Expression of matrix metalloprotease-2, -7 and -9 on human colon, liver and bile duct cell lines by enteric and gastricHelicobacterspecies

Helicobacter pullorum and Helicobacter canadensis: Etiology, pathogenicity, epidemiology, identification, and antibiotic resistance implicating food and public health

Nowadays, it is well-established that the consumption of poultry meat, especially chicken meat products has been drastically increasing. Even though more attentions are being paid to the major foodborne pathogens, it seems that scientists in the area of food safety and public health would prefer tackling the minor food borne zoonotic emerging or reemerging pathogens, namely Helicobacter species. Recently, understanding the novel aspects of zoonotic Enterohepatic Helicobacter species, including pathogenesis, isolation, identification, and genomic features is regarded as a serious challenge. In this regard, considerable attention is given to emerging elusive zoonotic Enterohepatic Helicobacter species, comprising Helicobacter pullorum and Helicobacter canadensis. In conclusion, the current review paper would attempt to elaborately summarize and somewhat compare the etiology, pathogenesis, cultivation process, identification, genotyping, and antimicrobial resistance profile of both H. pullorum and H. Canadensis. Further, H. pullorum has been introduced as the most significant food borne pathogen in chicken meat products.

Bacterial-Viral Interactions in Human Orodigestive and Female Genital Tract Cancers: A Summary of Epidemiologic and Laboratory Evidence

Infectious agents, including viruses, bacteria, fungi, and parasites, have been linked to pathogenesis of human cancers, whereas viruses and bacteria account for more than 99% of infection associated cancers. The human microbiome consists of not only bacteria, but also viruses and fungi. The microbiome co-residing in specific anatomic niches may modulate oncologic potentials of infectious agents in carcinogenesis. In this review, we focused on interactions between viruses and bacteria for cancers arising from the orodigestive tract and the female genital tract. We examined the interactions of these two different biological entities in the context of human carcinogenesis in the following three fashions: (1) direct interactions, (2) indirect interactions, and (3) no interaction between the two groups, but both acting on the same host carcinogenic pathways, yielding synergistic or additive effects in human cancers, e.g., head and neck cancer, liver cancer, colon cancer, gastric cancer, and cervical cancer. We discuss the progress in the current literature and summarize the mechanisms of host-viral-bacterial interactions in various human cancers. Our goal was to evaluate existing evidence and identify gaps in the knowledge for future directions in infection and cancer.

Metalloproteinase-1, Metalloproteinase-7, and p53 Immunoexpression and their Correlation with Clinicopathological Prognostic Factors in Colorectal Adenocarcinoma

Aim

The aim of this study was to analyze the immunoexpression of metalloproteinase-1, metalloproteinase-7, and p53 in colorectal adenocarcinoma, and to correlate this with clinicopathological prognostic factors.

Material and methods

Formalin-fixed paraffin-embedded tumor tissue from 82 patients was analyzed by means of immunohistochemistry, using the streptavidin-biotin method and the tissue microarray technique. Protein tissue expression was correlated with the variables of the degree of cell differentiation, stage, relapse-free survival, recurrence, survival, and specific mortality.

Results

All of the tumors were positive for metalloproteinase-1, while 50 (61%) were positive for metalloproteinase-7, and 32 (39%) were negative for the latter. For p53, 70 (85.4%) of the tumors were positive and 12 (14.6%) were negative. Correlation of the marker expressions separately and in conjunction did not produce any statistically significant data.

Conclusion

The immunoexpression of metalloproteinase-1, metalloproteinase-7, and p53 did not correlate with recurrence, mortality, relapse-free survival, survival, degree of cell differentiation, or staging of colorectal cancer.

cag Pathogenicity island-dependent upregulation of matrix metalloproteinase-7 in infected patients with Helicobacter pylori

