SYK基因启动子甲基化对肝细胞癌侵袭力的影响

Effect of the methylation of SYK gene promoter in hepatocellular carcinoma cell lines on invasion

目的探讨肝癌细胞中SYK基因启动子甲基化的状态及其对肝细胞癌侵袭力的影响。方法分别用逆转录-聚合酶链反应(RT-PCR)方法和甲基化特异性聚合酶链反应(MSP)检测SYK基因在肝(癌)细胞系L02、HepG2、MHCC97H、MHCC97L中的表达和甲基化状态;对SYK基因甲基化阳性的MHCC97H和HepG2细胞株利用TRANSWELL小室检测去甲基化药物5-氮杂-2'-脱氧胞苷(5-Aza-CdR)处理前后肝癌细胞穿膜的细胞数,作为评价肝癌细胞体外浸润能力的指标。结果 L02、MHCC97L表达SYK mRNA,MHCC97H、HepG2不表达SYK mRNA;L02、MHCC97L细胞SYK基因甲基化阴性,MHCC97H、HepG2细胞SYK基因甲基化阳性。甲基化阳性的MHCC97H、HepG2细胞经5-Aza-CdR处理后,SYK基因异常甲基化状态得到逆转,体外浸润能力显著下降(P<0.001)。结论肝癌细胞中SYK基因的表达与启动子甲基化有关,SYK基因可抑制肝癌细胞的体外浸润能力。

【Objectives】To investigate the methylation status of SYK gene promoter in hepatocellular car-cinoma cell lines and their effect on invasion.【Methods】Using RT-PCR and MSP technique,the expression and the methylation status of SYK gene were detected in L02,HepG2,MHCC97H and MHCC97L respective-ly.Cell invasion and motility were evaluated by Transwell chamber assay in MHCC97H and HepG2 before and after a treatment with a DNA methyltransferase（DNMT） inhibitor 5-aza-2′deoxycytidine（5-Aza-CdR）.The number of cells passing through the Transwell membrane was counted as the indicator of cell invasion in vitro.【Results】SYK was expressed in L02 and MHCC97L,and was silenced in MHCC97H and HepG2.SYK was methylated in MHCC97H and HepG2,and unmethylated in L02 and MHCC97L.After the treatment with 5-Aza-CdR,the transcription of SYK was reactivated in MHCC97H and HepG2,and the number of cells passing through the Transwell membrane was significantly decreased（P 0.001）.【Conclusions】The aberrant SYK methylation is responsible for the loss of expression in HCC cells.SYK can inhibit the invasive ability of HCC cells in vitro.