中文摘要：

目的：探讨微小RNA-6803（mi R-6803）及其宿主基因蛋白磷酸酶6调节亚单位1（protein phosphatase 6 regulation subunit 1,PPP6R1）在食管鳞状细胞癌（ESCC）中的表达和PPP6R1基因启动子区甲基化状态及其在ESCC发生及发展中的作用。方法：采用2013年至2014年间河北医科大学第四医院生物标本库的72例ESCC手术患者癌组织及对应的癌旁组织标本,用实时荧光定量PCR法检测mi R-6803和PPP6R1在ESCC组织及其癌旁组织和DNA甲基化转移酶抑制剂5-氮杂-2’-脱氧胞苷（5-Aza-d C）处理前后的ESCC细胞株TE1、TE13、Eca109、T.TN、Kyse170中的表达水平。用甲基化特异性PCR（MSP）法检测ESCC细胞系和组织及其癌旁组织中PPP6R1的甲基化状态,分析其与患者临床病理特征的关系。结果：ESCC组织中mi R-6803和PPP6R1的表达水平显著低于癌旁组织（0.318±0.156,0.408±0.177 vs 1.000±0.001,均P〈0.05）,mi R-6803表达水平与淋巴结转移、组织分化程度及TNM分期密切相关（均P〈0.05）;PPP6R1表达水平与TNM分期和组织学分化程度密切相关（均P〈0.05）。ESCC组织中mi R-6803和PPP6R1基因的表达具有显著相关性（P〈0.05）。ESCC组织中PPP6R1的启动子区甲基化率显著高于癌旁组织（56.94%vs 36.11%,P〈0.05）,并与TNM分期和组织学分化程度密切相关（均P〈0.05）,mi R-6803和PPP6R1基因的低表达与PPP6R1启动子区甲基化明显相关（P〈0.05）。经5-Aza-d C处理后,5种ESCC细胞中mi R-6803和PPP6R1的表达均升高,并且TE1、TE13、Kyse170细胞中PPP6R1基因甲基化程度降低,非甲基化程度增加,其余2种细胞中PPP6R1基因均表现为非甲基化状态。结论：mi R-6803及其宿主基因PPP6R1的低表达可能与ESCC的发生发展密切相关,其启动子区甲基化可能是mi R-6803和PPP6R1表达沉默的机制之一。

英文摘要：

Objective：To investigate the expression of micro RNA-6803（mi R-6803） and its host gene PPP6R1 in esophageal squamous cell carcinoma（ESCC） and the role of promoter methylation status of PPP6R1 in the tumorigenisis and progression of ESCC.Methods：ESCC tissues and corresponding para-cancerous tissues from 72 cases of ESCC patients stored in the bio-specimen base of the Fourth Hospital Affiliated to Heibei Medical University during 2013 and 2014 were collected for this study.Real-time fluorescence quantitative PCR（q PCR） was used to detect the expression of mi R-6803/PPP6R1 in collected tissues and in ESCC cell lines（TE1,TE13,Eca109,T.TN,Kyse170） treated or untreated with DNA methyl-transferase inhibitor 5-aza-2＇-detoxycytidine（5-Aza-d C）.Methylation specific PCR（MSP） method was used to detect the methylation status of PPP6R1 in esophageal cancer cell lines and collected tissues,respectively.Results：The relative expressions of mi R-6803 and PPP6R1 in ESCC tissues were significantly reduced compared to correspondingtissues（0.318±0.156,0.408±0.177 vs 1.000±0.001,all P〈0.05）,and expression of mi R-6803 was associated with lymph node metastasis,TNM stage and pathological differentiation（all P〈0.05）;The expression of PPP6R1 was associated with TNM stage and pathological differentiation（all P〈0.05）.There was a significant correlation between the relative expression of mi R-6803 and PPP6R1 in ESCC tissues（P〈0.05）.The promoter methylation frequency of PPP6R1 in ESCC tissues was significantly higher than that in corresponding normal tissues（56.94% vs 36.11%,P〈0.05）,and was also associated with TNM stage and pathological differentiation（all P〈0.05）.The low expression of mi R-6803/PPP6R1 was significantly correlated with promoter methylation of PPP6R1 in ESCC tissues（P〈0.05）.The relative expression level of mi R-6803 and PPP6R1 in5 ESCC cell lines was enhanced after the treatment with 5-Aza-d C.After treatment with 5-Aza-d C,the methylation level of PP