To examine a） the effect of organophosphorus pesticide exposure on activity of carboxylic esterases, namely butyrylcholinesterase （BChE）, carboxylesterase （CarbE） and paraoxonase （PonE）; and b） the association...To examine a） the effect of organophosphorus pesticide exposure on activity of carboxylic esterases, namely butyrylcholinesterase （BChE）, carboxylesterase （CarbE） and paraoxonase （PonE）; and b） the association of polymorphisms of BChE and PonE with individual genetic susceptibility to organophosphorus pesticide exposure. Methods A cross-sectional study was conducted in 75 workers exposed to organophosphorus pesticides and 100 non-exposed controls. The serum activity of these enzymes was measured. Variant forms of BCHE-K, PON-192, and PON-55 were detected. A symptom score was developed as a proxy measure of clinical outcomes. Results Activities of both BChE and CarbE were lower in exposed workers （27.3±21.65 runol.hl.mL^-l and 235.6±104.03 nmol-min^-l.mL^-l） than in non-exposed workers （78.313±30.354 nmol.h^-l.mL^-1 and 362.681_＋194.997 nmol.min^-1.mL^-1）. The activity of PonE was not associated with exposure status. The AChE activity in the exposed workers with BCHE-K genotype UU （61 cases）, genotype UK （12 cases） and genotype KK （2 cases） was 105.05, 84.42 and 79.00 mmol-h^-1.mL^-1, respectively and the accumulative symptom scores were 3.74, 9.17, and 12.50 accordingly. The AChE activity in the exposed workers with PON-192 genotype BB （37）, genotype AB （27） and genotype AA （11） was 116.8, 91.2, and 72,3 mmol-h^-1.mL^-1, respectively and the symptom scores were 2.00, 6.74, and 9.73 accordingly. The AChE activity in those with PON-55 genotype LL （70） and genotype LM （5） was 102.4 and 82.8 mmol-h^-1.mL^-1 and the symptom scores were 4.53 and 9.20. The symptom score was the highest in individuals with abnormal homozygote for each of the three gene loci. Condusions Long-term exposure to organophosphorus pesticides can inhibit BChE and CarbE activity, but exerts no inhibitory effect on PonE activity. Different genotypes of BCHE-K, PON-192, and PON-55 may be related to the severity of adverse health effects of organophosphorus pesticide exposure. Implications of potentially higher susceptibility of workers with mutant homozygotes should be evaluated to reduce health risks.展开更多
AIM:To evaluate the utility of measuring epigenetic alterations in pancreatic and biliary fluids in determining molecular markers for pancreatobiliary cancers.METHODS:DNA was extracted from undiluted pancreatic and bi...AIM:To evaluate the utility of measuring epigenetic alterations in pancreatic and biliary fluids in determining molecular markers for pancreatobiliary cancers.METHODS:DNA was extracted from undiluted pancreatic and biliary fluids.As a surrogate for a genomewide hypomethylation assay,levels of long interspersed nuclear element-1(LINE-1) methylation were analyzed using bisulfite pyrosequencing.CpG island hypermethylation of 10 tumor-associated genes,aryl-hydrocarbon receptor repressor,adenomatous polyposis coli,calcium channel,voltage dependent,T type α1G subunit,insulin-like growth factor 2,O-6-methyl-guanine-DNA methyltransferase,neurogenin 1,CDKN2A,runt-related transcription factor 3(RUNX3),secreted frizzled-related protein 1,and ubiquitin carboxyl-terminal esterase L1(UCHL1),was analyzed using MethyLight.To examine the role of CpG methylation and histone deacetylation in the silencing of UCHL1,human gallbladder carcinoma cell lines and pancreatic carcinoma cell lines were treated with 2 or 5 μmol/L 5-AZA-dC for 72 h or 100 nmol/L Trichostatin A for 24 h.After the treatment,UCHL1 expression was