Aim The present study developed a CYP3A4-expressed Caco-2 monolayer model at which effects of the efflux-metabolism alliance on the transport and uptake of clausenamide（CLA） enantiomers as CYP3A4 substrates were inv...Aim The present study developed a CYP3A4-expressed Caco-2 monolayer model at which effects of the efflux-metabolism alliance on the transport and uptake of clausenamide（CLA） enantiomers as CYP3A4 substrates were investigated. The apparent permeability coefficients （Papp） of （ - ） and （ ＋ ）CLA were higher in the ab- sorptive direction than those in the secretory direction with efflux ratios（ER） of 0. 709 ± 0.411 and 0. 867± 0. 250 （ Х10^-6 -1 cm · s ）, respectively. Their bidirectional transports were significantly reduced by （75.6 ± 87.5）% af- ter treatment with verapamil （ a P-glycoprotein inhibitor） that increased the rate of metabolism by CYP3 A4, whereas the CYP3A4 inhibitor ketoconazole treatment markedly enhanced the basolateral to apical flux of （ - ） and （ ＋ ） CLA with ERs being 2. 934 ± 1. 432 and 1. 877 ± 0. 148 （ Х 10^-6 cm/s） respectively. These changes could be blocked by the duel CYP3A4/P-glycoprotein inhibitor cyclosporine A, consequently, Papp values for CLA enanti- omers in both directions were significantly greater than those obtained by using verapamil or ketoconazole, and their ERs were similar to those following （ - ） or （ ＋ ）-isomer treatment alone. Furthermore, the uptake of （ - ）CLA was more than that of （ ＋ ）CLA in the transfected cells. Incubation with ketoeonazole decreased the intracellular concentrations of the two enantiomers. This effect disappeared in the presence of a CYP3A4 inducer dexametha- sone. These results indicated that CYP3A4 could influence P-gp efflux, transport and uptake of CLA enantiomers as CYP3A4 substrates and that a duel inhibition to CYP3A4/ P-glycoprotein could enhance their absorption and bioavailability, which provides new insight into the efflux-metabolism alliance and will benefit the clinical pharma- cology of （？） CLA as a candidate drug for treatment of Alzheimer＇ s disease.展开更多
In the etiology of hepatocellular carcinoma (HCC), in addition to hepatitis B virus and hepatitis C virus infections, chemical carcinogens also play important roles. For example, aflatoxin B 1 (AFB 1 ) epoxide reacts ...In the etiology of hepatocellular carcinoma (HCC), in addition to hepatitis B virus and hepatitis C virus infections, chemical carcinogens also play important roles. For example, aflatoxin B 1 (AFB 1 ) epoxide reacts with guanine in DNA and can lead to genetic changes. In HCC, the tumor suppressor gene p53 codon 249 mutation is associated with AFB 1 exposure and mutations in the K -ras oncogene are related to vinyl chloride exposure. Numerous genetic alterations accumulate during the process of hepatocarcinogenesis. Chemical carcinogen DNA-adduct formation is the basis for these genetic changes and also a molecular marker which reflects exposure level and biological effects. Metabolism of chemical carcinogens, including their activation and detoxification, also plays a key role in chemical hepatocarcinogenesis. Cytochrome p450 enzymes, N -acetyltransferases and glutathione S -transferases are involved in activating and detoxifying chemical carcinogens. These enzymes are polymorphic and genetic variation influences biological response to chemical carcinogens. This genetic variation has been postulated to influence the variability in risk for HCC observed both within and across populations. Ongoing studies seek to fully understand the mechanisms by which genetic variation in response to chemical carcinogens impacts on HCC risk.展开更多
This review highlights therapeutic agents from recent cancer therapeutic trials showing the greatest potential for further clinical use for sunitinib in the near future. In fact, sunitinib is one of multi-tyrosine kin...This review highlights therapeutic agents from recent cancer therapeutic trials showing the greatest potential for further clinical use for sunitinib in the near future. In fact, sunitinib is one of multi-tyrosine kinase inhibitors;tyrosine kinases are enzymes, which transfer phosphate groups from ATP to the hydroxyl group of tyrosine residues on signal transduction molecules. Phosphorylation of signal transduction molecules, in turn, induces dramatic changes in tumor growth, including activation of angiogenesis and DNA synthesis. Therefore, sustain efforts have been directed for developing inhibitors for angiogenesis, which is the marginal process for tumor growth and development through targeting TKs. Almost if not all angiogenesis inhibitors target the vascular endothelial growth factor (VEGF) signaling pathway.展开更多
