Rab14基因介导上皮间质转化在膀胱癌侵袭和转移中的分子机制研究

The mechanisms of bladder cancer cell metastasis and invasion mainly leading to death or unfavorable treatment are however not clear at present. Our data in previous study demonstrate that Rab14 protein, compared to normal bladder tissues, is highly expressed in bladder cancer tissues. Additionally, its expression level is positively associated with invasive capacity of cancer cells and expression of Vimentin whereas negatively associated with protein expression of E-cadherin. From this, here we forward hypothesis that abnormal expression of Rab14 may contribute to the metastasis and invasion of bladder tissues via involving in processes of epithelial mesenchymal transition (EMT). In our study, we observe the biological characteristics of bladder cancer cells and EMT process as the changes of Rab14 expression level in bladder cancer cells or nude mice model using gene silencing or overexpression technologies. Then, we explore the underlying mechanism of EMT according to repeat above-mentioned experiments to observe the effects upon stimulation of ectogenous TGF-β and influences on Ras/MAPK signaling pathway as Rab14 different expression level. In order to elucidate the role of Ras/MAPK signaling pathway in EMT process, MAPK viability inhibitor will be added in cell culture. The purpose of this research is to investigate the role and molecular mechanisms of Rab14 protein regulate EMT process to boost cancer cell metastasis and invasion via Ras/MAPK signaling pathway, providing theoretical and experimental basis to looking for new target of gene therapy in bladder cancer.

侵袭和转移是影响膀胱癌患者疗效和死亡的主要原因，其分子调控机制仍不清楚。项目申请人前期研究发现Rab14基因在侵袭和转移性膀胱癌组织中显著高表达，其表达量与膀胱癌细胞的侵袭转移潜能以及癌组织中上皮-间质转化（EMT）相关蛋白Vimentin表达正相关,而与E-cadherin负相关。故我们假设: Rab14可能通过调控EMT作用而促进膀胱癌侵袭和转移，以此调控膀胱癌的病理进程。本项目拟通过基因过表达和沉默等技术在细胞和裸鼠模型中探讨Rab14表达改变对膀胱癌细胞生长和EMT的影响；结合外源性TGF-β刺激实验和MAPK抑制剂作用，从而阐明Rab14作用于潜在Ras/MAPK信号通路以调控膀胱癌细胞侵袭转移过程中的分子机制。为膀胱癌基因治疗靶点和药物开发提供理论基础和实验依据。

膀胱癌是最常见的的恶性肿瘤之一，其死亡率占所有肿瘤死因的5%。其发生发展机制尚不清楚，且缺乏特异性的分子治疗靶点。我们研究发现RAB14在膀胱癌组织及细胞系中呈高表达，其表达水平与有无淋巴结转移(p=0.001)、临床分期(p=0.009)、分化程度(p<0.001)及患者预后(p=0.003)密切相关。干扰RAB14表达后，膀胱癌细胞中EMT关键转录调控因子Twist1表达减少，膀胱癌细胞侵袭及二维迁移能力明显受抑制(p<0.05)。同时，RAB14表达敲减可诱导膀胱癌细胞凋亡及抑制其增殖，体内成瘤能力亦受到明显抑制。RAB14表达敲减后癌细胞中MAPK1/MAPK8表达明显减少，DUSP6/SHC1/FOS蛋白表达明显增加减少。故Rab14是膀胱癌潜在的原癌基因，可能是通过介导MAPK信号通路，调控DUSP6/SHC1/FOS表达，促进了膀胱癌的发生及进展；可为膀胱癌的筛查及诊断提供潜在的生物标志物，为其治疗提供新的分子靶点，为其相关研究提供理论基础及实验依据。