AIM: To characterize cytochrome P4501A1 (CYPIA1), glutathione S-transferases (GSTs) and microsomal epoxide hydrolase (mEH) polymorphisms in Chinese esophageal cancer patients. METHODS: Multiplex polymerase chain react...AIM: To characterize cytochrome P4501A1 (CYPIA1), glutathione S-transferases (GSTs) and microsomal epoxide hydrolase (mEH) polymorphisms in Chinese esophageal cancer patients. METHODS: Multiplex polymerase chain reaction (PCR) and PCR based restriction fragment length polymorphisms (PCRRFLP) were used to detect polymorphism changes of CYP,GSTs and mEH on esophageal cancerous and precancerous lesions as well as in case control group. All the examination samples were obtained from Linzhou (formerly Linxian), Henan Province, the highest incidence area for esophageal. RESULTS: The frequency of CYP1A1 3'' polymorphism in case control group (26/38, 68 %) was significantly higher than in esophageal squamous cell carcinoma^roup (ESCC) (29/62, 47 %) (P<0.05). A significant difference in the incidence of mEH slow allele variant was observed between case control group (15/38, 39 %) and esophageal dysplasiagroup (22/32, 69 %) or ESCC group (39/62, 63 %) (P<0.05). However, no significant difference was observed among different groups in the polymorphisms of CYPIA1 exon 7, GSTM1, GSTT1, GSTP1 and mEH fast allele. CONCLUSION: The present results suggest that CYPIA1 3'' polymorphism may be one of the promising protectivef actors and its wild gene type may be an indicator for higher susceptibility to esophageal cancer, mEH slow allele variant,associated with the progression of esophageal precancerous lesions, may conthbute to the high susceptibility to esophageal carcinoma.展开更多
AIM： To explore whether polymorphisms of the CYPIA1 and GSTM1 genes are associated with susceptibility of stomach cancer. METHODS： A total of 102 stomach cancer cases and 62 healthy persons were diagnosed by patholo...AIM： To explore whether polymorphisms of the CYPIA1 and GSTM1 genes are associated with susceptibility of stomach cancer. METHODS： A total of 102 stomach cancer cases and 62 healthy persons were diagnosed by pathology in 1998- 2000 in the Qilu Hospital of Shandong University. Gene polymorphisms were detected by the PCR using sequencespecific primers. Data analysis of the case-control study was carried out using the unconditional logistic method. RESULTS： After adjustment for age, sex, educational levels, and occupation, the risk factors for stomach cancer were shown to be smoking, Helicobacter pylori （H pylon）, and presence of the CYPIM G/G and GSTM1O/O genotypes. Interaction was observed between the combined genotypes of either CYPIA1 G/G and GSTM1O/O or Hpyloriinfection, or GSTM1O/O and Hpyloriinfection or smoking. CONCLUSION： Polymorphisms of the CYPIA1 and GSTM1 genes, Hpyloriinfection and smoking are related to susceptibility to stomach cancer.展开更多
AIM:To evaluate the association between CYP1A1 and GSTs genetic polymorphisms and susceptibility to esophageal squamous cell carcinoma(SCC)and esophageal adenocarcinoma(ADC)in a high risk area of northwest of France. ...AIM:To evaluate the association between CYP1A1 and GSTs genetic polymorphisms and susceptibility to esophageal squamous cell carcinoma(SCC)and esophageal adenocarcinoma(ADC)in a high risk area of northwest of France. METHODS:A case-control study was conducted to investigate the genetic polymorphisms of these enzymes (CYPIAI*2C and GSTP1 exon 7 Val alleles,GSTMI*2/*2 and GSTTl *2/*2 null genotypes).A total of 79 esophageal cancer cases and 130 controls were recruited. RESULTS:GSTMI*2/*2 and CYPIAI*IA/*2C genotype frequencies were higher among squamous cell carcinomas at a level dose to statistical significance(OR =1.83,95% CI 0.88-3.83,P=0.11;OR=3.03,95% CI 0.93-9.90,P=0.07, respectively).For GSTP1 polymorphism,no difference was found between controls and cases,whatever their histological status.Lower frequency of GSTT1 deletion was observed in ADC group compared to controls with a statistically significant difference(OR=13.31,95% CI 1.66-106.92,P<0.01). CONCLUSION:In SCC,our results are consistent with the strong association of this kind of tumour with tobacco exposure.In ADC,our results suggest 3 distinct hypotheses: (1)activation of exogenous procarcinogens,such as small halogenated compounds by GSTT1;(2)contribution of GSTT1 to the inflammatory response of esophageal mucosa,which is known to be a strong risk factor for ADC, possibly through leukotriene synthesis;(3)higher sensitivity to the inflammatory process associated with intracellular depletion of glutathione.展开更多