Helicobacter pylori (H. pylori) infection has been involved in the pathogenesis of most important gastroduodenal diseases. Matrix metalloproteinases (MMPs) are a large family of zincendopeptidases which play important roles in degradation of extracellular matrix (ECM) and various inflammatory diseases. Therefore, we examined MMP-7 mRNA levels in the gastric mucosa of patients with H. pylori infection and evaluated the effects of virulence factors, such as vacA (vacuolating cytotoxin A) and cagA (cytotoxin-associated gene), in H. pylori-infected patients upon the MMP-7 mRNA mucosal levels. We also determined the correlation between mucosal MMP-7 mRNA levels and the types of disease. Total RNA was extracted from gastric biopsies of 50 H. pylori-infected patients and 50 uninfected individuals. Mucosal MMP-7 mRNA expression level in H. pylori-infected and non-infected gastric biopsies was determined by real-time polymerase chain reaction (PCR). The presences of cagA and vacA virulence factors was evaluated using PCR. MMP-7 expression was significantly higher in biopsies of patients infected with H .pylori compared to uninfected individuals. In addition, mucosal MMP-7 mRNA expression in H. pylori-infected patients significantly associated with the cagA status and the types of disease. Our results suggest that MMP-7 might be involved in the pathogenesis of H. pylori. Peptic ulcer was associated with cag pathogenicity island-dependent MMP-7 upregulation.

Helicobacter pullorum: An Emerging Zoonotic Pathogen

Helicobacter pullorum (H.pullorum) commonly colonizes the gastrointestinal tract of poultry causing gastroenteritis. The bacterium may be transmitted to humans through contaminated meat where it has been associated with colitis and hepatitis. Despite the high prevalence of H. pullorum observed in poultry, little is known about the mechanisms by which this bacterium establishes infection in host and its virulence determinants. In this article we aim to provide an overview of this emerging zoonotic pathogen; its general characteristics, hosts, prevalence, and transmission as well as its pathogenic potential. We also discuss possible control strategies and risk of disease emergence.

Serum IL-10, MMP-7, MMP-9 Levels in Helicobacter pylori Infection and Correlation with Degree of Gastritis

AIM

Helicobacter pylori causes gastric mucosal inflammation and immune reaction. However, the increase of IL-10, MMP-7, and MMP-7 levels in the serum is still controversial. The objective of this study was to investigate the serum levels of IL-10, MMP-7 & MMP-9 in gastritis patients with H. pylori infection.

MATERIALS AND METHODS

A cross-sectional study was done on seventy gastritis patients that consecutive admitted to endoscopy units. The diagnosis of gastritis was made based on histopathology and diagnosis of H. pylori infection was based on rapid urease test. Serum samples were obtained to determine to circulate IL-10, MMP-7, and MMP-9 level. Univariate and bivariate analysis were done by SPSS version 22.

RESULTS

Forthy percentages of the patients were infected with H. pylori. The IL-10 level was significantly higher in H. pylori-infected patients compared to non-infected patients. However, there were no differences between serum levels of MMP-7 and MMP-9 in infected and non-infected H. pylori patients.

CONCLUSIONS

The immune response to H. pylori promotes systemic inflammation, which was reflected by the increased levels of serum IL-10. However, there were no significant differences in MMP-7 and MMP-9 serum levels between positive and negative infected H. pylori patients.

CagA phosphorylation-dependent MMP-9 expression in gastric epithelial cells

BACKGROUND

Infection of cagA-positive Helicobacter pylori is associated with increased expression of MMPs in gastric epithelial cells. The role of phosphorylated CagA in the induction of MMP-9, a protease-degrading basement membrane, in gastric epithelial cells has not been clearly defined yet. The aim of this study is to analyze whether the presence of CagA and its phosphorylation status play a role in increased expression of MMP-9 in gastric epithelial cells.

MATERIALS AND METHODS

Induction of MMP-9 secretion was analyzed in gastric epithelial AGS cells harboring CagA with or without EPIYA motif, which is injected by H. pylori or ectopically expressed. In addition, signaling pathways involved in the CagA-dependent MMP-9 production have been studied.

