三氧化二砷对人肺腺癌细胞A549/DDP裸鼠体内的多药耐药逆转作用

目的研究三氧化二砷（As_2O_3）对人肺腺癌耐顺铂细胞A549/顺铂（DDP）裸鼠移植瘤的耐药逆转作用。方法建立人肺腺癌裸鼠移植瘤模型,观察As_2O_3、DDP及联合用药对体内移植瘤生长状况的影响;采用流式细胞术（FCM）测定不同用药对肿瘤细胞凋亡率变化和耐药细胞A549/DDP P-糖蛋白（P-gp）表达;采用RT-PCR检测不同用药对A549/DDP移植瘤组织MRP1-mRNA和LRP-mRNA表达的变化。结果体内裸鼠抑瘤实验显示As_2O_3有一定抑瘤作用,联合应用DDP可显著抑制肿瘤生长。FCM结果显示应用As_2O_3后肿瘤细胞平均凋亡率,明显高于对照组（P〈0.05）（17.204±3.091）%vs（3.436±0.537）%],低浓度As_2O_3联合DDP后肿瘤细胞的凋亡率,明显高于DDP组（P〈0.05）（14.472±3.891）%vs（5.612±1.167）%]。FCM对P-gp表达检测提示As_2O_3对移植瘤Pgp水平无影响。RT-PCR检测结果示含As_2O_3组MRP1表达明显低于不含As_2O_3组（P〈0.05）,肺癌耐药相关蛋白（LRP）在转录水平呈现相对低表达,含As_2O_3组同不含As_2O_3组间比较差异无统计学意义（P〉0.05）。结论 As_2O_3能在体内逆转A549/DDP细胞的耐药性,其机制可能是As_2O_3可通过下调MRP1基因表达,提高A549/DDP细胞对DDP敏感性逆转其耐药,并可能通过诱导肿瘤细胞凋亡来起作用。

Reversal of Multidrug Resistance of A549/DDP in Nude Mice by Arsenic Trioxide

Objective To study the reversing effect of arsenic trioxide（As_2O_3） on multidrug resistacne （MDR） of A549/DDP cell in vivo.Methods The transplantable lung carcinoma cell line A549/DDP model was developed in BALB/C mice by subcutaneous implantation.To observe the volume of tumor and detect the changes of P-gp expression and apoptosis rate after different drug treatment.RT-PCR assay was used to determine the expressive level of MRP1 and LRP-mRNA.Results As_2O_3 had some effect on inhibition of tumor growth combined with DDP could significantly inhibit tumor growth in BALB/C mice, the volume and weight of tumor which treated by As_2O_3 was lower than that in the control.0.25mg/kg As_2O_3 could effectively reverse the resistance of A549/DDP cell to DDP in vivo.FCM results showed that the expression of P-gp after using DDP was relatively higher than that using other drugs.The rate of apoptosis in groups in which arsenic trioxide treatment was used was significantly increased compared with that in both the control and the group DDP.RT-PCR was used to detect the MRP1-mRNA and LRP-mRNA. The expression of MRPl-mRNA was significantly higher in the groups in which As2O3 was used for treatment than that both in the control and the group DDP（P〈0.05）.However,the expression of LRP-mRNA was same in the both groups（P〉0.05）.Conclusion As2O3 can effectively reverse the resistance of A549/DDP cells in BALB/C to DDP and induce apoptosis of A549/DDP cells in vivo,which may complete by downregulating MRP1 gene expression,enhance the sensibility of A549/DDP to DDP and inducing the apoptosis of tumor cell.