5-Aza-dC和TSA对胃癌细胞系p16和hMLH-1基因甲基化水平及表达的影响  

Effects of 5-Aza-2'-deoxycitydine and trichostatin A on expression and methylation of p16 and hMLH-1 gene in human gastric cancer cell lines

作　　者：朱新江[1] 孟春风[1] 彭过[1] 戴冬秋[1] 

机构地区：[1]中国医科大学附属第一医院肿瘤外科,普通外科教研室,胃肠肿瘤外科,辽宁省沈阳市110001

出　　处：《世界华人消化杂志》2008年第17期1837-1841,共5页World Chinese Journal of Digestology

基　　金：国家自然科学基金资助项目;No.30572162;No.30271477;教育部高校博士点基金资助项目;No.20050159001~~

摘　　要：目的:探讨5-Aza-dC及TSA对胃癌细胞系中抑癌基因p16和hMLH-1基因甲基化水平和基因表达的影响.方法:5-Aza-dC及TSA处理体外培养的MKN-45细胞和MGC-803细胞,应用逆转录PCR(RT-PCR)法及甲基化特异性PCR(MSP)法分别检测两株细胞药物干预前后抑癌基因p16和hMLH-1的表达及甲基化情况.结果:MKN-45和MGC-803细胞系经TSA,5-Aza-dC及联合作用后使原来不表达或有弱表达的抑癌基因p16和hMLH-1重新表达或表达增强.胃癌细胞系MKN-45和MGC-803均显示p16、hMLH-1基因启动子区存在高甲基化,其中p16基因在两种胃癌细胞系中均表现为甲基化,hMLH-1基因在胃癌细胞系MGC-803中表现为甲基化而在胃癌细胞系MKN-45中表现为半甲基化.在5-Aza-dC及TSA的作用下,MKN-45和MGC-803细胞系中p16及hMLH-1基因的甲基化状态得到逆转.结论:胃癌细胞系中抑癌基因p16和hMLH-1基因启动子甲基化可能是导致其基因失活的主要原因,5-Aza-dC单独作用和5-Aza-dC及TSA联合应用效果相似,均能显著增强甲基化的肿瘤抑制基因的重新表达.To investigate effects of 5-Aza-2＇-deoxy- citydine （5-Aza-dC） and trichostatin A （TSA） on the expression and methylation of p16 and hMLH-1 gene in gastric carcinoma cells. METHODS： Human gastric cancer cell lines MKN45 and MGC-803 were cultured in vitro in RPMI 1640 and then treated with different con- centrations of 5-Aza-dC and TSA. The methylation of p16 and of hMLH-1 gene in the two kind of cell lines was detected using methylation-specific-polymerase chain reaction （MSP）, and the expression levels of p16 and hMLH-1 gene were detected using reverse transcription-polymerase chain reaction （RT-PCR）. RESULTS： Reexpression or raised expressions of p16 and hMLH-1 mRNA was detected in MGC-803 and MKN-45 gastric cancer cell lines after treatment with 5-Aza-dC alone, or in combination with TSA, or with TSA alone. The two cell lines showed a characteristic DNA methylation status in each promoter region of p16 gene and hMLH-1 gene. p16 gene was hypermethylated in MGC-803 and MKN-45; hMLH-1 gene was hypermethylated in MGC-803, but hemi- methylated in MKN-45. The methylation of p16 and hMLH-1 gene in MKN-45 and MGC-803 cells was reversed after either 5-Aza-dC treatment or TSA treatment. CONCLUSION： Aberrant methylation of p16 and hMLHol gene is a common event in the occurrence and progression of gastric cancer. The methylation of promoter region in CPG island is a main cause for p16 and hMLH-1 gene transcriptional inactivation. Siginificantly raised reexpression of methylated tumor suppressor genes was detected after either treatment with 5-Aza-dC alone or in combination with TSA.

关 键 词：胃癌 DNA甲基化 5-氮杂-2'-脱氧胞苷 TrichostatinA P16基因 hMLH-1基因 

分 类 号：R735.2[医药卫生—肿瘤] R734.2[医药卫生—临床医学]