Xu C J, Zhang Y, Wang J, Zhang T M
Department of Pharmacology, He-nan Institute of Medical Science, Zhengzhou, China.
Zhongguo Yao Li Xue Bao. 1998 May;19(3):273-6.
To study the effect of menadione (Men) reducing doxorubicin (Dox) resistance in Ehrlich ascites carcinoma (EAC) cells resistant to Dox (EAC/Dox cells).
Glutathione (GSH) content and membrane fluidity were measured by fluorometric assay and fluorescence depolarization assay, respectively. Glutathione S-transferase (GST) activity was measured with 1-chloro-2,4-dinitrobenzene as the substrate. Cell viability was determined by 3-(4, 5-dimethylthiazol)-2, 5-diphenyltetrazolium bromide assay.
GSH content, GST activity, and membrane fluidity in EAC/Dox cells were higher than those in EAC cells (P < 0.01). The IC50 (95% confidence limits) for Dox on EAC/Dox cell was 22.3 (15.8-28.8) mg.L-1. Relative resistance of Dox in EAC/Dox cells was 42-fold. Pretreatment of EAC/Dox cells with Men 5 or 10 mg.L-1 decreased intracellular GSH content (P < 0.01). Men 1 mg.L-1 had no obvious effect on GSH content in EAC/Dox cells (P > 0.05), but decreased the elevated membrane fluidity efficiently (P < 0.05). Men had no obvious effect on GST activity in EAC/Dox cells (P > 0.05). IC50 of Dox was reduced to 9.6 (7.8-11.3), 6.0 (2.8-9.2), or 5.3 (3.9-6.7) mg.L-1 in EAC/Dox cells pretreated with Men 1, 5, or 10 mg.L-1.
Men reduced Dox resistance effectively due in part to its depletion of GSH content in EAC/Dox cells.
研究甲萘醌(Men)降低多柔比星(Dox)耐药的艾氏腹水癌(EAC)细胞(EAC/Dox细胞)对多柔比星(Dox)耐药性的作用。
分别采用荧光分析法和荧光偏振分析法测定谷胱甘肽(GSH)含量和膜流动性。以1-氯-2,4-二硝基苯为底物测定谷胱甘肽S-转移酶(GST)活性。采用3-(4,5-二甲基噻唑)-2,5-二苯基四氮唑溴盐法测定细胞活力。
EAC/Dox细胞中的GSH含量、GST活性和膜流动性均高于EAC细胞(P<0.01)。Dox对EAC/Dox细胞的半数抑制浓度(IC50,95%置信区间)为22.3(15.8 - 28.8)mg·L-1。EAC/Dox细胞对Dox的相对耐药倍数为42倍。用5或10 mg·L-1的Men预处理EAC/Dox细胞可降低细胞内GSH含量(P<0.01)。1 mg·L-1的Men对EAC/Dox细胞中的GSH含量无明显影响(P>0.05),但能有效降低升高的膜流动性(P<0.05)。Men对EAC/Dox细胞中的GST活性无明显影响(P>0.05)。在用1、5或10 mg·L-1的Men预处理的EAC/Dox细胞中,Dox的IC50分别降至9.6(7.8 - 11.3)、6.0(2.8 - 9.2)或5.3(3.9 - 6.7)mg·L-1。
Men能有效降低Dox耐药性,部分原因是其降低了EAC/Dox细胞中的GSH含量。