Cyclooxygenase-2 induction by arsenite through the IKKbeta/NFkappaB pathway exerts an antiapoptotic effect in mouse epidermal Cl41 cells.

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Ouyang W, Zhang D, Ma Q, Li J, Huang C

Cyclooxygenase-2 induction by arsenite through the IKKbeta/NFkappaB pathway exerts an antiapoptotic effect in mouse epidermal Cl41 cells.

Environ Health Perspect. 2007 Apr;115(4):513-8. Epub 2006 Dec 14.

PubMed ID
17450217 [ View in PubMed
]
Abstract

BACKGROUND: Arsenic contamination has become a major public health concern worldwide. Epidemiologic data show that long-term arsenic exposure results in the risk of skin cancer. However, the mechanisms underlying carcinogenic effects of arsenite on skin remain to be studied. OBJECTIVES: In the present study we evaluated cyclooxygenase-2 (COX-2) expression, the signaling pathways leading to COX-2 induction, and its antiapoptotic function in the response to arsenite exposure in mouse epidermal JB6 Cl41 cells. METHODS: We used the luciferase reporter assay and Western blots to determine COX-2 induction by arsenite. We utilized dominant negative mutant, genetic knockout, gene knockdown, and gene overexpression approaches to elucidate the signaling pathway involved in COX-2 induction and its protective effect on cell apoptosis. RESULTS: The induction of COX-2 by arsenite was inhibited in Cl41 cells transfected with IKKbeta-KM, a dominant mutant inhibitor of kbeta (Ikbeta) kinase (IKKbeta), and in IKKbeta-knockout (IKKbeta(-/-)) mouse embryonic fibroblasts (MEFs). IKKbeta/nuclear factor kappaB (NFkappaB) pathway-mediated COX-2 induction exerted an antiapoptotic effect on the cells exposed to arsenite because cell apoptosis was significantly enhanced in the Cl41 cells transfected with IKKbeta-KM or COX-2 small interference RNA (siCOX-2). In addition, IKKbeta(-/-) MEFs stably transfected with COX-2 showed more resistance to arsenite-induced apoptosis compared with the same control vector-transfected cells. CONCLUSIONS: These results demonstrate that arsenite exposure can induce COX-2 expression through the IKKbeta/NFkappaB pathway, which thereby exerts an antiapoptotic effect in response to arsenite. In light of the importance of apoptosis evasion during carcinogenesis, we anticipate that COX-2 induction may be at least partially responsible for the carcinogenic effect of arsenite on skin.

DrugBank Data that Cites this Article

Drug Targets
DrugTargetKindOrganismPharmacological ActionActions
Arsenic trioxideInhibitor of nuclear factor kappa-B kinase subunit betaProteinHumans
Yes
Inducer
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