Tannic acid inhibits proliferation, migration, invasion of prostate cancer and modulates drug metabolizing and antioxidant enzymes

The aim of this study was to investigate the effects of plant phenolic compound tannic acid (TA) on proliferative, metastatic, invasive properties of prostate cancer (PCa) cells; PC-3 and LNCaP, as well as drug metabolizing and antioxidant enzymes. Characterization of TA was done by using FT-IR and NMR. TA dose dependently inhibited the proliferation of PC-3 and LNCaP cells with IC50 values 35.3 μM and 29.1 μM, respectively. Wound healing assay showed that TA significantly inhibited (92.7%) migration of PCa cells (p<0.0001). In addition, TA was found to have anti-invasive potential on PC-3 cells and it inhibited (80.9%, p<0.0001) invasion of PC-3 cells into matrigel. Only 17.8% of PC-3 cells can form colony in the 0.7% agarose after treatment of cells with TA at the IC50 value concentration. Furthermore, flow cytometry analyses with Annexin V-APC and 7-AAD staining demonstrated that TA increases early apoptosis rate of PC-3 cells by 25.8% and LNCaP cells by 20.9%. Besides, Western blot and qRT-PCR analyses also demonstrated that TA regulates protein and mRNA expressions of CYP17A1, CYP3A4, CYP2B6, NQO1, GSTM1 and GSTP1 enzymes. The results obtained from this study show that TA might be a good candidate for combinational therapy and highly effective strategic molecule for reducing the occurrence of PCa.