雷公藤内酯醇逆转Jurkat细胞apc基因甲基化及其机制的初步研究  

Effect of Triptolide on Reversing Hypermethylation of Apc Gene in Jurkat Cells and Its Possible Mechanisms

作　　者：吴雪梅 沈建箴[2] 沈松菲[2] 范丽萍[2] 

机构地区：[1]福建省福州儿童医院血液科,福建福州350004 [2]福建医科大学附属协和医院、血液病研究所,福建福州350000

出　　处：《中国实验血液学杂志》2010年第4期866-872,共7页Journal of Experimental Hematology

基　　金：福建省自然基金(编号:CO540014);福建省百千万人才工程基金(编号:303052801);福建医科大学重点科研项目基金(编号:09ZD021)

摘　　要：本研究探讨中药雷公藤内酯醇(triptolide,TPL)对急性T淋巴细胞白血病Jurkat细胞中抑癌基因——apc基因去甲基化作用,并对其机制进行初步探讨。采用生长曲线、MTT法、集落形成实验及流式细胞术DNA含量分析法分别探讨TPL对Jurkat细胞生长、增殖及细胞周期的影响。以巢式甲基特异性PCR检测TPL对Jurkat细胞apc基因甲基化模式的影响,半定量RT-PCR检测TPL作用后Jurkat细胞apc基因、甲基转移酶dnmt3a、dnmt3bmRNA的表达,Western blot检测TPL作用前后APC蛋白的表达水平。结果表明:与对照组相比,不同浓度TPL均能明显抑制Jurkat细胞生长、增殖,并呈时间及剂量依赖性,48小时IC50为19.7ng/ml;未处理组Jurkat细胞基因组DNA的胞嘧啶保持不变,而经TPL作用的Jurkat细胞基因组DNA的胞嘧啶均已变为胸腺嘧啶,这表明Jurkat细胞存在apc基因甲基化;TPL作用后apc基因的高甲基化被逆转,并呈剂量依赖性;未处理组APC蛋白不表达,TPL作用48小时后APC蛋白表达增强,亦呈剂量依赖性。结论:小剂量TPL可明显抑制Jurkat细胞的生长;TPL可通过甲基转移酶和(或)直接作用使apc基因去甲基化,使apc基因表达上调,恢复其活性,从而抑制Jurkat细胞的增殖。This study was aimed to investigate the effect of traditional Chinese medicine, Triptolide （TPL） on reversing hypermethylation of antioncogene （ apc gene） in acute lymphoblastic leukemia cell line Jurkat in vitro and to explore its mechanisms. The effects of TPL on cell growth, proliferation and cell cycle were detected by growth curve, MTT assay, colony formation test and flow cytometry, respectively. The effect of TPL on apc gene methylation of Jurkat cells was analyzed by nested methylation specific PCR; the expressions of apc gene, dnnt3a, dnmt3b mRNA were measured by RT-PCR; the protein expression of apc gene was detected by Western blot. The results showed that as compared with untreated control cells, the TPL of different concentrations could significantly inhibit growth and proliferation of Jurkat cells in dose-and time-dependent manners with IC50 19.7 ng/ml at 48 hours. All cytosines in CpG dinucleotides in untreated Jurkat cells had no changed, while all cytosines in Jurkat cells treated with TPL had been converted to thymidine suggesting the methylation of apc gene in Jurkat cells. The TPL could reverse hypermethylation of apc gene and induced the mRNA and protein expression of apc gene in dose-dependent manner. It is concluded that the small dose of TPL can obviously suppress the proliferation of Jurkat cells, activate and up-regulate the expression of apc gene through demethylation of apc gene resulting from DNMT and/or direct action, thereby inhibit the proliferation rate of Jurkat cells.

关 键 词：雷公藤内酯醇 甲基化 APC JURKAT 

分 类 号：R733.4[医药卫生—肿瘤] R979.1[医药卫生—临床医学]