PHB在膀胱癌中Wnt/β-catenin通路激活中的作用、临床意义及分子机制研究

Bladder urothelial carcinoma is one of the most common malignant tumors in the urinary system, but the mechanism of its metastasis is not yet clear. Prohibitin1 (PHB) has been proved to be widely existed in many kinds of tumors, play an important role. Prohibitin1 acts as a membrane-bound chaperone with different genes and plays multiple functions. PHB may play an important role in tumor invasion and metastasis as a specific marker, but the specific mechanism has not been reported. Our preliminary experiments found that the expression of PHB in bladder urothelial carcinoma tissue or cell line is positively correlated with activation of Wnt/ β -catenin pathway, and PHB was binding with β-catenin to stabilize β-catenin structure and inhibit the degradation in bladder urothelial carcinoma , and the overexpress of β-catenin activate Wnt / β-catenin pathway which induced bladder urothelial carcinoma EMT and promoted metastasis. However, the specific mechanism and clinical significance of β-catenin regulated by PHB are not clear. we will use the methods of immunohistochemistry, co-precipitation, site mutation, kinase analysis and analysis a large number of clinical samples of bladder cancer correlation with EMT marks . Furthermore we plan to reveal the mechanism of PHB was binding with β-catenin to inhibit the degradation, and the overexpress of β-catenin activate Wnt / β-catenin pathway which induced bladder urothelial carcinoma epithelial mesenchymal transition(EMT). This project will provide experiment base and new clues to clarify the metastatic mechanisms of bladder cancer.

膀胱癌是泌尿系最常见的恶性肿瘤之一，但其转移机制尚未清楚。Prohibitin1(PHB)在多种肿瘤中通过与不同蛋白分子结合定位于不同的细胞器，从而发挥不同的功能。研究显示PHB可作为某些肿瘤的特异性标记物，在肿瘤的侵袭转移中发挥重要作用，但具体机制未见报道。我们预实验发现：PHB在膀胱癌组织及细胞株中的表达与Wnt/β-catenin通路激活成正相关，PHB通过与β-catenin结合并抑制β-catenin泛素化降解从而激活Wnt/β-catenin通路促进膀胱癌细胞EMT。但PHB调控β-catenin的具体机制及临床意义尚未清楚。本研究拟通过建立体外细胞模型和膀胱移植瘤、转移瘤动物模型，采用免疫组化、免疫共沉淀、位点突变、激酶分析等分子生物学技术明确PHB调控β-catenin泛素化降解激活Wnt/β-catenin通路的分子机制和临床意义。本研究将为揭示膀胱癌转移机制提供新线索。

本课题PHB作为在膀胱癌高表达的支架蛋白，介导诸多调控细胞命运的关键RNA和蛋白相互作用。但目前有关PHB与RNA相互作用机理在 膀胱癌进展中的作用还有诸多盲点。因此，本研究拟借助RIP-SEQ技术进一步解析与PHB蛋白结合的各类RNA，以及各类与PHB结合RNA在膀胱癌进展中的作用及机制。.同时研究期间因目前临床实践中膀胱癌TNM分期不能完全概括膀胱癌的预后，我们研究发现肌层浸润性膀胱癌和正常膀胱组织的膀胱癌免疫浸润分布景观是不同的，我们发现11种浸润性免疫细胞与肌层浸润性膀胱癌生存有关，基于TIICs的模型可以提供很好的预测价值，以补充现有的预测生存的分期系统。.除此因环状RNA(circRNAs)在膀胱癌中的潜在功能和表达谱尚不清楚。我们还研究发现circCA12具有miRNA-1184分子海绵作用，通过竞争性结合miRNA-1184，从而上调RAS家族(NRAS, KRAS, HRAS)的表达影响膀胱癌进展，故cicrCA12/miRNA-1184/RAS家族调节轴被证实为膀胱癌进展的一种可能机制。