Rosmarinic acid (RA), a main phenolic compound contained in rosemary which is used as tea, oil, medicine and so on, has been known to present anti-inflammatory, anti-oxidant and anti-cancer effects. Histone deacetylases (HDACs) are enzymes that play important roles in gene expression by removing the acetyl group from histone. The aberrant expression of HDAC in human tumors is related with the onset of human cancer. Especially, HDAC2, which belongs to HDAC class I composed of HDAC 1, 2, 3 and 8, has been reported to be highly expressed in prostate cancer (PCa) where it downregulates the expression of p53, resulting in an inhibition of apoptosis. The purpose of this study is to investigate the effect of RA in comparison with suberoylanilide hydroxamic acid (SAHA), an HDAC inhibitor used as an anti-cancer agent, on survival and apoptosis of PCa cell lines, PC-3 and DU145, and the expression of HDAC. RA decreased the cell proliferation in cell viability assay, and inhibited the colony formation and tumor spheroid formation. Additionally, RA induced early- and late-stage apoptosis of PC-3 and DU145 cells in Annexin V assay and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, respectively. In western blot analysis, RA inhibited the expression of HDAC2, as SAHA did. Proliferating cell nuclear antigen (PCNA), cyclin D1 and cyclin E1 were downregulated by RA, whereas p21 was upregulated. In addition, RA modulated the protein expression of intrinsic mitochondrial apoptotic pathway-related genes, such as Bax, Bcl-2, caspase-3 and poly (ADP-ribose) polymerase 1 (PARP-1) (cleaved) via the upregulation of p53 derived from HDAC2 downregulation, leading to the increased apoptosis of PC-3 and DU145 cells. Taken together, treatment of RA to PCa cell lines inhibits the cell survival and induces cell apoptosis, and it can be used as a novel therapeutic agent toward PCa.

Prostate carcinoma is one of the most common malignancies and the second most common cause of cancer-related deaths in men world-wide and is affected by the action of dehydrotestosteron (DHT) via androgen receptor (AR). Resveratrol as a phytochemical in grapes and red wine has diverse effects such as anti-inflammation, anti-oxidant and anti-cancer. CXCR4 as a chemokine receptor has been found to be upregulated in cancer metastasis and has been used as a prognostic marker in various types of cancer, including leukemia, breast cancer, and prostate cancer. In this study, we focused on the role of DHT in the induction of prostate cancer progression by affecting the AR and CXCR4 pathway. Also, we investigated the inhibition effect of resveratrol on DHT - induced prostate cancer metastasis. In cell viability assay, DHT increased the cell viability of LNCaP prostate cancer cell on the other hand, resveratrol and its combination with bicalutamide (BCT) as an AR-antagonist or AMD3100 as a CXCR4 inhibitor significantly reduced the cell viability promoted by DHT. Trans-well migration assay and wound healing assay represented the similar results with cell viability assay. According to the results of tunnel assay, the apoptotic activity was induced by treatment of resveratrol. As results of western blot analysis, the expression of AR, CXCR4, and the downstream genes related with epithelial-mesenchymal transition (EMT) were decreased and the expression of the apoptosis-related genes was increased by treatment of resveratrol and its combination with BCT or AMD3100. This study would suggest that resveratrol and its combination with AR and CXCR4 antagonists can be used in order to suppress the metastatic behaviors of prostate cancer.