miRNA203在Barrett食管和食管癌中的表达及相关性研究

Expression and correlation of miRNA203 in Barrett's esophagus and esophageal carcinoma

目的研究miRNA203(miR203)在Barrett食管癌变中的表达及其可能的甲基化机制,探讨其启动子区甲基化状态与Barrett食管癌变的关系。方法用荧光定量PCR法检测经去甲基化处理前及处理后的Barrett食管、食管癌和正常食管粘膜细胞中miR203的表达水平,并检测Barrett食管、食管癌及病变邻近正常组织中miR203的表达水平;运用甲基化特异性PCR(MSP)检测miR203启动子甲基化水平,免疫组化检测Barrett食管、食管癌以及相邻正常食管组织中K-RAS蛋白的表达情况。结果 Barrett食管与食管癌细胞miR203表达水平相比,正常食管粘膜细胞显著减低(P=0.003);经过去甲基化处理后,上述样本中miR203表达水平显著升高(P=0.043),食管癌细胞miR203表达水平较Barrett食管细胞升高的幅度更大(P=0.03),Barrett食管(P=0.001)和食管癌(P=0.000)组织miR203表达水平明显低于相邻正常组织。MSP结果表明,食管癌细胞和Barrett食管细胞miR203启动子经过去甲基化处理后表现为低甲基化或非甲基化表达,食管癌和Barrett食管组织miR203启动子甲基化程度高于相邻病变旁正常组织。免疫组化显示,K-RAS蛋白在食管癌和Barrett食管组织中较相邻正常食管组织高,且食管癌组织较Barrett食管组织表达更高。结论 miR203表达水平在正常食管、Barrett食管和食管癌细胞中表达呈逐渐降低趋势,提示miR203启动子高甲基化是导致miR203表达下调的原因之一,且参与Barrett食管的癌变过程,miR203表达水平及其启动子甲基化程度可能成为监测和预防Barrett食管癌变的重要分子生物学指标。

Objective To explore the relationship between MiR203 promoter methylation and Barrett esophagus cancerous. Methods RT-PCR detected the expression level of miRNA-203 in Barrett esophagus, esophageal cancer and normal esophageal mucosa cells, before and after demethylation processing. MiR203 promoter methylation level was measured by MSP. Immunohistochemistry was used to test the expression and distribution of K-Ras, a target of miR203 in esophageal cancer, BE and normal esophagus tissues. Results MiR203 expressions levels were reduced obviously in Barrett esophagus and esophageal cancer cells than normal esophageal cells （P= 0. 003）. After demethylation treatment, miR203 expressions are significantly increased in Barrett＇s esophagus and esophageal cancer ceils, the differences are sta- tistically significant （P=0.03）. MSP showed miR203 promoter changes to he low-methylation or non-methylation. Con- clusion MiR203 in Barrett＇s esophagus and esophageal cancer cells reduced expression is related to its Promoter methyla- tion, miR203 promoter methylation throughout the carcinogenesis of Barretfs esophagus, it may become a key molecular biomarker in process of Barrett esophagus cancerous, and may become the prevention and treatment targets of Barrett e- sophagus cancerous.