目的用Cocktail探针药物法研究参麦注射液对大鼠细胞色素P450酶（CYP450）6种亚型活性的影响。方法将SD大鼠随机分组,实验组ip给予参麦注射液（10 m L/kg）,对照组ip给予等量生理盐水,诱导7 d,分别以非那西丁、安非他酮、甲苯磺丁脲、...目的用Cocktail探针药物法研究参麦注射液对大鼠细胞色素P450酶（CYP450）6种亚型活性的影响。方法将SD大鼠随机分组,实验组ip给予参麦注射液（10 m L/kg）,对照组ip给予等量生理盐水,诱导7 d,分别以非那西丁、安非他酮、甲苯磺丁脲、奥美拉唑、美托洛尔和咪达唑仑作为CYP1A2、CYP2B1、CYP2C9、CYP2C19、CYP2D6和CYP3A4的探针药物。UPLC-MS/MS法检测大鼠血浆中探针药物的血药浓度,采用DAS3.0软件估算药动学参数。结果与对照组相比,非那西丁、安非他酮和奥美拉唑的AUC0^∞、CL和Cmax显著降低（P〈0.05）,甲苯磺丁脲、美托洛尔和咪达唑仑的AUC0^∞、CL和Cmax无显著性差异。结论参麦注射液对大鼠CYP1A2、CYP2B1和CYP2C19亚型的活性有明显的抑制作用,而对CYP2C9、CYP2D6和CYP3A4亚型的活性无显著性影响。展开更多
RNA interference(RNAi)is useful for selective gene silencing.Cytochrome P4503A4(CYP3A4),which metabolizes approximately 50% of drugs in clinical use,plays an important role in drug metabolism.In this study,we aimed to...RNA interference(RNAi)is useful for selective gene silencing.Cytochrome P4503A4(CYP3A4),which metabolizes approximately 50% of drugs in clinical use,plays an important role in drug metabolism.In this study,we aimed to develop a short hairpin RNA(shRNA)to modulate CYP3A4 expression.Three new shRNAs(S1,S2 and S3)were designed to target the coding sequence(CDS)of CYP3A4,cloned into a shRNA expression vector,and tested in different cells.The mixture of three shRNAs produced optimal reduction(55%)in CYP3A4 CDS-luciferase activity in both CHL and HEK293 cells.Endogenous CYP3A4 expression in HepG2 cells was decreased about 50%at both mRNA and protein level after transfection of the mixture of three shRNAs.In contrast,CYP3A5 gene expression was not altered by the shRNAs,supporting the selectivity of CYP3A4 shRNAs.In addition,HepG2 cells transfected with CYP3A4 shRNAs were less sensitive to Ginkgolic acids,whose toxic metabolites are produced by CYP3A4.These results demonstrate that vector-based shRNAs could modulate CYP3A4 expression in cells through their actions on CYP3A4 CDS,and CYP3A4 shRNAs may be utilized to define the role of CYP3A4 in drug metabolism and toxicity.展开更多
Background In recent years, it is found that the polymorphisms of genes which are involved in the pharmacokinetic and pharmacodynamic pathways play important roles in the clinical anticoagulation treatment with warfar...Background In recent years, it is found that the polymorphisms of genes which are involved in the pharmacokinetic and pharmacodynamic pathways play important roles in the clinical anticoagulation treatment with warfarin. The aim of the study was to investigate the impact of the genetic polymorphism of r-glutamic acid carboxylase （gamma-glutamyl carboxylase gene, GGCX） on the response of warfarin initial anticoagulant therapy. Methods Seven hundred and ninety-eight Chinese Han patients who received valve replacement surgery and orally taken warfarin in long term for anticoagulant therapy in Guangdong General Hospital from 2000 to 2008 were enrolled in the study, a polymorphic SNPs point （rs699664） of GGCX was selected, and SnaPshot was adopted to perform single nucleotide polymorphism （SNP） test, and by grouping according to genotype, GGCX average daily dose of warfarin, time for PT-INR to reach the target value and differences in the incidence of excessive coagulation between different genotypes were compared respectively. Hardy-Weinberg genetic equilibrium test was applied for population representative test. Results Within the 20 days of warfarin initial therapy, male average daily dose of warfarin （2.92 ± 1.18 mg/d） was apparently higher than that of female （2.64 ± 0.98 mg/d）, while there were no significant differences in the average time required for PT-INR to reach the target value （ 1.8） and the excessive coagulation ratio at the initial therapy stage between male and female. And there were no significant differences in the average daily dose of warfarin, time to reach the target value and excessive coagulation ratio among different GGCX genotypes. Conclusions GGCX genovariation had no significant impact on the warfarin daily dose within the 20-day initial therapy of Chinese Han Population, and for the conventional dosage program, the risk of bleeding in the GGCX mutation individuals did not increase obviously at the initial administration period.展开更多
