Functional characterization of WAC, a candidate tumor suppressor gene in colorect

描述（由申请人提供）：结直肠癌（CRC）是一种遗传性疾病，其进展是由癌基因和肿瘤抑制基因的突变或表观遗传改变的积累驱动的。尽管取得了重大进展，但仍需要进一步的工作来确定驱动这一过程的异质遗传事件，并了解它们如何在疾病进展中相互合作。基于在小鼠肠道肿瘤的三个正向基因筛选中WAC的功能缺失，我们已经确定了WW结构域含适配器与线圈（WAC）作为结直肠癌的候选肿瘤抑制基因。尽管对WAC的功能知之甚少，但已经证明WAC蛋白在多种生物过程中作为多种蛋白质复合物的接头起作用，包括转录偶联组蛋白修饰和高尔基生物发生。我们假设WAC的破坏有助于人类结直肠癌，基于初步数据显示，在条件永生化的结肠上皮细胞中，WAC的消耗导致体外非锚定生长的增加。此外，在74个人类结直肠癌样本中对WAC基因进行测序，发现WAC的非沉默突变频率为2.7%。在未来的工作中，我们计划明确WAC表达降低导致锚定独立性的机制，并表征癌症相关WAC突变体的功能缺陷和转化能力。最后，我们的目标是描述WAC复合物在锚定不依赖条件下调控的完整转录程序，以描述一种新的肿瘤抑制途径，其破坏可能促进结直肠癌的进展。

DESCRIPTION (provided by applicant): Colorectal Cancer (CRC) is a genetic disease in which progression is driven by the accumulation of mutations or epigenetic alterations in oncogenes and tumor suppressor genes. Despite significant progress, additional work remains to identify the heterogeneous genetic events that drive this process and to understand how they cooperate in disease progression. We have identified WW domain containing adaptor with coiled-coil (WAC) as a candidate tumor suppressor gene in colorectal cancer, based on its loss of function in three forward genetic screens for intestinal tumors in mice. Although little is know about the function of WAC, it has been shown that the WAC protein functions as an adaptor in multiple protein complexes in diverse biological processes, including transcription-coupled histone modification and golgi biogenesis. We hypothesize that disruption of WAC contributes to human colorectal cancer based on preliminary data showing that depletion of WAC in conditionally immortalized colonic epithelial cells leads to increased anchorage-independent growth in vitro. Additionally, sequencing the WAC gene in a set of 74 human colorectal cancer samples identified non- silent mutations in WAC at a frequency of 2.7%. In future work, we propose to define the mechanism by which decreased WAC expression contributes to anchorage-independence, and to characterize the functional deficits and transforming capacity of cancer-associated WAC mutants. Finally, we aim to describe the full transcriptional program regulated by the WAC complex under conditions of anchorage-independence, in order to describe a novel tumor suppressor pathway whose disruption may facilitate progression of colorectal cancer. PUBLIC HEALTH RELEVANCE: Relevance of this research to public health Colorectal cancer is the third-leading cause of cancer-related mortality in the United States and a significant publi health problem. The proposed work will expand our understanding of the genetic mechanisms of colorectal cancer. This understanding will contribute to the development of better pre-clinical models that faithfully recapitulate the human disease. Additionally, discovering and validating new genetic drivers will provide novel targets for drug development to improve treatment options and outcomes in colorectal cancer.