Suppressor of activator protein-1 regulated by interferon expression in prostate cancer tissues and cells

Purpose: The aim of this study was to investigate the role of the suppressor of activator protein-1 regulated by interferon (SARI), in the development and progression of prostate cancer. Methods: Sixty-seven prostate cancer tissue specimens and 20 benign prostatic hyperplasia specimens were used to investigate the correlation between SARI expression and clinicopathologic parameters. Immunohistochemistry was used to detect the SARI and E-cadherin protein expression in the prostate cancer and benign prostatic hyperplasia specimens, and their correlation was established. Quantitative PCR (qPCR) was used to determine the SARI mRNA expression in a normal prostate cell line (RWPE-1) and prostate cancer cell lines (LNCaP and PC3). Western blotting was used to detect the SARI protein expression in the RWPE-1, LNCaP, and PC3 cell lines. Results: SARI protein expression did not correlate with the prostate cancer patients' age or serum Prostate-Specific Antigen value but did show a correlation with the tumor stage of prostate cancer and Gleason score. SARI and E-cadherin expression in the prostate cancer tissue was significantly lower than in the benign prostatic hyperplasia specimens, suggesting a positive correlation between the SARI and E-cadherin expression. SARI mRNA and protein were highly expressed in RWPE-1, the normal prostate cell line, but SARI mRNA and protein expression were reduced in the prostate cancer cell lines, LNCaP and PC3. Significant differences in the expression were found between the prostate cancer cell lines and the normal prostate cell line. Conclusion: In this study, high SARI expression was found to be negatively correlated with the development and progression of prostate cancer.