p53 and ATF-2 partly mediate the overexpression of COX-2 in H(2)O (2)-induced premature senescence of human fibroblasts.

Cyclooxygenase-2 and release of prostaglandin E2 are up-regulated in replicative senescence of dermal and prostate fibroblasts and in H(2)O(2)-induced premature senescence of IMR-90 lung fibroblasts expressing the catalytic subunit of telomerase. Inhibition of cyclooxygenase-2 activity by specific chemical inhibitor or siRNA attenuates the H(2)O(2)-induced increase of senescence associated beta-galactosidase positive cells and attenuates growth arrest. In this work, p38(MAPK) activation and increased DNA binding activities of ATF-2 and p53 are shown to mediate cyclooxygenase-2 overexpression in premature senescence.