目的:观察肺、肝、肾脏器内P-GP、CYP2C8蛋白的表达变化,分析针刺联合紫杉醇与P-GP、CYP2C8表达的相关性并探讨其机制。方法:将72只肺癌小鼠随机分为4组,每组18只,即模型组、针刺肺俞组、药物组、药物加肺俞组,各组又按药物腹腔注射后...目的:观察肺、肝、肾脏器内P-GP、CYP2C8蛋白的表达变化,分析针刺联合紫杉醇与P-GP、CYP2C8表达的相关性并探讨其机制。方法:将72只肺癌小鼠随机分为4组,每组18只,即模型组、针刺肺俞组、药物组、药物加肺俞组,各组又按药物腹腔注射后的时间不同随机分为1 h、2 h、8 h 3组,每组6只小鼠,采用elisa试剂盒检测各组织中P-GP和CYP2C8的表达情况。结果:各脏器相同时间不同治疗组组间的比较,药物组和药物加肺俞组P-GP、CYP2C8的浓度明显低于模型组和针刺肺俞组,药物加肺俞组最低(P<0.05);各脏器相同治疗组不同时间组组间的比较,各组浓度差异无显著性(P>0.05)。结论:针刺联合紫杉醇具有抑制P-GP、CYP2C8蛋白表达的作用,两者协同增效。说明"针药并举"肿瘤化疗技术的进步具有重要的科学意义和潜在的临床应用前景。展开更多
The cytochrome P450 (CYP) superfamily plays a key role in the oxidative metabolism of a wide range of exogenous chemicals. CYP2C8 is the principal enzyme responsible for the metabolism of the anti-cancer drug paclitax...The cytochrome P450 (CYP) superfamily plays a key role in the oxidative metabolism of a wide range of exogenous chemicals. CYP2C8 is the principal enzyme responsible for the metabolism of the anti-cancer drug paclitaxel in the human liver, and carries out the oxidative metabolism of at least 5% of clinical drugs. Polymorphisms in CYP2C8 have been closely implicated in individualized medication. CYP2C8.3, a common polymorph of CYP2C8 with dual amino acid substitutions R139K and K399R, is found primarily in Caucasians. In this study, CYP2C8.3 and its wild type (WT) CYP2C8 were expressed in E. coli, and their purified proteins were characterized by UV-visible spectroscopy, mass spectrometry, and circular dichroism. Their thermal stability, substrate binding ability, and metabolic activity against paclitaxel were investigated. The electron transfer kinetics during paclitaxel metabolism by WT CYP2C8 or CYP2C8.3 was studied by stopped-flow kinetics. The results revealed that mutations in CYP2C8.3 did not greatly influence the heme active site or protein thermal stability and paclitaxel binding ability, but the metabolic activity against paclitaxel was significantly depressed to just 11% of that of WT CYP2C8. Electron transfer from CYP reductase to CYP2C8.3 was found to be significantly slower than that to WT CYP2C8 during catalysis, and this might be the main reason for the depressed metabolic activity. Since the polymorph CYP2C8.3 is defective in catalyzing substrates of CYP2C8 in vitro, it might be expected to have important clinical and pathophysiological consequences in homozygous individuals, and this study provides valuable information in this aspect.展开更多
This study was conducted to evaluate the effect of sex differences on the pharmacokinetics of repaglinide in healthy subjects. One hundred twenty one healthy volunteers (61 male and 60 female;aged 18 - 50 years) were ...This study was conducted to evaluate the effect of sex differences on the pharmacokinetics of repaglinide in healthy subjects. One hundred twenty one healthy volunteers (61 male and 60 female;aged 18 - 50 years) were included in the study. Subjects were administered a single 4-mg repaglinide oral dose. Blood samples were taken at 0, 30, 60, 120, 180 and 240 min. Serum repaglinide levels were determined by a high-performance liquid chromatography (HPLC) method. Subjects were also genotyped by polymerase chain reactions - restriction fragment length polymorphisms (PCR-RFLP) for CYP3A4*4, *5 and *18 alleles and by an allele-specific multiplex PCR for CYP2C8*2, *3, *4 and *5 alleles. The pharmacokinetics of repaglinide were comparable between male and female subjects. The mean clearance (CL) of repaglinide was 16.0% lower (p = 0.03), the mean area under the serum concentration-time curve (AUC) was 12.8% higher (p = 0.04) and the peak serum concentration (Cmax) was 13.2% higher (p = 0.03) in females compared to male subjects. The mean rate of elimination (kel) and mean CL of repaglinide were 47.67% (p = 0.03) higher and 29.25% (p = 0.03) higher, respectively, in male subjects having CYP2C8*5 allele compared to female subjects. We also found that the mean half-life (t1/2) of repaglinide was 42.43% higher (p = 0.03), and the mean AUC was 35.83% higher (p = 0.03) in female subjects when compared to the male subjects having CYP2C8*5 allele. Sex differences significantly influence the pharmacokinetics of repaglinide.展开更多
