Cytochromes P450(CYPs)play a prominent role in catalyzing phase I xenobiotic biotransformation and account for about 75%of the total metabolism of commercially available drugs,including chemotherapeutics.The gene expr...Cytochromes P450(CYPs)play a prominent role in catalyzing phase I xenobiotic biotransformation and account for about 75%of the total metabolism of commercially available drugs,including chemotherapeutics.The gene expression and enzyme activity of CYPs are variable between individuals,which subsequently leads to different patterns of susceptibility to carcinogenesis by genotoxic xenobiotics,as well as differences in the efficacy and toxicity of clinically used drugs.This research aimed to examine the presence of the CYP2B6*9 polymorphism and its possible association with the incidence of B-CLL in Egyptian patients,as well as the clinical outcome after receiving cyclophosphamide chemotherapy.DNA was isolated from whole blood samples of 100 de novo B-CLL cases and also from 100 sex-and age-matched healthy individuals.The presence of the CYP2B6*9(G516T)polymorphism was examined by PCR-based allele specific amplification(ASA).Patients were further indicated for receiving chemotherapy,and then they were followed up.The CYP2B6*9 variant indicated a statistically significant higher risk of B-CLL under different genetic models,comprising allelic(T-allele vs.G-allele,OR=4.8,p<0.001)and dominant(GT+TT vs.GG,OR=5.4,p<0.001)models.Following cyclophosphamide chemotherapy,we found that the patients with variant genotypes(GT+TT)were less likely to achieve remission compared to those with the wild-type genotype(GG),with a response percentage of(37.5%vs.83%,respectively).In conclusion,our findings showed that the CYP2B6*9(G516T)polymorphism is associated with B-CLL susceptibility among Egyptian patients.This variant greatly affected the clinical outcome and can serve as a good therapeutic marker in predicting response to cyclophosphamide treatment.展开更多
AIM: To identify the new alternative splicing variants of human CYP2D6 in human extratumoral liver tissue with RT-PCR and sequencing. METHODS: Full length of human CYP2D6 cDNAs was amplificated by reverse transcriptio...AIM: To identify the new alternative splicing variants of human CYP2D6 in human extratumoral liver tissue with RT-PCR and sequencing. METHODS: Full length of human CYP2D6 cDNAs was amplificated by reverse transcription-polymerase chain reaction (RT-PCR) from a human extratumoral liver tissue and cloned into pGEM-T vector. The cDNA was sequenced. Exons from 1 to 4 of human CYP2D6 cDNAs were also amplificated by RT-PCR from extratumoral liver tissues of 17 human hepatocellular carcinomas. Some RT-PCR products were sequenced. Exons 1 to 4 of CYP2D6 gene were amplified by PCR from extratumoral liver tissue DNA. Two PCR products from extratumoral liver tissues expressing skipped mRNA were partially sequenced. RESULTS: One of the CYP2D6 cDNAs had 470 nucleotides from 79 to 548 (3' portion of exons 1 to 5' portion of exon 4), and was skipped. Exons 1 to 4 of CYP2D6 cDNA were assayed with RT-PCR in 17 extratumoral liver tissues. Both wild type and skipped mRNAs were expressed in 4 samples, only wild type mRNA was expressed in 5 samples, and only skipped mRNA was expressed in 8 samples. Two more variants were identified by sequencing the RT-PCR products of exons 1 to 4 of CYP2D6 cDNA. The second variant skipped 411 nucleotides from 175 to 585. This variant was identified in 4 different liver tissues by sequencing the RT-PCR products. We sequenced partially 2 of the PCR products amplified of CYP2D6 exon 1 to exon 4 from extratumoral liver tissue genomic DNA that only expressed skipped mRNA by RT-PCR. No point mutations around exon 1, intron 1, and exon 4, and no deletion in CYP2D6 gene were detected. The third variant was the skipped exon 3, and 153 bp was lost. CONCLUSION: Three new alternative splicing variants of CYP2D6 mRNA have been identified. They may not be caused by gene mutation and may lose CYP2D6 activity and act as a down-regulator of CYP2D6.展开更多
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
AIM: Genetic polymorphism in enzymes of carcinogen metabolism has been found to have the influence on the susceptibility to cancer. Cytochrome P450 2E1 (CYP2E1) is considered to play an important role in the metabolic...AIM: Genetic polymorphism in enzymes of carcinogen metabolism has been found to have the influence on the susceptibility to cancer. Cytochrome P450 2E1 (CYP2E1) is considered to play an important role in the metabolic activation of procarcinogens such as N-nitrosoamines and low molecular weight organic compounds. The purpose of this study is to determine whether CYP450 2E1 polymorphisms are associated with risks of gastric cancer. METHODS: We conducted a population based case-control study in Changle county, Fujian Province, a high-risk region of gastric cancer in China. Ninety-one incident gastric cancer patients