Cyclooxygenase-2 in human non-small cell lung cancer

Aim: Recent studies report that the expression of cyclooxygenase (COX) in non-small cell lung cancer (NSCLC) is increased, especially in adenocarcinoma. Platelet activating factor (PAF), n-sodium butyrate (n-BT), and phorbol myristate acetate (PMA) are important mediators of the inflammatory process. Method: Expression of COX-2 in 67 stage 1 NSCLC paraffin-embedded tumor samples was determined by immunohistochemistry (IHC). Four NSCL cell lines were incubated and stimulated by PAF, n-BT and PMA for 48 h. Expression of COX-2 was determined by IHC, immunoblotting, and reverse transcription-polymerase chain reaction (RT-PCR). Result: IHC showed increasing immunoreactivity in 35 of 67 (52%) in stage I NSCLC, 31 of 53 (59%) in adenocarcinoma and 13 of 15 (87%) in bronchoalveolar cell carcinoma, but only 2 of 12 (17%) in epidermoid carcinoma. The COX-2 expression in NSCLC cells was 75% (3/4) and the COX-1 expression in NSCLC cells was 100% (4/4). After stimulation with PMA, n-BT, PAF and n-BT+PAF, the COX-2 expression in NSCLC cells was significantly increased in all cell lines. Conclusions: The expression of COX-2 in NSCLC cells is high and was up-regulated by PMA, n-BT and PAF. We consider that COX-2 inhibitors will play an important role in the therapy of NSCLC.