RESULTS

The 147C strain of H. pylori expressing tyrosine-phosphorylated CagA (EPIYA present) induced higher MMP-9 secretion by AGS cells than the 147A strain expressing non-tyrosine-phosphorylated CagA (EPIYA absent). In addition, in bacteria-free CagA-inducible AGS cells, expression of wild-type CagA induced more MMP-9 secretion than phosphorylation-resistant CagA. Inhibition of CagA phosphorylation by the Src family kinase inhibitor PP1 downregulated CagA-mediated MMP-9 secretion. Knockdown of SHP-2 phosphatase dramatically reduced MMP-9 secretion. ERK inhibitors, PD98059 and U0126, and NF-κB pathway inhibitors, sulfasalazine and N-acetyl-l-cysteine, also inhibited MMP-9 expression.

CONCLUSION

These results support a model whereby the EPIYA motif of CagA is phosphorylated by Src family kinases in gastric epithelial cells, which initiates activation of SHP-2. In addition, they suggest that the resultant activation of ERK pathway along with CagA-dependent NF-κB activation is critical for the induction of MMP-9 secretion.

Ribonucleotide reductase small subunit M2B prognoses better survival in colorectal cancer

Ribonucleotide reductase subunit RRM2B (p53R2) has been reported to suppress invasion and metastasis in colorectal cancer (CRC). Here, we report that high levels of RRM2B expression are correlated with markedly better survival in CRC patients. In a fluorescence-labeled orthotopic mouse xenograft model, we confirmed that overexpression of RRM2B in nonmetastatic CRC cells prevented lung and/or liver metastasis, relative to control cells that did metastasize. Clinical outcome studies were conducted on a training set with 103 CRCs and a validation set with 220 CRCs. All participants underwent surgery with periodic follow-up to determine survivability. A newly developed specific RRM2B antibody was employed to carry out immunohistochemistry for determining RRM2B expression levels on tissue arrays. In the training set, the Kaplan-Meier and multivariate Cox analysis revealed that RRM2B is associated with better survival of CRCs, especially in stage IV patients (HR = 0.40; 95% CI = 0.18-0.86, P = 0.016). In the validation set, RRM2B was negatively related to tumor invasion (OR = 0.45, 95% CI = 0.19-0.99, P = 0.040) and lymph node involvement (OR = 0.48, 95% CI = 0.25-0.92, P = 0.026). Furthermore, elevated expression of RRM2B was associated with better prognosis in this set as determined by multivariate analyses (HR = 0.48, 95% CI = 0.26-0.91, P = 0.030). Further investigations revealed that RRM2B was correlated with better survival of CRCs with advanced stage III and IV tumors rather than earlier stage I and II tumors. Taken together, our findings establish that RRM2B suppresses invasiveness of cancer cells and that its expression is associated with a better survival prognosis for CRC patients.

Liver immunolocalization and plasma levels of MMP-9 in non-alcoholic steatohepatitis (NASH) and hepatitis C infection

Non-alcoholic steatohepatitis (NASH) is a progressive fibrotic disease. Many issues related to the pathogenesis of this disease remain unresolved. Because of NASH association with the activation of liver fibrogenesis, we examined the plasma levels and liver immunolocalization of matrix metalloprotease-9 (MMP-9), a molecule involved in the remodelling processes of fibrogenesis. In addition, patients with chronic hepatitis C (HCV) were analyzed. Plasma concentrations of MMP-9 were determined by ELISA from peripheral blood and immunohistochemistry of the same protein was carried out in formalin-fixed and paraffin wax-embedded liver specimens. The mean value of circulating concentrations of MMP-9 in healthy controls was 39.7 ng/ml (SD: +/-4.6). In NASH and HCV-infected patients, MMP-9 concentrations were higher: 69.0 ng/ml (SD: +/-14.5) and 61.7 ng/ml (SD: +/-11.0), respectively. In NASH livers, MMP-9 was mainly immunolocalized on neutrophils, whereas in HVC-infected livers it was mainly localized over biliary canaliculi, bile ducts and hepatocyte cytoplasm. The different MMP-9 immunolocalization patterns in the examined diseases suggest the presence of a different pathophysiological involvement of this protease in the fibrogenesis underlying these diseases.

Gene expression profiles of Beta-cell enriched tissue obtained by laser capture microdissection from subjects with type 2 diabetes

Background

Changes in gene expression in pancreatic beta-cells from type 2 diabetes (T2D) should provide insights into their abnormal insulin secretion and turnover.

