Increased COX-1 expression in benign prostate epithelial cells is triggered by mitochondrial dysfunction

Prostatic inflammation is closely linked to the development and progression of benign prostatic hyperplasia (BPH). Clinical studies of non-steroidal anti-inflammatory drugs, which inhibit cyclooxygenase-2 (COX-2), targeting prostate inflammation patients with symptomatic BPH have demonstrated conflicting

Our findings suggest COX-1 is elevated in BPH epithelial cells and is associated with increased presence of CD8+ cytotoxic T-cells. COX-1 can be induced in benign prostate epithelial cells in response to mitochondrial complex I inhibition, and knockdown of the complex 1 protein NDUFS3. COX-1 and mitochondrial dysfunction may play more of a role than previously recognized in the development of age-related benign prostatic disease.

The expression of COX-1 was analyzed in a cohort of donors and BPH patients by immunohistochemistry and compared to previously determined characteristics for this same cohort. The impact of mitochondrial dysfunction on COX-1 and COX-2 was determined in experiments treating human benign prostate epithelial cell lines BPH-1 and RWPE-1 with rotenone and MitoQ. RWPE-1 cells were transfected with small interfering RNA specific to complex 1 gene NDUFS3.

COX-1 expression was increased in the epithelial cells of BPH specimens compared to young healthy organ donor and normal prostate adjacent to BPH and frequently co-occurred with COX-2 alteration in BPH patients. COX-1 immunostaining was associated with the presence of CD8+ cytotoxic T-cells, but was not associated with age, prostate size, COX-2 or the presence of CD4+, CD20+ or CD68+ inflammatory cells. In cell line studies, COX protein levels were elevated following treatment with inhibitors of mitochondrial function. MitoQ significantly decreased mitochondrial membrane potential in RWPE-1 cells. Knockdown of NDUFS3 stimulated COX-1 expression.