分化/DNA结合抑制因子-1在肌层浸润性膀胱癌发生和进展中的作用及机制研究

The molecular mechanism of tumorigenesis and progression in muscle invasive bladder caner is still unclear. It has been shown that inhibitor of differention/DNA binding-1(Id-1) is a potential oncogene which is related with tumor progression and drug resistance. Our preliminary study has shown that activation of Id-1 can lead to the induction of epithelial to mesenchymal transition（EMT）, which contributes to tumor progression, including invasion and metastasis. Moreover, up-regulation of Id-1 in bladder cancer cells leads to increased cell viability in response to epirubicin by its improved anti-apoptotic role, and down-regulation of Id-1 increases cellular sensitivity to epirubicin by increased anticancer drug-induced apoptosis. In this project, we will make use of pathological tissue samples and follow-up data to investigate the correlation between Id-1 and the progression or prognosis for muscle invasive bladder cancer patients. We will also screen the possible interactive molecules and signaling pathways by the bladder cancer cell line models with Id-1 up-regulation or down-regulation. In addition, the bladder tumor in situ bioluminescent mouse model will be used to study the effects of Id-1 on the initiation and progression in muscle invasive bladder cancer, and to verify the interactive molecules and signaling pathways in vivo. Finally, we will also use the mouse model to investigate the influence of Id-1 on chemosensitivity. We expect the results of this study can elucidate the role and molecular mechanism of Id-1 in tumorigenesis and progression of muscle invasive bladder cancer, and provide a novel candidate molecular marker and therapeutic target for prognosis and treatment.

目前，肌层浸润性膀胱癌发生和进展的分子生物学机制还没有明确。研究证明，分化/DNA结合抑制因子-1（inhibitor of differentiation/DNA binding-1，Id-1）作为一种致癌基因与多种恶性肿瘤的进展和耐药相关。我们的前期体外实验证明，Id-1表达与膀胱癌上皮向间质转化有关，提示其与膀胱癌进展的相关性；而且Id-1上调能够降低膀胱癌细胞系对药物化疗的敏感性。本研究将进一步利用膀胱癌患者组织标本及随访资料，研究Id-1与肌层浸润性膀胱癌的进展及预后的相关性；通过利用Id-1上调和下调的膀胱癌细胞模型，筛选Id-1在膀胱癌进展过程中可能的相互作用分子及信号通路；还将通过膀胱癌原位生物发光小鼠模型，体内实验证实Id-1表达对肌层浸润性膀胱癌发生和进展的影响和分子机制，以及对药物化疗敏感性的影响。可望通过本研究阐明Id-1在肌层浸润性膀胱癌发生和进展中的作用和机制。

目前，肌层浸润性膀胱癌发生和进展的分子生物学机制还没有明确。研究证明，分化/DNA结合抑制因子-1（inhibitor of differentiation/DNA binding-1，Id-1）作为一种致癌基因与多种恶性肿瘤的进展和耐药相关。我们的前期体外实验证明，Id-1表达与膀胱癌上皮向间质转化有关，提示其与膀胱癌进展的相关性；而且Id-1上调能够降低膀胱癌细胞系对药物化疗的敏感性。本研究中通过对膀胱癌组织中Id1表达的检测，与膀胱癌组织的肿瘤分级进行相关性分析，结果显示肿瘤分级越高，Id1表达的阳性率越高。我们构建了Id1稳定上调和下调的膀胱癌细胞株，用瞬时转染方法构建了Id-1的剪接变异体之一Id1 b下调的膀胱癌细胞株，建立了小鼠原位膀胱癌模型；通过对Id-1上调和下调的膀胱癌细胞株的生物学特性检测，我们证实Id1分子促进膀胱癌细胞增殖和迁移，Id1功能的发挥可能是通过上调基质金属蛋白酶MMP3和MMP9实现， Id1 b不参与细胞的EMT过程及细胞侵袭，这与文献报道的Id1 a的功能是完全不同的；通过免疫共沉淀方法分离出膀胱癌细胞株中Id1的相互作用分子MYH9、WAVE2，三者可能为一个蛋白复合体中的不同成分，相互作用，发挥功能；经过检测RT4、5637、T24、BIU87和EJ等5株膀胱癌细胞株Id1 b与干细胞标记物的表达情况，发现 Id1 b的表达与干细胞标记物的表达具有相关性。本研究对膀胱癌发生机制中Id1作用的阐明提供了更多线索。