Design and Development of a Small Molecule-controlled Activator of RAS

描述（由申请人提供）：自“向癌症宣战”四十多年以来，恶性肿瘤仍然是人类健康的祸害。在这一声明发表后不久，编码RAS蛋白的三个基因被发现是癌症中最重要的分子角色。RAS就像一个分子开关，存在于“开”或“关”状态。当RAS开启时，它会引发各种各样的信号级联反应，这些信号级联反应控制着存活、增殖和许多其他细胞过程。在健康细胞中，RAS整合来自细胞外的信号来决定细胞反应。然而，在大约20%的人类肿瘤中，RAS的突变导致它“卡”在on位置。这种组成型活性RAS导致异常的下游信号传导和细胞的恶性转化。总之，这三种RAS亚型构成了人类癌症中最常见的突变癌基因。值得注意的是，RAS突变在一些最难治性的恶性肿瘤中尤其普遍，如胰腺癌、肺癌和结肠癌。然而，经过近四十年的研究，尚未发现针对突变型RAS肿瘤的靶向治疗方法。在很大程度上，这是RAS“不可药物化”的结果：众所周知，用小分子药物直接抑制RAS是非常困难的。RAS的顽固性意味着必须对其信号进行深入剖析，以确定靶向这些肿瘤的替代策略。尽管进行了广泛的研究，但人们仍然不清楚这样一个简单的开关是如何控制如此复杂的细胞反应的，或者为什么在某些情况下，激活的RAS会导致细胞增殖，而在另一些情况下，它会导致细胞衰老。为了解决RAS和癌症生物学中这些长期存在的问题，我们设计了一种化学诱导的RAS激活剂（CIAR）。有了这个结构，我们能够以快速和剂量依赖的方式用小分子激活RAS信号。这种控制将允许以前无法获得的RAS信号传导对磷蛋白组、转录组和恶性表型的影响的大小和持续时间的研究。此外，通过将CIAR定位到不同的亚细胞区室，我们将探讨RAS信号的时空区室化如何影响信号传导和转录网络以及表型。从这些研究中收集到的信息可以指导确定针对携带RAS突变的肿瘤的新策略。

DESCRIPTION (provided by applicant): Over forty years since the declaration of the "War on Cancer," malignancy remains a scourge on human health. Not long after that declaration, the three genes that encode RAS proteins were discovered to be among the most prominent molecular players in cancer. RAS functions as a molecular switch, existing in either an "on" or "off" state. When on, RAS instigates a wide variety of signaling cascades that control survival, proliferation, and many other cellular processes. In healthy cells, RAS integrates signals coming from outside the cell to determine cellular response. In approximately 20% of human tumors, however, mutations in RAS cause it to become "stuck" in the on position. This constitutively active RAS leads to aberrant downstream signaling and malignant transformation of the cell. Together, the three RAS isoforms constitute the most frequently mutated oncogene in human cancers. Notably, RAS mutations are especially prevalent in some of the most intractable malignancies, e.g. pancreatic, lung, and colon cancers. Yet, after nearly four decades of research, no targeted therapy for mutant RAS tumors has been discovered. In large part, this is a result of RAS being "undruggable": it is notoriously difficult to directly inhibit with a drug-lie small molecule. The obstinance of RAS means that it's signaling must be dissected with uncompromising depth to identify alternate strategies for targeting these tumors. Despite extensive study, it is still unclear how such a simple on/off switch can govern so many cellular responses of such complexity, or why in some circumstances, activated RAS causes a cell to proliferate, but in others, it causes the cell to senesce. To address these long-standing questions in RAS and cancer biology, we have engineered a chemically-induced activator of RAS (CIAR). With this construct, we are able to activate RAS signaling with a small molecule in a rapid and dose-dependent fashion. This control will permit previously inaccessible studies of the effects of the magnitude and duration of RAS signaling on the phosphoproteome, transcriptome, and malignant phenotype. Furthermore, by localizing CIAR to different subcellular compartments, we will address how spatiotemporal compartmentalization of RAS signaling and effects signaling and trancriptional networks as well as phenotype. The information gleaned from these studies may then guide the identification of novel strategies for targeting tumors bearing RAS mutations.