Effects of a selective cyclooxygenase-2 inhibitor on cancer cells in vitro.

The cyclooxygenase (COX) family of enzymes has been implicated in cell proliferation and angiogenesis in many tumors, including colon cancer. Indeed, cyclooxygenase-2 (COX-2) inhibitors recently have been approved for use for prophylaxis in individuals with familial adenomatous polyposis. We now report on the effects of a selective COX-2 inhibitor, celecoxib, on cell proliferation, matrix metalloproteinase (MMP) concentration, angiogenesis using an in vitro assay, and apoptosis in several human cancer cell lines. We demonstrate that celecoxib modestly reduces proliferation in some cell lines and does not affect MMP concentrations. However, celecoxib significantly decreases microtubule formation in stimulated human umbilical vein endothelial cells (HUVECs) exposed to cancer cell supernatants, an in vitro angiogenesis model, when compared to controls incubated with supernatants from untreated cells. Celecoxib does not consistently induce apoptosis in these cell lines, as determined by DNA laddering in agarose gels and by a caspase assay. Thus, it appears that COX-2 inhibitors have beneficial effects in reducing malignant cell behavior in vitro and warrant further study to elucidate their mechanisms of action and to examine their mechanisms of action in this role and their utility in vivo in a variety of animal and human tumors.