Roles of p85, Ras, and elF3i/Trip1 in pI3-kinase oncogenic transformation

描述（由申请人提供）：P13-激酶信号传导途径在许多癌症中上调。PI 3-激酶催化亚基p110 α的热点突变发生在约30%的几种类型的实体瘤中。该提案的目标是了解癌症特异性突变体p110 α诱导的致癌转化的分子机制，并为突变体特异性抑制剂作为抗癌药物的设计提供见解。本申请中提出的实验将广泛使用逆转录病毒构建体来分析由p110 α突变体诱导的致癌转化。p85和Ras已显示调节p110 α的激酶活性。我将通过体外激酶试验和体内细胞转化试验研究致癌p110 α是否失去了p85的抑制性调节。我将使用生化分析、细胞转化试验和RNAi来确定p110 α的致癌性是否依赖于Ras结合并引起Ras的组成性激活。我已经确定了一个新的p110 α结合伴侣，elF 3 i/Trip 1。在这里，我将首先通过敲低elF 3 i/Trip 1来测试elF 3 i/Trip 1在PI 3激酶转化中的重要性，然后研究致癌p110 α对elF 3 i介导的翻译起始和TGF β/Trip 1通路介导的转录调控的可能影响。

DESCRIPTION (provided by applicant): The Pl3-kinase signaling pathway is upregulated in numerous cancers. Hot spot mutations in the catalytic subunit of PI3-kinase, p110 alpha, occur in approximately 30% of several types of solid tumors. The goal of this proposal is to understand the molecular mechanism underlying the oncogenic transformation induced by cancer specific mutant p110 alpha and provide insight into the design of mutant specific inhibitors as anti- cancer drugs. The experiments proposed in this application will make extensive use of retroviral constructs to analyze oncogenic transformation induced by p110 alpha mutants. p85 and Ras have been shown to regulate the kinase activity of p110 alpha. I will examine if oncogenic p110 alpha losses the inhibitory regulation by p85 via in vitro kinase assays and in vivo cell transformation assays. I will determine if the oncogenicity of p110 alpha depends on Ras binding and causes constitutive activation of Ras using biochemical analysis, cell transformation assay, and RNAi. I have identified a new p110 alpha-binding partner, elF3i/Trip1. Here, I will first test the importance of elF3i/Trip1 in PI3-kinase transformation by knocking down elF3i/Trip1, and then investigate the possible impact of oncogenic p110 alpha on translation initiation mediated by elF3i and transcriptional regulation mediated by TGF beta/Tripl pathways.