Cyclooxygenase-2 has been reported to play an important role in colorectal
carcinogenesis. The effects of meloxicam (a COX-2 inhibitor) on the growth
of two colon cancer cell lines that express COX-2 (HCA-7 and Moser-S) and a
COX-2 negative cell line (HCT-116) were evaluated. The growth rate of thes
e cells was measured following treatment with meloxicam. HCA-7 and Moser-S
colony size were significantly reduced following treatment with meloxicam;
however, there was no significant change in HCT-116 colony size with treatm
ent, lit vivo studies were performed to evaluate the effect of meloxicam on
the growth of HCA-7 cells when xenografted into nude mice. We observed a 5
1% reduction in tumor size after 4 weeks of treatment. Analysis of COX-1 an
d COX-2 protein levels in HCA-7 tumor lysates revealed a slight decrease in
COX-2 expression levels in tumors taken from mice treated with meloxicam a
nd no detectable COX-1 expression. Here we report that meloxicam significan
tly inhibited HCA-7 colony and tumor growth but had no effect on the growth
of the COX-2 negative HCT-116 cells.