• Asian Pacific Journal of Cancer Prevention
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• 제16권15호
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• pp.6645-6650
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• 2015

Background: Gastric cancer (GC) is the third most common cancer regarding mortality in the world. The cag pathogenicity island (PAI) of Helicobacter pylori which contains genes associated with a more aggressive phenotype may involve in the pathogenesis of gastrointestinal disease. We here aimed to examine the associations of cagH, cagL, orf17, and cagG genotypes of H. pylori cag PAI with severe gastrointestinal disease. Materials and Methods: A total of 242 H. pylori strains were genotyped. Histopathological examination and classification of subjects were performed. Results: The frequencies of the cagH, cagL, cagG, and orf17 genotypes were 40/54 (74.1%), 53/54 (98.1%), 38/54 (70.4%), and 43/54 (79.6%), respectively, in patients with peptidic ulceration (PU),while in the control group, the frequencies were 87/147 (59.6%) for cagH, 121/146 (82.9%) for cagL, 109/146 (74.7%) for cagG, and 89/146 (61.0%) for orf17. The results of simple logistic regression analysis showed that the cagL and orf17 genotypes were significantly associated with an increased risk of PU not GC; the ORs (95% CI) were 10.950 (1.446-82.935), and 2.504 (1.193-5.253), respectively. No significant association was found between the cagH and cagG genotypes and the risk of both the PU and the GC in Iran (P>0.05). Finally, multiple logistic regression analysis showed that the cagL genotype was independently and significantly associated with the age-and sex-adjusted risk for PU; the OR (95% CI) was 9.557 (1.219-17.185). Conclusions: We conclude that the orf17 and especially cagL genotypes of H. pylori cag PAI could be factors for risk prediction of PU, but not GC in Iran.

• Journal of Microbiology and Biotechnology
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• 제25권7호
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• pp.1146-1153
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• 2015

This study was conducted to assess the relationship between occurrence of gastric cancer and peptic ulcer, and the presence of H. pylori cagA gene and anti-CagA IgG, and to estimate the value of these antibodies in detecting infection by cagA gene-positive H. pylori strains in Saudi patients. The study included 180 patients who were subjected to upper gastrointestinal endoscopy in Taif province and Western region of Saudi Arabia (60 gastric cancer, 60 peptic ulcer, and 60 with non-ulcer dyspepsia). Gastric biopsy specimens were obtained and tested for H. pylori infection by rapid urease test and culture. PCR was performed on the isolated strains and biopsy specimens for detection of the cagA gene. Blood samples were collected and tested for CagA IgG by ELISA. H. pylori infection was detected among 72.8% of patients. The cagA gene and anti-CagA IgG were found in 63.4% and 61.8% of H. pylori-infected patients, respectively. They were significantly (p < 0.01) higher in patients with gastric cancer and peptic ulcer compared with those with non-ulcer dyspepsia. Detection of the CagA IgG was 91.6% sensitive, 89.6% specific, and 90.8% accurate compared with detection of the cagA gene. Its positive and negative predictive values were 93.8% and 86%, respectively. The study showed a significant association between the presence of the cagA gene and gastric cancer and peptic ulcer disease, and between anti-CagA IgG and the cagA gene in Saudi patients. However, a further larger study is required to confirm this finding.

• Toxicological Research
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• 제20권3호
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• pp.179-185
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• 2004

Helicobacter pylori (H. pylori) infects more than half of the people in the world as a major microbe to cause most of gastric diseases. Recently, cytotoxin associated-antigen A (CagA) is believed as one of the most important virulence factors of H. pylori. Molecular toxicological pathway of CagA is necessary to investigate for understanding the pathological and toxicological aspects of H. pylori, since this virulence protein harasses intercellular processes of host cells to get profit for the survival of H. pylori. CagA is coded from cag pathogenicity island (cag PAI) and translocated into host cells by Type 4 secretion system (TFSS). Tyrosine phosphorylation of CagA targets Src homology 2-containing phosphotyrosine phosphatase (SHP-2) to form a CagA-SHP-2 complex. This complex depends on the similarity of sequence between EPIYA motif and Src homology 2 domain (SH2 domain) of CagA. The generation of growth factors is an essential role of CagA in protecting and healing gastric mucosa for the survival of H. pylori. On the other hand, the activation of IL-8 by CagA induces neutrophils generating inflammation and free radicals. Indeed, free radicals are well known carcinogen to induce DNA damage. In addition, the transduction of mitogen-activation signal by CagA is one of the interesting features to understand how to cause cancer. The relationship between cancer and inflammation with CagA was mainly discussed in this review.

