缺氧诱导因子-1α调控肝癌细胞对奥沙利铂耐药的机制

Mechanism of Hypoxia-inducible Factor-1α Inducing Drug Resistance to Oxaliplatin in Hepatic Carcinoma

目的探讨微环境缺氧及缺氧诱导因子-1α(hypoxia inducible factor-1,HIF-1α)和多药耐药相关(multidrug resistance,MDR)基因在肝癌细胞耐药中可能的作用机制。方法运用浓度梯度诱导法建立肝癌奥沙利铂耐药细胞株,流式细胞术检测不同耐药亚系细胞内活性氧(reactive oxygen species,ROS)的含量及细胞凋亡的情况。RT-PCR及Western blot检测HIF-1α及耐药相关基因MDR1、MRP1、BCRP的mRNA及蛋白表达。结果随着耐药浓度的增加,细胞内活性氧含量逐渐减少,细胞凋亡率明显减少,HIF-1α、MDR1、MRP1、BCRP mRNA含量增加,蛋白水平和mRNA水平相一致。结论肝癌细胞的微环境缺氧是诱导肝癌细胞对奥沙利铂产生耐药的重要原因之一。缺氧可以通过HIF-1α调控肝癌细胞内多药耐药相关MDR1、MRP1、BCRP基因的表达,也可以通过抑制凋亡而出现获得性耐药,从而使肝癌细胞对奥沙利铂产生获得性耐药。

Objective To investigate the potential mechanism of hypoxia microenvironment, hypoxiainducible factor-1α and multidrug resistance gene inducing drug resistance to oxaliplatin in hepatic carcinoma(Hep G2/oxal). Methods A resistant cell line Hep G2/oxal were established by increasing dose of oxaliplatin from 2.5 to 5.0 μg/ml. The intracellular reactive oxygen species(ROS) and cell apoptosis rates were detected by flow cytometry. mRNA and protein levels of HIF-1α and multidrug-resistance proteins, MDR1, MRP1 and BCRP were detected by RT-PCR and Western blot. Results With the increasing resistance drug dose, intracellular ROS and apoptosis rates were decreased, mRNA contents of HIF-1α, MDR1, MRP1, BCRP were increased, and the protein levels were as same as mRNA levels Hep G2/oxal cells. Conclusion Hypoxia microenvironment is a significant reason for drug resistance to oxaliplatin in hepatic carcinoma. Hypoxia could modulate the expression of multidrug-resistance genes, MDR1, MRP1 and BCRP1, and the apoptosis tolerance via upregulating HIF-1α expression, which may cause the acquired resistance to oxaliplatin in hepatic carcinoma.