Methodology/Principal Findings

Frozen sections were obtained from cadaver pancreases of 10 control and 10 T2D human subjects. Beta-cell enriched samples were obtained by laser capture microdissection (LCM). RNA was extracted, amplified and subjected to microarray analysis. Further analysis was performed with DNA-Chip Analyzer (dChip) and Gene Set Enrichment Analysis (GSEA) software. There were changes in expression of genes linked to glucotoxicity. Evidence of oxidative stress was provided by upregulation of several metallothionein genes. There were few changes in the major genes associated with cell cycle, apoptosis or endoplasmic reticulum stress. There was differential expression of genes associated with pancreatic regeneration, most notably upregulation of members of the regenerating islet gene (REG) family and metalloproteinase 7 (MMP7). Some of the genes found in GWAS studies to be related to T2D were also found to be differentially expressed. IGF2BP2, TSPAN8, and HNF1B (TCF2) were upregulated while JAZF1 and SLC30A8 were downregulated.

Conclusions/Significance

This study made possible by LCM has identified many novel changes in gene expression that enhance understanding of the pathogenesis of T2D.

Hepatocellular carcinoma: prevalence and molecular pathogenesis of Helicobacter spp

Helicobacter pylori infection is one of the most common chronic bacterial infections in humans. The association of other Helicobacter spp. with extragastric diseases in animals is well established, and a role of these bacteria in human liver disease is becoming clearer. Several case-control studies have reported possible associations of Helicobacter spp. with various liver diseases, including hepatocellular carcinoma, which is the fifth most common type of carcinoma among men worldwide, and the eighth most common among women. Thus, it is important to understand molecular mechanisms that may lead to hepatotoxicity or hepatocellular dysfunction in which Helicobacter spp. may play a role in inducing malignant transformation of liver cells.

Enhanced systemic matrix metalloproteinase response in Helicobacter pylori gastritis

BACKGROUND

Helicobacter pylori causes chronic gastritis, peptic ulcer disease, and is the most important risk factor for non-cardia gastric cancer, and has been shown to upregulate matrix metalloproteinases (MMPs) in infected gastric mucosa. MMPs are proteolytic enzymes regulated by tissue inhibitors of metalloproteinases (TIMPs).

AIMS

We set up this study to find out whether H. pylori gastritis induces systemic MMP response.

METHODS

Serum samples were collected from patients undergoing gastroscopy; 26 patients had H. pylori gastritis and 18 were H. pylori-negative controls with normal gastric mucosa. Serum MMP levels were analysed by enzyme-linked immunosorbent assay.

RESULTS

Significantly elevated serum levels of collagenase-2 (MMP-8), gelatinase B (MMP-9), neutrophil elastase (NE), and myeloperoxidase (MPO), and reduced serum levels of gelatinase A (MMP-2) and TIMP-1 were demonstrated in patients with H. pylori gastritis as compared to H. pylori-negative controls. No significant differences were shown in serum matrilysin-1 (MMP-7) levels.

CONCLUSIONS

For the first time, we show enhanced MMP-8 response in H. pylori infection together with other neutrophil degranulation products (MMP-9, MPO, NE). Elevated circulating neutrophil degranulation product levels in serum of H. pylori-positive patients reflect accelerated proteolysis and oxidative stress, and may contribute to extraintestinal sequelae, such as cardiovascular diseases.

Metaloproteinases 1 e 7 e câncer colorretal

A metaloproteinase-1 (MMP-1) e a metaloproteinase-7 (MMP-7) são proteinases da matriz extracelular (MEC), zinco-dependentes, envolvidas no processo inicial da carcinogênese por permitirem a invasão tumoral na célula e promover o processo de metastatização. O polimorfismo dessas proteinases tem sido estudado recentemente com o objetivo de validar susa expressão e/ou atividade como marcador prognóstico. Evidências cumulativas revelam importante papel das MMP's 1 e 7 em diferentes fases da carcinogênese. A MMP-1 tem ação direta sobre a principal proteína da MEC, que é o colágeno do tecido intersticial conectivo. Sua expressão aumentada neste tecido pode indicar alto potencial de disseminação tumoral em diferentes tipos de câncer, incluindo o colorretal. A associação deste aumento da expressão também parece ser verdadeira para a MMP-7.

