Identification of JWA as a novel functional gene responsive to environmental oxidative stress induced by benzo[a]pyrene and hydrogen peroxide

Oxidative stress has been implicated as one of the primary mechanisms inducing DNA damage and believed to mediate aging and progression of numerous age-related diseases, including cancer. JWA, a gene previously described to mediate differentiation of leukemic cells, is also involved in cellular responses to environmental exposures linked to heat shock and chemical-mediated oxidative stresses. However, the precise pathways and mechanisms underlying these phenomena remain to be resolved. Our studies demonstrated that H2O2 is the primary oxidative product responsible for benzo[a]pyrene (B[a]P)-induced JWA expression, and knockdown of JWA elevates H2O2 (100 mu M)- and B[a]P (100 mu M)-induced DNA damage. In oxidative stress cell culture models, JWA was upregulated. JWA expression regulated a parallel rise in the base excision repair protein XRCC1 but a reduction in PARPI in response to H2O2-induced DNA damage. Furthermore, we found that both H2O2 and B[a]P exposure activated nuclear transcription factor I (NFI) in NIH-3T3 cells, which specifically bound to the CCAAT element in the JWA proximal promoter (-58/-28 bp) and thereby induced JWA expression. Consistently siRNA mediated a knockdown of NFI, which prevented JWA induction. These findings indicate that JWA may serve as a novel environmental stress sensor to protect cells against reactive oxygen species-associated DNA damage. (c) 2007 Elsevier Inc. All rights reserved.