analyzed by real-time reverse transcription-polymerase chain reaction.RESULTS:Pancreatobiliary cancers exhibited significantly lower LINE-1 methylation levels in pancreatic and biliary fluids than did noncancerous pancreatobiliary disease(58.7% ± 4.3% vs 61.7% ± 2.2%,P = 0.027;53.8% ± 6.6% vs 57.5% ± 1.7%,P = 0.007);however,LINE-1 hypomethylation was more evident in pancreatic cancer tissues than in pancreatic fluids(45.4% ± 5.5% vs 58.7% ± 4.3%,P < 0.001).CpG island hypermethylation of tumor-associated genes was detected at various frequencies,but it was not correlated with LINE-1 hypomethylation.Hypermethylation of the UCHL1 gene was cancer-specific and most frequently detected in pancreatic(67%) or biliary(70%) fluids from patients with pancreatobiliary cancer.As a single marker,hypermethylation of the UCHL1 gene in pancreatic and biliary fluids was most useful for the detection of pancreatic and pancreatobiliary cancers,respectively(100% specificity).Hypermethylation of the UCHL1 and RUNX3 genes in pancreatic and biliary fluids was the most useful combined marker for pancreatic(87% sensitivity and 100% specificity) and pancreatobiliary(97% sensitivity and 100% specificity) cancers.Treatment with a demethylating agent,5-AZA-2'-deoxycytidine,restored UCHL1 expression in pancreatobiliary cancer cell lines.CONCLUSION:Our results suggest that hypermethylation of UCHL1 and RUNX3 in pancreatobiliary fluid might be useful for the diagnosis of pancreatobiliary cancers.展开更多
Camel Liver Esterase （LE） was isolated through five consecutive steps： Extraction with Tris/HCl buffer, pH 8, precipitation with ammonium sulfate, affinity chromatography on Affi-gel-butyric acid and on Affi-gel-ol...Camel Liver Esterase （LE） was isolated through five consecutive steps： Extraction with Tris/HCl buffer, pH 8, precipitation with ammonium sulfate, affinity chromatography on Affi-gel-butyric acid and on Affi-gel-oleic acid, and preparative polyacrylamide gel electrophoresis （PAGE）. The Km values were found as： methyl butyrate （8.3 mM）, α-naphthyl acetate （3.65 mM）, 13-naphthyl myristate （66.7 mM）, p-nitrophenyl acetate （0.29 mM）, and phenyl acetate （5.26 mM）. The Ki of LE inhibition by bis（4-nitrophenyl） phosphate was 7.9 p.M, and 58 μM by phenyl-methyl-sulfonyl fluoride. The inhibition by these inhibitors is irreversible. p-Hydroxymercuribenzoate or ethylenediamine-tetra-acetic acid did not inhibit the enzyme. LE showed a dimeric structure with molecular weight of 129 kD. The energy of activation of LE was 15.0, 5.5 and 10.75 Kcal, using the substrates： a-naphthyl acetate, p-nitrophenyl acetate, and methyl butyrate, respectively. The optimal pH for LE was between 8 and 10. The N-terminus was found as aspartic acid. The percentage of glycine residues （13.3%） was the highest whereas the percentage of cysteine residues （0.68%） was the lowest in LE. Amino acid composition shows that LE has -50% of its histidine residues as N-methylhistidines.展开更多
Detoxification plays a crucial role in agricultural pests to withstand pesticides,and cytochrome P450s,carboxyl/choline esterases(CCEs),and glutathione-S-transferases are the main proteins responsible for their detoxi...Detoxification plays a crucial role in agricultural pests to withstand pesticides,and cytochrome P450s,carboxyl/choline esterases(CCEs),and glutathione-S-transferases are the main proteins responsible for their detoxification ability.The activity of CCEs can be upregulated,downregulated,or modified by mutation.However,few studies have examined the role of alternative splicing in altering the properties of CCEs.We identified 2 variants of TcCCE23 in Tetranychus