PAR_2与小鼠结肠肿瘤局部进展的相关性分析

Involvement of PAR_2 in the development of colitis-associated carcinogenesis in mouse

目的拟研究蛋白酶活化受体2(protease-activated receptor 2,PAR_2)信号通路是否参与结肠肿瘤的进展。方法利用氧化偶氮甲烷(azoxymethane,AOM)和葡聚糖硫酸钠(dextran sodium sulfate,DSS)成功建立小鼠结肠炎相关结肠癌模型,取小鼠不同阶段的结肠组织提取总RNA,逆转录为cDNA后采用实时荧光定量聚合酶链反应检测PAR_2、miR-125b及Grb2协同结合蛋白2(Grb2associated binding protein 2,Gab2)的表达水平。结果 AOM联合3个周期的DSS后,小鼠结肠可见多发的腺瘤和不典型增生;而AOM联合4个周期的DSS后,小鼠结肠腺瘤突破基底层侵入黏膜下层形成腺癌。在肿瘤进展过程中,PAR_2 mRNA的表达水平显著升高,而miR-125b的表达水平则明显降低。Gab2 mRNA在腺癌中的表达水平显著高于其在腺瘤中的表达水平(P=0.0267)。结论 PAR_2信号通路与结肠肿瘤的局部浸润密切相关。PAR_2可能通过miR-125b及其靶基因Gab2促进结肠腺瘤的局部侵袭和浸润。

Objective To explore the role ofprotease-activated receptor 2 （PARz） and miR-125b in colitis- associated colorectal carcinogenesis. Method We established colitis-associated colorectal cancer model using azoxymethane （AOM） and dextran sulfate sodium （DSS）. Colonic tissue were collected at different time during colitis-associated carcinogenesis. The mRNA expression of PAR2, miR-125b and Grb2 associated binding protein 2 （Gab2） were detected by real-time fluorescence quantitative PCR after reverse transcription. Result Neoplasia broke through the base membrane and invaded into the submucosa layer after 4 cycles of DSS, while it limited in mucosa layer after 3 cycles of DSS. Compared with adenoma, PAR2 expression was significantly higher and miR-125b expression was inhibited in adenocarcinoma. Moreover, the expression of miR-125b target gene Gab2 was significantly up-regulated in adenocarcinoma than adenoma. Conclusion The PAR2 signaling closely associates with the development of colitis-associated carcinogenesis in vivo. PAR2 might promote the invasion of cancer through miR-125b and Gab2.