肝癌干细胞分化、转移的生物力学干预及其相关分子机制

Cancer stem cell (CSC) is a cell within malignant tumor that possesses the capacity to self-renew and differentiate to lead to the heterogeneous lineages of cancer cells that comprise the tumor, and is the root to cause metastasis, recurrence and bad prognosis of the cancer. Targeting CSC is a novel therapeutic strategy for management and treatment of the cancer. In this proposal, using a self-developed flow-migration chamber system, we will set up a metastasis model of liver CSC through blood circulation, and study the effects of shear stress on differentiation, adhesion to endothelial cells and transendothelial migration of liver CSC. Moreover, we will also explore the roles of polymorphonuclear neutrophil (PMN) and adhesive molecules, such as VLA-4/VCAM-1, beta2 integrins (LFA-1, Mac-1)/ICAM-1, in the process of metastasis of liver CSC. The aim of this investigation is to disclose the characteristics of mechanobiological behaviors of liver CSC differentiation and metastasis and its involved molecular mechanisms under hemodynamic force. The results from this study will not only highlight the importance in understanding influencing factors and its rules during differentiation and metastasis of liver CSC from the view of biomechanics, but also contribute to elucidation of molecular basis in regulating liver CSC differentiation and metastasis by shear stress. These findings in the identification and characterization of liver CSC differentiation and metastasis under shear stress will provide a new ideal for researching liver carcinogenesis and progression, and will lend and offer experimental foundation and great promise for developing better therapeutic strategies for targeting liver CSC against this disease in clinic.

癌干细胞是形成不同分化程度癌细胞和癌症复发、转移及预后不良的根源，在癌症转移、复发中起决定作用，其靶向干预是癌症治疗的全新策略。本项目应用生物力学、细胞生物学及分子生物学等方法，以肝癌干细胞为研究对象，利用自行研制的流动迁移腔系统建立肝癌干细胞血道转移模型，研究剪切应力作用下肝癌干细胞分化、与血管内皮细胞粘附和跨内皮迁移行为的变化特征及相关规律，并对白细胞及粘附分子VLA-4/VCAM-1、beta2 integrins（LFA-1、Mac-1）/ICAM-1在肝癌干细胞转移中的作用进行定量描述，力图揭示血流作用下肝癌干细胞分化、转移的力生物学行为特征及其相关分子机理。项目研究结果不仅对从生物力学角度认识肝癌干细胞分化、转移的影响因素及其规律有重要意义，而且有助于阐明肝癌干细胞分化、转移的分子调控机理，为肝癌发生发展机制研究开辟全新思路，为临床上癌干细胞靶向干预的肝癌治疗策略提供实验依据。

癌干细胞是形成不同分化程度癌细胞和癌症复发、转移及预后不良的根源，在癌症转移、复发中起决定作用，其靶向干预是癌症治疗的全新策略。本项目应用生物力学、细胞生物学及分子生物学等方法，以肝癌干细胞和肝癌细胞为研究对象，利用自行研制的流动迁移腔系统建立肝癌干细胞血道转移模型，研究了血流剪切应力作用下肝癌干细胞（LCSCs）分化、转移行为的变化特征及相关规律，考察了内皮细胞微环境对肝癌细胞癌干细胞表型和LCSCs迁移行为的影响，分析了肝癌细胞与干细胞交互对话对细胞力生物学行为的影响及分子机理，探索了盐霉素作用下LCSCs运动能力、分化行为的改变特征。结果发现：通过体外肿瘤球培养方法可以从高转移性肝癌细胞MHCC97H中筛选、富集LCSCs，LCSCs生物力学特质与其高转移潜能密切相关。低剪切应力（2 dyn/cm2）加载LCSCs 6h后，可通过FAK-ERK1/2-β-catenin信号途径诱导细胞骨架F-actin重排，降低细胞硬度，增加LCSCs的迁移能力。但长时间（2天）的剪切应力加载可诱导LCSCs发生分化，癌干细胞特征减弱，在体致瘤能力明显下降。内皮细胞微环境能够促进MHCC97H细胞的癌干细胞表型，通过改变细胞骨架组装调节LCSCs的力学特性，促进LCSCs的迁移能力。盐霉素作用LCSCs 24小时后可通过FAK-ERK1/2信号通路促进细胞F-actin表达，增加细胞硬度，减少MMP-2、MMP-9的分泌，从而抑制LCSCs的迁移和侵袭能力。盐霉素作用LCSCs 2天后，通过Wnt/β-catenin信号通路诱导肝癌干细胞的分化，降低其体内致瘤能力。肝癌细胞微环境通过ERK1/2信号促进骨髓间充质干细胞（MSCs）的增殖，并通过SDF-1/CXCR4-ERK1/2信号途径促进MSCs的迁移能力。募集到肝癌组织中的MSCs参与肝癌微环境的重塑，可能促进肝癌细胞的生长和转移。本项目研究结果揭示了血流动力作用下肝癌干细胞分化、转移的力生物学行为特征及其相关分子机理，该研究结果不仅对从生物力学角度认识肝癌干细胞分化、转移的力、化学影响因素及其规律有重要意义，而且有助于阐明肝癌干细胞分化、转移的分子调控机理，为肝癌发生发展机制研究开辟了新思路，为临床上癌干细胞靶向干预的肝癌治疗策略提供了实验依据。