The role of herbs and spices in cancer prevention

Historically, herbs and spices have enjoyed a rich tradition of use for their flavor enhancement characteristics and for their medicinal properties. The rising prevalence of chronic diseases worldwide and the corresponding rise in health care costs is propelling interest among researchers and the public for multiple health benefits related to these food items, including a reduction in cancer risk and modification of tumor behavior. A growing body of epidemiological and preclinical evidence points to culinary herbs and spices as minor dietary constituents with multiple anticancer characteristics. This review focuses on the antimicrobial, antioxidant, and antitumorigenic properties of herbs and spices; their ability to influence carcinogen bioactivation; and likely anticancer contributions. While culinary herbs and spices present intriguing possibilities for health promotion, more complete information is needed about the actual exposures to dietary components that are needed to bring about a response and the molecular target(s) for specific herbs and spices. Only after this information is obtained will it be possible to define appropriate intervention strategies to achieve maximum benefits from herbs and spices without eliciting ill consequences.

A role for membrane-bound CD147 in NOD2-mediated recognition of bacterial cytoinvasion

NOD2 is an intracellular receptor for the bacterial cell wall component muramyl dipeptide. Mutations in the leucine-rich repeat region of NOD2, which lead to an impaired recognition of muramyl dipeptide, have been associated with chronic inflammatory diseases of barrier organs such as Crohn disease, asthma and atopic eczema. In this study we identify CD147 (also known as BSG and EMMPRIN), a membrane-bound regulator of cellular migration, differentiation and inflammatory processes, as a protein interaction partner of NOD2. We demonstrate a complex influence of the CD147-NOD2 interaction on NOD2-dependent signaling responses. We show that CD147 itself acts as an enhancer of the invasion of Listeria monocytogenes, an intracellular bacterial pathogen. We propose that the CD147-NOD2 interaction serves as a molecular guide to regulate NOD2 function at sites of pathogen invasion.

Gaining insight into microbial physiology in the large intestine: a special role for stable isotopes

The importance of the human large intestine for nutrition, health, and disease, is becoming increasingly realized. There are numerous indications of a distinct role for the gut in such important issues as immune disorders and obesity-linked diseases. Research on this long-neglected organ, which is colonized by a myriad of bacteria, is a rapidly growing field that is currently providing fascinating new insights into the processes going on in the colon, and their relevance for the human host. This review aims to give an overview of studies dealing with the physiology of the intestinal microbiota as it functions within and in interaction with the host, with a special focus on approaches involving stable isotopes. We have included general aspects of gut microbial life as well as aspects specifically relating to genomic, proteomic, and metabolomic studies. A special emphasis is further laid on reviewing relevant methods and applications of stable isotope-aided metabolic flux analysis (MFA). We argue that linking MFA with the '-omics' technologies using innovative modeling approaches is the way to go to establish a truly integrative and interdisciplinary approach. Systems biology thus actualized will provide key insights into the metabolic regulations involved in microbe-host mutualism and their relevance for health and disease.

Relationship of Helicobacter pylori to Bcl-2 family expression, DNA content, and pathological characteristics of gastric cancer

BACKGROUND

Despite the fact that the association of Helicobacter pylori with an increased risk of gastric cancer has been well documented, the exact mechanisms of this association have not been fully elucidated. Scarce data on H. pylori infection and its relationship with the different pathological characteristics are available in Egypt.

AIM OF THE STUDY

The rationale of the present study was to determine the prevalence of H. pylori in a group of gastric cancer patients and to analyze the relationship between H. pylori infection with the different pathological characteristics including the types of gastric cancer and tumor location within the stomach, in addition, to investigate the Bcl-2 and Bax expressions along with DNA flow cytometric analysis in the gastric cancer patients with and without H. pylori infection.

METHODS

Samples were obtained from 66 consecutive patients with gastric cancer (46 males and 20 females). The youngest patient was 20 yr old, the oldest 76 yr with mean age of 52.8 yr. The samples were subjected for histopathological characterization, H. pylori detection, DNA flow cytometric analysis, and Bcl-2 and Bax expressions detection, in addition to apoptosis analysis.

