胃癌是全球第三大常见恶性肿瘤,主要由幽门螺杆菌感染、遗传因素和环境因素诱发,其中幽门螺杆菌感染是最重要危险因素之一。细胞毒素相关蛋白A(cytotoxin-associated protein A,CagA)是幽门螺杆菌中重要的毒力因子,其蛋白羧基末端谷氨酸...胃癌是全球第三大常见恶性肿瘤,主要由幽门螺杆菌感染、遗传因素和环境因素诱发,其中幽门螺杆菌感染是最重要危险因素之一。细胞毒素相关蛋白A(cytotoxin-associated protein A,CagA)是幽门螺杆菌中重要的毒力因子,其蛋白羧基末端谷氨酸-脯氨酸-异亮氨酸-酪氨酸-丙氨酸基序(Glu-Pro-Ile-Tyr-Ala,EPIYA)包含多个重复序列单元,其数量和排列方式会导致CagA蛋白的功能差异。该区域也是酪氨酸磷酸化的主要结合位点,能够参与多种信号通路影响胃癌的发生。本文通过概述CagA EPIYA多态性参与的Wnt/β-catenin、MAPK和PI3K/Akt关键信号通路,探讨CagA EPIYA多态性诱导宿主细胞的重要信号蛋白异常表达,激活信号通路效应差异,从而进一步明确CagA EPIYA多态性在胃癌发生机制中的作用,为控制幽门螺杆菌感染及精准治疗胃癌靶点提供新思路和新策略。展开更多
目的:比较研究幽门螺杆菌毒素相关蛋白A(Cag A)不同分型对胃上皮细胞AGS形态及IL-8表达影响的差异。方法:设计、人工合成并优化不同cag A基因型,构建相应表达载体,转染胃上皮细胞AGS后观察不同型Cag A对细胞形态及IL-8表达的影响。结果...目的:比较研究幽门螺杆菌毒素相关蛋白A(Cag A)不同分型对胃上皮细胞AGS形态及IL-8表达影响的差异。方法:设计、人工合成并优化不同cag A基因型,构建相应表达载体,转染胃上皮细胞AGS后观察不同型Cag A对细胞形态及IL-8表达的影响。结果:转染后每6 h进行细胞形态观察,于24、36 h对形成蜂鸟状细胞的数量进行统计分析,结果表明,各型Cag A均能引起发生蜂鸟状改变的细胞数量增加;较空载体对照,Cag A的6种型别皆有非常显著差异,Cag A ABCCC与其余5种Cag A型别有非常显著差异。同时于转染后12、36 h对细胞分泌的IL-8进行检测,统计分析表明,转染后12 h,转染各型Cag A细胞的IL-8表达量开始出现差异;转染后36 h,较空载体对照,Cag AABD、Cag A J-Western、Cag A ABDD和Cag A ABCCC存在非常显著差异,Cag A ABDD和Cag A ABCCC分别与Cag AABD、Cag A ABC存在非常显著差异。结论:幽门螺杆菌Cag A可引起转染后的AGS细胞发生蜂鸟状改变及IL-8表达增加,EPIYA基序C数目的增加与细胞蜂鸟状改变呈正相关,EPIYA基序C和D数目的增加与IL-8表达呈正相关。展开更多
BACKGROUND Polymorphisms of human leukocyte antigen(HLA)genes are suggested to increase the risk of gastric cancer(GC).AIM To investigate the HLA allele frequencies of patients with GC relative to a control group in t...BACKGROUND Polymorphisms of human leukocyte antigen(HLA)genes are suggested to increase the risk of gastric cancer(GC).AIM To investigate the HLA allele frequencies of patients with GC relative to a control group in terms of CagA+multiple(≥2)EPIYA-C repeats.METHODS The patient group comprised 94 patients[44 GC and 50 duodenal ulcer(DU)patients],and the control group comprised 86 individuals[(50 non-ulcer dyspepsia patients and 36 people with asymptomatic Helicobacter pylori(H.pylori)].Polymerase chain reaction was performed for the amplification of the H.pylori cagA gene and typing of EPIYA motifs.HLA sequence-specific oligonucleotide(SSO)typing was performed using Lifecodes SSO typing kits(HLA-A,HLA-B HLA-C,HLA-DRB1,and HLA-DQA1-B1 kits).RESULTS The comparison of GC cases in terms of CagA+multiple(≥2)EPIYA-C repeats showed that only the HLA-DQB1*06 allele[odds ratio(OR):0.37,P=0.036]was significantly lower,but significance was lost after correction(Pc=0.1845).The HLA-DQA1*01 allele had a high ratio in GC cases with multiple EPIYA-C repeats,but this was not significant in the univariate analysis.We compared allele frequencies in the DU cases alone and in GC and DU cases together using the same criterion,and none of the HLA alleles were significantly associated with GC or DU.Also,none of the alleles were detected as independent risk factors after the multivariate analysis.On the other hand,in a multivariate logistic regression with no discriminative criterion,HLA-DQA1*01(OR=1.848),HLA-DQB1*06(OR=1.821)and HLA-A*02(OR=1.579)alleles were detected as independent risk factors for GC and DU.CONCLUSION None of the HLA alleles were detected as independent risk factors in terms of CagA+multiple EPIYA-C repeats.However,HLA-DQA1*01,HLA-DQB1*0601,and HLA-A*2 were independent risk factors with no criterion in the multivariate analysis.We suggest that the association of these alleles with gastric malignancies is not specifically related to cagA and multiple EPIYA C repeats.展开更多
