项目名称： E3连接酶MDM2泛素化调节Akt在乳腺癌进展及赫赛汀耐药中的作用及机制研究

项目编号： No.81502296

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 医药、卫生

项目作者： 熊晶

作者单位： 华中科技大学

项目金额： 18万元

中文摘要： 癌蛋白MDM2和Akt在多数乳腺癌中均有过度表达，与患者预后较差及治疗抵抗关系密切。我们首次发现MDM2可与Akt蛋白结合，在小鼠胚胎成纤维细胞中促进EGF诱导的Akt泛素化及磷酸化活化。MDM2作为重要的E3连接酶，可能参与了Akt的泛素化调控，但其机制及在乳腺癌进展和赫赛汀耐药中的作用不明。本项目将通过Co-IP、GST-Pull Down、体内和体外泛素化实验、激光共聚焦等实验探索MDM2作为Akt泛素化E3连接酶的可能性，阐明该泛素化诱导Akt膜转位、磷酸化活化、促进pAkt核内移位、协助完成后续信号传递的分子机制，并借助与EGF及其受体关系密切的乳腺癌模型，探讨MDM2介导Akt泛素化是否参与乳腺癌的进展及赫赛汀耐药，最终形成以抑制MDM2泛素连接酶活性为基础的药物联用，提高单纯以Akt为靶点的靶向治疗效果的思路，为控制乳腺癌进展及增强赫赛汀治疗敏感性提供理论基础及实验依据。

中文关键词： 乳腺肿瘤；MDM2；Akt；泛素化；赫赛汀耐药

英文摘要： MDM2 and Akt oncoproteins are overexpressed in the majority of breast cancers, and their overexpressions are closely related to poor prognosis and therapy resistance. We observed a direct physical interaction between endogenous MDM2 and Akt, which promotes epidermal growth factor (EGF)-induced Akt ubiquitination and phosphorylation/activation in mouse embryonic fibroblasts. As an important E3 ubiquitin ligase, MDM2 may be engaged in Akt ubiquitination, but the exact mechanisms and the possible roles in breast cancer progression and resistance to Herceptin treatment remain unclear. Through Co-immunoprecipitation (Co-IP) assay, Glutathione-S-transferase (GST)-Pull Down assay, in vivo and in vitro ubiquitination assays, and confocal immunofluorescence, this grant will study the specific mechanisms by which MDM2 regulates Akt ubiquitination, membrane recruitment, phosphorylation/activation, and nuclear trafficking of the activated form of Akt. Further, in breast cancer models which are highly correlated with the EGFR signaling, we will explore whether MDM2-mediated Akt ubiquitination is involved in breast cancer progression and Herceptin resistance. Our results will provide proof-of-principle that MDM2 targeting is a compelling therapeutic strategy as a combinatory therapy for breast cancer treatment.

英文关键词： breast cancer;MDM2;Akt;ubiquitination;Herceptin resistance