Hepatoprotective effects of S-adenosyl-L-methionine against alcohol-and cytochrome P450 2E1-induced liver injury

S-adenosyl-L-methionine (SAM) acts as a methyl donor for methylation reactions and participates in the synthesis of glutathione. SAM is also a key metabolite that regulates hepatocyte growth, differentiation and death. Hepatic SAM levels are decreased in animal models of alcohol liver injury and in patients with alcohol liver disease or viral cirrhosis. This review describes the protection by SAM against alcohol and cytochrome P450 2E1-dependent cytotoxicity both in vitro and in vivo and evaluates mechanisms for this protection.

Functionalized selenium nanoparticles ameliorated acetaminophen-induced hepatotoxicity through synergistically triggering PKCδ/Nrf2 signaling pathway and inhibiting CYP 2E1

Selenium nanoparticles(SeNPs)have been demonstrated potential for use in diseases associated with oxidative stress.Functionalized SeNPs with lower toxicity and higher biocompatibility could bring better therapeutic activity and clinical application value.Herein,this work was conducted to investigate the protective effect of Pleurotus tuber-regium polysaccharide-protein complex funtionnalized SeNPs(PTR-SeNPs)against acetaminophen(APAP)-induced oxidative injure in HepG2 cells and C57BL/6J mouse liver.Further elucidation of the underlying molecular mechanism,in particular their modulation of Nrf2 signaling pathway was also performed.The results showed that PTR-SeNPs could significantly ameliorate APAP-induced oxidative injury as evidenced by a range of biochemical analysis,histopathological examination and immunoblotting study.PTR-SeNPs could hosphorylate and activate PKCδ,depress Keap1,and increase nuclear accumulation of Nrf2,resulting in upregulation of GCLC,GCLM,HO-1 and NQO-1 expression.Besides,PTR-SeNPs suppressed the biotransformation of APAP to generate intracellular ROS through CYP 2E1 inhibition,restoring the mitochondrial morphology.Furthermore,the protective effect of PTR-SeNPs against APAP induced hepatotoxicity was weakened as Nrf2 was depleted in vivo,indicating the pivotal role of Nrf2 signaling pathway in PTR-SeNPs mediated hepatoprotective efficacy.Being a potential hepatic protectant,PTR-SeNPs could serve as a new source of selenium supplement for health-promoting and biomedical applications.

Genetic polymorphisms in cytochrome P4502E1, alcohol and aldehyde dehydrogenases and the risk of esophageal squamous cell carcinoma in Gansu Chinese males

AIM:To evaluate the association between genetic polymorphisms in CYP2E1, ALDH2 and ADH1B and the risk of esophageal squamous cell carcinoma (ESCC) in a high risk area of Gansu Province, in Chinese males. METHODS: A case-control study was conducted to investigate the genetic polymorphisms of these enzymes (CYP2E1 *c1/*c2, ALDH2 *1/*2 and ADH1B *1/*1 genotypes). A total of 80 esophageal cancer cases and 480 controls were recruited. RESULTS: Compared with controls, cases had a greater prevalence of heavier alcohol consumption (53.8% vs 16.2%) and a higher proportion of alcohol drinkers with > 30 drink-years (28.8% vs 13.5%). Heavier alcohol consumption and alcohol drinking with > 30 drink- years increased the risk of ESCC, with ORs (95% CI) of 3.20 (1.32-9.65) and 1.68 (0.96-3.21). CYP2E1 (*c1/*c1), ALDH2 (*1/*2) and ADH1B (*1/*1) genotype frequencies were higher among patients with squamous cell carcinomas, at a level close to statistical significance (P = 0.014; P = 0.094; P = 0.0001 respectively). There were synergistic interactions among alcohol drinking and ALDH2, ADH1B and CYP2E1 genotypes. The risk of the ESCC in moderate-to-heavy drinkers with an inactive ALDH2 encoded by ALDH2 *1/*2 as well as ADH1B encoded by ADH1B *1/*1 and CYP2E1 encoded by CYP2E1 *c1/*c1 was higher than that in the never/rare-to-light drinkers with an active ALDH2 (*1/*1 genotype) as well as ADH1B (*1/*2 + *2/*2) and CYP2E1 (*c1/*c2 + *c2/*c2) genotypes, with a statistically significant difference; ORs (95% CI) of 8.58 (3.28-22.68), 27.12 (8.52-70.19) and 7.64 (2.82-11.31) respectively. The risk of the ESCC in moderate-to-heavy drinkers with ALDH2 (*1/*2) combined the ADH1B (*1/*1) genotype or ALDH2 (*1/*2) combined the CYP2E1 (*c1/*c1) genotype leads to synergistic interactions, higher than drinkers with ALDH2 (*1/*1) + ADH1B (*1/*2 + *2/*2), ALDH2 (*1/*1) + CYP2E1 (*c1/*c2 + *c2/*c2) respectively , ORs (95% CI) of 7.46 (3.28-18.32) and 6.82 (1.44-9.76) respectively. Individuals with the ADH1B combined the CYP2E1 genotype showed no synergistic interaction. CONCLUSION: In our study, we found that alcohol consumption and polymorphisms in the CYP2E1, ADH1B and ALDH2 genes are important risk factors for ESCC, and that there was a synergistic interaction among polymorphisms in the CYP2E1, ALDH2 and ADH1B genes and heavy alcohol drinking, in Chinese males living in Gansu Province, China.

