We have evaluated the role of mitogen-activated protein kinases (MAPKs) and their relationship with nuclear factor kappaB (NF-kappaB) and peroxisome proliferator-activated receptor gamma (PPARgamma) in indomethacin-induced apoptosis of colon cancer cells. We demonstrated that indomethacin can induce the prolonged activation of MAPKs in colon cancer cells; and that of these MAPKs, p38 MAPK may play a partial but significant role in indomethacin-induced apoptosis. Furthermore, indomethacin-induced p38 MAPK-mediated apoptosis of colon cancer cell lines is independent of caspase activation and not associated with indomethacin-induced NF-kappaB suppression and PPARgamma activation.