Parkin基因甲基化在鼻咽癌发生发展中的作用

Methylation of Parkin gene promoter in nasopharyngeal carcinoma

目的探讨Parkin基因甲基化在鼻咽癌发生发展中的作用。方法应用甲基化特异性PCR技术对5个鼻咽癌细胞株(CNE1、CNE2、TW03、HONE1、C666)和1个正常鼻咽上皮细胞株(NP69)、54例鼻咽癌组织和16例正常鼻咽上皮组织的Parkin基因启动子区甲基化状态进行检测,并分析鼻咽癌组织中Parkin基因甲基化与临床特征的关系;应用RT-PCR检测加入甲基转移酶抑制剂(5-氮-2-脱氧胞苷)后CNE1、CNE2中Parkin基因转录表达,分析去甲基化对Parkin基因转录表达的影响。结果1个正常鼻咽上皮细胞株和16例正常鼻咽上皮组织中均未检测到Parkin基因甲基化;5个鼻咽癌细胞株和54例鼻咽癌组织中Parkin基因甲基化频率分别为60.00%和62.96%;54例鼻咽癌患者中Parkin基因甲基化状态与临床因素均无关(均P>0.05)。经过5-氮-2-脱氧胞苷处理后,Parkin基因在CNE1、CNE2中转录表达增加,分别从0提高至3.65和2.15。结论鼻咽癌中Parkin基因甲基化与转录表达密切相关,是基因表达调节的一种重要方式;可能成为鼻咽癌早期分子生物学辅助诊断的标志物和去甲基化基因治疗的靶点。

Objective To investigate the methylation of Parkin gene promoter in nasopharyngeal carcinoma （NPC）.Methods The methylation-specific PCR （MSP） was used to detect methylation status of Parkin gene promoter in 54 specimens of NPC tissues and 16 specimens of normal nasopharyngeal epithelia （NNE） tissues,as well as in 5 NPC cell lines （CNE1,CNE2,TW03,HONE1,C666） and 1 normal nasopharyngeal epithelia cell line （NP69）.The expressionof Parkin mRNA in NPC cell lines CNE1 and CNE2 were analyzed before and after treatment with the methyltransferase inhibitor 5-aza-2-deoxycytidine.In addition,alterations of mRNA expression of Parkin gene were detected by semi-quantitative reverse transcription PCR （RT-PCR）.The relationship between promoter methylation and clinicalfeatures,demethylation and expression of Parkin mRNA was analyzed.Results Methylation of Parkin promoter was detected in 60.00％（3/5） NPC cell lines and 62.96％（34/54） NPC tissue specimens,but not in NNE tissues and NP69 cells.There was no significant association between Parkin promoter methylation andclinical features of NPC （P＞0.05）.After 5-aza-2-deoxycytidine treatment,the expression of Parkin mRNA was increased in CNE1 and CNE2 cells.Conclusion The close correlation between Parkin methylation and low mRNA expression suggests that methylation might be associated with the regulation of gene expression.Parkin gene promoter methylation has high specificity in distinguishing cancers from normal tissues,which indicates methylation of Parkin promoter may provide a novel molecular target for diagnosis and treatment of NPC.