Apoptosis Inducing Activity of Rhinacanthin-C in Doxorubicin-Resistant Breast Cancer MCF-7 Cells.

Rhinacanthin-C is a natural bioactive naphthoquinone ester with potential chemotherapeutic value in cancer treatment. In this study, we investigated its apoptotic induction ability and the involved mechanisms through the mitogen-activated protein kinases (MAPK) and protein kinase B/glycogen synthase kinase-3β/nuclear factor erythroid 2-related factor 2 (Akt/GSK-3β/Nrf2) signaling pathways in doxorubicin-resistant breast cancer MCF-7 (MCF-7/DOX) cells. Our 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that rhinacanthin-C (3-28 µM) significantly decreased the viability of MCF-7/DOX cells and potentiated hydrogen peroxide cytotoxicity.