Proteomic comparison of prostate cancer cell lines LNCaP-FGC and LNCaP-r reveals heatshock protein 60 as a marker for prostate malignancy

BACKGROUND: Androgen-sensitive prostate cancer cell-line LNCaP-FGC and androgen-resistant line LNCaP-r constitute a model for development of androgen resistance in prostate cancer. METHODS: Proteins differently expressed in the two cell-lines were identified by two-dimensional (2-D) electrophoresis and mass spectrometry. HSP60, more abundant in LNCaP-r, was studied by RT-PCR and immunohistochemistry in specimens of human prostate cancer. RESULTS: HSP60 was upregulated in LNCaP-r, nm23 in LNCaP-FGC, and titin (two isoforms) in either LNCaP-r or LNCaP-FGC. In non-malignant prostate, HSP60-staining was in the glandular compartment, particularly basal epithelial cells. In prostate cancer, most epithelial cells showed moderate-strong staining without apparent correlation between staining intensity and Gleason grade. CONCLUSIONS: The LNCaP-FGC/LNCaP-r model, characterized by 2-D electrophoresis, reveals distinct proteomic alterations. With HSP60, results from cell-lines correlated with clinical results, indicating that this model can be used for dissection of mechanisms involved in transformation to androgen resistance and assignment of protein markers in prostate cancer.     

Inhibition of SULT2B1b expression alters effects of 3beta-hydroxysteroids on cell proliferation and steroid hormone receptor expression in human LNCaP prostate cancer cells

BACKGROUND: Sulfation is an important steroid inactivation in human tissues. Sulfotransferase (SULT) 2B1b selectively conjugates 3beta-hydroxysteroids and is expressed in epithelial cells of normal and cancerous prostate tissues. Dehydroepiandrosterone (DHEA) and Delta(5)-androstenediol (Delta(5)-Adiol) sulfation prevents their conversion to more potent androgens and estrogens in tissues although both compounds may also be biologically active. METHODS: SULT2B1b expression and activity were inhibited >85% in human LNCaP prostate adenocarcinoma cells using short interference RNA (siRNA). The effects of treating control and SULT2B1b-deficient LNCaP cells with DHEA, Delta(5)-Adiol, and 5alpha-androstane-3beta-17beta-diol (Anstane-diol) on cellular proliferation, estrogen receptors (ERs), androgen receptor (AR), and prostate specific antigen protein levels were examined. RESULTS: Physiological concentrations of DHEA and Delta(5)-Adiol increased proliferation of control cells and the proliferative effects were significantly increased in SULT2B1b-siRNA cells. DHEA, but not Delta(5)-Adiol increased AR levels at concentrations >/=1,000 nM in SULT2B1b-siRNA cells but not in control LNCaP cells. ER-alpha levels were not affected with any of the compounds tested. Physiological concentrations of DHEA and Delta(5)-A-diol decreased ER-beta levels in control cells and had significantly greater effects in SULT2B1b-siRNA cells. In contrast, Anstane-diol had no effect on AR or ER-alpha levels but induced more elevation of ER-beta levels in SULT2B1b-siRNA cells at concentrations >/=1,000 nM. CONCLUSIONS: SULT2B1b is involved in regulating prostate cell responsiveness to DHEA and Delta(5)-Adiol. Inhibition of SULT2B1b increased cell proliferation and ER-beta repression after treatment with physiological levels of DHEA and Delta(5)-Adiol indicating that SULT2B1b has an inhibitory effect on DHEA and Delta(5)-Adiol activity.