Interaction of methylenetetrahydrofolate reductase C677T,cytochrome P4502E1 polymorphism and environment factors in esophageal cancer in Kazakh population

AIM： To evaluate the association and interaction of genetic polymorphisms in methylenetetrahydrofolate reductase （MTHER） and cytochrome P4502E1 （CY- P4502E1）, environment risk factors with esophageal cancer （EC） in Kazakh, a high EC incidence area of Xinjiang Uygur Autonomous Region, China. METHODS： A 1：2 matched case-control study was conducted with 120 cases of EC and 240 populationor hospital-based controls. The controls were matched for sex, nationality, area of residence and age within a 5-year difference. MTHER and CYP4502E1 genotypes were identified by PCR-based restriction fragment length polymorphism （RFLP）. A conditional logistic regression model was established to identify risk factors. The strata method was adopted in interaction analysis. RESULTS： Low consumption of green vegetables and fresh fruits, alcohol drinking, and unsafe water （shallow well, or river） were found to be the risk factors for EC. Individuals with the MTHFR677 （C/T ＋ T/T） genotype had a 2.62-fold （95% CI： 1.61-4.28） risk of developing EC compared with those who carried the C/C genotype. Individuals with the CYP4502EIC1/C1 genotype had a 3.00-fold （95% CI： 1.82-4.96） risk compared with those who carried the CYP4502E1 （C1/C2 ＋ C2/C2） genotype. Gene-environment interaction analysis showed that MTHFR677 gene polymorphism was correlated with consumption of green vegetables and fresh fruit, while CYP4502E1 C1/C1 was correlated with alcohol drinking and unsafe drinking water. MTHFR and CYP4502E1 analysis of gene-gene interaction showed that individuals with the MTHFR677 （C/T ＋ T/T） and CYP4502EIC1/ C1 genotypes had a 7.41-fold （95% CI： 3.60-15.25） risk of developing EC compared with those who carried the MTHFR677C/C and CYP4502E1 RsaI C1/C2 ＋ C2/C2 genes, and the interaction rate was higher than that of the two factors alone. CONCLUSION： Low consumption of green vegetables and fresh fruits, alcohol drinking, and unsafe water （shallow well, or river） and polymorphisms in MTHFR and CYP4502E1 genes are important risk factors for EC. There is a synergistic interaction among polymorphisms in MTHFR and CYP4502E1 genes and environment factors. MTHFR and CYP4502E1 genes can be used as biomarkers for prevention of EC in Kazakh, Xinjiang Uygur Autonomous Region, China.

Cytochrome P450 2E1 genetic polymorphism and gastric cancer in Changle,Fujian Province

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.

