Aim To establish a HPLC method for determining five major metabolites of caffeine in the urine,5-acetylamino-6-formylamino-3-methyluracil(AFMU),1-methylxanthine(1X),1-methyluric acid(1U),1,7-dimethyluric acid(17U) and...Aim To establish a HPLC method for determining five major metabolites of caffeine in the urine,5-acetylamino-6-formylamino-3-methyluracil(AFMU),1-methylxanthine(1X),1-methyluric acid(1U),1,7-dimethyluric acid(17U) and 1,7-dimethylxanthine(17X) and assess the activity of cytochrome P-450 CYP2A6.Methods The contents of five major metabolites of caffeine in the urine were determined by RP-HPLC method.Frequency distribution histogram was drawn by calculating the 17U/(AFMU+1X+1U+17X+17U) and then evaluated the activity of CYP2A6.Results The frequency distribution histograms of CYP2A6 approximately indicated three distinct groups,the cut of point is 0.23 between fast metabolizer and intermediate type.And the cut of point is 0.15 between slow metabolizer and intermediate type.Conclusion The method is simple and rapid,suitable for the determination of metabolites of caffeine in urine.The method can be used to assay the activity of CYP2A6.展开更多
目的运用系统回顾和Meta分析的方法评价CYP2A6基因多态性与S-1化疗获益的关系。方法检索Pubmed、CNKI、CBM和万方中文数据库,按照纳入和排除标准筛选关于CYP2A6基因与S-1化疗获益相关的病例对照研究或队列研究,检索时限为数据库建库至2...目的运用系统回顾和Meta分析的方法评价CYP2A6基因多态性与S-1化疗获益的关系。方法检索Pubmed、CNKI、CBM和万方中文数据库,按照纳入和排除标准筛选关于CYP2A6基因与S-1化疗获益相关的病例对照研究或队列研究,检索时限为数据库建库至2014年6月。使用Rev Man 5.3和Stata 11.2进行统计分析。结果共纳入7篇文献进入分析,文献质量评价结果显示纳入研究质量良好。一般资料结果显示,在东方人种中,CYP2A6＊1/＊1（W/W）频率平均为25.6%;CYP2A6＊4A,＊7,＊9,＊10存在一种突变（W/V）频率平均为48.8%,CYP2A6＊4A,＊7,＊9,＊10存在2种突变（V/V）频率平均为25.6%。Meta分析发现：1突变型V/V与野生型W/W及突变型W/V患者的S-1化疗敏感性差异有统计学意义,合并优势比（OR）为0.27（95%CI：0.14~0.51）;2野生型W/W与突变型W/V及V/V生存HR差异有统计学意义,合并HR值为1.71（95%CI：0.99~2.94）。结论 CYP2A6＊4A,＊7,＊9,＊10与晚期肿瘤患者S-1化疗获益存在一定关联性。但因为纳入研究的数量有限,需要有大样本、多变量的分析研究来进一步证实和完善本研究结果。展开更多
AIM: Caffeine metabolite ratios in urine can be used to evaluate the activity of CYP1A2, CYP2A6, NAT2 and XO in vivo. In this study, an HPLC method was developed to quantify the concentrations of caffeine metabolites ...AIM: Caffeine metabolite ratios in urine can be used to evaluate the activity of CYP1A2, CYP2A6, NAT2 and XO in vivo. In this study, an HPLC method was developed to quantify the concentrations of caffeine metabolites in 24 Chinese healthy volunteers. METHODS: 100 mg of caffeine was given to each subject as a probe drug and the urine samples of 0-12 h were collected. Urine samples were extracted with chloroform/isopropanol (9∶1, v/v) under acerbic environment (pH 3.5) and separated on a Hypersil BDS C18 column with gradient elution. The mobile phase was composed of phase A (acetonitrile) and phase B (10 mmol/L ammonium formate/formic acid (998/2, v/v) (pH 3.5) from 98/2 to 70/30, the detection wave length was 280 nm. CYP1A2 phenotype was calculated from the metabolite ratio of (AFMU+1X+1U)/17U, CYP2A6 from the ratio of 17U/(17U+17X+1U+1X+AFMU), NAT2 from the ratio of AFMU/(AFMU+1U+1X) and XO from the ratio of 1U/1X+1U. RESULTS: The calibration curves of AFMU, 1U, 1X, 17U, 17X, 137X were linear over the range of 1.25-160 μmol/L, yielding correlation of coefficients from 0.991 to 0.999. The LOD were 2.5 ng/mL for AFMU, 1X, 1U and 1 ng/mL for 17U, 17X, 137X. Recoveries for the analytes wereranged from 81%-94%, Intra-and Inter-day coefficients of variation were ranged from 2.56%-9.48% and 5.74%-10.91%, respectively. After logarithmic transformation of these metabolite ratios, phenotype of CYP1A2, CYP2A6, NAT2 were shown normal distribution, while the phenotype of XO was shown non-normal distribution with two subjects appearing with very low metabolic capacity. It was also found a negative association between the phenotype of CYP2A6 and CYP1A2 which might be explained by the fact that CYP2A6 plays an influential role in 17X metabolism. CONCLUSION: In brief, the experiment demonstrates an accurate, stable and replicable HPLC method for phenotyping of these enzymes in Chinese volunteers.展开更多