AIM To evaluate effect of treatment failure on cag A and vac A genotypes in Helicobacter pylori(H. pylori) isolates from Colombia.METHODS One hundred and seventy-six participants infected with H. pylori from Colombia ...AIM To evaluate effect of treatment failure on cag A and vac A genotypes in Helicobacter pylori(H. pylori) isolates from Colombia.METHODS One hundred and seventy-six participants infected with H. pylori from Colombia were treated during 14 d with the triple-standard therapy. Six weeks later, eradication was evaluated by 13C-Urea breath test. Patients with treatment failure were subjected to endoscopy control; biopsies obtained were used for histopathology and culture. DNA from H. pylori isolates was amplified using primers specific for cag A and vac A genes. The phylogenetic relationships among isolates obtained before and after treatment were established by conglomerate analysis based on random amplified polymorphic DNA(RAPD) fingerprinting.RESULTS Treatment effectiveness was at 74.6%. Of the par-ticipants with treatment failure, 25 accepted subjected to a second endoscopy. Prevalence of posttreatment infection was 64%(16/25) and 40%(10/25) by histology and culture, respectively. Upon comparing the cag A and vac A genotypes found before and after therapy, multiple cag A genotypes(cag A-positive and cag A-negative) were found before treatment; in contrast, cag A-negative genotypes decreased after treatment. vac A s1m1 genotype was highly prevalent in patients before and after therapy. The 3'cag A region was successfully amplified in 95.5%(21/22) of the isolates obtained before and in 81.8%(18/22) of the isolates obtained after treatment. In the isolates obtained from patients with treatment failure, it was found that 72.7%(16/22) presented alterations in the number of EPIYA motifs, compared to isolates found before treatment.CONCLUSION Unsuccessful treatment limits colonization by lowvirulence strains resulting in partial and selective eradication in mixed infections, and acts on the cag A-positive strains inducing genetic rearrangements in cag A variable region that produces a loss or gain of EPIYA repetitions.展开更多
目的分析我国不同地区幽门螺杆菌(H.pylori)的CagA羧基端可变区特征,比较CagA可变区序列差异。方法选取分离自西安、浙江、云南地区的41株H.pylori,PCR扩增CagA羧基端可变区。测序后使用Primer Premier 5软件将核苷酸序列翻译为氨基酸序...目的分析我国不同地区幽门螺杆菌(H.pylori)的CagA羧基端可变区特征,比较CagA可变区序列差异。方法选取分离自西安、浙江、云南地区的41株H.pylori,PCR扩增CagA羧基端可变区。测序后使用Primer Premier 5软件将核苷酸序列翻译为氨基酸序列,使用Vector NTI Suit6软件将所有菌株的CagA羧基端可变区氨基酸序列进行比较分析。结果41株菌的CagA氨基酸序列可分为东亚型和西方型两类:38株分离株为东亚型模式,其中有31株为典型东亚型,7株为变异东亚型;1株分离株为典型的西方型模式,2株表现为片段缺失的变异西方型。结论中国不同地区H.pylori的CagA蛋白序列以东亚型模式为主,占92.7%(38/41);但在至少2个地区的菌株中发现有2株和1株菌CagA羧基端可变区为西方型模式。展开更多
Gastric cancer is the fifth most common malignancy and third leading cancerrelated cause of death worldwide.Helicobacter pylori is a Gram-negative bacterium that inhabits the gastric environment of 60.3%of the world’...Gastric cancer is the fifth most common malignancy and third leading cancerrelated cause of death worldwide.Helicobacter pylori is a Gram-negative bacterium that inhabits the gastric environment of 60.3%of the world’s population and represents the main risk factor for the onset of gastric neoplasms.CagA is the most important virulence factor in H.pylori,and is a translocated oncoprotein that induces morphofunctional modifications in gastric epithelial cells and a