Cytochrome P450 2E1 RsaI/PstI and DraI Polymorphisms Are Risk Factors for Lung Cancer in Mongolian and Han Population in Inner Mongolia

Objective： To explore the relationship between cytochrome P450 2E1 （CYP2E1） RsaI/PstI and DraI polymorphism and lung cancer susceptibility in Mongolian and Han population in Inner Mongolia of China. Methods： CYP2E1 RsaI/PstI and DraI polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism in 64 lung cancer patients, 150 healthy Mongolian and 150 healthy Han individuals. The distribution of genotype and allele frequencies of CYP2E1 RsaI/PstI and DraI polymorphisms were studied. Results： The risk of lung cancer was increased in individuals with CYP2E1 （cl/cl） and CYP2E1 （DD） with OR values of 2.431 （95%CI=1.082-5.460） and 2.778 （95%CI=1.358-5.683） respectively （P0.05）. When CYP2E1 RsaI/PstI and DraI polymorphisms were combined, the risk of lung cancer was reduced in individuals with CYP2E1 （cl/c2＋c2/c2 and DD＋CC） with OR values of 0.233 （95%CI=0.088-0.615, P0.05）. In smokers, the susceptibility to lung cancer was higher in the individuals with CYP2E1 （c1/c1） and CYP2E1 （DD） than in the individuals with c2 and C allele （P0.05, OR=2.643 and 4.308 respectively）. There was no significant difference in distribution of CYP2E1 genotype frequency between healthy Mongolian, Han population and lung cancer patients, healthy controls in Inner Mongolia. Conclusion： CYP2E1 （c1/c1） and CYP2E1 （DD） are predisposing factors of lung cancer in population in Inner Mongolia. CYP2E1 （c2﹢C） co-mutation may decrease the risk of lung cancer. Smoking exerts synergetic effect with CYP2E1 （c1/c1） and CYP2E1 （DD） on the occurrence of lung cancer.

Cytochrome P450 family 17 subfamily A member 1 mutation causes severe pseudohermaphroditism: A case report

BACKGROUND 17α-Hydroxylase deficiency(17-OHD)is a rare form of congenital adrenal hyperplasia,characterized by hypertension,hypokalemia,and gonadal dysplasia.However,due to the lack of a comprehensive understanding of this disease,it is prone to misdiagnosis and missed diagnosis,and there is no complete cure.CASE SUMMARY We report a female patient with 17-OHD.The patient was admitted to the Department of Neurology of our hospital due to limb weakness.During treatment,it was found that the patient’s condition was difficult to correct except for hypokalemia,and her blood pressure was difficult to control with various antihypertensive drugs.She was then transferred to our department for further treatment.On physical examination,the patient's gonadal development was found to be abnormal,and chromosome analysis demonstrated karyotype 46,XY.Considering the possibility of 17-OHD,the cytochrome P450 family 17 subfamily A member 1(CYP17A1)test was performed to confirm the diagnosis.CONCLUSION The clinical manifestations of 17-OHD are complex.Hormone determination,imaging examination,chromosome determination and CYP17A1 gene test are helpful for early diagnosis.

过氧化物酶体增殖物激活受体γC161-T、细胞色素P450ⅡE1基因多态性与脂肪性肝病相关性研究

目的探讨过氧化物酶体增殖物激活受体γC161-T(PPARγC161-T)、细胞色素P450ⅡE1(CYPⅡE1)基因多态性脂肪性肝病的关系。方法检测183例脂肪肝患者和40例健康对照者PPARγC161-T、CYPⅡE1的基因多态性。检测所有受试者的BMI、腰围、血压,测定谷丙转氨酶(ALT)、谷草转氨酶(AST)、谷氨酰转肽酶(GGT)、空腹血糖(FBG)、腹胰岛素(FINS)、总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)等指标。结果脂肪肝组腰围、BMI、SBP、FBG、HOMA-IR、TG、TC、UA、ALT、AST、GGT均高于对照组;PPAR-γC161-T基因型频率及等位基因频率在脂肪肝组与对照组差异无显著性;PPAR-γC161-T基因型CC和CT/TT型比较,对照组中基因型CT/TT的FBG较CC基因型高;CYPⅡE1基因型C_1C_2、C_2C_2频率及等位基因C_2频率脂肪肝较对照组增加。CYPⅡE1基因型C_1C_1和C_1C_2/C_2C_2型比较,脂肪肝组C_1C_2/C_2C_2型的GGT增高。结论 CYPⅡE1基因多态性与脂肪肝脂质过氧化密切相关,等位基因C_2与脂肪肝的发病密切相关。CYPⅡE1基因多态性可能在脂肪肝的形成中起着决定性的作用。