文摘目的:观察肺、肝、肾脏器内P-GP、CYP2C8蛋白的表达变化,分析针刺联合紫杉醇与P-GP、CYP2C8表达的相关性并探讨其机制。方法:将72只肺癌小鼠随机分为4组,每组18只,即模型组、针刺肺俞组、药物组、药物加肺俞组,各组又按药物腹腔注射后的时间不同随机分为1 h、2 h、8 h 3组,每组6只小鼠,采用elisa试剂盒检测各组织中P-GP和CYP2C8的表达情况。结果:各脏器相同时间不同治疗组组间的比较,药物组和药物加肺俞组P-GP、CYP2C8的浓度明显低于模型组和针刺肺俞组,药物加肺俞组最低(P<0.05);各脏器相同治疗组不同时间组组间的比较,各组浓度差异无显著性(P>0.05)。结论:针刺联合紫杉醇具有抑制P-GP、CYP2C8蛋白表达的作用,两者协同增效。说明"针药并举"肿瘤化疗技术的进步具有重要的科学意义和潜在的临床应用前景。
基金supported by the National Natural Science Foundation of China (20771029)Shanghai Pujiang Talent Project (08PJ14017)+1 种基金Shang-hai Leading Academic Discipline Project (B108)Beijing Synchrotron Radiation Facility (BSRF) in the Institute of High Energy Physics,Chinese Academy of Sciences
文摘The cytochrome P450 (CYP) superfamily plays a key role in the oxidative metabolism of a wide range of exogenous chemicals. CYP2C8 is the principal enzyme responsible for the metabolism of the anti-cancer drug paclitaxel in the human liver, and carries out the oxidative metabolism of at least 5% of clinical drugs. Polymorphisms in CYP2C8 have been closely implicated in individualized medication. CYP2C8.3, a common polymorph of CYP2C8 with dual amino acid substitutions R139K and K399R, is found primarily in Caucasians. In this study, CYP2C8.3 and its wild type (WT) CYP2C8 were expressed in E. coli, and their purified proteins were characterized by UV-visible spectroscopy, mass spectrometry, and circular dichroism. Their thermal stability, substrate binding ability, and metabolic activity against paclitaxel were investigated. The electron transfer kinetics during paclitaxel metabolism by WT CYP2C8 or CYP2C8.3 was studied by stopped-flow kinetics. The results revealed that mutations in CYP2C8.3 did not greatly influence the heme active site or protein thermal stability and paclitaxel binding ability, but the metabolic activity against paclitaxel was significantly depressed to just 11% of that of WT CYP2C8. Electron transfer from CYP reductase to CYP2C8.3 was found to be significantly slower than that to WT CYP2C8 during catalysis, and this might be the main reason for the depressed metabolic activity. Since the polymorph CYP2C8.3 is defective in catalyzing substrates of CYP2C8 in vitro, it might be expected to have important clinical and pathophysiological consequences in homozygous individuals, and this study provides valuable information in this aspect.
文摘This study was conducted to evaluate the effect of sex differences on the pharmacokinetics of repaglinide in healthy subjects. One hundred twenty one healthy volunteers (61 male and 60 female;aged 18 - 50 years) were included in the study. Subjects were administered a single 4-mg repaglinide oral dose. Blood samples were taken at 0, 30, 60, 120, 180 and 240 min. Serum repaglinide levels were determined by a high-performance liquid chromatography (HPLC) method. Subjects were also genotyped by polymerase chain reactions - restriction fragment length polymorphisms (PCR-RFLP) for CYP3A4*4, *5 and *18 alleles and by an allele-specific multiplex PCR for CYP2C8*2, *3, *4 and *5 alleles. The pharmacokinetics of repaglinide were comparable between male and female subjects. The mean clearance (CL) of repaglinide was 16.0% lower (p = 0.03), the mean area under the serum concentration-time curve (AUC) was 12.8% higher (p = 0.04) and the peak serum concentration (Cmax) was 13.2% higher (p = 0.03) in females compared to male subjects. The mean rate of elimination (kel) and mean CL of repaglinide were 47.67% (p = 0.03) higher and 29.25% (p = 0.03) higher, respectively, in male subjects having CYP2C8*5 allele compared to female subjects. We also found that the mean half-life (t1/2) of repaglinide was 42.43% higher (p = 0.03), and the mean AUC was 35.83% higher (p = 0.03) in female subjects when compared to the male subjects having CYP2C8*5 allele. Sex differences significantly influence the pharmacokinetics of repaglinide.
