肿瘤细胞上皮间质转化EMT过程中细胞力学特性和行为研究

Invasion and metastasis are main causes of cancer fatality. Epithelial-mesenchymal transition (EMT) can make a transition from the tumor epithelial cells to mesenchymal-like cells which possess the capacity to invade and migrate. Cancer cell microenvironment is dynamically evolving during cancer progression, such as the stiffening of the matrix. However, how play the roles of cancer cell mechanics characteristic and cell migration behavior still remain largely unknown when EMT happened, and the molecular mechanism is not clear. However, current researches are mostly based on traditional two-dimensional (2D) cancer models, which do not recapitulate the 3D cancer microenvironment in vivo. Thus it is important to develop convenient technologies capable of rapidly engineering 3D models for cancer EMT study. To solve these problems, with advanced micro/nano manufacturing technology, we propose a kind of method to construct 3D tumor cells EMT model and compare with 2D models. Then, based on the 2D, 3D cancer cell model in vitro , we will quantitatively measure the cell stiffness (Young’s modulus) of a single cancer cell using advanced magnetic tweezers technology. Further, we measure and analysis the cell mechanics characteristic such as cellular morphology, cell volume, cell structure (cytoskeleton) etc., and cell behavior (the capacity of cell migration) in the EMT process. Thereinto, the method of character the capacity of cell migration using advanced optical tweezers technology in 3D model. Base on the study of protein and molecular of key factor, we use the method of immunofluorescent staining, western blot, and RT-PCR and so on. Finally, to establish the theory of relationship between EMT and cell mechanics characteristic and the behavior. The aim is for looking for new targets by blocking EMT in intervention of tumor metastasis. The project features with the help of biomechanics of quantitative research thoughts, measurement method and 3D model, the tumor cell mechanical properties during the process of EMT and the change of behavior; Using tissue, cell, protein, molecular research methods, different levels of technology such as revealed in the process of EMT cell mechanics properties and behavior change rule and the molecular mechanism, so as to find intervention and reverse tumor metastasis potential new targets, is expected to provide new strategies for the prevention and treatment of tumor diseases.

针对肿瘤细胞浸润转移过程中，EMT发生对于细胞力学特性和行为影响规律不清，分子机制不明这一科学问题，针对三维肿瘤细胞EMT模型中细胞的力学检测、表征这一技术难题，本研究拟体外构建不同EMT状态的二、三维肿瘤细胞模型，通过先进的光镊、磁镊等技术对其细胞力学特性、以及迁移行为进行测量和表征，揭示EMT过程中细胞力学特性和迁移行为的作用规律，并阐明其影响机制，建立细胞力学特性和行为与EMT之间的理论关联，为将来通过阻断EMT干预肿瘤转移新靶点的寻找提供理论依据和实验参考。本项目特色在于借助生物力学的定量研究的思想、测量手段以及三维组织模型，研究肿瘤EMT过程中细胞力学特性和行为的变化；采用组织、细胞、蛋白、分子等不同层次的技术研究方法，揭示EMT过程中细胞力学特性和行为变化规律和分子机制，从而发现干预和逆转肿瘤浸润转移的潜在新靶点，有望为肿瘤疾病的预防和治疗提供新策略。

肿瘤转移是一个复杂、动态、连续的多步骤生物学过程，也是导致癌症病人死亡的一个非常重要的原因。上皮-间充质转化（EMT）是指上皮细胞通过特定程序转化为具有间质表型细胞的生物学过程，在癌症转移的过程中发挥了重要的作用。恶性肿瘤细胞往往通过EMT来获得迁移和侵袭能力。但是，目前对于肿瘤细胞浸润转移过程中的EMT细胞力学特性、分子机制和行为影响规律尚不清楚。因此，针对肿瘤的EMT过程以及细胞力学特性、三维肿瘤模型构建及肿瘤微环境影响等一系列问题，我们开展了以下研究，并取得了一定的研究成果：1）成功构建了二维、三维EMT肿瘤模型，研究了模型内细胞形态、结构特性和运动行为；2）揭示了肿瘤细胞迁移过程中，在力的驱动下形成的“隧道网络”。解释了细胞间通信和下游ECM重构在隧道网络形成中的作用。阐述了机械信号传导和ECM重构作为乳腺癌治疗靶点的可能性；3）通过分子动力学模拟研究了斑片状纳米颗粒（NPs）与人血清白蛋白（HSA）之间的吸附机制，提高纳米颗粒靶向性和转运效率；4）研究了纳米颗粒在肿瘤微环境中扩散与细胞外基质的关联性，初步了解了肿瘤ECM物理特性对纳米粒子扩散的影响；5）开展了干细胞对难愈伤口修复机制及肿瘤治疗的研究等。我们力求通过本课题的研究，能为阐明肿瘤发生的EMT机制以及细胞力学特性提供理论支撑，为纳米药物靶向肿瘤治疗方案提供临床参考，为肿瘤疾病的预防和治疗提供新策略。