G蛋白信号调控因子6（RGS6）抑制TGF-β诱导EMT的分子机制的研究

Applicant’s previous study revealed that RGS6 can promote acetylation of DNMT1 by Tip60 and acetylation-dependent ubiquitination and degradation by facilitating interaction between Tip60 and DNMT1. Our preliminary work showed that RGS6 significantly reduced migration of NSCLC cells induced by TGF-β, suggesting that RGS6 may inhibit TGF-β-induced EMT. Consistently, RGS6 over-expression inhibited TGF-β-induced activation of EMT signaling and upregulation of DNMT1 protein level. Based upon our preliminary data and results of literature search, we hypothesize the molecular mechanism by which RGS6 inhibits TGF-β-induced EMT as follow: RGS6 promotes ubiquitination and degradation of DNMT1 by facilitating interaction between DNMT1 and Tip60, therefore preventing activation of EMT signaling downstream of TGF-β-induced DNMT1, resulting in inhibition of TGF-β-induced EMT. The proposed study aims in systemically investigating to verify the hypothesized molecular mechanism by which RGS6 inhibits TGF-β-induced EMT in NSCLC cells. The study proposes to introduce RGS6 by transient transfection or making a NSCLC cell line stably expressing RGS6. Moreover, the results from in vitro studies will be tested in animal studies. The proposed study is valuable for us to gain deeper insights into the anti-cancer effect of RGS6 and its cellular and molecular mechanism, through which we can evaluate the feasibility of using RGS6 as a new target for developing anti-cancer drug or therapy.

申请人之前的研究结果揭示了RGS6通过协助Tip60与DNMT1结合促进Tip60介导的DNMT1乙酰化导致DNMT1泛素化降解。我们在前期工作中发现RGS6显著削弱TGF-β诱导的NSCLC细胞迁移，表明RGS6可能抑制TGF-诱导的EMT。与之相符，RGS抑制TGF-β诱导的EMT信号以及DNMT1蛋白水平上调。综合国内外研究结果，我们提出了RGS6抑制TGF-β诱导的EMT的分子机制的假设：RGS6 通过协助Tip60与DNMT1结合而促进DNMT1的泛素化降解，从而阻断DNMT1下游EMT信号的激活来抑制TGF-β诱导的EMT。本项目以NSCLC为系统，通过瞬时转染和建立RGS6稳转细胞株系统地研究验证RGS6抑制TGF-β诱导的EMT的分子机制假设，并在动物体内进行检验。本项目对我们深入了解RGS6的抗癌作用和机制以估量RGS6作为抗癌药物或疗法的新靶点的可行性具有重要的意义。