cinnabarinus:a long version(CCE23-V1)and a short version that is 18 nucleotides shorter than CCE23-V1(CCE23-V2).Whether splicing affects the activity of TcCCE23 remains unclear.Overexpression of CCE23-V2 in fenpropathrin-resistant T.cinnabarinus revealed that splicing affected the detoxification of fenpropathrin by CCE23-V2.The mortality of mites was significantly higher when the expression of CCE23-V2 was knocked down(43.2%±3.3%)via injection of CCE23-dsRNA(double-stranded RNA)compared with the control group injected with green fluorescent protein-dsRNA under fenpropathrin exposure;however,the downregulation of CCE23-V1(61.3%±6.3%)by CCE23-small interfering RNA had no such effect,indicating CCE23-V2 plays a greater role in xenobiotic metabolism than CCE23-V1.The tolerance of flies overexpressing CCE23-V2 to fenpropathrin(50%lethal dose[LD_(50)]=19.47μg/g)was significantly higher than that of Gal4/UAS-CCE23-V1 transgenic flies(LD_(50)=13.11μg/g).Molecular docking analysis showed that splicing opened a“gate”that enlarges the substrate binding cavity of CCE23-V2,might enhance the ability of CCE23-V2 to harbor fenpropathrin molecules.These findings suggest that splicing might enhance the detoxifying capability of TcCCE23.Generally,our data improve the understanding of the diversity and complexity of the mechanisms underlying the regulation of CCEs.展开更多
Aim: This study aimed to decipher the molecular mechanism underlying the synergistic effect of inhibitors of the mevalonate-cholesterol pathway (i.e., statins) and aminopeptidase inhibitors (APis) on APi-sensitive and...Aim: This study aimed to decipher the molecular mechanism underlying the synergistic effect of inhibitors of the mevalonate-cholesterol pathway (i.e., statins) and aminopeptidase inhibitors (APis) on APi-sensitive and -resistant acute myeloid leukemia (AML) cells.Methods: U937 cells and their sublines with low and high levels of acquired resistance to (6S)-[(R)-2-((S)-Hydroxy-hydroxycarbamoyl-methoxy-methyl)-4-methyl-pentanoylamino]-3,3 dimethyl-butyric acid cyclopentyl ester (CHR2863), an APi prodrug, served as main AML cell line models. Drug combination effects were assessed with CHR2863 and in vitro non-toxic concentrations of various statins upon cell growth inhibition, cell cycle effects, and apoptosis induction. Mechanistic studies involved analysis of Rheb prenylation required for mTOR activation.Results: A strong synergy of CHR2863 with the statins simvastatin, fluvastatin, lovastatin, and pravastatin was demonstrated in U937 cells and two CHR2863-resistant sublines. This potent synergy between simvastatin and CHR2863 was also observed with a series of other human AML cell lines (e.g., THP1, MV4-11, and KG1), but not with acute lymphocytic leukemia or multiple solid tumor cell lines. This synergistic activity was: (i) specific for APis (e.g., CHR2863 and Bestatin), rather than for other cytotoxic agents;and (ii) corroborated by enhanced induction of apoptosis and cell cycle arrest which increased the sub-G1 fraction. Consistently, statin potentiation of CHR2863 activity was abrogated by co-administration of mevalonate and/or farnesyl pyrophosphate, suggesting the involvement of protein prenylation;this was experimentally confirmed by impaired Rheb prenylation by simvastatin.Conclusion: These novel findings suggest that the combined inhibitory effect of impaired Rheb prenylation and CHR2863-dependent mTOR inhibition instigates a potent synergistic inhibition of statins and APis on human AML cells.展开更多
基金This work was supported by the grant from National 973 Project (2002CB512902) and the grant from Shanghai Shuguang Program.
