Helicobacter pyloriVacuolating Cytotoxin Binds to the 140-kDa Protein in Human Gastric Cancer Cell Lines, AZ-521 and AGS

Yahiro, Kinnosuke; Niidome, Takuro; Hatakeyama, Tomomitsu; Aoyagi, Haruhiko; Kurazono, Hisao; Padilla, Philip Ian; Wada, Akihiro; Hirayama, Toshiya

doi:10.1006/bbrc.1997.7345

Cited by 74 publications

(71 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast, studies with radiolabeled VacA have not demonstrated convincing evidence of a saturable binding process, and the binding of radiolabeled VacA was only partially inhibited by excess unlabeled VacA (20,31). At least five different putative receptors for VacA have been reported, including receptor protein tyrosine phosphatase ␤, an unidentified 140-kDa protein, the epidermal growth factor receptor, heparan sulfate, and various lipids (22,23,(62)(63)(64)(65). It has also been reported that that treatment of cells with either nystatin or PI-PLC inhibits VacA cytotoxicity, and based on this observation, it was proposed that intact lipid rafts and GPI-anchored proteins are required for VacA susceptibility (31).…”

Section: Discussionmentioning

confidence: 99%

Association of Helicobacter pylori Vacuolating Toxin (VacA) with Lipid Rafts

Schraw

McClain

et al. 2002

Journal of Biological Chemistry

132

149

View full text Add to dashboard Cite

Section: Discussionmentioning

confidence: 99%

Association of Helicobacter pylori Vacuolating Toxin (VacA) with Lipid Rafts

Schraw

McClain

et al. 2002

Journal of Biological Chemistry

132

149

View full text Add to dashboard Cite

“…VacA Preparation-The toxin-producing H. pylori strain ATCC49503 was used as the source of VacA for purification according to a modification of our published procedure (26,27). In brief, after growth of H. pylori in Brucella broth containing 0.1% ␤-cyclodextrin at 37°C for 4 days with vigorous shaking in a controlled microaerophilic atmosphere of 10% O 2 and 10% CO 2 , VacA was precipitated from culture supernatant with 50% saturated ammonium sulfate and purified by VacA affinity column, which was coupled with anti-VacA-specific IgG antibody and equilibrated with RX buffer (10 mM KCl, 0.3 mM NaCl, 0.35 mM MgCl 2 , and 0.125 mM EGTA in 1 mM HEPES, pH 7.3).…”

Section: Methodsmentioning

confidence: 99%

Helicobacter pylori VacA Activates the p38/Activating Transcription Factor 2-mediated Signal Pathway in AZ-521 Cells

Nakayama

Kimura

Wada

et al. 2004

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

Persistent Helicobacter pylori colonization in the stomach induces gastritis and peptic ulcer and interferes with ulcer healing. Most strains of H. pylori produce a cytotoxin, VacA, that induces cytoplasmic vacuolation in epithelial cells with structural and functional changes, leading to gastric injury. VacA is known to cause cell death by mitochondrial damage. We hypothesized that VacA might disrupt other signaling pathways; to that end, we examined the effects of VacA on MAPKs to elucidate their role in the abnormalities seen in VacAtreated cells. VacA stimulated phosphorylation of p38 and Erk1/2, but not JNK, in AZ-521 cells. Both phosphorylation and kinase activation of p38 were maximal 10 -30 min after addition of VacA and declined thereafter. Treatment with anti-VacA antibody or the p38 inhibitor SB203580 blocked p38 phosphorylation caused by VacA and inhibited VacA-induced phosphorylation of activating transcription factor 2 (ATF-2), which is implicated in transcriptional control of stress-responsive genes. These data indicate that VacA stimulates a p38/ ATF-2-mediated signal pathway. However, 10 M SB203580, which is sufficient to decrease p38 phosphorylation, did not inhibit VacA-induced cellular vacuolation, decrease in mitochondrial membrane potential, or cytochrome c release from mitochondria. These results suggest that VacA-induced activation of p38/ATF-2-mediated signal pathway is independent of cellular vacuolation, decrease in mitochondrial membrane potential, or cytochrome c release from mitochondria caused by VacA. The cytotoxin may thus act independently on several cellular targets, leading to disruption of signaling, regulatory, and metabolic pathways.Persistent Helicobacter pylori infection results in the development of chronic gastritis, peptic ulcer, and gastric cancer. Pathogenic strains of H. pylori produce and secrete a potent vacuolating cytotoxin, VacA, that is capable of directly inducing progressive vacuolation (1), mitochondrial damage (2), cytochrome c release (3), and apoptotic death of epithelial cells (4). Both epidemiological study (5) and animal experiments (6 -10) have demonstrated that VacA is a major virulence factor associated with the damage to gastric mucosa. VacA is produced as a 140-kDa precursor and cleaved at the bacterial outer membranes, generating the 87-95-kDa mature toxin (11). The mature toxin contains two major domains, the N-terminal region of 37 kDa that exhibits vacuolating activity and the C-terminal region of 58 kDa responsible for toxin binding to target cells (12)(13)(14)(15).In gastric tissues infected with H. pylori, many apoptotic cells were observed due to inflammation resulting from overproduction of cytokines induced by H. pylori (9, 16 -19). Recent work on the gastric mucosal inflammatory response to persistent H. pylori infection suggested that the p38 mitogen-activated protein kinase (MAPK) 1 signal pathway plays a significant role (20,21). Activation of p38 MAPK in response to environmental stress and inflammatory cytokines can result in ap...

show abstract

“…Cells were incubated with 50 l of freshly prepared 0.05% neutral red in PBS containing 0.3% bovine serum albumin and then washed three times with 0.1 ml of PBS containing 0.3% bovine serum albumin. After addition of 0.1 ml of 70% ethanol in water containing 0.4% HCl, absorbance at 540 nm (A 540 ) was measured (30).…”

Section: Methodsmentioning

confidence: 99%