Influences of V5-epitope tag on the metabolic activation of AFB1 by human cytochrome P450 2A13

Objective： To explore the impact of V5-epitope tag inserted in the commercial pcDNA5/FRT/V5-His TOPO expression vector on the metabolic activation of AFB1 by human CYP2A13. Methods ： A C-terminal 6 × Histag was first introduced into CYP2A13 cDNA by PCR and subsequently transferred into the expressing vector pcDNA5/FRT. Another commercial pcDNA5/FRT/V5-His TOPO expression vector was used to develop the construct directly via PCR. Both of the constructs were then transfected into Flp-In CHO and allowed for the stable expression of CYP2A13. The mouse CYP2A5 and the vector alone were used as positive and negative control, respectively. The presence of CYP2A5 and CYP2A13 cDNA and their protein expression in the stable transfectant cells were deterrrfined by immunoblotting assay using a monoclonal antibody against 6 × Histag. The AFBl-induced cytotoxicity in these tranfected CHO cells were conducted by MTS assay and the IC50 of cell viability was used to compare the CYP enzyme metabolic activity in AFB1 metabolism among these cells. Results： In accordance with the Flp-In system working mechanism, all the transfectant cells presented same protein expression level. The CHO cells expressing CYP2A5 was more sensitive to AFB1 treatment than those cells expressing CYP2A13, there was about 30-fold ICs0 difference between the two cells （2.1 nmol/L vs 58 nmol/L）. Interestingly, CYP2A13 fused with V5-Histag had the lost of metabolic activity to AFB1 than that fused with Histag alone, the ICa, of the viability in CHO-2A13-His-V5 cells was about 20-fold less than CHO-2A13- His （〉 1 000 nmol/L vs 58 nmol/L）. However, there was no change between CYP2A5 fused with V5-Histag and Histag alone （2.4 nmol/L vs 2.1 nmol/L）. Conclusion： The results demonstrate that CYP2A13 fused with V5-epitope has a significant impact on its metabolic activation to AFB1, which indicated that it should be careful to select a new expressing vector for evaluating the enzyme activity in carcinogen metabolism.

<i>In vivo</i>effects of genistein, herbimycin a and geldanamycin on rat hepatic cytochrome P4501A

Cytochrome P4501A (the CYP1A1 and CYP1A2 enzymes) are regulated through the aryl hydrocarbon receptor (AhR)-dependent signal transduction pathway and are generally known as enzymes which metabolize anthropogenic xenobiotics such as dioxin to carcinogenic and mutagenic compounds. However, recently the facts of CYP1A activation under physiological conditions or under action of non-dioxin-like compounds appear. In the present study we show that genistein, herbimycin A and geldanamycin (the protein-tyrosine kinase inhibitors) affect in vivo to CYP1A1 activity, the CYP1A1 mRNA level and the CYP1A1 protein level. These data provide insight into the role of protein kinases in CYP1A regulation may facilitate the understanding of CYP1A regulation.

Long-term modifications of blood pressure in normotensive and spontane-ously hypertensive rats by gene delivery of rAAV-mediated cytochrome P450 arachidonic acid hydroxylase