chronic inflammatory response that increases the risk of developing precancerous lesions.Upon translocation and tyrosine phosphorylation,CagA moves to the cell membrane and acts as a pathological scaffold protein that simultaneously interacts with multiple intracellular signaling pathways,thereby disrupting cell proliferation,differentiation and apoptosis.All these alterations in cell biology increase the risk of damaged cells acquiring pro-oncogenic genetic changes.In this sense,once gastric cancer sets in,its perpetuation is independent of the presence of the oncoprotein,characterizing a“hit-and-run”carcinogenic mechanism.Therefore,this review aims to describe H.pylori-and CagA-related oncogenic mechanisms,to update readers and discuss the novelties and perspectives in this field.展开更多
文摘目的:比较研究幽门螺杆菌毒素相关蛋白A(Cag A)不同分型对胃上皮细胞AGS形态及IL-8表达影响的差异。方法:设计、人工合成并优化不同cag A基因型,构建相应表达载体,转染胃上皮细胞AGS后观察不同型Cag A对细胞形态及IL-8表达的影响。结果:转染后每6 h进行细胞形态观察,于24、36 h对形成蜂鸟状细胞的数量进行统计分析,结果表明,各型Cag A均能引起发生蜂鸟状改变的细胞数量增加;较空载体对照,Cag A的6种型别皆有非常显著差异,Cag A ABCCC与其余5种Cag A型别有非常显著差异。同时于转染后12、36 h对细胞分泌的IL-8进行检测,统计分析表明,转染后12 h,转染各型Cag A细胞的IL-8表达量开始出现差异;转染后36 h,较空载体对照,Cag AABD、Cag A J-Western、Cag A ABDD和Cag A ABCCC存在非常显著差异,Cag A ABDD和Cag A ABCCC分别与Cag AABD、Cag A ABC存在非常显著差异。结论:幽门螺杆菌Cag A可引起转染后的AGS细胞发生蜂鸟状改变及IL-8表达增加,EPIYA基序C数目的增加与细胞蜂鸟状改变呈正相关,EPIYA基序C和D数目的增加与IL-8表达呈正相关。
基金Supported by the Istanbul University Research Fund,No.45151.
文摘BACKGROUND Polymorphisms of human leukocyte antigen(HLA)genes are suggested to increase the risk of gastric cancer(GC).AIM To investigate the HLA allele frequencies of patients with GC relative to a control group in terms of CagA+multiple(≥2)EPIYA-C repeats.METHODS The patient group comprised 94 patients[44 GC and 50 duodenal ulcer(DU)patients],and the control group comprised 86 individuals[(50 non-ulcer dyspepsia patients and 36 people with asymptomatic Helicobacter pylori(H.pylori)].Polymerase chain reaction was performed for the amplification of the H.pylori cagA gene and typing of EPIYA motifs.HLA sequence-specific oligonucleotide(SSO)typing was performed using Lifecodes SSO typing kits(HLA-A,HLA-B HLA-C,HLA-DRB1,and HLA-DQA1-B1 kits).RESULTS The comparison of GC cases in terms of CagA+multiple(≥2)EPIYA-C repeats showed that only the HLA-DQB1*06 allele[odds ratio(OR):0.37,P=0.036]was significantly lower,but significance was lost after correction(Pc=0.1845).The HLA-DQA1*01 allele had a high ratio in GC cases with multiple EPIYA-C repeats,but this was not significant in the univariate analysis.We compared allele frequencies in the DU cases alone and in GC and DU cases together using the same criterion,and none of the HLA alleles were significantly associated with GC or DU.Also,none of the alleles were detected as independent risk factors after the multivariate analysis.On the other hand,in a multivariate logistic regression with no discriminative criterion,HLA-DQA1*01(OR=1.848),HLA-DQB1*06(OR=1.821)and HLA-A*02(OR=1.579)alleles were detected as independent risk factors for GC and DU.CONCLUSION None of the HLA alleles were detected as independent risk factors in terms of CagA+multiple EPIYA-C repeats.However,HLA-DQA1*01,HLA-DQB1*0601,and HLA-A*2 were independent risk factors with no criterion in the multivariate analysis.We suggest that the association of these alleles with gastric malignancies is not specifically related to cagA and multiple EPIYA C repeats.
