低浓度吉西他滨对肺癌A549(p53wt)细胞系细胞周期的影响

The cell cycle-specific effects of noncytotoxic Gemcitabine in the human non-small lung cancer cell line-A549(P53wt) in vitro

目的:研究低浓度吉西他滨作用于非小细胞肺腺癌A549细胞系后,在不同的时间点对细胞周期的影响.方法:MTT法和细胞培养集落计数法选择对细胞生长抑制率≤10%的药物浓度(IC10),用选择出的IC10药物浓度温育A549细胞24小时后,通过流式细胞仪测定对照无药组和用药后不同时间点(30min,1h,3 h,6 h,12 h和24h)各组细胞周期的分布.结果:①吉西他滨对A549细胞的IC10为0.02 μmol/L,此时细胞集落抑制率为9.8±9.82%,与对照组无显著差异(P>0.05).②吉西他滨IC10作用A549细胞24小时后,细胞周期分布呈时间依赖性,用药组与对照组相比30分钟时尽管大多数细胞仍处于G1期(分别为0.486±0.093;0.682±0.122),但已经明显下降(P<0.01)而S期细胞比例迅速增加(分别为0.323±0.102;0.198±0.081)(P<0.01).这种变化在第3小时最为明显,用药前G1期细胞比为0.185±0.114而S期细胞为0.815±0.132,与其他各组均有显著差别(P<0.001).在6小时后S期细胞比例减少同时G1期细胞比例增加,与对照组相比差别无显著意义(P>0.05).结论:本实验表明低浓度吉西他滨作用24小时后使非小细胞肺腺癌A549细胞系短暂阻滞于S期,这种阻滞作用具有一定的时间依赖性,以用药后1～3小时最为明显.

Purpose:To study cell cycle distribution after A549 cells were exposed to noncytotonic(IC 10) Gemcitabine. Methods:The noncytotoxic concentration (IC 10) dFdC was selected through the MTT assay and cell culture. The A549 cells were exposed to the noncytotoxic dFdC concentration for 24 hours, and the distributions of cell cycles of control groups and disposal groups at different time points(30min,1hr,3 h,6 h,12 h and 24h) were measured by flow cytometry(FCM). Results:① After culture of 24 hours the non-cytotoxic concentration(IC 10) of dFdC was 0.02 umol/L. Under this concentration, the inhibition rate of cell growth was 9.8±9.82%. Compared with control group, there were no significant differences(P>0.05). ② The distributions of cell cycles was affected by noncytotonic Gemcitabine with the exposure time from 30min to 3hrs.Compared with control group, the majority of cells of the 30min’s group were in G1-phase(0.682± 0.122,0.486±0.093 respectively) which had decreased significantly(P<0.01). At the same time, the rate of S-phase increased markedly(0.198±0.081, 0.323±0.102 respectively)(P<0.01).This difference was more evident in the 3~ rd hour in which the rate of G1-phase and S-phase was 0.185±0.114 and 0.815±0.132 respectively, which had significant differences with others(P<0.001). However, after exposure for 6 hours, the rate of G1-phase increased and the S- phase compartment decreased, and both were almost equivalent to control group (P>0.05). Conclusions:It shows that the non-cytotoxic concentration(IC 10) of dFdC has the ability to leads phase arrest of drug treated A549 cells after 24 hours. This block depends on the time, and is most evident was from 1~ st to 3~ rdhour after drug treatment.