文摘To examine a） the effect of organophosphorus pesticide exposure on activity of carboxylic esterases, namely butyrylcholinesterase （BChE）, carboxylesterase （CarbE） and paraoxonase （PonE）; and b） the association of polymorphisms of BChE and PonE with individual genetic susceptibility to organophosphorus pesticide exposure. Methods A cross-sectional study was conducted in 75 workers exposed to organophosphorus pesticides and 100 non-exposed controls. The serum activity of these enzymes was measured. Variant forms of BCHE-K, PON-192, and PON-55 were detected. A symptom score was developed as a proxy measure of clinical outcomes. Results Activities of both BChE and CarbE were lower in exposed workers （27.3±21.65 runol.hl.mL^-l and 235.6±104.03 nmol-min^-l.mL^-l） than in non-exposed workers （78.313±30.354 nmol.h^-l.mL^-1 and 362.681_＋194.997 nmol.min^-1.mL^-1）. The activity of PonE was not associated with exposure status. The AChE activity in the exposed workers with BCHE-K genotype UU （61 cases）, genotype UK （12 cases） and genotype KK （2 cases） was 105.05, 84.42 and 79.00 mmol-h^-1.mL^-1, respectively and the accumulative symptom scores were 3.74, 9.17, and 12.50 accordingly. The AChE activity in the exposed workers with PON-192 genotype BB （37）, genotype AB （27） and genotype AA （11） was 116.8, 91.2, and 72,3 mmol-h^-1.mL^-1, respectively and the symptom scores were 2.00, 6.74, and 9.73 accordingly. The AChE activity in those with PON-55 genotype LL （70） and genotype LM （5） was 102.4 and 82.8 mmol-h^-1.mL^-1 and the symptom scores were 4.53 and 9.20. The symptom score was the highest in individuals with abnormal homozygote for each of the three gene loci. Condusions Long-term exposure to organophosphorus pesticides can inhibit BChE and CarbE activity, but exerts no inhibitory effect on PonE activity. Different genotypes of BCHE-K, PON-192, and PON-55 may be related to the severity of adverse health effects of organophosphorus pesticide exposure. Implications of potentially higher susceptibility of workers with mutant homozygotes should be evaluated to reduce health risks.
基金Supported by Grants-in-Aid for Scientific Research from the Ministry of Education,Culture,Sports,Science and Technology of Japan (to Yamamoto H and Shinomura Y)
文摘AIM:To evaluate the utility of measuring epigenetic alterations in pancreatic and biliary fluids in determining molecular markers for pancreatobiliary cancers.METHODS:DNA was extracted from undiluted pancreatic and biliary fluids.As a surrogate for a genomewide hypomethylation assay,levels of long interspersed nuclear element-1(LINE-1) methylation were analyzed using bisulfite pyrosequencing.CpG island hypermethylation of 10 tumor-associated genes,aryl-hydrocarbon receptor repressor,adenomatous polyposis coli,calcium channel,voltage dependent,T type α1G subunit,insulin-like growth factor 2,O-6-methyl-guanine-DNA methyltransferase,neurogenin 1,CDKN2A,runt-related transcription factor 3(RUNX3),secreted frizzled-related protein 1,and ubiquitin carboxyl-terminal esterase L1(UCHL1),was analyzed using MethyLight.To examine the role of CpG methylation and histone deacetylation in the silencing of UCHL1,human gallbladder carcinoma cell lines and pancreatic carcinoma cell lines were treated with 2 or 5 μmol/L 5-AZA-dC for 72 h or 100 nmol/L Trichostatin A for 24 h.After the treatment,UCHL1 expression was analyzed by real-time reverse transcription-polymerase chain reaction.RESULTS:Pancreatobiliary cancers exhibited significantly lower LINE-1 methylation levels in pancreatic and biliary fluids than did noncancerous pancreatobiliary disease(58.7% ± 4.3% vs 61.7% ± 2.2%,P = 0.027;53.8% ± 6.6% vs 57.5% ± 1.7%,P = 0.007);however,LINE-1 hypomethylation was more evident in pancreatic cancer tissues than in pancreatic fluids(45.4% ± 5.5% vs 58.7% ± 4.3%,P < 0.001).CpG island hypermethylation of tumor-associated genes was detected at various frequencies,but it was not correlated with LINE-1 hypomethylation.Hypermethylation of the UCHL1 gene was cancer-specific and most frequently detected in pancreatic(67%) or biliary(70%) fluids from patients with pancreatobiliary cancer.As a single marker,hypermethylation of the UCHL1 gene in pancreatic and biliary fluids was most useful for the detection of pancreatic and pancreatobiliary cancers,respectively(100% specificity).Hypermethylation of the UCHL1 and RUNX3 genes in pancreatic and biliary fluids was the most useful combined marker for pancreatic(87% sensitivity and 100% specificity) and pancreatobiliary(97% sensitivity and 100% specificity) cancers.Treatment with a demethylating agent,5-AZA-2'-deoxycytidine,restored UCHL1 expression in pancreatobiliary cancer cell lines.CONCLUSION:Our results suggest that hypermethylation of UCHL1 and RUNX3 in pancreatobiliary fluid might be useful for the diagnosis of pancreatobiliary cancers.