文摘Aim The present study developed a CYP3A4-expressed Caco-2 monolayer model at which effects of the efflux-metabolism alliance on the transport and uptake of clausenamide（CLA） enantiomers as CYP3A4 substrates were investigated. The apparent permeability coefficients （Papp） of （ - ） and （ ＋ ）CLA were higher in the ab- sorptive direction than those in the secretory direction with efflux ratios（ER） of 0. 709 ± 0.411 and 0. 867± 0. 250 （ Х10^-6 -1 cm · s ）, respectively. Their bidirectional transports were significantly reduced by （75.6 ± 87.5）% af- ter treatment with verapamil （ a P-glycoprotein inhibitor） that increased the rate of metabolism by CYP3 A4, whereas the CYP3A4 inhibitor ketoconazole treatment markedly enhanced the basolateral to apical flux of （ - ） and （ ＋ ） CLA with ERs being 2. 934 ± 1. 432 and 1. 877 ± 0. 148 （ Х 10^-6 cm/s） respectively. These changes could be blocked by the duel CYP3A4/P-glycoprotein inhibitor cyclosporine A, consequently, Papp values for CLA enanti- omers in both directions were significantly greater than those obtained by using verapamil or ketoconazole, and their ERs were similar to those following （ - ） or （ ＋ ）-isomer treatment alone. Furthermore, the uptake of （ - ）CLA was more than that of （ ＋ ）CLA in the transfected cells. Incubation with ketoeonazole decreased the intracellular concentrations of the two enantiomers. This effect disappeared in the presence of a CYP3A4 inducer dexametha- sone. These results indicated that CYP3A4 could influence P-gp efflux, transport and uptake of CLA enantiomers as CYP3A4 substrates and that a duel inhibition to CYP3A4/ P-glycoprotein could enhance their absorption and bioavailability, which provides new insight into the efflux-metabolism alliance and will benefit the clinical pharma- cology of （？） CLA as a candidate drug for treatment of Alzheimer＇ s disease.
文摘In the etiology of hepatocellular carcinoma (HCC), in addition to hepatitis B virus and hepatitis C virus infections, chemical carcinogens also play important roles. For example, aflatoxin B 1 (AFB 1 ) epoxide reacts with guanine in DNA and can lead to genetic changes. In HCC, the tumor suppressor gene p53 codon 249 mutation is associated with AFB 1 exposure and mutations in the K -ras oncogene are related to vinyl chloride exposure. Numerous genetic alterations accumulate during the process of hepatocarcinogenesis. Chemical carcinogen DNA-adduct formation is the basis for these genetic changes and also a molecular marker which reflects exposure level and biological effects. Metabolism of chemical carcinogens, including their activation and detoxification, also plays a key role in chemical hepatocarcinogenesis. Cytochrome p450 enzymes, N -acetyltransferases and glutathione S -transferases are involved in activating and detoxifying chemical carcinogens. These enzymes are polymorphic and genetic variation influences biological response to chemical carcinogens. This genetic variation has been postulated to influence the variability in risk for HCC observed both within and across populations. Ongoing studies seek to fully understand the mechanisms by which genetic variation in response to chemical carcinogens impacts on HCC risk.
文摘This review highlights therapeutic agents from recent cancer therapeutic trials showing the greatest potential for further clinical use for sunitinib in the near future. In fact, sunitinib is one of multi-tyrosine kinase inhibitors;tyrosine kinases are enzymes, which transfer phosphate groups from ATP to the hydroxyl group of tyrosine residues on signal transduction molecules. Phosphorylation of signal transduction molecules, in turn, induces dramatic changes in tumor growth, including activation of angiogenesis and DNA synthesis. Therefore, sustain efforts have been directed for developing inhibitors for angiogenesis, which is the marginal process for tumor growth and development through targeting TKs. Almost if not all angiogenesis inhibitors target the vascular endothelial growth factor (VEGF) signaling pathway.
