Background: Epidemiological studies have revealed a protective effect of NSAIDs, which principally target cyclooxygenase (COX)-1 and COX-2, on the development of colorectal cancer. Increased expression of COX-2 was shown in colorectal adenocarcinoma. However, some effects were shown to be COX-independent. Here, we compared two selective COX-2 inhibitors for their effect on the growth of colorectal tumour cells in vitro.
Materials and methods: Fifteen tumour cell lines were characterized for COX-1 and COX-2 expression by Western blot and RT-PCR. The effect of celecoxib and rofecoxib on their growth was assessed by staining of DNA with crystal violet.
Results: COX-2 expression varied among cell lines, whereas COX-1 was always expressed. Rofecoxib displayed a limited dose-related effect on cell proliferation, whereas celecoxib strongly inhibited cell growth at high concentrations. Both effects appeared COX-2-independent.
Conclusion: Rofecoxib, which is devoid of apoptotic effect at high concentration but efficient at pharmacological concentrations, revealed a potential new mechanism of action of NSAIDs towards colorectal cancer.