文摘Camel Liver Esterase （LE） was isolated through five consecutive steps： Extraction with Tris/HCl buffer, pH 8, precipitation with ammonium sulfate, affinity chromatography on Affi-gel-butyric acid and on Affi-gel-oleic acid, and preparative polyacrylamide gel electrophoresis （PAGE）. The Km values were found as： methyl butyrate （8.3 mM）, α-naphthyl acetate （3.65 mM）, 13-naphthyl myristate （66.7 mM）, p-nitrophenyl acetate （0.29 mM）, and phenyl acetate （5.26 mM）. The Ki of LE inhibition by bis（4-nitrophenyl） phosphate was 7.9 p.M, and 58 μM by phenyl-methyl-sulfonyl fluoride. The inhibition by these inhibitors is irreversible. p-Hydroxymercuribenzoate or ethylenediamine-tetra-acetic acid did not inhibit the enzyme. LE showed a dimeric structure with molecular weight of 129 kD. The energy of activation of LE was 15.0, 5.5 and 10.75 Kcal, using the substrates： a-naphthyl acetate, p-nitrophenyl acetate, and methyl butyrate, respectively. The optimal pH for LE was between 8 and 10. The N-terminus was found as aspartic acid. The percentage of glycine residues （13.3%） was the highest whereas the percentage of cysteine residues （0.68%） was the lowest in LE. Amino acid composition shows that LE has -50% of its histidine residues as N-methylhistidines.
基金supported in part by the National Nature Sciences Foundation(32001935 and 31972297)the Fundamental Research Funds for the Central Universities(SWU-KR22005).
文摘Detoxification plays a crucial role in agricultural pests to withstand pesticides,and cytochrome P450s,carboxyl/choline esterases(CCEs),and glutathione-S-transferases are the main proteins responsible for their detoxification ability.The activity of CCEs can be upregulated,downregulated,or modified by mutation.However,few studies have examined the role of alternative splicing in altering the properties of CCEs.We identified 2 variants of TcCCE23 in Tetranychus cinnabarinus:a long version(CCE23-V1)and a short version that is 18 nucleotides shorter than CCE23-V1(CCE23-V2).Whether splicing affects the activity of TcCCE23 remains unclear.Overexpression of CCE23-V2 in fenpropathrin-resistant T.cinnabarinus revealed that splicing affected the detoxification of fenpropathrin by CCE23-V2.The mortality of mites was significantly higher when the expression of CCE23-V2 was knocked down(43.2%±3.3%)via injection of CCE23-dsRNA(double-stranded RNA)compared with the control group injected with green fluorescent protein-dsRNA under fenpropathrin exposure;however,the downregulation of CCE23-V1(61.3%±6.3%)by CCE23-small interfering RNA had no such effect,indicating CCE23-V2 plays a greater role in xenobiotic metabolism than CCE23-V1.The tolerance of flies overexpressing CCE23-V2 to fenpropathrin(50%lethal dose[LD_(50)]=19.47μg/g)was significantly higher than that of Gal4/UAS-CCE23-V1 transgenic flies(LD_(50)=13.11μg/g).Molecular docking analysis showed that splicing opened a“gate”that enlarges the substrate binding cavity of CCE23-V2,might enhance the ability of CCE23-V2 to harbor fenpropathrin molecules.These findings suggest that splicing might enhance the detoxifying capability of TcCCE23.Generally,our data improve the understanding of the diversity and complexity of the mechanisms underlying the regulation of CCEs.