文摘目的用Cocktail探针药物法研究参麦注射液对大鼠细胞色素P450酶（CYP450）6种亚型活性的影响。方法将SD大鼠随机分组,实验组ip给予参麦注射液（10 m L/kg）,对照组ip给予等量生理盐水,诱导7 d,分别以非那西丁、安非他酮、甲苯磺丁脲、奥美拉唑、美托洛尔和咪达唑仑作为CYP1A2、CYP2B1、CYP2C9、CYP2C19、CYP2D6和CYP3A4的探针药物。UPLC-MS/MS法检测大鼠血浆中探针药物的血药浓度,采用DAS3.0软件估算药动学参数。结果与对照组相比,非那西丁、安非他酮和奥美拉唑的AUC0^∞、CL和Cmax显著降低（P〈0.05）,甲苯磺丁脲、美托洛尔和咪达唑仑的AUC0^∞、CL和Cmax无显著性差异。结论参麦注射液对大鼠CYP1A2、CYP2B1和CYP2C19亚型的活性有明显的抑制作用,而对CYP2C9、CYP2D6和CYP3A4亚型的活性无显著性影响。
基金This project was supported by the grants from National Natural Science Foundation of China(81173120,81302834)Major Program of National Natural Science Foundation of China(2012ZX09506001-004).
文摘RNA interference(RNAi)is useful for selective gene silencing.Cytochrome P4503A4(CYP3A4),which metabolizes approximately 50% of drugs in clinical use,plays an important role in drug metabolism.In this study,we aimed to develop a short hairpin RNA(shRNA)to modulate CYP3A4 expression.Three new shRNAs(S1,S2 and S3)were designed to target the coding sequence(CDS)of CYP3A4,cloned into a shRNA expression vector,and tested in different cells.The mixture of three shRNAs produced optimal reduction(55%)in CYP3A4 CDS-luciferase activity in both CHL and HEK293 cells.Endogenous CYP3A4 expression in HepG2 cells was decreased about 50%at both mRNA and protein level after transfection of the mixture of three shRNAs.In contrast,CYP3A5 gene expression was not altered by the shRNAs,supporting the selectivity of CYP3A4 shRNAs.In addition,HepG2 cells transfected with CYP3A4 shRNAs were less sensitive to Ginkgolic acids,whose toxic metabolites are produced by CYP3A4.These results demonstrate that vector-based shRNAs could modulate CYP3A4 expression in cells through their actions on CYP3A4 CDS,and CYP3A4 shRNAs may be utilized to define the role of CYP3A4 in drug metabolism and toxicity.
基金supported by National Natural Science Foundation of China (No.30772620)Guangdong Medical Science and Technology Research Foundation (NO.A2007048)
文摘Background In recent years, it is found that the polymorphisms of genes which are involved in the pharmacokinetic and pharmacodynamic pathways play important roles in the clinical anticoagulation treatment with warfarin. The aim of the study was to investigate the impact of the genetic polymorphism of r-glutamic acid carboxylase （gamma-glutamyl carboxylase gene, GGCX） on the response of warfarin initial anticoagulant therapy. Methods Seven hundred and ninety-eight Chinese Han patients who received valve replacement surgery and orally taken warfarin in long term for anticoagulant therapy in Guangdong General Hospital from 2000 to 2008 were enrolled in the study, a polymorphic SNPs point （rs699664） of GGCX was selected, and SnaPshot was adopted to perform single nucleotide polymorphism （SNP） test, and by grouping according to genotype, GGCX average daily dose of warfarin, time for PT-INR to reach the target value and differences in the incidence of excessive coagulation between different genotypes were compared respectively. Hardy-Weinberg genetic equilibrium test was applied for population representative test. Results Within the 20 days of warfarin initial therapy, male average daily dose of warfarin （2.92 ± 1.18 mg/d） was apparently higher than that of female （2.64 ± 0.98 mg/d）, while there were no significant differences in the average time required for PT-INR to reach the target value （ 1.8） and the excessive coagulation ratio at the initial therapy stage between male and female. And there were no significant differences in the average daily dose of warfarin, time to reach the target value and excessive coagulation ratio among different GGCX genotypes. Conclusions GGCX genovariation had no significant impact on the warfarin daily dose within the 20-day initial therapy of Chinese Han Population, and for the conventional dosage program, the risk of bleeding in the GGCX mutation individuals did not increase obviously at the initial administration period.