Arachidonic acid cytochrome P-450 （CYP） hydroxylase 4A isoforms, including 4A1, 4A2, 4A3 and 4A8 in the rat kidney, catalyze arachidonic acid to produce 19/20-Hydroxyeicosatetraenoic acids （20-HETE）, a biologically active metabolite, which plays an important role in the regulation of blood pressure. However, controversial results have been reported regarding the exact role of 20-HETE on blood pressure. In the present study, we used recombinant adenoassociated viral vector （rAAV） to deliver CYP 4A1 cDNA and antisense 4A1 cDNA into Sprague-Dawley （SD） rats and spontaneously hypertensive rats （SHR）, respectively, to investigate the effects of long-term modifications of blood pressure and the potential for gene therapy of hyperténsion. The mean systolic pressure increased by 14.2±2.5 mm Hg in rAAV.4A 1-treated SD rats and decreased by 13.7±2.2 mm Hg in rAAV.anti4A l-treated SHR rats 5 weeks after the injection compared with controls and these changes in blood pressure were maintained until the experiments ended at 24 weeks. In 4A1 treated animals CYP4A was overexpressed in various tissues, but preferentially in the kidney at both mRNA and protein levels. In anti-4Al-treated SHR, CYP4A mRNA in various tissues was probed, especially in kidneys, but 4A l protein expression was almost completely inhibited. These results suggest that arachidonic acid CYP hydroxylases contribute not only to the maintenance of normal blood pressure but also to the development of hypertension. rAAV-mediated anti4A administration strategy has the potential to be used as targeted gene therapy in human hypertension by blocking expression of CYP 4A in kidneys.

大鼠酒精性肝病细胞凋亡与细胞色素P450 2E1和氧化应激的关系

目的 观察酒精性肝病（ALD）大鼠肝组织病理学改变,探讨细胞凋亡与细胞色素P4502E1（CYP2E1）的表达以及与氧化应激的关系。方法 用乙醇灌胃法制备ALD大鼠模型,模型组（37只）给予体积分数为40%的乙醇8g·kg^-1·d^-1分两次灌胃,连续8周;对照组（33只）给予等量生理盐水灌胃。实验第8周末,各组选30只大鼠观察肝组织的病理学改变;用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记法（TUNEL）检测肝细胞凋亡,用全自动生化仪检测丙氨酸转氨酶（ALT）、天冬氨酸转氨酶（AST）值,用聚合酶链反应（PCR）法测定肝CYP2E1的表达;分别用硫代巴比妥酸法和黄嘌呤氧化酶法测定血清丙二醛（MDA）含量和超氧化物歧化酶（SOD）活性。结果 模型组凋亡的肝细胞明显增多,主要分布在中央静脉周围、点状和灶状坏死区。对照组CYP2E1的c1基因频率为91.65%、c2基因频率为8.35%;模型组c1基因频率为53.35%、c2基因频率为46.65%,差异均有显著性（P均〈0.05）。长期摄入乙醇的大鼠血清MDA含量增加,SOD活性下降,与ALD肝细胞凋亡程度有相关性（rMDA=0.644,rSOD=-0.511,P均〈0.05）,且MDA与SOD两指标间呈负相关（r=-0.582,P〈0.05）。结论 长期摄入乙醇可引起大鼠ALD及肝功能损伤,肝细胞凋亡明显增加。CYP2E1基因Pst及Rsa限制性片段长度多态性与ALD有关,其中c2基因可能与大鼠ALD的发生有关。MDA含量和SOD活性在ALD的肝细胞凋亡过程及脂质过氧化反应中发挥重要作用。

细胞色素P450 2E1基因多态与肝癌遗传易感性研究

目的：探讨细胞色素 P450 2E1基因多态与肝癌的关系。方法：应用 PCR RFLP方法对 84例肝癌患者和 144例健康对照的细胞色素 P450 2E1基因 Rsa I多态进行检测。结果：病例组基因型 A频率为 71.43％，等位基因 c1频率为 84.52％，对照组则分别为 55.56％和 75.35％，两组差别均有统计学意义 (P0.05)。结论：细胞色素 P450 2E1基因 Rsa I多态位点的基因型 A或等位基因 c1增加了个体患肝癌的危险性。

