Specific inhibition of cyclooxygenase-2 results in inhibition of proliferation of oral cancer cell lines via suppression of prostaglandin E-2 production

Prostaglandins (PGs) are known to play important roles in the proliferation of various types of cancer cells. PGs are produced by the action of cycloo xygenase (COX) enzymes, and two forms of COX, COX-1 and COX-2, have been de scribed. Previous studies have demonstrated that overexpression COX-2 is as sociated with colon carcinogenesis, tumor invasion and metastatic potential of colon cancer. In this study, the role of COX-2 on proliferation of squa mous cell carcinoma cell lines was investigated, NS-398, a selective COX-2 inhibitor, inhibited proliferation of NA cells, a squamous cell carcinoma c ell line that constitutively expresses COX-2 mRNA. NS-398 suppressed the sp ontaneous production of PGE(2) by NA cells, and the antiproliferative effec t of NS-398 was abolished by addition of PGE(2). Similar results were obtai ned from experiments using COX-2 antisense oligonucleotide. These results s uggest that specific inhibition of COX-2 inhibits proliferation of cancer c ells expressing COX-2 mRNA via suppression of PGE(2) production.