and ninety-four healthy controls were included in our study. Datas including demographic characteristics, diet intake, and alcohol and tobacco consumption of individuals in our study were completed by a standardized questionnaire.PCR-RFLP revealed three genotypes:heterozygote (C1/C2) and two homozygotes (C1/C1 and C2/C2) in CYP2E1. RESULTS: The frequency of variant genotypes (C1/C2 and C2/C2) in gastric cancer cases and controls was 36.3% and 24.5%, respectively. The rare homozygous C2/C2 genotype was found in 6 individuals in gastric cancer group(6.6%), whereas there was only one in the control group (1.1%). However, there was no statistically significant difference between the two groups (two-tailed Fisher's exact test P=0.066). Individuals in gastric cancer group were more likely to carry genotype C1/C2 (odds ratio, OR=1.50) and C2/C2 (OR=7.34) than individuals in control group (chi(2) =4.597, for trend P=0.032). The frequencies of genotypes with the C2 allele (C1/C2 and C2/C2 genotypes) were compared with those of genotypes without C2 allele (C1/C1 genotype) among individuals in gastric cancer group and control group according to the pattern of gastric cancer risk factors. The results show that individuals who exposed to these gastric cancer risk factors and carry the C2 allele seemed to have a higher risk of developing gastric cancer. CONCLUSION: Polymorphism of CYP2E1 gene may have some effect in the development of gastric cancer in Changle county, Fujian Province.展开更多
Lung cancer is one of the most important causes of cancer-related mortality worldwide. Human cytochrome P450 2A13 enzyme （CYP2A13） is predominantly expressed in the respiratory tract and could catalyze various carci...Lung cancer is one of the most important causes of cancer-related mortality worldwide. Human cytochrome P450 2A13 enzyme （CYP2A13） is predominantly expressed in the respiratory tract and could catalyze various carcinogens. In this study, we quantified CYP2A13 expression in non-small cell lung cancer （NSCLC） tissues and examined the relation between CYP2A13 and clinicopathologic factors. Thirty-five paired lung cancer and normal tissues were studied for the expression of the CYP2A13 gene by using real-time PCR and Western blot- ting assays. We also investigated the relationship between CYP2A13 expression and clinicopathologic factors such as age, gender, histology and lymph node status in tumor tissues. SPSS （17.0） statistical software was applied for data analysis. The real-time PCR results showed that there was no significant difference in the CYP2A13 mRNA transcript levels between tumor and paired normal tissues in the 35 samples and in 12 paired squamous cell car- cinomas. In adenocarcinoma, the expression of CYP2A13 mRNA in tumor tissues was 12.5% of that in adjacent tissues （P 〈 0.05） and it was not associated with age, gender, histology and lymph node status of the patients. The amounts of CYP2A13 proteins detected by Western blotting assays correlated well with those of the correspond- ing mRNAs. In conclusion, the expression of CYP2A13 was downregulated in lung adenocarcinoma. CYP2A13 may be involved in the development and progression of lung adenocarcinoma.展开更多
文摘Cytochromes P450(CYPs)play a prominent role in catalyzing phase I xenobiotic biotransformation and account for about 75%of the total metabolism of commercially available drugs,including chemotherapeutics.The gene expression and enzyme activity of CYPs are variable between individuals,which subsequently leads to different patterns of susceptibility to carcinogenesis by genotoxic xenobiotics,as well as differences in the efficacy and toxicity of clinically used drugs.This research aimed to examine the presence of the CYP2B6*9 polymorphism and its possible association with the incidence of B-CLL in Egyptian patients,as well as the clinical outcome after receiving cyclophosphamide chemotherapy.DNA was isolated from whole blood samples of 100 de novo B-CLL cases and also from 100 sex-and age-matched healthy individuals.The presence of the CYP2B6*9(G516T)polymorphism was examined by PCR-based allele specific amplification(ASA).Patients were further indicated for receiving chemotherapy,and then they were followed up.The CYP2B6*9 variant indicated a statistically significant higher risk of B-CLL under different genetic models,comprising allelic(T-allele vs.G-allele,OR=4.8,p<0.001)and dominant(GT+TT vs.GG,OR=5.4,p<0.001)models.Following cyclophosphamide chemotherapy,we found that the patients with variant genotypes(GT+TT)were less likely to achieve remission compared to those with the wild-type genotype(GG),with a response percentage of(37.5%vs.83%,respectively).In conclusion,our findings showed that the CYP2B6*9(G516T)polymorphism is associated with B-CLL susceptibility among Egyptian patients.This variant greatly affected the clinical outcome and can serve as a good therapeutic marker in predicting response to cyclophosphamide treatment.