While we studied pharmacokinetics of SM-12502 which was under development as an anti-PAF agent, we found three subjects showing a slow metabolic phenotype in its pharmacokinetics. Analyzing the genes for CYP2A6 from t...While we studied pharmacokinetics of SM-12502 which was under development as an anti-PAF agent, we found three subjects showing a slow metabolic phenotype in its pharmacokinetics. Analyzing the genes for CYP2A6 from the three subjects, we discovered that the three subjects possessed the whole CYP2A6 gene deletion (CYP2A6*4C), a novel genetic polymorphism of the CYP2A6 gene. Genetically engineered Salmonella YG7108 cells expressing human CYP2A6 or CYP2E1 together with the NADPH-CYP reductase were established in our laboratory to compare the mutagen-producing capacity of these enzymes for various N-nitrosamines. We found that CYP2E1 was responsible for the metabolic activation of N-nitrosamines with relatively short alkyl chains, whereas CYP2A6 was involved in the metabolic activation of N-nitrosamines possessing relatively bulky alkyl chains such as a tobacco-specific nitrosamine, NNK, which has been known to cause lung tumor in rodents. Thus, to examine a hypothesis that individuals possessing the CYP2A6*4C have the reduced risk of lung cancer due to the lack of the capacity of the metabolic activation of certain carcinogens in tobacco smoke, a case-control study was performed.展开更多
Dietary exposure to aflatoxin B1(AFB1)is harmful to the health and performance of domestic animals.The hepatic cytochrome P450s(CYPs),CYP1A1 and CYP2A6,are the primary enzymes responsible for the bioactivation of AFB1...Dietary exposure to aflatoxin B1(AFB1)is harmful to the health and performance of domestic animals.The hepatic cytochrome P450s(CYPs),CYP1A1 and CYP2A6,are the primary enzymes responsible for the bioactivation of AFB1to the highly toxic exo-AFB1-8,9-epoxide(AFBO)in chicks.However,the transcriptional regulation mechanism of these CYP genes in the liver of chicks in AFB1metabolism remains unknown.Dual-luciferase reporter assay,bioinformatics and site-directed mutation results indicated that specificity protein 1(SP1)and activator protein-1(AP-1)motifs were located in the core region-1,063/-948,-606/-541 of the CYP1A1 promoter as well as-636/-595,-503/-462,-147/-1 of the CYP2A6 promoter.Furthermore,overexpression and decoy oligodeoxynucleotide technologies demonstrated that SP1 and AP-1 were pivotal transcriptional activators regulating the promoter activity of CYP1A1 and CYP2A6.Moreover,bioactivation of AFB1to AFBO could be increased by upregulation of CYP1A1 and CYP2A6 expression,which was trans-activated owing to the upregulation of AP-1,rather than SP1,stimulated by AFB1-induced reactive oxygen species.Additionally,nano-selenium could reduce ROS,downregulate AP-1 expression and then decrease the expression of CYP1A1 and CYP2A6,thus alleviating the toxicity of AFB1.In conclusion,AP-1 and SP1 played important roles in the transactivation of CYP1A1 and CYP2A6 expression and further bioactivated AFB1to AFBO in chicken liver,which could provide novel targets for the remediation of aflatoxicosis in chicks.展开更多
