人肺腺癌紫杉醇耐药细胞系DNA polβ的表达

Expression of DNA polymerase β in a paclitaxel-induced human lung adenocarcinoma drug-resistant cell line

目的建立人肺腺癌紫杉醇多药耐药细胞系,测定耐药细胞系DNA聚合酶β(DNA polβ)基因和蛋白表达。方法以紫杉醇为诱导药,人肺腺癌细胞系(A 549)为诱导对象,逐步增加紫杉醇药物浓度进行诱导,建立耐紫杉醇的多药耐药细胞系A 549/TXL 20。采用M TT法检测A 549/TXL 20耐药指数,同时对顺铂、长春新碱、5氟脲嘧啶、丝裂霉素和羟基尿素五种药物进行交叉耐药检测。RC-PCR法和W estern b lotting法分别测定细胞内DNA polβ表达水平。结果A 549/TXL 20对紫杉醇及其他五种抗癌药物均有不同程度的耐药性。A 549/TXL 20细胞中DNA polβmRNA及蛋白的表达水平均高于A 549细胞(P<0.05)。结论A 549/TXL 20具有多药耐药表型,耐药性产生可能与细胞内DNA polβ表达增高有关。

[Objective] To establish a multidrug resistant cell line of human lung adenocarcmoma reduced by paelitaxel and observe the relationship between its drug resistance and the overexpression of the DNA polymerase beta （polβ）. [Methods] Paclitaxel-resistant sublines （A549/TXL20） were established in vitro by exposure to stepwise increased concentrations of the drug in a cell culture medium. Western blotting and semi-quantitative RT-PCR were employed to analyze expression of the DNA polβ protein and DNA polβ mRNA, respectively. [Results] The resistant cells, A549/TXL20 were cross-resistance to paclitaxel, cisplatin, mitomycin, vinblastine, hydroxyeamptothecine, and 5-fluouracil （5-Fu）, The.expression of DNA polβ mRNA and protein in the A549/TXL20 cells were significantly higher than those in A549 cells. [Conclusions] The A549/TXL20 cell line shows drug resistant phenotype and may be related to overexpression of DNA polβ.