Nonsteroidal anti-inflammatory drugs (NSAIDs) have a preventive effect against colorectal cancer. Although inhibition of cyclooxygenase-2 plays a crucial role in the suppression of tumors, precise mechanisms of their action remain to be disclosed. To identify genes involved in the growth-suppressive effect of NSAIDs, we utilized cDNA microarray containing 23,040 genes and analyzed time-dependent alteration of gene expression in response to sulindac or aspirin in NSAIDs-sensitive SW480 and SW948 colon-cancer cells as well as in relatively resistant SNU-C4 cells. Consequently we identified 112 genes with commonly altered expression by sulindac and 176 with commonly altered expression by aspirin in the three lines. Addition of sulindac and that of aspirin altered expression levels of 130 and 140 genes, respectively, in SW480 and SW948 cells but not in SNU-C4 cells. These data may lead to a better understanding of growth-suppressive effects on colonic epithelium, and may provide clues for identifying novel therapeutic and/or preventive molecular targets of colon cancer. (C) 2002 Elsevier Science (USA).