pGL3-Basic-COX-2-promoter报告基因重组质粒的构建及其功能鉴定

Helicobacter pylori infection increases the transcriptional activity of COX-2 promoter via the p38MAPK signal transduction pathway in MKN45 cells

AIM: To investigate the effect of Helicobacter pylori (H.pylori) infection on the transcriptional activity of cyclooxygenase-2 (COX-2) promoter in gastric cancer MKN45 cells and to explore potential mechanisms involved.

METHODS: The recombinant vector pGL3-Basic-COX-2-promoter and a control vector (pRL-SV40) was transiently co-transfected into MKN45 cells. Twelve hours later, the transfected cells were infected with H.pylori (100 times the number of cells) for different durations. The COX-2 promoter activity was detected using the dual luciferase assay. The activation of p38MAPK pathway was evaluated by Western blot. The p38MAPK signal transduction pathway was then blocked with a specific inhibitor SB203580 to detect the effect of H.pylori infection on COX-2 promoter activity.

RESULTS: After transient transfection, the activity of COX-2 promoter in MKN45 cells was increased with time. At 40 h after transfection, the activity of dual-luciferase was 3.5 folds higher than that at 8 h (P < 0.05). H.pylori infection significantly increased the activity of dual-luciferase compared with control cells (all P < 0.05 or 0.01). The activity of dual-luciferase in cells infected with H.pylori at 40 h after transfection was 5 folds higher than that at 8 h (P < 0.01). The expression of p38MAPK was up-regulated at 20 min after infection and reached the peak at 60 min. Blockage of the p38MAPK signal transduction pathway with SB203580 significantly reduced the COX-2 promoter activity.

CONCLUSION: H.pylori infection increases the transcriptional activity of COX-2 promoter via the p38MAPK signal transduction pathway, which may be one of the important mechanisms by which H.pylori infection causes gastric cancer.