全反式维甲酸对人肺腺癌A549细胞放射敏感性的影响

Effect of all-trans retinoic acid on radiosensitivity of lung cancer cell line A549

摘要:

目的：研究全反式维甲酸(All-trans retinoic acid，ATRA)对体外培养的人肺腺癌A549细胞的放射敏感性的影响及其可能的作用机制。方法：对数生长期的A549细胞，分为对照组、单纯ATRA组、单纯照射组、联合组（ATRA+照射组）。MTT法检测生长抑制率并筛选最佳实验浓度；克隆形成实验检测放射增敏作用；流式细胞术(Flow cytometry，FCM)检测各组的细胞周期及凋亡；反转录聚合酶链反应(Reverse transcription Polymerase chain reaction,RT-PCR)法检测各组VEGF mRNA表达；酶联免疫吸附测定法(Enzyme-linked immunosorbent assay,ELISA)法检测各组细胞上清液中血管内皮生长因子(Vascular endothelial growth factor,VEGF)值。结果:选择10 μmol/L的ATRA作为最佳实验浓度；ATRA对A549细胞有放射增敏作用；单纯ATRA组的G0/G1期比例较对照组明显增加(P<0.05)，细胞凋亡率差异有统计学意义(P＜0.05)；联合组VEGF mRNA的表达较单纯放疗组明显减少（P＜0.05）；联合组上清液VEGF水平较单纯照射组明显减少（P＜0.05）。结论：ATRA对A549细胞有放射增敏作用，其机制可能与ATRA对A549细胞的直接抑制、诱导细胞周期的再分布、诱导凋亡和下调肿瘤细胞VEGF的表达有关。

Abstract:

Objective:To investigate the radiosensitive effect of all trans retinoic acid(ATRA) on lung cancer cell line A549 cultured in vitro and its possible mechanism. Methods: The A549 cells in the logarithmic growth phase were divided into four groups: control group, ATRA group, radiation group, combination group(ATRA combined with radiation). MTT assay was used to detect the growth inhibition rate and to further filter out the best experimental concentration of ATRA. The radiosensitive effect was detected by clone formation test. The cell cycle and apoptosis was measured by flow cytometry. The expression of VEGF mRNA was detected by RT-PCR. The VEGF values in the cell supernatant were detected by ELISA. Results: The optimal dose of ATRA was 10 μmol/L. ATRA can enhance the radiosensitivity of A549 cells. The proportion of G0/G1 phase in ATRA group was significantly increased compared with that in control group（P<0.05）;statistic differences in apoptosis rate were observed between ATRA group and control group（P<0.05）. The expressions of VEGF mRNA were significantly reduced in combination group compared with those in radiation group（P<0.05）. The VEGF levels in the supernatant of combination group were significantly decreased compared with those in radiation group（P<0.05）. Conclusion: All-trans retinoic acid can increase the radiosensitivity of A549 cells. The mechanism may be related with the direct inhibition of ATRA on A549 cells, redistribution of the inducing cell cycle, inducement of the apoptosis and down regulation of the expression of VEGF in tumor cells.