• 생명과학회지
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• 제26권10호
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• pp.1214-1217
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• 2016

Rebamipoide는 위궤양과 위염치료에 쓰이는 위보호제로 임상에서 사용되고 있지만 위암에서의 역할에 대해서는 알려지바가 거의 없다. 헬리코박토 파일로리(Helicobacter pylori)의 주요독성인자인 CagA는 위암의 발생과 관련이 있다. CagA는 위암세포에서 NFκB의 활성을 증가시켜 PLD1 단백질의 발현을 증가시킴으로써 위암세포의 증식과 침윤을 유도한다. Rebamipide는 NFκB의 활성을 억제함으로써 H. pylori의 CagA에 의해 유도되는 PLD1의 발현을 저해하는것으로 규명되었다. 게다가, rebamipide는 H. pylori의 CagA에 의해 유도되는 β-catenin과 그 표적 유전자로서 인 암줄기세포 마커 단백질의 발현을 증가시킴으로써 위암줄기세포의 자가재생능력을 감소시킨다. 또한 rebamipide는 항암제 내성을 극복하는 화학감수성을 증가시켜서 위암생성을 감소시키는 것으로 나타났다. 그래서 rebamipide는 위암치료제로서의 잠재적 효능을 가지고 있는 약물로서의 가능성이 제시되고 있다.

• Asian Pacific Journal of Cancer Prevention
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• 제13권12호
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• pp.6305-6310
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• 2012

Objectives: This study aimed to demonstrate the tyrosine phosphorylation motif (TPM) and 3' region structure of the Helicobacter pylori CagA gene as well as its SHP-2 binding activity in AGS cells and relation to gastric carcinogenesis. Methods: Sixteen clinical isolate H. pylori strains from eight duodenal ulcer and eight gastric adenocarcinoma patients were studied for CagA repeat sequence EPIYA motifs, C-terminal structure, and western blot analysis of CagA protein expression, translocation, and SHP-2 binding in AGS cells. Results: Except for strain 547, all strains from the gastric adenocarcinoma patients were positive for CagA by PCR and had three EPIYA copy motifs. Western blotting showed that all strains were positive for CagA protein expression (100%), CagA protein translocation (100%), and SHP-2 binding (100%). CagA protein expression was significantly higher in the gastric adenocarcinoma patients than in the duodenal ulcer patients (P=0.0023). CagA protein translocation and SHP-2 binding in the gastric adenocarcinoma patients were higher than those in the duodenal ulcer patients, but no significant differences were found between the two groups (P=0.59, P=0.21, respectively). Conclusions: The TPMs and 3' region structures of the H. pylori CagA gene in the duodenal ulcer and gastric adenocarcinoma patients have no significant differences.

• 생명과학회지
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• 제15권6호
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• pp.904-908
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• 2005

최근에 발표된 연구 결과에 의하면 pylori CagA내에 존재하는 SHP-2 binding site의 아미노산 서열을 분석한 후, 특정 서열이 위선암의 발병과 연관되어 있다고 보고하였다. 그러나 한국인을 대상으로 CagA 내 에 존재하는 SHP-2 binding site아미노산 서열의 특성을 밝힌 연구는 없다. 따라서 본 연구는 한국인에서 획득한 H. pylori의 CagA SHP-2 binding site에 대해 아미노산 서열을 분석하여 그 특성을 알아보고자 하였다. 총 62 균주의 H. pylori 를 분석한 결과 환자의 질환과 관계없이 모든 H. pylori 균주에서 East Asian (A-B상 혹은 A-B-B-D)을 보여주었다. 일본과 더불어 한국은 위선암 유병률이 높은 나라이므로, 연구 대상의 모든 한국인에서 East Asian type CagA를 가진 H. pylori가 발견된 것이 위선암 유병률과 연관될 가능이 높아 보인다. 그러나 H. pylori의 발병 기전을 보다 더 명확히 이해하기 위해서는 보다 많은 국가와 지역을 대상으로 이러한 유전형 조사가 필요할 것 같다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권2호
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• pp.733-738
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• 2016

Background: Ardabil, a Northwestern province of Iran, was found to have the highest rate of gastric cancer (GC) in the country (ASRs = 51.8/100,000 for males and 24.9/100,000 for females) and one of the highest gastric cardia cancer rates in the world. The aim of the present study was to assess the associations of the cagA and babA2 status of Helicobacter pylori with GC in the Ardabil population. Materials and Methods: A total of 103 patients with non-atrophic gastritis (56) and GC (47), who underwent endoscopy at the Imam Khomeini Hospital in Ardabil, were assessed. The status of 16S rDNA, cagA and babA2 genes was determined using PCR and histopathological assessment was performed. Results: The following genotypic frequency was observed: cagA+ (50.6%), cagA-(49.4%), babA2+ (26.5%), babA2- (73.5%) cagA+/babA2+ (19.3%), cagA-/babA2+ (7.2%), cagA+/babA2-(31.3%), cagA-/babA2-(42.2%). Although the frequency of the cagA+, cagA+/babA2+ and cagA-/babA2+ genotypes in patients with GC (55.6%, 25.9%, and 14.8%, respectively) was higher than in those with NAG (48.2%, 16.1%, and 3.6%, respectively), the difference did not reach significance. In contrast, the presence of the babA2 gene (40.7% vs 19.6%) significantly increased the risk of GC; the age-sex-adjusted odds ratio (95% confidence interval) was 5.068 (1.506-17.058; P=0.009), by multiple logistic regression. Conclusions: It is proposed that the H. pylori babA2 positivity might be considered as an important determinant of GC risk in Ardabil.