RESULTS

The obtained results showed that the H. pylori infection was found in 38/66 (57.6%) [Odds ratio=1.357 with 95% confidence interval (CI) 0.84-2.2]. There was a statistical significance for Bcl-2, Bax, and apoptosis with H. pylori status (p = 0.009, 0.008, 0.032, respectively). On the other hand, There was a statistical significance for H. pylori infection with the disease grade (p = 0.015) and lymph node metastasis (p = 0.05). No statistical significance was found between H. pylori status with the patients' age, gender, tumor site, tumor type, depth of invasion, and stromal reaction.

CONCLUSIONS

These data may indicate that the H. pylori infection not only contributes in the disease formation through the apoptosis dysregulation but also takes a part in the disease dissemination and progression. In addition, it may reflect a biologic, pathogenic, and ethnic background affecting the relationship of H. pylori infection to gastric cancer in the Egyptian patients. A high rate of smoking in Egypt and the diet are important factors that may affect such background. Further studies are warranted.

Effects of Helicobacter hepaticus on the proteome of HEp-2 cells

Helicobacter hepaticus infects the bowel and biliary tree of several animals, producing inflammation. Colonisation of mouse livers can induce hepatocellular carcinomas. The effects of H. hepaticus on the proliferation and global protein expression of human HEp-2 cells were studied by examining the changes in the protein profiles of cells exposed to the bacterium. HEp-2 cells were grown for four days under a microaerobic atmosphere or under the same conditions in co-cultures with H. hepaticus at various inoculum densities. Enlargement, distension and elongation of HEp-2 cells were observed in co-cultures with H. hepaticus. The number of live cells declined by only an order of magnitude at bacterial inocula of approximately 10(9)cfu/ml, but were reduced to less than 10(3)cells/ml at approximately 10(10)cfu/ml bacteria inocula. Protein expression by HEp-2 cells was investigated employing two-dimensional gel electrophoresis. In cells grown with or without bacteria, 17 differentially expressed proteins were identified by tandem mass spectrometry. These proteins participated in several biological functions including amino acid metabolism, cell growth and proliferation, stress response, protein translation and modification, etc. The onset of a catastrophic killing of HEp-2 cells at a bacterial density of approximately 10(9)cfu/ml suggested a multimodal action for H. hepaticus infection, and the modulation of the expression of proteins involved in different biological functions showed that the presence of H. hepaticus has broad effects on the physiology of HEp-2 cells.

The carbon monoxide-releasing molecule CORM-2 inhibits the inflammatory response induced by cytokines in Caco-2 cells

BACKGROUND AND PURPOSE

Recent evidence indicates that carbon monoxide-releasing molecules (CO-RMs) exhibit potential anti-inflammatory properties. In the present study, we have investigated whether tricarbonyl dichloro ruthenium(II) dimer (CORM-2) can control the inflammatory response induced by cytokines in a human colonic epithelial cell line, Caco-2.

EXPERIMENTAL APPROACH

Caco-2 cells were preincubated with CORM-2 for 30 minutes and then stimulated with interleukin (IL)-1beta, tumor necrosis factor-alpha and interferon-gamma for different times. Gene expression was analyzed by real-time PCR. Protein expression was investigated by Western blot and ELISA. Transcription factor activation was determined by the luciferase method.

KEY RESULTS

We have shown that CORM-2 significantly decreased the mRNA expression of nitric oxide synthase-2 (NOS-2) and the production of nitrite, in Caco-2 cells stimulated with cytokines. IL-8, IL-6 and metalloproteinase-7 (MMP-7) mRNA and protein were also significantly reduced by CORM-2. Time-course and small interfering RNA studies suggest that inhibition of IL-6 plays a role in the regulation of MMP-7 expression by CORM-2. These effects of CORM-2 can be dependent on the modulation of nuclear factor-kappaB (NF-kappaB), activator protein-1, CCAT/enhancer binding protein and the phosphorylated forms of NF-kappaB inhibitory protein-alpha, c-Jun N-terminal protein kinase 1/2, p38 and extracellular signal-regulated kinase 1/2.

