Effects of cyclooxygenase-2 on expression of vascular endothelial growth factor / 中华消化杂志

ABSTRACT

Objective It has been known that cyclooxygenase-2(COX-2) acts as a tumor promoter in rodent models for colorectal cancer, but its precise role in the processes of carcinogenesis remains unclear. The study was designed to observe the relationship between expression of COX and the expression of vascular endothelial growth factor (VEGF) in the mouse embryo fibroblast (MEF) with knock out of COX-1 gene (COX-1 -/- ) or COX-2 gene (COX-2 -/- ) and wild MEF cells (COX-1 +/+ /COX-2 +/+ ). Methods We cultured the mouse embryo fibroblasts, measured the VEGF levels in the culture medium of these cells using ELISA, and extracted mRNA from these cells to identify the expressions of VEGF isoforms by RT-PCR. Results VEGF level could hardly be measured in the COX 2-deficient cells (COX-2 -/- ), however, the VEGF level was significantly increased in the cells with COX-2 gene (COX-2 +/+ ) and decreased by celecoxib, a COX-2 inhibitor. The level of VEGF was not associated with COX-1 expression. COX-2 inhibited the expressions of three isoforms of VEGF at mRNA level. Conclusions COX-2 plays an important role in the VEGF secretion and synthesis and therefore, it has an effect on the angiogenesis and tumor growth.