全反式维甲酸提高人结肠癌LoVo细胞对奥沙利铂敏感性

All-trans retinoic acid-induced drug sensitivity of oxaliplatin in human colorectal cancer cell line LoVo

目的探讨全反式维甲酸(all-trans retinoic acid,AT-RA)提高人结肠癌LoVo细胞对奥沙利铂的药物敏感性和机制。方法MTT法筛选ATRA和奥沙利铂实验浓度。流式细胞仪检测ATRA对细胞周期的影响。分别用ATRA、奥沙利铂、ATRA联合奥沙利铂作用LoVo细胞;MTT法检测药物抑制率,流式细胞仪检测细胞周期及凋亡率,原子光谱吸收仪检测细胞DNA含铂(Pt)量。结果奥沙利铂抑制LoVo细胞作用呈量效依赖;其GI50(GI,inhibit net cell growth by%)为6.5mg.L-1,主要阻滞肿瘤细胞在S期。ATRA抑制LoVo细胞作用呈时效和量效依赖。1.0μmol.L-1ATRA作用12h后G1期细胞增多;48h后伴S期、G2/M期细胞减少并明显抑制肿瘤细胞增殖;作用12h至48h后联合奥沙利铂,两药联合由相加作用转变为协同作用;联合用药后S期细胞明显增多,细胞DNA含Pt量明显增加,但不提高奥沙利铂凋亡率。结论小剂量ATRA通过改变LoVo细胞周期和提高细胞DNA含Pt量,明显增加肿瘤细胞对奥沙利铂的药物敏感性。

Aim To investigate the roles of ATRA （All-traMs retinoic acid ） inducing drug sensitivity of oxaliplatin in human colorectal cancer cell line LoVo. Methods The drug concentrations of ATRA or Oxaliplatin in LoVo cells were determided by MTT screen assay. LoVo cell cycle changed by ATRA was detected by flow cytometry（FCM）. LoVo cells were cultured in three different ways： ATRA,oxaliplatin or ATRA combined with Oxaliplatin. Growth inhibitory activity against LoVo cells was determided by MTr assay. Cell cycle and apoptosis induced by different drug were assessed by FCM. Pt-DNA adducts in LoVo cells were determined by the atomic absorption spectrometer. Resuits In LoVo cells, oxaliplatin was a dose-dependent drug, which GI50 （ GI, inhibit net cell growth by % ） 6. 5 mg.L^-1 blocks LoVo cells mainly in S phase. ATRA was a dose-and time-dependent drug, which had significant growth inhibitory activity against IoVo cells after a 48 h continuous treatment at 1 μmol.L^-1. The percentage of cells in G1 phase began to increase after a 12 h ATRA treatment at 1 μmol.L^-1, that in S and G2/M phase decreased significantly after a 48 h treatment. The effect of oxaliplatin combined with ATRA in LoVo cells was changed gradually from addition to synergistic effect after a ATRA treatment from 12 h to 48 h. The percentage of cells in S phase treated with the combined drugs was higher than that treated with simple oxaliplatin. The apoptosis rate induced by the combined drugs was the same as that by simple oxaliplatin. Compared with that by simple oxaliplatin, more Pt-DNA adducts in LoVo cells were formed by the combined drugs. Conclusions A low dose ATRA can induce drug sensitivity of oxaliplatin in LoVo cells by changing cell cycle and increasing PtDNA adducts.