Li Jie, Xu Liangzhong, He Kailing, Guo Weijian, Zhu Xiongzeng, Zheng Yunhong, Xia Peng
Department of Oncology, Xin Hua Hospital Cancer Center, Shanghai Second Medical University, Shanghai 200092, China.
Zhonghua Zhong Liu Za Zhi. 2002 Mar;24(2):129-32.
To study the reversal effect of nomegestrol acetate (NOM) on mutidrug resistance (MDR) in MCF7/ADR and its mechanism.
Using tetrazolium dye assay, effects of various concentrations of NOM on sensitivity to ADR in MCF7/ADR was studied. Expression of MDR related genes MDR1, glutathoine S-transferase Pi (GSTpi), Topoisomerase II alpha (Topo II alpha) and MDR related protein (MRP) were assayed by reverse transcription-polymerase chain reaction (RT-PCR) and immunocytochemistry assay. Using flow cytometry (FCM), intracellular ADR concentration effects on cell cycle were observed.
NOM significantly reversed MDR in MCF7/ADR. After NOM 20, 10 and 5 micromol/L treatment, the chemosensitivity to ADR increased to 21, 12 and 8 times. The reversal activity of NOM was stronger than that of the precursor compound megestrol acetate, and was comparable to that of verapamail. After treatment with NOM 5 micromol/L both MDR1 and GSTpi mRNA genes expression began to decline on D2 (P < 0.05, & P < 0.01) and reached the lowest level on D3 (both P < 0.01), but the expression levels began to rise on D6 again (both P < 0.05). The expression of MRP and Topo II alpha gave no significant change. Changes of P-gp and GSTpi protein expressions were similar to those of their mRNA expressions, showing early decline and late rise. Two hours after NOM 20, 10, and 5 micromol/L treatment, intracellular ADR concentration increased 2.7, 2.3 and 1.5 times, respectively. FCM data showed that after forty-eight hours, combined administration of NOM (20 micromol/L) and ADR (from low concentration to high concentration), MCF7/ADR cells showed gradual arrest in the G(2)M phase with the increase of ADR dose.
NOM has strong reversal effects on MDR in MCF7/ADR. The reversal takes place via different routes, i.e. down regulating mRNA and protein expression levels of MDR1 and GSTpi, increasing intracellular drug concentration, and enhancing the arrest of ADR in cells at G(2)M phase.
研究醋酸诺美孕酮（NOM）对MCF7/ADR多药耐药（MDR）的逆转作用及其机制。
采用四氮唑染料法，研究不同浓度的NOM对MCF7/ADR细胞对阿霉素（ADR）敏感性的影响。通过逆转录聚合酶链反应（RT-PCR）和免疫细胞化学分析法检测多药耐药相关基因MDR1、谷胱甘肽S-转移酶Pi（GSTpi）、拓扑异构酶IIα（Topo IIα）和多药耐药相关蛋白（MRP）的表达。采用流式细胞术（FCM）观察细胞内ADR浓度对细胞周期的影响。
NOM显著逆转了MCF7/ADR的多药耐药性。经20、10和5 μmol/L的NOM处理后，对ADR的化疗敏感性分别提高到21、12和8倍。NOM的逆转活性强于前体化合物醋酸甲地孕酮，与维拉帕米相当。用5 μmol/L的NOM处理后，MDR1和GSTpi mRNA基因表达在第2天开始下降（P < 0.05和P < 0.01），并在第3天达到最低水平（均P < 0.01），但在第6天表达水平又开始上升（均P < 0.05）。MRP和Topo IIα的表达无显著变化。P-糖蛋白（P-gp）和GSTpi蛋白表达的变化与其mRNA表达相似，呈早期下降和后期上升。经20、10和5 μmol/L的NOM处理2小时后，细胞内ADR浓度分别增加了2.7、2.3和1.5倍。FCM数据显示，48小时后，联合给予NOM（20 μmol/L）和ADR（从低浓度到高浓度），MCF7/ADR细胞随着ADR剂量的增加逐渐停滞在G(2)M期。
NOM对MCF7/ADR的多药耐药有较强的逆转作用。其逆转通过不同途径发生，即下调MDR1和GSTpi的mRNA和蛋白表达水平、增加细胞内药物浓度以及增强ADR在细胞G(2)M期的阻滞。