文摘Aim To establish a HPLC method for determining five major metabolites of caffeine in the urine,5-acetylamino-6-formylamino-3-methyluracil(AFMU),1-methylxanthine(1X),1-methyluric acid(1U),1,7-dimethyluric acid(17U) and 1,7-dimethylxanthine(17X) and assess the activity of cytochrome P-450 CYP2A6.Methods The contents of five major metabolites of caffeine in the urine were determined by RP-HPLC method.Frequency distribution histogram was drawn by calculating the 17U/(AFMU+1X+1U+17X+17U) and then evaluated the activity of CYP2A6.Results The frequency distribution histograms of CYP2A6 approximately indicated three distinct groups,the cut of point is 0.23 between fast metabolizer and intermediate type.And the cut of point is 0.15 between slow metabolizer and intermediate type.Conclusion The method is simple and rapid,suitable for the determination of metabolites of caffeine in urine.The method can be used to assay the activity of CYP2A6.
文摘目的运用系统回顾和Meta分析的方法评价CYP2A6基因多态性与S-1化疗获益的关系。方法检索Pubmed、CNKI、CBM和万方中文数据库,按照纳入和排除标准筛选关于CYP2A6基因与S-1化疗获益相关的病例对照研究或队列研究,检索时限为数据库建库至2014年6月。使用Rev Man 5.3和Stata 11.2进行统计分析。结果共纳入7篇文献进入分析,文献质量评价结果显示纳入研究质量良好。一般资料结果显示,在东方人种中,CYP2A6＊1/＊1（W/W）频率平均为25.6%;CYP2A6＊4A,＊7,＊9,＊10存在一种突变（W/V）频率平均为48.8%,CYP2A6＊4A,＊7,＊9,＊10存在2种突变（V/V）频率平均为25.6%。Meta分析发现：1突变型V/V与野生型W/W及突变型W/V患者的S-1化疗敏感性差异有统计学意义,合并优势比（OR）为0.27（95%CI：0.14~0.51）;2野生型W/W与突变型W/V及V/V生存HR差异有统计学意义,合并HR值为1.71（95%CI：0.99~2.94）。结论 CYP2A6＊4A,＊7,＊9,＊10与晚期肿瘤患者S-1化疗获益存在一定关联性。但因为纳入研究的数量有限,需要有大样本、多变量的分析研究来进一步证实和完善本研究结果。
文摘AIM: Caffeine metabolite ratios in urine can be used to evaluate the activity of CYP1A2, CYP2A6, NAT2 and XO in vivo. In this study, an HPLC method was developed to quantify the concentrations of caffeine metabolites in 24 Chinese healthy volunteers. METHODS: 100 mg of caffeine was given to each subject as a probe drug and the urine samples of 0-12 h were collected. Urine samples were extracted with chloroform/isopropanol (9∶1, v/v) under acerbic environment (pH 3.5) and separated on a Hypersil BDS C18 column with gradient elution. The mobile phase was composed of phase A (acetonitrile) and phase B (10 mmol/L ammonium formate/formic acid (998/2, v/v) (pH 3.5) from 98/2 to 70/30, the detection wave length was 280 nm. CYP1A2 phenotype was calculated from the metabolite ratio of (AFMU+1X+1U)/17U, CYP2A6 from the ratio of 17U/(17U+17X+1U+1X+AFMU), NAT2 from the ratio of AFMU/(AFMU+1U+1X) and XO from the ratio of 1U/1X+1U. RESULTS: The calibration curves of AFMU, 1U, 1X, 17U, 17X, 137X were linear over the range of 1.25-160 μmol/L, yielding correlation of coefficients from 0.991 to 0.999. The LOD were 2.5 ng/mL for AFMU, 1X, 1U and 1 ng/mL for 17U, 17X, 137X. Recoveries for the analytes wereranged from 81%-94%, Intra-and Inter-day coefficients of variation were ranged from 2.56%-9.48% and 5.74%-10.91%, respectively. After logarithmic transformation of these metabolite ratios, phenotype of CYP1A2, CYP2A6, NAT2 were shown normal distribution, while the phenotype of XO was shown non-normal distribution with two subjects appearing with very low metabolic capacity. It was also found a negative association between the phenotype of CYP2A6 and CYP1A2 which might be explained by the fact that CYP2A6 plays an influential role in 17X metabolism. CONCLUSION: In brief, the experiment demonstrates an accurate, stable and replicable HPLC method for phenotyping of these enzymes in Chinese volunteers.
