Modulation of the pentose phosphate pathway alters phase I metabolism of testosterone and dextromethorphan in HepG2 cells  

作　　者：Wen-jing XIAO Ting MA Chun GE Wen-juan XIA Yong MAO Run-bin SUN Xiao-yi YU Ji-ye AA Guang-ji WANG 

机构地区：[1]Key Laboratory of Drug Metabolism and Pharmacokinetics, Jiangsu Key Laboratory of Drug Design and Optimization, State KeyLaboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China

出　　处：《Acta Pharmacologica Sinica》2015年第2期259-267,共9页中国药理学报（英文版）

摘　　要：Aim： The pentose phosphate pathway （PPP） is involved in the activity of glucose-6-phosphate dehydrogenase （G6PD） and generation of NADPH, which plays a key role in drug metabolism. The aim of this study was to investigate the effects of modulation of the PPP on drug metabolism capacity in vitro. Methods： A pair of hepatic cell lines, ie the cancerous HepG2 cells and normal L02 cells, was used. The expression of CYP450 enzymes, p53 and G6PD in the cells were analyzed. The metabolism of testosterone （TEST, 10 μmol/L） and dextromethorphan （DEM, I pmol/L）, the two typical substrates for CYP3A4 and CYP2D6, in the cells was examined in the presence of different agents. Results： Both the expression and metabolic activities of CYP3A4 and CYP2D6 were considerably higher in HepG2 cells than in L02 cells. The metabolism of TEST and DEM in HepG2 cells was dose-dependently inhibited by the specific CYP3A4 inhibitor ketoconazole and CYP2D6 inhibitor quinidine. Addition of the p53 inhibitor cyclic PFT-a （5, 25 pmol/L） in HepG2 cells dose-dependently enhanced the metabolism of DEM and TEST, whereas addition of the p53 activator NSC 66811 （3, 10, 25 μmol/L） dose-dependently inhibited the metabolism. Furthermore, addition of the G6PD inhibitor 6-aminonicotinamide （5, 15 μmol/L） in HepG2 cells dose-dependently inhibited the metabolism of DEM and TEST, whereas addition of the PPP activity stimulator menadione （1, 5, 15 pmol/L） dose- dependently enhanced the metabolism. Conclusion： Modulation of p53 and the PPP alters the metabolism of DEM and TEST, suggesting that the metabolic flux pattern of PPP may be closely involved in drug metabolism and the individual variance.Aim： The pentose phosphate pathway （PPP） is involved in the activity of glucose-6-phosphate dehydrogenase （G6PD） and generation of NADPH, which plays a key role in drug metabolism. The aim of this study was to investigate the effects of modulation of the PPP on drug metabolism capacity in vitro. Methods： A pair of hepatic cell lines, ie the cancerous HepG2 cells and normal L02 cells, was used. The expression of CYP450 enzymes, p53 and G6PD in the cells were analyzed. The metabolism of testosterone （TEST, 10 μmol/L） and dextromethorphan （DEM, I pmol/L）, the two typical substrates for CYP3A4 and CYP2D6, in the cells was examined in the presence of different agents. Results： Both the expression and metabolic activities of CYP3A4 and CYP2D6 were considerably higher in HepG2 cells than in L02 cells. The metabolism of TEST and DEM in HepG2 cells was dose-dependently inhibited by the specific CYP3A4 inhibitor ketoconazole and CYP2D6 inhibitor quinidine. Addition of the p53 inhibitor cyclic PFT-a （5, 25 pmol/L） in HepG2 cells dose-dependently enhanced the metabolism of DEM and TEST, whereas addition of the p53 activator NSC 66811 （3, 10, 25 μmol/L） dose-dependently inhibited the metabolism. Furthermore, addition of the G6PD inhibitor 6-aminonicotinamide （5, 15 μmol/L） in HepG2 cells dose-dependently inhibited the metabolism of DEM and TEST, whereas addition of the PPP activity stimulator menadione （1, 5, 15 pmol/L） dose- dependently enhanced the metabolism. Conclusion： Modulation of p53 and the PPP alters the metabolism of DEM and TEST, suggesting that the metabolic flux pattern of PPP may be closely involved in drug metabolism and the individual variance.

关 键 词：drug metabolism HepG2 cells pentose phosphate pathway G6PD p53 CYP TESTOSTERONE DEXTROMETHORPHAN KETOCONAZOLE QUINIDINE cyclic PFT-a NSC 66811 6-aminonicotinamide MENADIONE 

分 类 号：Q513[生物学—生物化学] TQ464.1[化学工程—制药化工]