Preclinical Development Garcinol Regulates EMT andWnt Signaling Pathways In Vitro and In Vivo , Leading to Anticancer Activity against Breast Cancer Cells

Anticancer properties of Garcinia indica–derived garcinol are just beginning to be elucidated. We have earlier reported its cancer cell–specific induction of apoptosis in breast cancer cells, which was mediated through the downregulationofNF-kBsignalingpathway. Togain furthermechanistic insight, here,we showfor the first time that garcinol effectively reverses epithelial-to-mesenchymal transition (EMT), that is, it inducesmesenchymal-toepithelial transition (MET) in aggressive triple-negative MDA-MB-231 and BT-549 breast cancer cells. This was associated with upregulation of epithelial marker E-cadherin and downregulation of mesenchymal markers vimentin, ZEB-1, and ZEB-2.We also found that garcinol upregulates the expression ofmiR-200 and let-7 family microRNAs (miRNAs), which provides a molecular mechanism for the observed reversal of EMT to MET. Transfection of cells with NF-kB p65 subunit attenuated the effect of garcinol on apoptosis induction through reversal of MET to EMT. Forced transfection of p65 and anti–miR-200s could also reverse the inhibitory effect of garcinol on breast cancer cell invasion.Moreover, treatment with garcinol resulted in increased phosphorylation of b-catenin concomitant with its reduced nuclear localization. The results were also validated in vivo in a xenograft mouse model where garcinol was found to inhibit NF-kB, miRNAs, vimentin, and nuclear b-catenin. These novel findings suggest that the anticancer activity of garcinol against aggressive breast cancer cells is, in part, due to reversal ofEMTphenotype,which ismechanistically linkedwith thederegulationofmiR-200s, let-7s, NF-kB, and Wnt signaling pathways. Mol Cancer Ther; 11(10); 1–9. 2012 AACR.