A reciprocal relationship exists between non-steroidal anti-inflammatory drug-activated gene-1 (NAG-1) and cyclooxygenase-2.

Non-steroidal anti-inflammatory drug (NSAID)-activated gene-1 (NAG-1) and COX-2 are involved in cellular processes such as inflammation, apoptosis, and tumorigenesis. To address the relationship between COX-2 and NAG-1 expression, we investigated the expression of NAG-1 and COX-2 in normal and tumor tissue from human patients, Apc(Min/+) mice, and COX-2(-/-) mice. While COX-2 expression is highly induced in tumor tissue, NAG-1 expression is reduced. Furthermore, PGE(2) reduces NAG-1 while celebrex induces NAG-1 expression. The results suggest that a possible inverse relationship exists between the expression of NAG-1 and COX-2 in tumor formation of colon tissue.