文摘While we studied pharmacokinetics of SM-12502 which was under development as an anti-PAF agent, we found three subjects showing a slow metabolic phenotype in its pharmacokinetics. Analyzing the genes for CYP2A6 from the three subjects, we discovered that the three subjects possessed the whole CYP2A6 gene deletion (CYP2A6*4C), a novel genetic polymorphism of the CYP2A6 gene. Genetically engineered Salmonella YG7108 cells expressing human CYP2A6 or CYP2E1 together with the NADPH-CYP reductase were established in our laboratory to compare the mutagen-producing capacity of these enzymes for various N-nitrosamines. We found that CYP2E1 was responsible for the metabolic activation of N-nitrosamines with relatively short alkyl chains, whereas CYP2A6 was involved in the metabolic activation of N-nitrosamines possessing relatively bulky alkyl chains such as a tobacco-specific nitrosamine, NNK, which has been known to cause lung tumor in rodents. Thus, to examine a hypothesis that individuals possessing the CYP2A6*4C have the reduced risk of lung cancer due to the lack of the capacity of the metabolic activation of certain carcinogens in tobacco smoke, a case-control study was performed.
基金partly supported by the Chinese Natural Science Foundation Projects(31772636,32072775,32272915)the National Key Research and Development Program of China(2023YFD1301003)+1 种基金the Fundamental Research Funds for the Central Universities(2662023DKPY002)the Top-notch Young Talent Supporting Program to LHS,a gift from Beijing Deyuanshun Biotechnology Co.,Ltd。
文摘Dietary exposure to aflatoxin B1(AFB1)is harmful to the health and performance of domestic animals.The hepatic cytochrome P450s(CYPs),CYP1A1 and CYP2A6,are the primary enzymes responsible for the bioactivation of AFB1to the highly toxic exo-AFB1-8,9-epoxide(AFBO)in chicks.However,the transcriptional regulation mechanism of these CYP genes in the liver of chicks in AFB1metabolism remains unknown.Dual-luciferase reporter assay,bioinformatics and site-directed mutation results indicated that specificity protein 1(SP1)and activator protein-1(AP-1)motifs were located in the core region-1,063/-948,-606/-541 of the CYP1A1 promoter as well as-636/-595,-503/-462,-147/-1 of the CYP2A6 promoter.Furthermore,overexpression and decoy oligodeoxynucleotide technologies demonstrated that SP1 and AP-1 were pivotal transcriptional activators regulating the promoter activity of CYP1A1 and CYP2A6.Moreover,bioactivation of AFB1to AFBO could be increased by upregulation of CYP1A1 and CYP2A6 expression,which was trans-activated owing to the upregulation of AP-1,rather than SP1,stimulated by AFB1-induced reactive oxygen species.Additionally,nano-selenium could reduce ROS,downregulate AP-1 expression and then decrease the expression of CYP1A1 and CYP2A6,thus alleviating the toxicity of AFB1.In conclusion,AP-1 and SP1 played important roles in the transactivation of CYP1A1 and CYP2A6 expression and further bioactivated AFB1to AFBO in chicken liver,which could provide novel targets for the remediation of aflatoxicosis in chicks.
