流体剪切力调控肝癌细胞迁移新机制：细胞自噬和上皮-间质转化(EMT)的作用及其相互关系

The autophagy and epithelial-mesenchymal transition (EMT) of tumor cells are regard as significant mechanisms of invasion and metastasis. Our previous study demonstrated that stable laminar flow with 0.14 Pa shear stress induced EMT of hepatoma carcinoma cells, simultaneously up-regulated the mRNA expression of autophagy-related protein (Atg). However, the synergistic effect and interaction between autophagy and EMT contributed to invasion and metastasis of cancer cells remains unclear. Accordingly, we hypothesize that shear stress is an important biomechanical factor, which could induce autophagy and EMT of hepatoma carcinoma cells (HCCs) and then lead to local infiltration and distant metastasis. The coupling effect of autophagy and EMT mediate invasion and metastasis of HCCs. In this project, the multi-disciplinary methods and techniques will be used to build a mechanical loading system to examine the role of shear stress on autophagy and EMT of HCCs. In addition, we will explore regulation mechanism of shear stress inducing autophagy and EMT by studying the expression and distribution alteration of crucial genes and proteins in “Integrin—ILK—GSK-3β—ZEB1—Snail” and “Integrin—Class III PI3K/AKT— mTOR—Snail” signal events. The findings of this project can illustrate the mechanical biology mechanism of invasion and metastasis of HCCs with autophagy and EMT, find potential drug targets, and provide new cues for prevention and cure of hepatoma.

自噬和上皮-间质转化是肿瘤细胞发生侵袭转移的重要机制。我们前期研究表明，流体剪切力不仅能诱导肝癌细胞发生EMT，还能上调自噬相关基因和蛋白的表达。本项目假设：“流体剪切力是诱导肝癌细胞发生自噬和EMT，继而引起其局部浸润和远处转移的重要生物力学因素；自噬和EMT协同调控肝癌细胞的侵袭和转移”。为此，通过构建体外力学加载系统，研究流体剪切力对肝癌细胞自噬和EMT的诱导作用；在此基础上，解析肝癌细胞"Integrin—ILK— GSK-3β—ZEB1—Snail”和"Integrin—Class III PI3K/AKT—mTOR—Snail"两条重要生物信息通路上关键分子的基因和蛋白表达的时序性变化，分析二者的交互作用及对肝癌细胞侵袭和迁移能力的调控机制。本项目的研究结果将从新的视角阐明肝癌细胞通过自噬和EMT发生侵袭转移的力学生物学机制，有助于发现潜在抗癌药物靶标，为肝癌防治提供新线索。

肝细胞肝癌（简称肝癌）是一种严重危害人类健康的恶性疾病，肝癌死亡原因多为侵袭转移。流体剪切力（FSS）在调控肿瘤细胞的侵袭转移中发挥关键作用。细胞自噬和EMT是肿瘤细胞发生侵袭转移的重要机制，阻止自噬或阻断EMT的发生便有可能成为抑制肿瘤细胞侵袭转移的新策略。本项目综合应用了生物力学、细胞生物学、分子生物学等多学科的方法和技术，深入研究了流体剪切力如何诱导肿瘤细胞自噬和EMT，以及细胞发生自噬和EMT对肿瘤细胞侵袭转移能力的影响。在此基础上，进一步探究自噬和EMT之间相互作用关系和协同作用，以及力学因素对肝癌细胞发生自噬和 EMT 的力学生物学机制。本项目的主要研究成果包括：①明确了FSS可诱导肝癌细胞发生EMT和自噬，进而导致其迁移和侵袭能力增强，证实了FSS是诱导肿瘤细胞发生自噬和EMT的重要生物力学因素。②FSS诱导肝癌细胞发生自噬依赖于Integrin—F-actin—PI3K/FAK—Rho GTPases这条信号轴，且Rho GTPases中RhoA在调控自噬中发挥中重要的作用。③自噬和EMT协同作用共同调控肝癌细胞的侵袭和转移，抑制自噬可以抑制由FSS引起的HepG2细胞EMT的发生。④YAP信号可能是FSS调控细胞自噬和EMT的重要信号分子，这将是我们进一步关注的重点。本项目的研究结果从新的视角阐明肝癌细胞通过自噬和EMT发生侵袭转移的力学生物学机制，有助于发现潜在抗癌药物靶标，为肝癌防治提供新线索。