Genetic and genomic analysis of Ras signaling in colorectal cancer progression

描述（由申请人提供）：我的主要目标是了解K-RAS的突变激活如何在结直肠癌恶性进展的早期诱导高度异型增生。我的工作假设是，突变的K-RAS信号通过B-RAF激酶抑制良性结肠肿瘤细胞的分化。拟议的研究包括旨在获得已知RAS效应通路的机制洞察的有针对性的研究和旨在确定K-RAS信号传导的新型效应子的探索性研究。我提出三个具体目标： 目标1.分析激活K-ras、H-ras或N-ras对肠上皮细胞的表型影响。 目标二。确定候选效应通路与K-ras诱导的肿瘤进展的相关性。 目标3：识别突变激活的K-ras的新型信号效应子。 我的研究将利用体外和体内实验系统，即人类结直肠癌细胞系和基因工程小鼠。在这些互补系统中进行的平行研究将产生对K-RAS信号传导的致癌特性的最大程度的了解。为了成功完成特定目标，我将使用小分子抑制剂，全基因组磷酸蛋白质组学分析和新兴的shRNA技术来剖析致癌K-RAS促进肿瘤进展所需的信号通路。最后，我相信RAS信号通路的治疗靶向将成为对抗结直肠癌恶性进展的有力手段。 与公共卫生的相关性：2005年1月，美国癌症协会宣布，癌症已取代心脏病成为美国的头号死因。在这个国家，仅结直肠癌每年就造成5万多人死亡。尽管我们已经了解了结直肠癌的分子发病机制，但在过去的二十年里，这种疾病的死亡率一直保持不变。通过我对K-RAS癌基因的功能研究，我的目标是确定根除结肠癌的新疗法的分子靶点。

DESCRIPTION (provided by applicant): My primary goal is to understand how mutational activation of K-RAS induces high grade dysplasia early during the malignant progression of colorectal cancer. My working hypothesis is that mutant K-RAS signals through the B-RAF kinase to suppress the differentiation of benign colonic tumor cells. The proposed studies include targeted investigations aimed at gaining mechanistic insight into known RAS effector pathways and exploratory studies aimed at identifying novel effectors of K-RAS signaling. I propose three specific aims: Aim 1. Analyze the phenotypic effects on the intestinal epithelium of activating K-ras, H-ras, or N-ras. Aim 2. Determine the relevance of candidate effector pathways to K-ras-induced tumor progression. Aim 3. Identify novel signaling effectors of mutationally activated K-ras. My studies will utilize both in vitro and in vivo experimental systems, namely human colorectal cancer cell lines and genetically engineered mice. Parallel studies conducted in these complementary systems will yield the greatest amount of insight into the oncogenic properties of K-RAS signaling. To successfully complete the Specific Aims, I will use small molecule inhibitors, genome-wide phosphoproteomic analysis, and emerging shRNA technology to dissect the signaling pathways that are required for oncogenic K-RAS to promote tumor progression. In the end, I am confident that therapeutic targeting of the RAS signaling pathway will represent a powerful means of fighting the malignant progression of colorectal cancer. Relevance to public health: In January, 2005 the American Cancer Society announced that cancer has replaced heart disease as the number one cause of death in the United States. Colorectal cancer alone accounts for more than 50,000 deaths per year in this country. Despite all that we have learned about the molecular pathogenesis of colorectal cancer, mortality due to this disease has remained constant over the past twenty years. Through my functional studies of the K-RAS oncogene, I aim to identify molecular targets for novel therapeutics that will eradicate colon cancer.