RGC-32通过参与缺氧和TGF-β通路之间的串话诱导胰腺癌上皮间质转化的机制研究

Although its mechanism is not clear yet, epithelial-mesenchymal transition (EMT) is considered to be an important pathological process that promotes tumor infiltration and metastasis. Response gene to complement-32 (RGC-32) is a recently discovered gene that is differentially expressed in response to complement activation. RGC-32 has been found to be expressed abnormally in different kinds of human tumors. However, the role of RGC-32 in pancreatic cancer has not been reported until now. Our preliminary experiments confirmed for the first time that RGC-32 was highly expressed in pancreatic cancer tissues and was correlated with invasion and metastasis of pancreatic cancer.Meanwhile, we revealed that both transforming growth factor-β (TGF-β) and hypoxia could independently induce EMT in pancreatic cancer cells with RGC-32 expression elevated. Further researches demonstrated that RGC-32 mediates TGF-β-induced EMT in pancreatic cell line BxPC-3， but the mechanism in detail was not clear. In this study, by means of gene transfection, RNA interference and cDNA microarray in vitro, we try to clarify whether RGC-32 regulates EMT of pancreatic cancer by being involved in the crosstalk between hypoxia and TGF-β signal pathways and to further investigate the upstream pathways of RGC-32 and the downstream molecules regulating EMT. Finally, we will verify the effect of RGC-32 in EMT, invasion and metastasis of pancreatic cancer in vivo. The research is expected to improve the regulation mechanism of EMT in pancreatic cancer, and to provide new insights into the exploration of new molecular targets for gene therapy clinically.

上皮间质转化(EMT)是促进肿瘤浸润和转移的重要病理过程，目前其机制尚未阐明。RGC-32是一种新发现的补体激活基因，在多种肿瘤中异常表达，但其在胰腺癌中的达标和作用尚无报道。我们的预实验首次证实，RGC-32在胰腺癌组织中高表达，并与胰腺癌的侵袭和转移有关；TGF-β和缺氧刺激均可独立诱导胰腺癌细胞发生EMT，且均伴有RGC-32表达水平升高；我们还发现，在胰腺癌BxPC-3细胞中，RGC-32介导TGF-β诱导的EMT过程，但其具体机制不详。本研究拟通过基因转染、RNA干扰及基因芯片技术，分析RGC-32是否通过参与缺氧和TGF-β信号通路之间的串话调控胰腺癌的EMT过程，阐明RGC-32上游通路及其下游调控EMT的关键分子；最后从整体水平证实RGC-32在胰腺癌EMT和侵袭转移中的作用。本研究有望进一步完善胰腺癌EMT的调控机制，为临床探索胰腺癌基因治疗的分子靶点提供新的思路。

胰腺癌是一种恶性程度高、易早期转移、预后极差的消化道肿瘤，其早期诊断十分困难，诊断胰腺癌的患者五年生存率不到5%。深入研究胰腺癌的浸润和转移机制，对于控制其进展，延长患者的生存期具有重要的意义。目前研究认为，上皮间质转化（EMT）是促进胰腺癌浸润和转移的重要病理过程，但目前其机制尚未阐明。RGC-32是一种新发现的补体激活基因，在多种肿瘤中异常表达，但其在胰腺癌中的表达和作用尚无报道。我们的预实验首次证实，RGC-32在胰腺癌组织中高表达，并与胰腺癌的侵袭和转移有关；TGF-β和缺氧刺激均可独立诱导胰腺癌细胞发生EMT，且均伴有RGC-32表达水平升高；我们还发现，在胰腺癌BxPC-3细胞中，RGC-32介导TGF-β诱导的EMT过程，但其具体机制不详。本研究通过基因转染、RNA干扰实验，证实RGC-32同时参与TGF-β及缺氧两条信号通路，并参与两者之间的串话。RGC-32至少可通过Erk-MAPK和p38-MAPK两条通路介导TGF-β诱导的EMT过程。同时，RGC-32作为HIF-1α下游分子参与缺氧信号通路。Snail和Zeb1是RGC-32下游促进胰腺癌EMT的效应分子。重组腺病毒转染动物实验证实过表达RGC-32可促进胰腺癌生长，并促进胰腺癌发生EMT转化。本研究有望进一步完善胰腺癌EMT的调控机制，有望发现胰腺癌新的潜在致癌因子，为临床探索胰腺癌基因治疗的分子靶点提供新的思路。