洛拉曲克对3株肿瘤细胞胸苷酸合成酶mRNA水平的影响

Effect of nolatrexed on the thymidylate synthase mRNA expression in three tumor cell lines

目的 研究3株肿瘤细胞的胸苷酸合成酶mRNA(thymidylate synthase,TS mRNA)水平在洛拉曲克作用后的动态变化规律。 方法 细胞用不同剂量的洛拉曲克处理不同的时间后提取总RNA,用逆转录多聚酶链式反映(RT-PCR)检测TS mRNA／β-actin mRNA的比率反映TS mRNA的动态变化。结果 RT-PCR结果显示,在3种肿瘤细胞的时间曲线中,TS／β-actin比值与对照相比 均有一定的变化趋势。但3种细胞的变化趋势各不相同,C6细胞呈升高后平台形,SRS-82细胞是升高后又降低呈峰形,LoVo细 胞呈持续升高的趋势。在剂量曲线中,除LoVo细胞变化不明显以外,其余两种细胞表现相似,即浓度在IC90值附近或比其低浓度 的洛拉曲克可使TS/β-actin比值升高,但更高浓度则使比值降低,表现出细胞毒性。结论 尽管理论上经洛拉曲克作用后不应 该影响TS mRNA水平,但本实验证明TS mRNA水平在洛拉曲克作用下确有动态变化,提示洛拉曲克药理作用的复杂性。

OBJECTIVE To study the pattem of dynamic changes of TS mRNA levels in three tumor cell lines treated with nolatrexed.METHODS All cell lines were exposed to nolatrexed in different concentrations for indicated time intervals and then total RNA was obtained for RT-PCR. TS and β-actin mRNA were amplified and the dynamic changes of TS mRNA were reflected by TS/β-actin ratio.RESULTS The RF-PCR results demonstrated that in the time course of the 3 cell lines, TS/β-actin ratio in drug-treated cells had dynamic change compared with control. Interestingly, there were different changing patterns in the three tumor cell lines, the. ratio in C6 was elevated at first,and then reached a plateau, the ratio in SRS-82 was initially increased, and then went down to form a peak, where as the ratio in LoVo follow a tendency of up all along within the time period. In the dosing group,except for LoVo in which the ratio had no obvious change,the changing patterns of the ratio in the other two cell lines were similar, that was, treatment with nolatrexed in concentrations equal to or less than the IC90 raised the ratio and that more than the IC50 lowed the ratio, exhibiting cytotoxity.CONCLUSION Although nolatrexed does not affect the TS mRN expression theoretically, our data demonstrates that TS mRNA is dynanfieally changed after treatment of the cells with nolatrexed,suggesting diversity of phanmcological mechanism of the drug.