Published online before print August 23, 2007

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Copyright © 2007 American Society for Investigative Pathology
American Journal of Pathology, doi:10.2353/ajpath.2007.070199

Accepted for publication July 3, 2007.

Article

Sex Hormones Induce Direct Epithelial and Inflammation-Mediated Oxidative/Nitrosative Stress That Favors Prostatic Carcinogenesis in the Noble Rat

Neville N.C. Tam^*, Irwin Leav, and Shuk-Mei Ho^*@

From the Department of Environmental Health,^* Division of Environmental Genetics and Molecular Toxicology, University of Cincinnati Medical Center, Cincinnati, Ohio; and the Department of Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts

^@ To whom correspondence should be addressed. E-mail: shuk-mei.Ho{at}uc.edu.

	Abstract

Oxidative and nitrosative stress have been implicated in prostate carcinogenesis, but the cause(s) of redox imbalance in the gland remains poorly defined. We and others have reported that administration of testosterone plus 17-estradiol to Noble rats for 16 weeks induces dysplasia and stromal inflammation of the lateral prostate (LP) but not the ventral prostate. Here, using laser capture microdissected specimens, we found that the combined hormone regimen increased the expression of mRNA of specific members of NAD(P)H oxidase (NOX-1, NOX-2, and NOX4), nitric-oxide synthase [NOS; inducible NOS and endothelial NOS], and cyclooxygenase (COX-2) in the LP epithelium and/or its adjacent inflammatory stroma. Accompanying these changes was the accumulation of 8-hydroxy-2'-deoxyguanosine, 4-hydroxynonenal protein adducts, and nitrotyrosine, primarily in the LP epithelium, suggesting that NOX, NOS, and COX may mediate hormone-induced oxidative/nitrosative stress in epithelium. We concluded that the oxidative/nitrosative damage resulting from the testosterone-plus-17-estradiol treatment is not solely derived from stromal inflammatory lesions but likely also originates from the epithelium per se. In this context, the up-regulation of COX-2 from epithelium represents a potential mechanism by which the hormone-initiated epithelium might induce inflammatory responses. Thus, we link alterations in the hormonal milieu with oxidative/nitrosative/inflammatory damage to the prostate epithelium that promotes carcinogenesis.