文摘目的观察体外循环(cardiopulmonary bypass,CPB)和非CPB下行手术的主动脉缩窄患儿中血清泛素羧基末端水解酶L1(ubiquitin carboxyl-terminal esterase-L1,UCH-L1)浓度变化,评价UCH-L1是否是一个主动脉弓部手术后CPB相关脑损伤的预测指标。方法 2012年1月和2013年6月首都医科大学附属北京儿童医院共39例主动脉缩窄患儿接受了主动脉成型手术;其中A组17例未行CPB,B组22例应用选择性脑灌注分别在6个时间点(麻醉诱导后,关胸,术后2、8、24、48 h)收集血清标本,采用酶联免疫吸附法分别测定UCH-L1、神经胶质蛋白S-100β和神经元特异性烯醇化酶(neuron specific enolase,NSE)浓度。在术后8 h,拔除气管插管后6 h和出院前进行神经系统功能评分。结果 2组血清中UCH-L1浓度在术前基本相同[A组(0.184±0.066)μg/L vs B组(0.194±0.067)μg/L]。B组术后2 h后血清UCH-L1浓度较A组明显升高[A组(0.238±0.067)μg/L vs B组(0.327±0.151)μg/L,P<0.05],并于术后8 h达到高峰。在术后24 h,2组血清UCH-L1浓度差异无统计学意义[A组(0.208±0.078)μg/L vs B组(0.201±0.081)μg/L,P>0.05]。B组血清UCH-L1的峰值浓度和CPB时间明显相关(r=0.575,P=0.005)。术后所有患者均未出现持续存在的严重神经系统合并症。结论与非CPB手术相比,应用选择性脑灌注的小儿主动脉弓部手术可引起血清UCH-L1浓度显著升高,并且与CPB时间密切相关。UCH-L1可以作为一个CPB相关脑损伤诊断的潜在生物标志物。
基金This study was supported by Cancer Center Amsterdam grants 07/36 and 2012-1-08.
文摘Aim: This study aimed to decipher the molecular mechanism underlying the synergistic effect of inhibitors of the mevalonate-cholesterol pathway (i.e., statins) and aminopeptidase inhibitors (APis) on APi-sensitive and -resistant acute myeloid leukemia (AML) cells.Methods: U937 cells and their sublines with low and high levels of acquired resistance to (6S)-[(R)-2-((S)-Hydroxy-hydroxycarbamoyl-methoxy-methyl)-4-methyl-pentanoylamino]-3,3 dimethyl-butyric acid cyclopentyl ester (CHR2863), an APi prodrug, served as main AML cell line models. Drug combination effects were assessed with CHR2863 and in vitro non-toxic concentrations of various statins upon cell growth inhibition, cell cycle effects, and apoptosis induction. Mechanistic studies involved analysis of Rheb prenylation required for mTOR activation.Results: A strong synergy of CHR2863 with the statins simvastatin, fluvastatin, lovastatin, and pravastatin was demonstrated in U937 cells and two CHR2863-resistant sublines. This potent synergy between simvastatin and CHR2863 was also observed with a series of other human AML cell lines (e.g., THP1, MV4-11, and KG1), but not with acute lymphocytic leukemia or multiple solid tumor cell lines. This synergistic activity was: (i) specific for APis (e.g., CHR2863 and Bestatin), rather than for other cytotoxic agents;and (ii) corroborated by enhanced induction of apoptosis and cell cycle arrest which increased the sub-G1 fraction. Consistently, statin potentiation of CHR2863 activity was abrogated by co-administration of mevalonate and/or farnesyl pyrophosphate, suggesting the involvement of protein prenylation;this was experimentally confirmed by impaired Rheb prenylation by simvastatin.Conclusion: These novel findings suggest that the combined inhibitory effect of impaired Rheb prenylation and CHR2863-dependent mTOR inhibition instigates a potent synergistic inhibition of statins and APis on human AML cells.
