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

项目摘要 随着对肿瘤发生和肿瘤进展的分子驱动因素的认识的增长，我们的能力也在增长。 来部署更有效、毒性更小的分子疗法。例如，靶向癌症治疗， ALK和EGFR抑制剂在肺癌中的应用可改善临床结局。然而，并非所有患者 受益于这种新兴的精准医疗方法，例如患有KRAS突变癌症的患者， 那些最初确实受益于靶向治疗的患者最终死于肿瘤进展， 耐药性更好地了解驱动癌症的异常细胞信号调节 启动、进展和耐药性对于扩大和改善以下疾病的分子治疗选择至关重要： 患者延长生存期。该领域的一个主要空白是对潜在的存在知之甚少 和功能的亚细胞结构，可以组织细胞信号传导，在癌症特异性的方式，以促进 癌症发病机制通过研究ALK靶向应答和耐药的分子决定因素， 在ALK基因重排肺腺癌的治疗中，我们发现致癌ALK基因 重排是唯一和精确地依赖于RAS-RAF-MEK-ERK（RAS/MAPK）信号转导， 成长和生存。我们的研究表明，依赖性的基础是这种致癌ALK 从细胞内、细胞质区室而不是脂膜区室激活RAS， 细胞这是令人惊讶的，因为受体激酶，如天然ALK和RAS，都是典型的信号转导， 排他地从脂膜隔室如质膜中释放。我们的发现促使 一个有趣的假设，RAS信号可以发生在细胞质中的蛋白质颗粒，而不是脂质， 某些癌症的细胞膜区室。我们提出了四个具体目标，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设，目的是首次证明， 在哺乳动物细胞中，RAS信号可以从细胞质中以有组织的蛋白质为基础的结构发出 缺乏脂膜的细胞我们将首先在伴有致癌ALK的肺癌中检验这一假设， 扩展到那些由其他异常激酶基因融合引起的致癌信号传导，这些激酶基因融合可能从一个细胞中发出信号。 类似的基于细胞内蛋白质的平台。如果我们的假设是正确的，这些发现将改变我们的 了解癌症的分子基础，并推翻了25年来认为RAS信号转导 只能从脂膜隔室中产生。这些发现将使人们对这一角色有一个新的认识。 蛋白质颗粒在癌症发病机制，从而归因于一个意想不到的生物功能， 新兴的亚细胞结构。我们的努力对设计全新的 诊断和治疗策略，以利用特异性亚细胞组织的致癌性， 为患者提供更好的治疗方案。该项目可能会产生广泛的影响， 了解癌症发病机制，并为更好地控制癌症的新分子策略铺平道路。

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.