Molecular cytotoxic mecanism of Dioscorealide B on human breast cancer cells
Dioscorealide B is an active compound from the rhizome of Dioscorea membranacea Pierre which locally is known as „Hua-Khao-Yen“ . This medicinal plant has long been used in the anticancer prescription of Thai traditional medicine. SRB (Sulphorhodamine B) assays  were used to assess the cytotoxic activity against MCF-7, human breast cancer cell lines.
It was demonstrated that Dioscorealide B inhibited proliferation of human breast adenocarcinoma cells (MCF-7) with IC50 =0.94µg/ml. MCF-7 cells treated with Dioscorealide B showed induction of apoptosis via the activation of caspase-7 in a dose- and time- dependent manner. In the present study, the mRNA level for p53 and Bax showed an increase while Bcl-2 was decreased after the treatment. The active compound also activated caspase-8 and caspase-9. These results showed that the mechanism of action of Dioscorealide B might be involved in both intrinsic and extrinsic pathways. In addition, our results demonstrated that the expression of p21, p27 and p57, the cyclin-kinase inhibitors, were regulated in mRNA level and Dioscorealide B might cause cell cycle arrest in breast cancer cells.
Acknowledgement: Prince of Songkhla University for the financial support.
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