PLAGL2与结肠癌侵袭能力的相关性研究

Pleomorphic adenoma gene like-2 enhances the invasive ability of cancer cells in human colon adenocarcinoma

目的探讨多形性腺瘤基因样因子2(PLAGL2)在结肠癌和癌旁组织中的表达水平以及与结肠癌临床病理因素之间的关系,研究PLAGL2对结肠癌细胞侵袭能力的影响及其机制。方法通过免疫组化检测40例新鲜结肠癌组织及40例癌旁组织中PLAGL2的表达情况,根据术前影像检查结果及术后组织病理结果判断病人分期情况,分析PLAGL2与临床病理因素之间的关系。构建重组质粒pc DNA3.1-PLAGL2,利用转染试剂脂质体2000对SW480细胞进行转染PLAGL2质粒及对照组空载体质粒,分SW480、Vector、PLAGL2三组进行细胞培养,通过Transwell侵袭实验比较三组细胞侵袭能力的差异,并通Western-blot方法检测三组细胞中E-cadherin、vimentin及MMP-7的表达情况。结果 PLAGL2在Ⅲ~Ⅳ期、Ⅰ~Ⅱ期结肠癌组织与癌旁组织中的免疫组化评分(IS值)分别为8.12±2.997、5.71±2.494、2.17±0.984,差异有统计学意义(F=64.225,P<0.01)。卡方检验结果提示PLAGL2表达增高的病例临床分期较晚(χ2=5.700,P=0.017)、肿瘤较大(χ2=8.174,P=0.008)以及更易发生远隔脏器转移(χ2=13.610,P<0.001);Transwell侵袭实验比较细胞侵袭个数,PLAGL2组明显高于SW480和Vector两组,差异有统计学意义(F=27.997,P<0.01);Western-blot方法检测PLAGL2组细胞中E-cadherin表达明显降低(F=38.461,P<0.01)、vimentin(F=28.741,P<0.01)及MMP-7表达升高(F=24.520,P<0.01),差异有统计学意义。结论 PLAGL2的表达上调与结肠癌的发生、发展密切相关,并且能够促进结肠癌细胞的侵袭能力,可能机制与诱发上皮间质化(EMT)形成有关。

Objective To investigate the expression of PLAGL2 in colon cancer tissues and adjacent normal tissues and its relationship with the clinicopathological factors of colon cancer,to study the function of PLAGL2 on invasive process of colon cancer cells and its mechanism.Methods The expressions of PLAGL2 were detected in 40 fresh colon cancer tissues and control normal tissues by immunohistochemistry.According to the results of preoperative imaging examinations and postoperative pathological staging of patients,the relationship between the expression of PLAGL2 and the clinicopathological factors was analyzed.After construction of the recombinant plasmid pcDNA3.1-PLAGL2,SW480 cells were transfected with the plasmid pcDNA3.1-PLAGL2 and empty vector using Lipofectamine?2000.Three groups of cell line including SW480,Vector and PLAGL2 were cultured and compared the difference of invasive ability by Transwell assay.Finally,Western-blot detected the expression of E-cadherin,vimentin and MMP-7 among cell line of the three groups.Results The immunoreactivity scores of PLAGL2 in stageⅢ-Ⅳ,stageⅠ-Ⅱand adjacent normal tissues were 8.12±2.997、5.71±2.494、2.17±0.984 respectively,indicating a statistically significant difference(F=64.225,P<0.01).Chi square test showed that the patients with PLAGL2-over expression had more advanced stages(χ2=5.700,P=0.017)、bigger sizes(χ2=8.174,P=0.008)and easier to happen metastasis(χ2=13.610,P<0.001).The invasion of the cells were significantly promoted in PLAGL2 group than other two groups by Transwell assay(F=27.997,P<0.01).Western-blot method for detection of PLAGL2 cells significantly decreased expression of E-cadherin(F=38.461,P<0.01)and increased the expression of vimentin(F=28.741,P<0.01)and MMP-7(F=24.520,P<0.01),with statistically significant difference compared other two groups.Conclusions The upregulation of PLAGL2,which is closely correlated to the occurrence and development of colon cancer and can promote the invasive ability of colon cancer cells,may be related to the formation of EMT.