CDCA3调控DAB2IP泛素化促进胃癌发生、发展的机制研究

Gastric cancer(GC) is one of the most common malignant tumors worldwide.The pathogenesis of GC is still unclear.Our previous study revealed that CDCA3 was upregulated in GC tissues compared to adjacent non-cancerous tissues, the proliferation of GC cells was enhanced when CDCA3 was upregulated and CDCA3 overexpression promoted the cell cycle transition from G0/G1 phase to S phase. Bioinformatics analysis suggest CDCA3 influenced ERK-MAPK signal pathway through DAB2IP,involved in the tumorigenesis and development of gastric cancer.This study include the following aspects:1.Verify the differential expression of CDCA3 in GC tissues and adjacent non-cancerous tissues；analyze the correlation between CDCA3 expression with clinical parameters or prognosis of patients.2.Determine the role of CDCA3 in the tumorigenesis and development of gastric cancer in vitro and in vivo by CDCA3 overexpression and interference. 3.Determine the regulation to ERK-MAPK pathway of CDCA3 via interaction with DAB2IP.4.Identify differential proteins when CDCA3 was differentially expressed；analysis the pathways related by bioinformatics and clarify the function and mechanism of CDCA3 in the tumorigenesis and development of gastric cancer.5.Identify the mechanisms of the abnormal expression of CDCA3 through genetic and epigenetic analysis.

胃癌是世界上发病率最高的恶性肿瘤之一，其发病机理不明。我们在前期研究中发现CDCA3在胃癌组织中是高表达的，过表达CDCA3能使胃癌细胞由G0/G1期向S期转变，增强胃癌细胞的生长和增殖能力。生物信息学分析提示CDCA3可能通过DAB2IP调控ERK-MAPK信号通路，参与胃癌的发生和发展。本研究的内容包括以下几方面：1.验证CDCA3在胃癌及癌旁组织的表达差异，分析CDCA3与患者临床病例资料及预后之间的关系2.借助过表达质粒及RNA干扰的方法，在细胞及动物水平探讨CDCA3在胃癌发生及发展中的作用3.探讨CDCA3与DAB2IP的相互作用及对ERK-MAPK信号通路的调控作用4.利用蛋白质组学筛查CDCA3表达变化后胃癌细胞蛋白表达谱的变化，生物信息学分析其参与的生物学过程及信号通路5.通过CDCA3启动子区的遗传学及表观遗传学分析，探讨CDCA3上调的分子机制。

胃癌是世界上发病率最高的恶性肿瘤之一，其发病机理不明。我们研究中发现CDCA3在胃癌组织及胃癌细胞系中是高表达的，CDCA3表达情况与胃癌肿瘤大小、分化程度、淋巴转移情况、TNM分期显著相关，且与患者总生存期相关。在后续的功能实验中，我们发现过表达CDCA3能使胃癌细胞由G0/G1期向S期转变，增强胃癌细胞的生长和增殖能力，而下调CDCA3能使细胞阻滞在G0/G1期，减弱胃癌细胞的生长和增殖能力。通过生物信息学分析和western-blotting分析，发现CDCA3是通过促进ERK-MAPK 信号通路相关蛋白磷酸化促进胃癌的发展。我们进一步通过甲基化分析，发现胃癌患者肿瘤组织中CDCA3启动子存在低甲基化，转录因子SP1可以通过与CDCA3启动子区SP1 binding sites 3，5结合，影响CDCA3的转录水平，而在过表达和干扰了SP1 后，胃癌细胞的生物学功能也产生了明显变化。本研究从表观学遗传学研究发现CDCA3的启动子区存在低甲基化状态，而这种低甲基化状态影响了转录因子SP1的结合，导致了CDCA3转录的增加，而高表达的CDCA3会促进ERK-MAPK 信号通路相关蛋白磷酸化，导致胃癌发展。该研究对寻找胃癌的发病机制，设计基因治疗面的药物提供了理论支持。