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目的研究miR-33b与高迁移率族蛋白A2(HMGA2)在食管鳞状细胞癌(ESCC)中的表达及意义。方法在ESCC组织及癌旁组织中采用茎环结构的逆转录实时定量PCR检测miR-33b的表达情况,实时荧光定量PCR检测HMGA2 mRNA的水平,免疫组织化学SP法检测HMGA2蛋白表达;将miR-33b模拟物、miR-33b抑制物、对照转染入TE-1细胞和Eca-109细胞;采用茎环结构的逆转录实时定量PCR法检测各组miR-33b的水平;实时荧光定量PCR、Western blot法分别检测各组HMGA2mRNA和蛋白的水平。结果在40例ESCC组织中,miR-33 b mRNA的表达量显著低于癌旁正常组织;HMGA2 mRNA的表达量显著高于癌旁正常组织;HMGA2蛋白在ESCC组织中的阳性率显著高于癌旁组织;HMGA2蛋白阳性表达组的miR-33b的表达量低于HMGA2阴性组;相关性分析显示miR-33b和HMGA2的mRNA在ESCC组织中的表达呈负相关。在转染miR-33b模拟物、miR-33b抑制物转染的食管癌细胞中,转染各组间HMGA2 mRNA水平无显著差异;在miR-33b过表达的细胞中HMGA2蛋白水平明显降低。结论 ESCC组织中miR-33b表达下调,HMGA2表达上调;增加食管癌细胞中miR-33b的表达能抑制HMGA2的蛋白表达水平,但HMGA2 mRNA水平不受影响,提示miR-33 b可能在转录后水平调控HMGA2蛋白的表达。
Objective To study the expression and significance of miR-33b and HMGA2 in esophageal squamous cell carcinoma (ESCC). Methods The expression of miR-33b was detected by RT-PCR in ESCC tissues and adjacent tissues. The level of HMGA2 mRNA was detected by real-time fluorescence quantitative PCR and the expression of HMGA2 protein by immunohistochemical SP method. The expression of miR- 33b mimics and miR-33b inhibitors were transfected into TE-1 cells and Eca-109 cells. The levels of miR-33b in each group were detected by RT-PCR with stem-loop structure. Real-time PCR and Western blot were used to detect HMGA2 mRNA and protein levels in each group. Results The expression of miR-33b mRNA in 40 ESCC tissues was significantly lower than that in adjacent normal tissues. The expression of HMGA2 mRNA in ESCC tissues was significantly higher than that in adjacent normal tissues. The positive rate of HMGA2 protein in ESCC tissues was significantly higher than that in cancer tissues The expression of miR-33b in HMGA2-positive group was lower than that in HMGA2-negative group. Correlation analysis showed that the expression of miR-33b and HMGA2 in ESCC was negatively correlated. In the esophageal cancer cells transfected with miR-33b mimics and miR-33b inhibitors, there was no significant difference in the level of HMGA2 mRNA between transfected groups; HMGA2 protein level was significantly decreased in miR-33b overexpressing cells. Conclusion The expression of miR-33b is down-regulated and the expression of HMGA2 is up-regulated in ESCC tissues. Increasing the expression of miR-33b in esophageal cancer cells can inhibit the expression of HMGA2 mRNA but the level of HMGA2 mRNA is not affected, suggesting miR-33b may be posttranscriptional level Regulates HMGA2 protein expression.