脂膜。我们将首先在患有致癌ALK和肺癌的肺癌中检验这一假设 扩大到那些具有致癌信号的人，这些信号是由其他异常的激酶基因融合引起的，这些信号可能来自 类似的基于细胞内蛋白质的平台。如果我们的假设是真的，这些发现将改变我们的 理解癌症的分子基础，推翻25年来坚持RAS信号转导的教条 只能发生在脂膜隔室中。这些发现将对这一角色产生新的理解 蛋白质颗粒在癌症发病机制中的作用，从而将其归因于一种意想不到的生物学功能 新兴的一类亚细胞结构。我们的努力对设计全新的小说具有重要的意义 利用致癌性亚细胞组织的诊断和治疗策略 发出信号，以改善未来患者的治疗选择。这个项目可能会对 了解癌症的发病机制，并为更好地控制癌症的新的分子策略铺平道路。

Project Summary As knowledge of the molecular drivers of oncogenesis and tumor progression has grown, so too has our ability to deploy more effective and less toxic molecular therapies. For example, targeted cancer therapies such as ALK and EGFR inhibitors in lung cancer are leading to improved clinical outcomes. However, not all patients benefit from this emerging precision medicine approach, such as patients with KRAS-mutant cancers, and those patients who do benefit initially from targeted therapy ultimately succumb to tumor progression due to drug resistance. Gaining a better understanding of the aberrant cell signaling regulation driving cancer initiation, progression, and drug resistance is essential to expand, and improve, molecular treatment options for patients to extend their survival. A major gap in the field is that very little is known about the potential presence and function of subcellular structures that can organize cell signaling in a cancer-specific manner to promote cancer pathogenesis. By studying the molecular determinants of response and resistance to ALK targeted therapy in ALK gene rearrangement lung adenocarcinoma, we discovered that oncogenic ALK gene rearrangements are uniquely and exquisitely dependent on RAS-RAF-MEK-ERK (RAS/MAPK) signaling for growth and survival. Our studies revealed that the basis of the dependence is that this oncogenic ALK activates RAS from an intracellular, cytoplasmic compartment instead of a lipid-membrane compartment in cells. This was surprising because receptor kinases such as native ALK and RAS both canonically signal exclusively from a lipid-membrane compartment such as the plasma membrane. Our findings prompt the intriguing hypothesis that RAS signaling can occur from a protein granule in the cytoplasm, rather than a lipid- membrane compartment in certain cancers. We propose four Specific Aims that leverage genetic, proteomic, biophysical, and cell biological studies to test this hypothesis, with the goal of demonstrating for the first time in mammalian cells that RAS signaling can emanate from the cytoplasm, in an organized protein-based structure that lacks lipid-membranes. We will test this hypothesis initially in lung cancers with oncogenic ALK and expand to those with oncogenic signaling caused by other aberrant kinase gene fusions that may signal from a similar intracellular protein-based platform. If our hypothesis is true, the findings will transform our understanding of the molecular basis of cancer and overturn 25 years of dogma that holds that RAS signaling can only occur from a lipid-membrane compartment. The findings will generate a new understanding of the role of protein granules in cancer pathogenesis, thereby ascribing an unanticipated biological function for this emerging class of subcellular structures. Our efforts hold important implications for designing entirely novel diagnostic and therapeutic strategies to exploit the pathognomonic subcellular organization of oncogenic signaling to improve treatment options for patients in the future. This project could have broad impacts on the understanding of cancer pathogenesis and pave the way for new molecular strategies to better control cancer.