TGF-β1/PI3K/AKT通路介导的线粒体功能转换在肺癌细胞EMT中的作用机制研究

Epithelial-mesenchymal transition (EMT) is a retro-differentiation phenomenon, while mitochondria (Mt) are known as a driving force of differentiation. We preciously found that TGF-β1 can cause drastic Mt proteome alterations, leading to increased oxidative phosphorylation and Mt network formation in A549 cells; inhibiting TGF-β1 or PI3K/AKT can reduce the ROS release from Mt, accompanied by declined expression of mesenchymal proteins. We hence posit that TGF-β1/PI3K/AKT axis induced Mt functional alterations represent a driving force of the EMT of lung cancer cells. In this study, we will use our well established cellular model, employing multiple cell lines representing different lung cancer types, to address our hypotheses. We will justify the similarity of proteome and transcriptome changes in these cell lines, while deriving systems biology models with integrative bioinformatics analyses. Finally, molecular and cellular biological approaches will be employed to prove the validity of such a model upon EMT. This study has potentials to discover a new mechanism in terms of Mt centralized EMT bioprocess induced by TGF-β1 r identify potential target pathway and protein, which will be biologically validated by in vitro and in vivo experiment to confirm the molecular mechanism. This study can potentially address the novel mechanism of mitochondrial regulation in TGF-β1-induced lung cancer cell EMT in lung cancer cells.

上皮间质转化（EMT）是细胞逆分化现象，而线粒体（Mt）已知是调控细胞分化的调控中心。我们前期工作表明，TGF-β1介导的肺癌细胞EMT中，Mt蛋白质组发生系统转换，表型上表现为促A549细胞氧化磷酸化和Mt网络化形成；而抑制TGF-β1或PI3K/AKT信号，可减少Mt的ROS信号的释放，并抑制间质标志物蛋白表达。我们进而假设，TGF-β1经PI3K/AKT通路介导的Mt功能转换是调控肺癌细胞EMT的动力机制之一。本项目拟利用已建立的细胞模型，以代表不同肺癌类型的多株细胞为研究对象，验证TGF-β1以及PI3K/AKT通路所扮演的角色，回答TGF-β1在不同肺癌细胞中介导Mt蛋白质组学和转录组改变的异同，以生物信息学解析该生物过程中的分子系统生物学机制，并以分子细胞生物学手段加以验证。本项目研究有望阐明Mt调控TGF-β1介导的肺癌细胞EMT的新机制。

转移是目前包括肺癌在内的癌症致命的主要原因，而上皮间质转化（EMT）是癌症转移前期上皮细胞的逆分化现象，赋予癌细胞干性和迁移侵袭能力。线粒体（Mt）已知是控制细胞分化的调控中心，然而目前对Mt在肺癌细胞EMT过程中的作用仍不清楚。本项目拟利用经典的TGF-β诱导肺癌细胞EMT模型，评价Mt表型的变化及其对EMT的作用，并通过多组学的手段构建其中分子系统网络，预测调控机制，最后结合生物学的方法验证通路和靶点，阐明Mt调控TGF-β介导的肺癌细胞EMT的新机制。本项目成功构建TGF-β1诱导的肺癌细胞EMT模型，并在此模型下发现Mt发生表型和功能改变，其产生的Mt ROS可促进细胞EMT的转化。通过定量蛋白组学，我们鉴定EMT前后Mt蛋白质组的变化，进一步通过转录组学和生物信息学，构建了此过程的分子网络，并预测其中调控的通路和靶蛋白。结合细胞生物学和分子生物等多种手段，我们阐明了TGF-β1通过Smad通路在转录水平上抑制PGC1a的表达，从而抑制Mt基因的表达，改变Mt的功能，促进细胞EMT转化。通过对临床的肺癌病人数据的相关性分析，我们也验证了此调控机制。本项目的研究阐明了Mt在TGF-β1介导的肺癌细胞EMT中的作用机制，为将来肺癌的治疗提供理论依据。