• Journal of Microbiology and Biotechnology
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• 제22권10호
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• pp.1343-1349
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• 2012

Most of the Helicobacter pylori strains containing the cag pathogenicity island (PAI) have been associated with more severe gastric disease in infected humans. The cag PAI is composed of 27 proteins, and some of the components are required for CagA translocation into host cells as well as induction of proinflammatory cytokines, such as interleukin-8 (IL-8); however, the exact function of most of the components remains unknown or poorly characterized. In this study, we demonstrated that CagT (HP0532), which is an essential structural component of the cag PAI apparatus, plays an important role in the translocation of CagA into host epithelial cells. In addition to being located on the bacterial surface, CagT is also partially localized in the inner membrane, where it acts as a chaperone-like protein and promotes CagA translocation. However, CagT secretion was not detected by immunoprecipitation analysis of cell culture supernatants. Meanwhile, CagT was related to the introduction of IL-8 of the host cell. These results suggest that CagT is expressed on both the inner and outer bacterial membranes, where it serves as a unique type IV secretion system component that is involved in CagA secretion and cag PAI apparatus assembly.

• 생명과학회지
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• 제14권6호
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• pp.906-912
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• 2004

한국에서 분리한 Helicobacter pylori 균주가 위암 세포주에서 IL-8를 유도하는 유도능을 관찰하고자 하였으며, 특히 4형 분비구조의 주요 구성체인 cagE 유전자의 다형성에 따라 IL-8 유도능의 차이 및 각 질환에서 분리한 균주에서의 차이가 있는지 검토하고자 하였다. 강남성모병원 내시경검사를 받은 환자들 중 H. pylori 감염 양성으로 확인된 위암 23명 $(31.0\%)$, 위염 24명$(32.6\%)$, 십이지장궤양27명$(36.4\%)$ 총 74명을 대상으로 하여 H. pylori를 분리한 후 PCR-RFLP방법을 이용하여 cagE 다형성을 확인하였으며, PCR 및 Real-time PCR을 이용하여 ragA TPMs를 결정하였다, 또한 분리된 균주를 위암세포주에 감염시켜 상등액을 취하여 ELISA방법으로 IL-8을 정량화 하였다. 전체 74개의 분리 균주 중 59개의 균주$(79.7\%)$에서 IL-8 유도능이 있는 것으로 확인되었으며, cagE 다형성 중에서 가장 높은 빈도로 관찰되는 형태는 MboI/NlaIII B-C, A-C 및 C-C 타입 이었으며, 이중 A-C와 B-C 형태가 C-C 형태에 비해 유의적으로 높은 IL-8 유도능을 나타냈다. 그러나 cagA TPMs의 분류 및 vacA m-아형 분류와 IL-8 유도능과는 연관성이 없었다. 비록 본 연구에서 cagE 다형성과 IL-8 유도능과 아주 밀접한 연관성이 나타나지는 않았지만 vacA m-아형이나 cagA TPMs 보다는 cagE 다형성이 IL-8 유도능과 연관성이 클 것으로 생각된다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제12권2호
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• pp.140-149
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• 2009

목 적: H. pylori는 소아기에 감염되어 대부분 무증상으로 지내나 소수에서 위장질환을 일으킨다. 정확한 기전은 아직 밝혀지지 않았으나 세균의 병독성 인자, 숙주 인자, 환경 인자가 복합적으로 작용한다. 소아에서 H. pylori 유전형과 임상질환의 연관성은 지역과 인종에 따라 다양하고 위점막 림프구에 관한 연구도 일치된 보고가 없다. 이에 H. pylori 감염 소아에서 H. pylori 유전형과 위점막 림프구의 상관성을 알아보고자 하였다. 방 법: H. pylori 감염 소화궤양군 10명과 H. pylori 감염 위염군 15명에서 채취된 후 냉동보관 되었던 위전정부 생검 조직에서 DNA를 분리하고 cagA, cagE, vacA, babA2의 특이적인 시발체로 중합효소연쇄반응을 시행하여 H. pylori 유전형을 분석하였다. 유전형과 임상질환, 조직 소견 및 위점막 림프구의 상관성을 비교하였다. 결 과: H. pylori 유전형 중 cagA 양성률은 80%, cagE 양성률은 60%였다. vacA는 s1m1이 84%, s1m2가 16%였으며 babA2 양성률은 88%였다. 가장 흔한 유전형 조합은 cagA+/vacA s1m1+/babA2+ 조합으로 68%에서 관찰되었다. cagA, cagE, vacA, babA2의 유전형에 따른 임상질환과 조직 소견 및 CD3, CD4, CD8 T세포 수와 CD20 B세포 수는 점막 고유층과 상피세포 내 모두에서 유의한 차이가 없었다. 결 론: 소아 H. pylori 감염에서 cagA, cagE, vacA 및 babA2 유전형과 위점막 림프구는 유의한 상관성이 없었다. 향후, H. pylori가 숙주의 면역을 회피하고 지속적으로 살아남아 다양한 위장질환을 일으키는 병인을 규명하기 위해 H. pylori 감염 소아를 대상으로 위점막 면역반응에 대한 대단위 연구가 필요하다.