Down-regulation of Bcl-2 is mediated by NF-κB activation in Helicobacter pylori-induced apoptosis of gastric epithelial cells.
ABSTRACT Bcl-2 family is involved in the regulation of apoptosis. NF-κB activation is associated with either the expression of Bcl-2 or down-regulation of Bcl-2 depending on cell types and stimuli. Previously, we showed NF-κB activation, decrease in the level of Bcl-2, and apoptosis in Helicobacter pylori (H. pylori)-infected gastric epithelial cells. The present study aims to investigate the relation of Bcl-2 expression and NF-κB activation in H. pylori-induced apoptotic cell death of AGS (gastric adenocarcinoma) cells.
AGS cells were transfected with mutant IκBα to suppress NF-κB activation or Bcl-2 gene to induce overexpression of Bcl-2. mRNA expression of Bcl-2, p53 and Bax, DNA fragmentation, cell viability, and the numbers of apoptotic cells were determined.
H. pylori induced decrease in Bcl-2, but increase in p53 and Bax at the levels of mRNA and protein in AGS cells. H. pylori-induced increment of apoptotic cells and decrease in Bcl-2 level were inhibited in the cells transfected with mutant IκBα gene as compared with the cells transfected with control vector. H. pylori-induced apoptosis determined by apoptotic cells, DNA fragmentation, and cell viability was inhibited in the cells transfected with Bcl-2 gene.
Down-regulation of Bcl-2 is mediated by NF-κB activation, which may be the underlying mechanism of apoptosis in H. pylori-infected gastric epithelial cells.
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ABSTRACT: A protein determination method which involves the binding of Coomassie Brilliant Blue G-250 to protein is described. The binding of the dye to protein causes a shift in the absorption maximum of the dye from 465 to 595 nm, and it is the increase in absorption at 595 nm which is monitored. This assay is very reproducible and rapid with the dye binding process virtually complete in approximately 2 min with good color stability for 1 hr. There is little or no interference from cations such as sodium or potassium nor from carbohydrates such as sucrose. A small amount of color is developed in the presence of strongly alkaline buffering agents, but the assay may be run accurately by the use of proper buffer controls. The only components found to give excessive interfering color in the assay are relatively large amounts of detergents such as sodium dodecyl sulfate, Triton X-100, and commercial glassware detergents. Interference by small amounts of detergent may be eliminated by the use of proper controls.Analytical Biochemistry 06/1976; 72:248-54. · 2.58 Impact Factor
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