TRPV4离子通道促进食管鳞癌的分子机制研究

In term of the morbidity and mortality, esophageal squamous cell carcinoma (ESCC) is ranked among the tops of all malignant tumors in China. Therefore, it is of great significance to clarify the mechanism to regulate its development，but the molecular mechanisms have not been fully elucidated. The role of disruption in intracellular Ca2+ homeostasis in the development of cancer has been a hot topic, but the underlying mechanisms are not entirely clear. Particularly, there have been no reports so far on the role of the Ca2+ permeable channel TRPV4 in the development of ESCC and the relevant mechanism. In the previous studies, we found that TRPV4 ion channels were highly expressed in ESCC cancer tissues and cells, which could significantly promote the proliferation and migration of cancer cells. Activation of TRPV4 induced Ca2+ influx to increase the intracellular Ca2+ concentration and promoted phosphorylation of AKT. Therefore, we hypothesize that the high expression of TRPV4 can promote the proliferation and migration of ESCC through intracellular Ca2+ signaling. In order to verify the hypothesis, we will use cellular and molecular approaches and physiological techniques to observe the effect of TRPV4 activation/inhibition and overexpression/silence on calcium concentrations. We will also study the role of TRPV4 in the regulation of proliferation and migration of ESCC cancer cells and reveal its signaling pathway at the levels of molecule, cell, tissue and whole animal. This study will elucidate a new molecular mechanism of TRPV4/Ca2+ for the development of ESCC and might provide novel biomarkers or potential targets to prevent/treat ESCC.

食管鳞癌（ESCC）的病死率居我国恶性肿瘤前列，因此阐明其发病机制意义重大。细胞内Ca2+信号/通道的紊乱在肿瘤中的作用是国外肿瘤界研究的热点之一，但TRPV4/Ca2+在ESCC中的作用及其机制迄今尚未阐明。我们发现TRPV4离子通道蛋白在ESCC癌组织及癌细胞内异常高表达，并显著促进癌细胞的增殖和迁移。激活TRPV4能增强胞外Ca2+内流，从而升高胞浆内Ca2+浓度，引起AKT的磷酸化。因此，TRPV4的高表达通过增强胞内Ca2+信号促进ESCC癌细胞的增殖和迁移，这可能是ESCC发生发展的新机制。为证实该假说，我们拟结合分子生物学和生理学技术并应用TRPV4活化/抑制和过表达/沉默，来研究ESCC癌细胞内Ca2+及其下游信号通路对细胞增殖和迁移的影响及机制。本课题将从新视角阐明TRPV4/Ca2+促ESCC发生发展的分子机制，以期为ESCC的防治提供新颖的生物标志物或新药研发靶点。

本研究旨在揭示TRPV4/Ca2+在ESCC癌细胞增殖迁移中的作用及相关信号转导通路，最后明确TRPV4作为一种新的促癌因子在ESCC发生发展过程中的重要作用。阐明TRPV4的促癌分子机制为今后的应用提供理论依据。非电压门控的TRPV4作为调控细胞内Ca2+平衡重要的信号分子，在神经系统和心脑血管系统等可兴奋性细胞上的研究较多，但是至今在消化道上皮细胞等非可兴奋性细胞上相对研究较少，而TRPV4在ESCC中的作用以及相关的分子机制迄今未见国内外报道。. 本项目以TRPV4在ESCC患者癌组织及其癌旁正常组织中的表达差异及与ESCC患者临床病理参数预后间的关系作为出发点，从TRPV4在ESCC癌细胞增殖迁移过程中发挥的重要作用以及TRPV4/Ca2+激活促进ESCC癌细胞增殖迁移的分子机制两个方向进行研究，揭示TRPV4作为一个新的促癌基因能够在体内外促进ESCC癌细胞增殖迁移；同时使用先进非标记定量蛋白组学方法对TRPV4特异性激动剂GSK101676A刺激后的ESCC癌细胞进行生物蛋白质谱分析，研究TRPV4/Ca2+对ESCC癌细胞内蛋白质的表达调控，找到调控AKT/β-catenin信号通路激活的关键蛋白PP2A-Aβ，更深入研究TRPV4/Ca2+信号通路激活促进ESCC癌细胞增殖迁移的分子机制。. 最终研究证明：激活TRPV4离子通道能够升高细胞浆内游离Ca2+浓度，促进细胞内ROS的积累，影响细胞内氧化还原环境，进而抑制PP2A-Aβ的功能和表达，通过调控细胞中的MAPK/Wnt/PI3-AKT信号通路来促进ESCC癌细胞的增殖迁移，进而在ESCC发生发展中发挥着重要作用。这一研究结果全新阐明TRPV4的促癌分子机制，在国内外尚属首次报道。. 相信通过本项目，将为TRPV4在消化道肿瘤中作用的研究提供新思路，进而为ESCC新颖生物标志物或新药靶点的研发提供新的理论依据。