Reg IV在脱氧胆酸促进APC min/+小鼠肠道息肉恶变中的作用和机制研究

It is said that 50% of colorectal cancer arising from adenomatous polyps, whereas the carcinogenesis is dependent of genetic background as well as environmental factors. We have previously confirmed that dysregulation of EGFR and Wnt signaling pathways played a pivotal role in the formation of polyps in an APCmin/+ mice. Additionally, DOC can accelerate the “adenoma-carcinoma” sequence by promoting the cell proliferation and inhibiting the apoptosis. Reg IV, a member of regenerating islet-derived protein, can also act as a trophic factor by the activation of EGFR and Wnt signaling pathways. I have published one paper identifying the expression level of Reg IV was upmost in the intestine in mice, suggesting the critical role of Reg IV in the pathogenesis of colorectal diseases. On the other hand, our preliminary results indicated that DOC treatment could increase the Reg IV mRNA expression of intestinal polys in APCmin/+ mice, but the underlying mechanism remains to be elucidated. So we aimed to investigate the possible role of Reg IV in the carcinogenesis of intestinal polyp promoted by DOC in APCmin/+ mice, including the effect on cell proliferation and apoptosis as well as signaling pathways. The accomplishment will assist in early prevention of colorectal cancer by targeting Reg IV.

50%以上的大肠癌源于腺瘤性息肉，其恶性转变是遗传背景和环境因素共同作用的结果。本课题组前期应用APC min/+小鼠验证了EGFR和Wnt信号通路失调在FAP的息肉形成中起着重要作用，而脱氧胆酸（DOC）刺激可以加速“腺瘤-癌”这一恶性转变过程。本申请人已发表的成果证实Reg IV在小鼠大肠特异性的高表达，提示在这些部位的病变中可能扮演了重要角色，而我们预实验的结果发现DOC刺激使APC min/+小鼠肠道息肉组织Reg IV表达水平升高，而Reg IV属于胰腺再生蛋白，新近报道其通过调控EGFR和Wnt信号通路可以促进细胞增殖和拮抗凋亡，但对肠道息肉恶变的作用和机制仍不明确。因此本研究将首次探讨Reg IV在DOC促进APC min/+小鼠息肉恶变中的作用，其对IMCE细胞增殖和凋亡能力及EGFR和Wnt信号通路的影响，旨在为以Reg IV为靶点的大肠癌早期防治奠定实验基础。

50%以上的大肠癌来源于大肠腺瘤性息肉，在遗传因素和环境因素的相互作用下，最终经历“腺瘤-癌”序列的恶性转变。本研究体内实验部分以APCmin/+小鼠为研究对象，发现DOC可以促进肠道息肉发生恶变，表现为腺瘤数目增多，病理类型上表现为更加显著的高级别瘤变和黏膜内癌，Ki-67/PCNA和TUNEL染色提示这一作用是通过促进增殖和拮抗凋亡实现的，进一步的WB提示DOC刺激可以使Reg IV在mRNA和蛋白表达水平升高，且cyclin D1、BCL-2/BCL-XL表达水平升高。体外研究发现，Reg IV促进IMCE细胞系合成和分泌Reg IV蛋白，WST-1和Annexin V-FITC实验结果说明其增殖和抗凋亡能力增强，而MAPK/AKT信号通途的激活与这些作用相关。本研究初步探讨了Reg IV在DOC促进肠道息肉恶变的分子生物学机制，为今后大肠癌的防治提供了可能的靶点。...