Kindlin-2通过改变肿瘤微环境促进膀胱癌细胞上皮—间质转化的机制研究

Epithelial-mesenchymal transition (EMT) represents an important mechanism in bladder cancer migration and invasion. Many steps of this process are affected by host contributions from the tumor microenvironment. Studying the tumor microenvironment as well as EMT of bladder cancer and identifying the molecules involved in these processes might provide new insight into bladder cancer treatment. Our preliminary study showed that cancer-associated fibroblasts (CAFs) in bladder cancer matrix tissues expressed increased levels of Kindlin-2 compared with normal fibroblasts, which was significantly associated with poor prognosis. In vitro, highly expressed Kindlin-2 in the CAFs can significantly promote migration and invasion of bladder cancer cells, and induce the loss of epithelial molecule E-cadherin as well as upregulation of mesenehymal marker N-cadherin. Thus, we speculated that Kindlin-2 may be a critical molecule that stimulates bladder cancer cell EMT in tumor microenvironment. The present study aims to clarify the role of Kindlin-2 in regulating CAFs to modify the tumor microenvironment and promote bladder cancer cell EMT, and investigate the molecular mechanisms underlying this process. In addition, the functions of Kindlin-2 in stimulating invasion and metastasis of bladder cancer cells were examined. Our results could provide a new strategy of targeting the bladder cancer microenvironment for anti-tumor treatments.

上皮—间质转化（EMT）是膀胱癌侵袭转移的重要机制，此过程的诸多环节受肿瘤微环境的影响。研究膀胱癌微环境和EMT的机制，寻找并阻断关键的介导分子可能为膀胱癌治疗提供新的思路。我们前期研究发现，膀胱癌基质组织中肿瘤相关成纤维细胞（CAFs）表达Kindlin-2高于正常成纤维细胞，并与肿瘤恶性程度显著相关；膀胱癌微环境中CAFs高表达Kindlin-2可显著提高膀胱癌细胞的侵袭迁移能力，并上调间质标志N-cadherin，下调上皮标志E-cadherin。推测Kindlin-2是膀胱癌微环境中促进肿瘤细胞EMT的关键分子。本课题拟用体内外实验来明确Kindlin-2调控CAFs改变肿瘤微环境促进膀胱癌细胞EMT的作用，探讨Kindlin-2调控EMT相关信号通路的分子机制。本研究旨在阐明Kindlin-2在膀胱癌微环境促进肿瘤侵袭转移中的作用，期望为靶向膀胱癌微环境的抗肿瘤治疗提供新的策略。

上皮—间质转化（EMT）是膀胱癌侵袭转移的重要机制，此过程的诸多环节受肿瘤微环境的影响。研究膀胱癌微环境和EMT的机制，寻找并阻断关键的介导分子可能为膀胱癌治疗提供新的思路，我们研究了膀胱癌基质中Kindlin-2在膀胱癌侵袭转移中的作用，并进一步明确了其调控的相关基因（PNO1及Med19）在膀胱癌发生发展中的作用，具体研究结果如下：.1）膀胱癌基质组织中肿瘤相关成纤维细胞（CAFs）中Kindlin-2表达高于正常成纤维细胞，并且与肿瘤的分级、分期及复发相关；高表达Kindlin-2的患者生存期更短(p< 0.01)。多因素分析显示膀胱癌基质组织高表达Kindlin-2是膀胱癌患者预后不佳的独立预测因子。.2）CAFs表达的Kindlin-2被抑制后，CAFs中α-SMA及细胞外基质蛋白表达明显下调，说明了Kindlin-2对CAFs的活化起促进作用。CAFs表达Kindlin-2可以通过外分泌TGF-β来促进膀胱癌细胞上皮-间质转化，进而影响膀胱癌细胞的侵袭及转移。.3）实验证实，PNO1基因能促进膀胱癌的生长及进展，抑制膀胱癌细胞的凋亡，促进癌细胞的侵袭及转移。机制研究发现PNO1是通过调控mTOR, p70 S6 kinase, p38 和 Caspase-3信号通路来影响膀胱癌细胞增殖、凋亡及迁移。.4）研究显示膀胱癌中Med19的表达与临床分期及病理分级密切相关。膀胱癌T24, UM-UC3和5637细胞中Med19表达下调后能明显抑制膀胱癌细胞的生长及迁移，其调控的Wnt/β-catenin信号通路及靶基因Cyclin-D1 和MMP-9的表达改变是其重要的作用机制。.本研究旨在阐明Kindlin-2在膀胱癌微环境促进肿瘤侵袭转移中的作用，期望为靶向膀胱癌微环境的抗肿瘤治疗提供新的策略。