Objective: To investigate the effects of Jianpi Jiedu Formula (JPJDF), a compound Chinese herbal medicine, on vascular endothelial growth factor (VEGF) expression induced by Helicobacter pylori (Hp) in human gastric cancer cells, and to explore the possible mechanism.
Methods: Human gastric MKN45 cancer cells were infected with standard Hp NCTC11637 by coculture, and the cells were divided into 7 groups: normal control group, Hp group, NS398 inhibitor group, blank serum group, and 5%, 10% and 20% JPJDF groups. The expressions of VEGF and cyclooxygenase-2 (COX-2) mRNAs in human gastric cancer cells infected by Hp were evaluated by real-time fluorogenic quantitative polymerase chain reaction (PCR). After inhibiting the expression of COX-2 with COX-2 specific inhibitor NS398 (50 μmol/L), VEGF mRNA expression induced by Hp in human gastric cancer MKN45 cells was evaluated by real-time fluorogenic quantitative PCR.
Results: Real-time fluorogenic quantitative PCR results showed that COX-2 mRNA expression increased significantly after MKN45 cells were infected with Hp for 6 h (P<0.01), and VEGF mRNA expression also increased significantly after MKN45 cells were infected with Hp for 12 h as compared with the normal control group (P<0.01). After inhibiting COX-2 expression with COX-2 specific inhibitor NS398, Hp-induced VEGF mRNA expression significantly reduced (P<0.01). 5%, 10% and 20% JPJDF-containing sera all down-regulated VEGF and COX-2 mRNA expressions induced by Hp in a dose-dependent manner as compared with the Hp infection group.
Conclusion: Hp could induce the expressions of COX-2 and VEGF in human gastric cancer cells, and JPJDF down-regulates Hp-induced expression of VEGF by inhibiting COX-2, which might be one of the important mechanisms of its prevention and treatment of gastric cancer.