CONCLUSIONS AND IMPLICATIONS

CORM-2 can regulate a number of genes relevant in intestinal inflammation and cancer progression. These findings provide new insights into the anti-inflammatory properties and potential applications of this class of compounds.

Helicobacter pylori induces gastric epithelial cell invasion in a c-Met and type IV secretion system-dependent manner

Helicobacter pylori interacts with gastric epithelial cells, activating signaling pathways important for carcinogenesis. In this study we examined the role of H. pylori on cell invasion and the molecular mechanisms underlying this process. The relevance of H. pylori cag pathogenicity island-encoded type IV secretion system (T4SS), CagA, and VacA for cell invasion was also investigated. We found that H. pylori induces AGS cell invasion in collagen type I and in Matrigel invasion assays. H. pylori-induced cell invasion requires the direct contact between bacteria and cancer cells. H. pylori-mediated cell invasion was dependent on the activation of the c-Met receptor and on increased MMP-2 and MMP-9 activity. The abrogation of the c-Met receptor using the specific NK4 inhibitor or the silencing of c-Met expression with small interference RNA suppressed both cell invasion and MMP activity. Studies with different H. pylori strains revealed that cell invasion, c-Met tyrosine phosphorylation, and increased MMP-2 and MMP-9 activity were all dependent on the presence of a functional bacterial T4SS, but not on VacA cytotoxicity. Our findings demonstrate that H. pylori strains with a functional T4SS stimulate gastric epithelial cell invasion through a c-Met-dependent signaling pathway that comprises an increase in MMP-2 and MMP-9 activity.

Cag pathogenicity island-independent up-regulation of matrix metalloproteinases-9 and -2 secretion and expression in mice by Helicobacter pylori infection

Helicobacter pylori cag pathogenicity island (PAI) is a major determinant of gastric injury via induction of several matrix metalloproteinases (MMPs). In the present study, we examined the influence of the cag PAI on gastric infection and MMP-9 production in mice and in cultured cells. A new mouse colonizing Indian H. pylori strain (AM1) that lacks the cag PAI was used to study the cag PAI importance in inflammation. Groups of C57BL/6 mice were inoculated separately with H. pylori strains AM1 and SS1 (cag+), gastric tissues were histologically examined, and bacterial colonization was scored by quantitative culture. Mice infected with either cag+ or cag- H. pylori strains showed gastric inflammation and elevated MMP-3 production. Significant up-regulation of pro-MMP-9 secretion and gene expression in H. pylori infected gastric tissues indicate dispensability of cag PAI for increased pro-MMP-9 secretion and synthesis in mice. In agreement, cell culture studies revealed that both AM1 and SS1 were equipotent in pro-MMP-9 induction in human gastric epithelial cells. Both strains showed moderate increase in MMP-2 activity in vivo and in vitro. In addition, increased secretion of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-6 induced pro-MMP-9 secretion and synthesis in AM1 or SS1 strain-infected mice suggesting elicitation of pro-inflammatory cytokines by both cag- and cag+ genotype. Moreover, tissue inhibitors of metalloproteinase-1 expression were decreased with increase in pro-MMP-9 induction. These data show that H. pylori may act through different pathways other than cag PAI-mediated for gastric inflammation and contribute to up-regulation of MMP-9 via pro-inflammatory cytokines.

Helicobacter pylori and hepatocellular carcinoma: correlated or uncorrelated?

Helicobacter pylori can be detected in liver tissue resected from patients with hepatocellular carcinoma. Conflicting reports regarding the relationship between H. pylori and hepatocellular carcinoma mean it is uncertain whether H. pylori acts as a troublemaker, co-risk factor or innocent bystander to the development of hepatocellular carcinoma. Clinical studies in patients without known causes of hepatocellular carcinoma are important to discover whether H. pylori is involved in the carcinogenesis of hepatocellular carcinoma. High quality prospective studies in patients with hepatocellular carcinoma, hepatitis C virus infection and no cirrhosis are needed to determine whether H. pylori is a co-risk factor for hepatocellular carcinoma.