基金Supported by the National Key Basic Research and Development Program of China,No.2002CB512901National Natural Science Foundation of China,No.39770868 and Natural Science Foundation of Zhejiang Province,No.397490
文摘AIM: To identify the new alternative splicing variants of human CYP2D6 in human extratumoral liver tissue with RT-PCR and sequencing. METHODS: Full length of human CYP2D6 cDNAs was amplificated by reverse transcription-polymerase chain reaction (RT-PCR) from a human extratumoral liver tissue and cloned into pGEM-T vector. The cDNA was sequenced. Exons from 1 to 4 of human CYP2D6 cDNAs were also amplificated by RT-PCR from extratumoral liver tissues of 17 human hepatocellular carcinomas. Some RT-PCR products were sequenced. Exons 1 to 4 of CYP2D6 gene were amplified by PCR from extratumoral liver tissue DNA. Two PCR products from extratumoral liver tissues expressing skipped mRNA were partially sequenced. RESULTS: One of the CYP2D6 cDNAs had 470 nucleotides from 79 to 548 (3' portion of exons 1 to 5' portion of exon 4), and was skipped. Exons 1 to 4 of CYP2D6 cDNA were assayed with RT-PCR in 17 extratumoral liver tissues. Both wild type and skipped mRNAs were expressed in 4 samples, only wild type mRNA was expressed in 5 samples, and only skipped mRNA was expressed in 8 samples. Two more variants were identified by sequencing the RT-PCR products of exons 1 to 4 of CYP2D6 cDNA. The second variant skipped 411 nucleotides from 175 to 585. This variant was identified in 4 different liver tissues by sequencing the RT-PCR products. We sequenced partially 2 of the PCR products amplified of CYP2D6 exon 1 to exon 4 from extratumoral liver tissue genomic DNA that only expressed skipped mRNA by RT-PCR. No point mutations around exon 1, intron 1, and exon 4, and no deletion in CYP2D6 gene were detected. The third variant was the skipped exon 3, and 153 bp was lost. CONCLUSION: Three new alternative splicing variants of CYP2D6 mRNA have been identified. They may not be caused by gene mutation and may lose CYP2D6 activity and act as a down-regulator of CYP2D6.
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.
基金Supported by Natural Science Foundation of Fujian Province,China,No.C001009
文摘AIM: Genetic polymorphism in enzymes of carcinogen metabolism has been found to have the influence on the susceptibility to cancer. Cytochrome P450 2E1 (CYP2E1) is considered to play an important role in the metabolic activation of procarcinogens such as N-nitrosoamines and low molecular weight organic compounds. The purpose of this study is to determine whether CYP450 2E1 polymorphisms are associated with risks of gastric cancer. METHODS: We conducted a population based case-control study in Changle county, Fujian Province, a high-risk region of gastric cancer in China. Ninety-one incident gastric cancer patients and ninety-four healthy controls were included in our study. Datas including demographic characteristics, diet intake, and alcohol and tobacco consumption of individuals in our study were completed by a standardized questionnaire.PCR-RFLP revealed three genotypes:heterozygote (C1/C2) and two homozygotes (C1/C1 and C2/C2) in CYP2E1. RESULTS: The frequency of variant genotypes (C1/C2 and C2/C2) in gastric cancer cases and controls was 36.3% and 24.5%, respectively. The rare homozygous C2/C2 genotype was found in 6 individuals in gastric cancer group(6.6%), whereas there was only one in the control group (1.1%). However, there was no statistically significant difference between the two groups (two-tailed Fisher's exact test P=0.066). Individuals in gastric cancer group were more likely to carry genotype C1/C2 (odds ratio, OR=1.50) and C2/C2 (OR=7.34) than individuals in control group (chi(2) =4.597, for trend P=0.032). The frequencies of genotypes with the C2 allele (C1/C2 and C2/C2 genotypes) were compared with those of genotypes without C2 allele (C1/C1 genotype) among individuals in gastric cancer group and control group according to the pattern of gastric cancer risk factors. The results show that individuals who exposed to these gastric cancer risk factors and carry the C2 allele seemed to have a higher risk of developing gastric cancer. CONCLUSION: Polymorphism of CYP2E1 gene may have some effect in the development of gastric cancer in Changle county, Fujian Province.
基金supported by the Project sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry (No.Z2005-2-45006)
文摘Lung cancer is one of the most important causes of cancer-related mortality worldwide. Human cytochrome P450 2A13 enzyme （CYP2A13） is predominantly expressed in the respiratory tract and could catalyze various carcinogens. In this study, we quantified CYP2A13 expression in non-small cell lung cancer （NSCLC） tissues and examined the relation between CYP2A13 and clinicopathologic factors. Thirty-five paired lung cancer and normal tissues were studied for the expression of the CYP2A13 gene by using real-time PCR and Western blot- ting assays. We also investigated the relationship between CYP2A13 expression and clinicopathologic factors such as age, gender, histology and lymph node status in tumor tissues. SPSS （17.0） statistical software was applied for data analysis. The real-time PCR results showed that there was no significant difference in the CYP2A13 mRNA transcript levels between tumor and paired normal tissues in the 35 samples and in 12 paired squamous cell car- cinomas. In adenocarcinoma, the expression of CYP2A13 mRNA in tumor tissues was 12.5% of that in adjacent tissues （P 〈 0.05） and it was not associated with age, gender, histology and lymph node status of the patients. The amounts of CYP2A13 proteins detected by Western blotting assays correlated well with those of the correspond- ing mRNAs. In conclusion, the expression of CYP2A13 was downregulated in lung adenocarcinoma. CYP2A13 may be involved in the development and progression of lung adenocarcinoma.
基金Natural science foundation project of Heilongjiang Province(D201186)scientific research item of health department of Heilongjiang Province(2012-179)~~