AIM： To study the effect of celecoxib （CXB） on diethylnitrosamine activation through the regulation of cytochrome P450 in a hepatocarcinogenesis model.METHODS： Six-week-old male Sprague-Dawley rats were randomly d...AIM： To study the effect of celecoxib （CXB） on diethylnitrosamine activation through the regulation of cytochrome P450 in a hepatocarcinogenesis model.METHODS： Six-week-old male Sprague-Dawley rats were randomly divided into five groups, a non-treated group （NT）, a diethylnitrosamine-treated group （DEN）, a DEN＋CXB-treated group （DEN＋CXB）,and CXB 8 d-treated and CXB 32 d-treated groups. The effects of celecoxib on the enzymatic activities of CYP1A1, 2A, 2B1/2, and 2E1 were assessed in hepatic microsomes 24 h after DEN administration.Changes in CYPIA1 and CYP2B1/2 protein expression were also evaluated. The rate of DEN metabolism was measured by the production of the deethylation metabolite acetaldehyde, and the denitrosation metabolite nitrite.RESULTS： DEN＋CXB administration produced a significant increase in the enzymatic activities ofCYP2B1/2 and 1A1, whereas it did not change the activities of CYP2A and 2E1, compared to that of the DEN group. CXB treatment for eight days did not produce a significant effect on enzymatic activity when compared to the NT group; however, when it was administered for prolonged times （CXB 32 d group）,the enzymatic activities were increased in a similar pattern to those in the DEN＋CXB group. The observed increase in the enzymatic activities in the DEN＋CXB group was accompanied by an increase in the CYP2B1/2 protein levels; no changes were observed in the levels of CYPIA1. In vitro, CXB increased the denitrosation of DEN, a pathway of metabolic detoxification. The addition of SKF-525A, a preferential inhibitor of CYP2B, abrogated the denitrosation of DEN.CONCLUSION： These results suggest that the mechanism of action of CXB involves enhancement of the detoxification of DEN by an increasing denitrosation via CYP2B1/2.展开更多
基金National Outstanding Young Scientist Award of China 30025016(China)State Key Project for Basic Research G 1998051206(China)+1 种基金Foundation of Henan Education Committee 1999125the U.S.NIH Grant CA65871
文摘AIM: To characterize cytochrome P4501A1 (CYPIA1), glutathione S-transferases (GSTs) and microsomal epoxide hydrolase (mEH) polymorphisms in Chinese esophageal cancer patients. METHODS: Multiplex polymerase chain reaction (PCR) and PCR based restriction fragment length polymorphisms (PCRRFLP) were used to detect polymorphism changes of CYP,GSTs and mEH on esophageal cancerous and precancerous lesions as well as in case control group. All the examination samples were obtained from Linzhou (formerly Linxian), Henan Province, the highest incidence area for esophageal. RESULTS: The frequency of CYP1A1 3'' polymorphism in case control group (26/38, 68 %) was significantly higher than in esophageal squamous cell carcinoma^roup (ESCC) (29/62, 47 %) (P<0.05). A significant difference in the incidence of mEH slow allele variant was observed between case control group (15/38, 39 %) and esophageal dysplasiagroup (22/32, 69 %) or ESCC group (39/62, 63 %) (P<0.05). However, no significant difference was observed among different groups in the polymorphisms of CYPIA1 exon 7, GSTM1, GSTT1, GSTP1 and mEH fast allele. CONCLUSION: The present results suggest that CYPIA1 3'' polymorphism may be one of the promising protectivef actors and its wild gene type may be an indicator for higher susceptibility to esophageal cancer, mEH slow allele variant,associated with the progression of esophageal precancerous lesions, may conthbute to the high susceptibility to esophageal carcinoma.
