食管鳞癌与细胞因子信号转导负调控因子3及其DNA甲基化的关系

目的 检测食管鳞癌(ESCC)组织中细胞因子信号转导负调控因子3(SOCS3)的DNA甲基化、mRNA及蛋白表达水平,探讨其在食管鳞癌发生、发展、浸润和转移中的作用.方法 采用甲基化特异性聚合酶链反应(MSP)、Real-Time聚合酶链反应(PCR)和Western blot法分别检测43例食管鳞癌组织中SOCS3的DNA甲基化、mRNA和蛋白表达水平,并与相应的癌旁正常食管组织进行对照研究,分析其与临床病理参数的关系.结果 (1)食管鳞癌组织SOCS3 DNA甲基化的阳性率(79.1%)明显高于癌旁组织(14.0%,P＜0.01);(2)食管鳞癌组织SOCS3 mRNA相对表达强度比值(0.53±0.30)明显低于癌旁组织(1.15±0.44,P＜0.01),食管鳞癌组织中甲基化组的SOCS3 mRNA表达(0.45±0.24)显著低于非甲基化组(0.86±0.29,P＜0.05);(3)食管鳞癌组织SOCS3蛋白表达(1.66±0.22)显著低于癌旁组织(1.83±0.15,P＜0.01),食管鳞癌组织中甲基化组SOCS3蛋白表达(1.61±0.21)显著低于非甲基化组(1.87±0.15,P＜0.01);(4)在TNM分期中Ⅲ期组表达均低于Ⅰ～Ⅱ期组(P＜0.05),伴有淋巴结转移组表达也都低于无淋巴结转移组(P＜0.05),未发现其在性别、年龄、家族史、吸烟史中有明显差异(P＞0.05);(5)食管鳞癌组织中SOCS3mRNA表达及其蛋白表达水平与肿瘤分化级别呈正相关(0.301＜r＜1,P＜0.05),与TNM分期、淋巴结转移呈负相关(-1＜r＜-0.301,P＜0.05).结论 食管鳞癌组织中SOCS3 DNA甲基化阳性率高,导致SOCS3基因表达下调,与食管鳞癌的分化、浸润和转移密切相关.

Relationship between SOCS3 and SOCS3 DNA methylation with esophageal squamous cell carcinoma

Objective By testing the expression of suppressor of cytokine signaling 3 (SOCS3) in esophageal squamous cell carcinoma (ESCC) tissue at DNA methylation, mRNA and protein levels, to study the function of SOCS3 in the occurrence, development, invasion and metastasis of ESCC. Methods By using adjacent normal esophageal tissues as controls, the expression of SOCS3 DNA methylation,SOCS3 mRNA and SOCS3 protein in 43 cases of ESCC was detected by methylation specific polymerease chain reaction (MSP) , real-time polymerase chain reaction (PCR) and Western blotting, and subsequently analyzed to find out the correlation with clinicopathological parameters. Results ( 1 ) The positive rate of SOCS3 DNA methylation in ESCC (79. 1% ) was significantly higher than normal tissue ( 14. 0%,P ＜0. 01 ); (2) Remarkably lower relative expression intensity of SOCS3 mRNA was found in ESCC tissue (0. 53 ±0. 30) than in normal esophageal tissue (1.15 ±0. 44, P ＜0. 01 ). In ESCC, the SOCS3 mRNA expression was notably lower in methylation group (0. 45 t 0. 24) than in non-methylation group (0. 86 ± 0. 29, P ＜ 0. 05 ); (3) SOCS3 protein expression in ESCC ( 1.66 ± 0. 22 ) was also evidently lower than adjacent normal tissue (1.83 ±0. 15, P ＜0. 01 ). In ESCC, the SOCS3 expression was notably lower in methylation group ( 1.61 ±0. 21 ) than non-methylation group ( 1.87 ±0. 15, P ＜ 0. 01 ); (4) TNM assay revealed that the expression was lower in stage Ⅲ than both stage Ⅰ and stage Ⅱ ( P ＜ 0. 05), and the expression in the group with lymph node metastasis was lower than that in the group without lymph node metastasis (P ＜ 0. 05 ). No obvious connection was found with the gender, age, family history and smoking history of patients (P ＞ 0. 05); (5) Expression of both SOCS3 mRNA and SOCS3 protein in ESCC was positively correlated with differentiation degree (0. 301 ＜r ＜ 1 ,P ＜0. 05), while it had a negative correlation with TNM staging and lymph node metastasis ( - 1 ＜ r ＜ - 0. 301, P ＜ O. 05 ). Conclusion The decrease of SOCS3 gene expression in ESCC is caused by the high positive rate of SOCS3 DNA methylation,which is closely connected with the differentiation, invasion and metastasis of ESCC.