细胞色素 P450 2E1 的研究进展

ＣＹＰ２Ｅ１在药物和人们经常接触的溶剂与环境污染物的代谢中具有重要作用。本文综述ＣＹＰ２Ｅ１的结构特点、基因、底物和探药以及影响其活性的主要因素。

酒精性肝损伤大鼠细胞色素P450 CYP2E1和细胞色素P450 CYP3A的代谢活性

目的观察酒精性肝损伤对大鼠细胞色素P450CYP3A(CYP3A)和细胞色素P450CYP2E1(CYP2E1)代谢活性的影响。方法采用ig给予白酒制备大鼠酒精性肝损伤模型,检测血清中谷丙转氨酶(GPT)和谷草转氨酶(GOT)活性,采用HE染色法光镜下观测酒精对肝脏损伤程度。大鼠ip给予CYP3A探针药物咪达唑仑10mg·kg-1或ig给予CYP2E1探针药物氯唑沙宗50mg·kg-1后,采用高效液相色谱法测定不同时间点大鼠血浆中咪达唑仑和氯唑沙宗的血药浓度,并应用3P87软件计算其药代动力学参数,以考察CYP2E1和CYP3A的代谢活性的变化。大鼠ig给予氯唑沙宗80mg·kg-1后,热板方法测定大鼠添足次数和添足反射潜伏期。结果酒精性肝损伤可致大鼠肝小叶结构不清,肝索排列紊乱,肝细胞体积增大,呈弥漫性中度水变性,肝窦受压,大部分肝细胞胞浆内见大小不等的脂肪空泡;与正常对照组相比,酒精性肝损伤组大鼠GPT和GOT活性分别增加了16.0%和20.0%(P<0.05,P<0.01)。酒精性肝损伤致大鼠CYP2E1对探针药物氯唑沙宗的代谢活性增强,AUC,t1/2和cmax分别降低了38.0%,30.5%和35.0%(P<0.05);酒精肝损伤组大鼠氯唑沙宗镇痛效果明显降低;酒精性肝损伤致大鼠CYP3A对探针药物咪达唑仑的代谢活性增强,AUC,t1/2和cmax分别降低了122.6%,54.9%和56.9%(P<0.01,P<0.05)。结论酒精性肝损伤可使大鼠CYP2E1和CYP3A代谢活性增强。

清肝活血方对酒精性肝病大鼠ADH及CYPⅡE1的影响

目的:观察清肝活血方对酒精性肝病大鼠乙醇代谢关键酶基因表达的影响。方法:用乙醇、玉米油、吡唑等制备酒精性肝病大鼠模型。RT-PCR法检测大鼠肝组织ADH及CYPⅡElmRNA表达。结果:酒粉性肝病大鼠模型表现为肝功能异常,以AST变化为显著;模型组ADH活性及其mRNA与CYPⅡE1 mRNA表达下降;高剂量清肝活血方组大鼠ADH活性及ADH与CYPⅡE1 mRNA的表达显著提高。结论:清肝活血方能显著提高模型组大鼠ADH活性及ADH与YPⅡE1mRNA的表达,促进肝脏的解毒功能。

细胞色素P450ⅡE1在肠道血吸虫病并结直肠癌患者肠黏膜中的表达

目的探讨细胞色素P450ⅡE1(CYPⅡE1)的蛋白表达与肠道血吸虫病并结直肠癌之间的相关性及其可能的作用机制。方法采用免疫组织化学SP法,检测60例肠道血吸虫并结直肠癌癌组织、60例单纯结直肠癌癌组织(无肠道血吸虫感染)、60例单纯肠道血吸虫感染组、50例无血吸虫感染的正常肠道组织中的CYPⅡE1蛋白的表达情况;分析肠道血吸虫病并结直肠癌癌组织中CYPⅡE1的表达与患者的性别、年龄、病理分型、淋巴结转移等临床病理参数的关系。结果肠道血吸虫病并结直肠癌组织中CYPⅡE1的表达阳性为73.33%,单纯肠道血吸虫感染组表达阳性为46.67%,60例单纯结直肠癌癌组织(无肠道血吸虫感染)表达阳性为31.67%,而正常组织中的表达为16%。在黏液腺癌中CYPⅡE1蛋白表达明显增高(P<0.01)。血吸虫并结直肠癌组CYPⅡE1蛋白表达阳性与性别、年龄、肿瘤部位、淋巴结转移无关,与组织分化程度和病理分型有关。逐步回归法进行Logistic多因素分析结果显示,组织学分型是CYPⅡE1表达阳性的唯一危险因素(OR=11.4,P=0.024)。结论 CYPⅡE1可能在肠道血吸虫病并结直肠癌的发病机制中有一定的作用。CYPⅡE1的表达与结直肠癌组织的病理分型有关。