基金Supported by the Association of Science and Technology of Shandong Province, No. Y97C21057
文摘AIM： To explore whether polymorphisms of the CYPIA1 and GSTM1 genes are associated with susceptibility of stomach cancer. METHODS： A total of 102 stomach cancer cases and 62 healthy persons were diagnosed by pathology in 1998- 2000 in the Qilu Hospital of Shandong University. Gene polymorphisms were detected by the PCR using sequencespecific primers. Data analysis of the case-control study was carried out using the unconditional logistic method. RESULTS： After adjustment for age, sex, educational levels, and occupation, the risk factors for stomach cancer were shown to be smoking, Helicobacter pylori （H pylon）, and presence of the CYPIM G/G and GSTM1O/O genotypes. Interaction was observed between the combined genotypes of either CYPIA1 G/G and GSTM1O/O or Hpyloriinfection, or GSTM1O/O and Hpyloriinfection or smoking. CONCLUSION： Polymorphisms of the CYPIA1 and GSTM1 genes, Hpyloriinfection and smoking are related to susceptibility to stomach cancer.
基金Supported by the Grants From Ligue Nationale Contre le Cancer,Comités Départementaux de la Manche,de l'Orne et du Calvados and from Université de Metz
文摘AIM:To evaluate the association between CYP1A1 and GSTs genetic polymorphisms and susceptibility to esophageal squamous cell carcinoma(SCC)and esophageal adenocarcinoma(ADC)in a high risk area of northwest of France. METHODS:A case-control study was conducted to investigate the genetic polymorphisms of these enzymes (CYPIAI*2C and GSTP1 exon 7 Val alleles,GSTMI*2/*2 and GSTTl *2/*2 null genotypes).A total of 79 esophageal cancer cases and 130 controls were recruited. RESULTS:GSTMI*2/*2 and CYPIAI*IA/*2C genotype frequencies were higher among squamous cell carcinomas at a level dose to statistical significance(OR =1.83,95% CI 0.88-3.83,P=0.11;OR=3.03,95% CI 0.93-9.90,P=0.07, respectively).For GSTP1 polymorphism,no difference was found between controls and cases,whatever their histological status.Lower frequency of GSTT1 deletion was observed in ADC group compared to controls with a statistically significant difference(OR=13.31,95% CI 1.66-106.92,P<0.01). CONCLUSION:In SCC,our results are consistent with the strong association of this kind of tumour with tobacco exposure.In ADC,our results suggest 3 distinct hypotheses: (1)activation of exogenous procarcinogens,such as small halogenated compounds by GSTT1;(2)contribution of GSTT1 to the inflammatory response of esophageal mucosa,which is known to be a strong risk factor for ADC, possibly through leukotriene synthesis;(3)higher sensitivity to the inflammatory process associated with intracellular depletion of glutathione.
基金Supported by Consejo Nacional de Ciencia y Tecnología (Mexico),grant 39525-M,and scholarship 119303 (M.E.S.N.)
文摘AIM： To study the effect of celecoxib （CXB） on diethylnitrosamine activation through the regulation of cytochrome P450 in a hepatocarcinogenesis model.METHODS： Six-week-old male Sprague-Dawley rats were randomly divided into five groups, a non-treated group （NT）, a diethylnitrosamine-treated group （DEN）, a DEN＋CXB-treated group （DEN＋CXB）,and CXB 8 d-treated and CXB 32 d-treated groups. The effects of celecoxib on the enzymatic activities of CYP1A1, 2A, 2B1/2, and 2E1 were assessed in hepatic microsomes 24 h after DEN administration.Changes in CYPIA1 and CYP2B1/2 protein expression were also evaluated. The rate of DEN metabolism was measured by the production of the deethylation metabolite acetaldehyde, and the denitrosation metabolite nitrite.RESULTS： DEN＋CXB administration produced a significant increase in the enzymatic activities ofCYP2B1/2 and 1A1, whereas it did not change the activities of CYP2A and 2E1, compared to that of the DEN group. CXB treatment for eight days did not produce a significant effect on enzymatic activity when compared to the NT group; however, when it was administered for prolonged times （CXB 32 d group）,the enzymatic activities were increased in a similar pattern to those in the DEN＋CXB group. The observed increase in the enzymatic activities in the DEN＋CXB group was accompanied by an increase in the CYP2B1/2 protein levels; no changes were observed in the levels of CYPIA1. In vitro, CXB increased the denitrosation of DEN, a pathway of metabolic detoxification. The addition of SKF-525A, a preferential inhibitor of CYP2B, abrogated the denitrosation of DEN.CONCLUSION： These results suggest that the mechanism of action of CXB involves enhancement of the detoxification of DEN by an increasing denitrosation via CYP2B1/2.
