藤黄酸与草酸铂间的相互作用及机制探讨

The natural interaction between gambogic acid and oxaliplatin and its probably mechanism

目的:探讨藤黄酸(gambogic acid,GA)联合奥沙利铂(Oxaliplatin,Oxa)体外对人低分化胃癌细胞株BGC-823和人高分化胃癌细胞株MKN-28的作用及可能机制。方法:采用MTT法测定GA、Oxa单药及联合作用于指数增殖期BGC-823细胞和MKN-28细胞的效应;应用中效原理进行统计分析,绘制单药及联合用药对肿瘤细胞生长的影响曲线,确定联合用药时的效应(Fa)-合用指数(CI)的关系,判定药物间的相互作用;用流式细胞仪检测GA联合Oxa对肿瘤细胞凋亡的影响;采用RT-qPCR Taqman探针方法检测GA对Oxa疗效相关基因ERCC1、BRCA1 mRNA表达的影响,推断GA与Oxa间相互作用的分子机制。结果:GA联合Oxa作用于指数增殖期BGC-823细胞,当Fa=0.10,CI≈1,两药合用效应相加;当Fa>0.10,CI<1,两药合用产生协同效应,凋亡细胞比例明显增加;当Fa<0.10,两药合用产生拮抗效应;GA联合Oxa作用于指数增殖期MKN-28细胞,当Fa=0.50,CI≈1,两药合用效应相加;当Fa>0.50,CI<1,两药合用产生协同效应;当Fa<0.50,两药合用产生拮抗效应;GA联合Oxa作用于BGC-823细胞产生了较好的协同效应。GA作用后BGC-823细胞的ERCC1及BRCA1 mRNA明显下调。结论:影响药物疗效相关基因的表达,可能是GA与Oxa联合应用产生协同效应的机制之一。

Objective：To assess the natural interaction between gambogic acid and oxaliplatin widely used in gastrointestinal cancer treatment,and to investigate the influence of gambogic acid on cell apoptosis and drug-associated gene expression. Methods：Synergistic interaction on human gastric cancer cell lines BGC-823 and MKN-28 was evaluated using the combination index （CI） method. The double staining with both Annexin-V-FITC and PI was employed to distinguish the apoptotic cells from others. Expression of drugassociated genes,i.e., excision repair cross-complementing（ERCC 1 ）, breast cancer susceptibility gene 1 （BRCA1） of BGC-823 with or without gambogic acid treatment were measured by real-time quantitative RT-PCR. Results：Gambogic acid had a synergistic effect on the cytotoxicity of oxaliplatin in BGC-823 cells. The combination of gambogic acid and oxaliplatin could also induce apoptosis in a synergistic manner. Most prominently,ERCC1,BRCA1 mRNA levels of BGC-823 were markedly suppressed at 0.070-,and O.140-fold respectively by the presentation of gambogic acid. Conclusion：Gambogic acid appears a promising candidate for combining with oxaliplatin in cancer chemotherapy treatment. The possible synergistic mechanisms maybe the synergistic apoptotic effect and the downregulation of drug-associated genes.