文摘AIM To evaluate effect of treatment failure on cag A and vac A genotypes in Helicobacter pylori(H. pylori) isolates from Colombia.METHODS One hundred and seventy-six participants infected with H. pylori from Colombia were treated during 14 d with the triple-standard therapy. Six weeks later, eradication was evaluated by 13C-Urea breath test. Patients with treatment failure were subjected to endoscopy control; biopsies obtained were used for histopathology and culture. DNA from H. pylori isolates was amplified using primers specific for cag A and vac A genes. The phylogenetic relationships among isolates obtained before and after treatment were established by conglomerate analysis based on random amplified polymorphic DNA(RAPD) fingerprinting.RESULTS Treatment effectiveness was at 74.6%. Of the par-ticipants with treatment failure, 25 accepted subjected to a second endoscopy. Prevalence of posttreatment infection was 64%(16/25) and 40%(10/25) by histology and culture, respectively. Upon comparing the cag A and vac A genotypes found before and after therapy, multiple cag A genotypes(cag A-positive and cag A-negative) were found before treatment; in contrast, cag A-negative genotypes decreased after treatment. vac A s1m1 genotype was highly prevalent in patients before and after therapy. The 3'cag A region was successfully amplified in 95.5%(21/22) of the isolates obtained before and in 81.8%(18/22) of the isolates obtained after treatment. In the isolates obtained from patients with treatment failure, it was found that 72.7%(16/22) presented alterations in the number of EPIYA motifs, compared to isolates found before treatment.CONCLUSION Unsuccessful treatment limits colonization by lowvirulence strains resulting in partial and selective eradication in mixed infections, and acts on the cag A-positive strains inducing genetic rearrangements in cag A variable region that produces a loss or gain of EPIYA repetitions.
文摘目的分析我国不同地区幽门螺杆菌(H.pylori)的CagA羧基端可变区特征,比较CagA可变区序列差异。方法选取分离自西安、浙江、云南地区的41株H.pylori,PCR扩增CagA羧基端可变区。测序后使用Primer Premier 5软件将核苷酸序列翻译为氨基酸序列,使用Vector NTI Suit6软件将所有菌株的CagA羧基端可变区氨基酸序列进行比较分析。结果41株菌的CagA氨基酸序列可分为东亚型和西方型两类:38株分离株为东亚型模式,其中有31株为典型东亚型,7株为变异东亚型;1株分离株为典型的西方型模式,2株表现为片段缺失的变异西方型。结论中国不同地区H.pylori的CagA蛋白序列以东亚型模式为主,占92.7%(38/41);但在至少2个地区的菌株中发现有2株和1株菌CagA羧基端可变区为西方型模式。
基金Supported by National Council for Scientific and Technological Development,CNPq Brazil.
文摘Gastric cancer is the fifth most common malignancy and third leading cancerrelated cause of death worldwide.Helicobacter pylori is a Gram-negative bacterium that inhabits the gastric environment of 60.3%of the world’s population and represents the main risk factor for the onset of gastric neoplasms.CagA is the most important virulence factor in H.pylori,and is a translocated oncoprotein that induces morphofunctional modifications in gastric epithelial cells and a chronic inflammatory response that increases the risk of developing precancerous lesions.Upon translocation and tyrosine phosphorylation,CagA moves to the cell membrane and acts as a pathological scaffold protein that simultaneously interacts with multiple intracellular signaling pathways,thereby disrupting cell proliferation,differentiation and apoptosis.All these alterations in cell biology increase the risk of damaged cells acquiring pro-oncogenic genetic changes.In this sense,once gastric cancer sets in,its perpetuation is independent of the presence of the oncoprotein,characterizing a“hit-and-run”carcinogenic mechanism.Therefore,this review aims to describe H.pylori-and CagA-related oncogenic mechanisms,to update readers and discuss the novelties and perspectives in this field.
