Li J, Xu L Z, Yao J J, Guo W J, Xia P, Chen Y
Department of Oncology, Cancer Center, Xin Hua Hospital, Shanghai Second Medical University, Shanghai 200092, China.
Acta Pharmacol Sin. 2001 Nov;22(11):1023-7.
To study the reversal effects of droloxifene (DRO) on multidrug resistance (MDR) in K562 cell line resistant to adriamycin (ADR).
K562 cell line resistant to ADR (K562/A02) and K562 cell line sensitive to ADR (K562) were treated with DRO. Using MTT assay, chemosensitivity to ADR in DRO-treated K562 cell lines was studied. Before and after the treatment with DRO 10 micromol/L, MDR1 and GSTpi gene expression were assayed by reverse transcription-polymerase chain reaction and immunocytochemistry assay. Flow cytometry was used to determine intracellular ADR concentration.
DRO significantly reversed MDR in K562/A02 (P < 0.01). After treatment of DRO 20, 10, and 5 micromol/L, the chemosensitivity to ADR was increased to 14, 13, and 4 folds, respectively. The reversal activity of DRO was similar to that of verapamil (VRP). After treated with DRO 10 micromol/L, both MDR1 and GSTpi mRNA expression began to decline on the 2nd day, and significantly decreased on the 5th day (P<0.01). The changes in P-gp and GSTpi protein expression were similar to that of their mRNA expression. Two hours after treatment of DRO 20, 10, and 5 micromol/L, intracellular ADR concentration in K562/A02 was increased to 2.9, 2.3, and 1.5 folds, respectively. However, DRO did not markedly increase ADR accumulation in K562.
DRO had strong reversal effect on MDR in K562/A02, which was comparable to that of VRP, but the reversal effect was via different pathways.
研究屈洛昔芬（DRO）对阿霉素（ADR）耐药的K562细胞系多药耐药（MDR）的逆转作用。
用DRO处理对ADR耐药的K562细胞系（K562/A02）和对ADR敏感的K562细胞系（K562）。采用MTT法研究经DRO处理的K562细胞系对ADR的化学敏感性。用逆转录-聚合酶链反应和免疫细胞化学分析法检测10 μmol/L DRO处理前后MDR1和GSTpi基因表达。采用流式细胞术测定细胞内ADR浓度。
DRO显著逆转K562/A02中的MDR（P < 0.01）。经20、10和5 μmol/L DRO处理后，对ADR的化学敏感性分别提高到14倍、13倍和4倍。DRO的逆转活性与维拉帕米（VRP）相似。用10 μmol/L DRO处理后，MDR1和GSTpi mRNA表达在第2天开始下降，第5天显著下降（P<0.01）。P-糖蛋白和GSTpi蛋白表达的变化与其mRNA表达相似。经20、10和5 μmol/L DRO处理2小时后，K562/A02细胞内ADR浓度分别增加到2.9倍、2.3倍和1.5倍。然而，DRO并未显著增加K562中ADR的蓄积。
DRO对K562/A02中的MDR有较强的逆转作用，与VRP相当，但逆转作用通过不同途径。
