Biochemical studies on the potentiation of antitumor activity of cisplatin by adriamycin

The RNA synthesis in vitro by E. coli RNA polymerase was found to be highly sensitive to cis-diamminedichloroplatinum (cisplatin) inhibition. The degree of inhibition was in proportion to the length of time of template preincubation with cisplatin, suggesting that cisplatin-template binding was involved in the inhibition of RNA polymerase. The effect of adriamycin on this inhibition was studied and it was found that adriamycin significantly enhanced the inhibitory effect of cisplatin and that the total effect was greater than the sum of the effects of each drug used individually. This synergistic effect was not observed when the effect of the combination of adriamycin and cisplatin on in vitro DNA synthesis was studied.     

siRNA抑制丙型肝炎病毒IRES介导的基因表达

以HCVIRES为靶位 ,应用T7RNA多聚酶体外转录合成了 5条小干扰RNA(siRNA) .脂质体转染法将其导入HCVIRES介导萤光素酶表达的转基因细胞 (HepG2 .970 6 )中 ,通过测定萤光素酶的量 ,评价T7siRNA对HCV介导基因表达的抑制作用 .结果表明 ,所合成的 5条T7siRNAs ,均能特异性地抑制萤光素酶基因的表达 ,抑制率分别为 94 31%、80 0 1%、78 0 1%、80 33%、85 6 4% ,其中以靶向HCVIRES第二茎环结构的T7siRNA1抑制率最高 ,且对HCV基因的抑制作用有剂量依赖性 ,随T7siRNA1量的增加 ,抑制率逐渐增强 .siRNA抑制HCV基因的作用具有良好的特异性 ,改变其中 1个核苷酸即无显著抑制作用 .