细胞色素P450 CYP2E1酶构型特征及其表达调控机制的研究进展

细胞色素P450CYP2E1酶参与代谢活化及失活多种前毒物、前致癌物和少数药物。在细胞色素P450超家族中,CYP2E1具有易介导自由基生成引发氧化应激反应的特征。CYP2E1表达水平可能是机体对环境和工业毒物或致癌物敏感程度的重要因素。研究表明,CYP2E1可被多种内、外源性物质所调控,并且CYP2E1的药理和毒理学功能与其以蛋白构型为基础的代谢行为密切相关。本文综述了CYP2E1基因多态性、酶构型特征与其代谢活性间的关系,并分析了其区别于其他细胞色素P450亚型的表达调控机制。

细胞色素P4502E1基因多态性与胃癌易患性

目的研究与前致癌物亚硝胺类代谢活化有关的细胞色素P4502E1(cytochromeP4502E1,CYP2E1)基因多态性与胃癌易患性的关系,探讨环境因素与遗传因素在胃癌发病中的作用。方法采用病例-对照分子流行病学方法,调查原发性胃癌患者和对照各48例,以聚合酶链反应-限制性片段长度多态(PCR-RFLP)检测被调查者的CYP2E1基因RsaI位点的多态性,条件Logistic回归模型进行资料分析。结果CYP2E1A、B和C3种基因型在病例组中的构成比分别为68.8%,29.2%和2.1%,对照组分别为45.83%,47.92%和6.25%,2组差异无统计学意义(χ2=5.389,P=0.068)。而病例和对照组CYP2E1基因RsaI位点等位基因c1和c2频率分别为83.3%,16.7%和69.8%,30.2%,差异有统计学意义(χ2=5.241,P<0.05)。环境因素中食盐、香肠和熟食的过多摄入以及肿瘤家庭史和c1等位基因作为胃癌的危险因素进入回归模型,而经常喝茶作为保护性因子可能降低胃癌的发生危险。结论CYP2E1基因RsaI位点等位基因c1与胃癌易感性相关联;某些饮食因素与胃癌的发生有关。

3Gyγ射线照射和丝裂霉素C对大鼠肝脏细胞色素P450含量及其同工酶CYP2B1、CYP2E1活性的影响

为研究3Gyγ射线全身照射和丝裂霉素C(MitomycinC,MMC)对雄性(Sprague-Dawley,SD)大鼠肝脏细胞色素P450含量、CYP2B1、CYP2E1活性的影响,分别给大鼠腹腔注射1mg/kgd的MMC(分1d,连续3d及6d用药三组),3mg/kg的MMC1d,3Gyγ射线全身照射,3Gyγ射线全身照射加1d3mg/kgMMC,另设空白对照和溶剂对照。各组处理结束后24h,处死大鼠取肝脏,制备微粒体,测P450含量、CYP2B1、CYP2E1活性。实验结果表明,给MMC1mg/kgd,1d后P450含量、CYP2B1活性变化无统计学差异(p>0.05),CYP2E1活性明显上升(p<0.01);连续3d或6d后,P450含量、CYP2B1、CYP2E1活性均无明显变化(p>0.05)。给3mg/kg的MMC1d,对P450含量、CYP2B1活性影响无统计学差异(p>0.05),CYP2E1活性上升明显(p<0.01);3Gyγ射线全身照射后,P450含量、CYP2B1活性无明显变化(p>0.05),CYP2E1活性下降(p<0.05);分析发现,3mg/kgMMC与3Gyγ射线之间没有交互作用。结果提示,γ射线可以抑制雄性SD大鼠肝脏CYP2E1活性,MMC对CYP2E1活性有诱导作用,但多次刺激使其耐受,P450含量、CYP2B1活性对γ射线、MMC不敏感。