The anticancer potential of steroidal saponin, dioscin, isolated from wild yam (Dioscorea villosa) root extract in invasive human breast cancer cell line MDA-MB-231 in vitro

Authors: AUMSUAWAN, PRANAPDA - University Of Mississippi; KHAN, SHABANA - University Of Mississippi; KHAN, IKHLAS - University Of Mississippi; ALI, ZULFIQAR - University Of Mississippi; AVULA, BHARATHI - University Of Mississippi; WALKER, LARRY - University Of Mississippi; SHARIAT-MADAR, ZIA - University Of Mississippi; HELFERICH, WILLIAM - University Of Illinois; KATZENELLENBOGEN, BENITA - University Of Illinois; DASMAHAPATRA, ASOK - University Of Mississippi

Submitted to: Archives of Biochemistry and Biophysics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2015
Publication Date: 2/1/2016
Citation: Aumsuawan, P., Khan, S.I., Khan, I.A., Ali, Z., Avula, B., Walker, L.A., Shariat-Madar, Z., Helferich, W.G., Katzenellenbogen, B.S., Dasmahapatra, A.K. 2016. The anticancer potential of steroidal saponin, dioscin, isolated from wild yam (Dioscorea villosa) root extract in invasive human breast cancer cell line MDA-MB-231 in vitro. Archives Of Biochemistry and Biophysics. 591:98-110. doi: 10.1016/j.abb.2015.12.001.

Interpretive Summary: Previously, we have observed that wild yam root extract (WYRE) is able to activate GATA binding protein-3 (GATA3) gene in human breast cancer cells, MCF-7(GATA3-positive, non-invasive, epithelial) and MDA-MB-231(GATA3-negative, invasive, mesenchymal), targeting epigenome. The present study aims to find out bioactive molecules of WYRE which can modulate GATA3 gene functions as well as prevent metastasis in human breast cancer cell lines at the molecular level. We identified eleven saponins and one sapogenin from WYRE and found that four of them have the anticancer activity. In this study we have evaluated dioscin (DS), a steroidal saponin which showed anticancer activity, for preventing metastatic potential of cancer cells using MDA-MB-231 cells. Our data indicate that DS like WYRE is able to reduce cell viability and induce GATA3 mRNA expression in both MCF-7 and MDA-MB-231 cells in a concentration-dependent manner. The calculated IC50 of DS after 72 h exposure is 3.85 'M for MCF-7 cells and 2.07 'M for MDA-MB-231 cells. The cellular morphology in MDA-MB-231 cells is altered by DS, from spindle shape (mesenchymal) to cuboidal (epithelial) shape as seen in MCF-7 cells. Invasion analyses based on cell migration, invasion, and wound-healing assays indicate that DS is able to inhibit invasion of MDA-MB-231 cells in vitro. In contrast to metastasis, GATA3 protein expression, as evidenced by western blot and immunocytochemistry, was enhanced by DS in MDA-MB-231 cells. To verify the effects of DS on metastasis at the molecular level we have evaluated the expression of four other genes which have significant influence on GATA3 expression as well as on metastasis. The mRNAs of ZFPM2, and E-Cad were increased while VIM and MMP9 were decreased by DS (5.76 'M). These findings indicate that DS has the potential to be used as a breast cancer preventive agent targeting metastasis.

Technical Abstract: Previously, we observed that wild yam (Dioscorea villosa) root extract (WYRE) was able to activate GATA3 in human breast cancer cells targeting epigenome. This study aimed to 'nd out if dioscin (DS), a bioactive compound of WYRE, can modulate GATA3 functions and cellular invasion in human breast cancer cells. MCF-7 and MDA-MB-231 cells were treated in the absence/presence of various concentrations of DS and subjected to gene analysis by RT-qPCR, immunoblotting, and immunocytochemistry. We determined the ability of MDA-MB-231 cells to migrate into wound area and examined the effects of DS on cellular invasion using invasion assay. DS reduced cell viability of both cell lines in a concentration and time-dependent manner. GATA3 expression was enhanced by DS(5.76 mM)in MDA-MB-231 cells. DS(5.76 mM)-treated MDA-MB-231 cells exhibited the morphological characteristic of epithelial-like cells; mRNA expression of DNMT3A, TET2, TET3, ZFPM2 and E-cad were increased while TET1, VIM and MMP9 were decreased. Cellular invasion of MDA-MB-231 was reduced by 65 ± 5% in the presence of 5.76 mM DS. Our data suggested that DS-mediated pathway could promote GATA3 expression at transcription and translation levels.We propose that DS has potential to be used as an anti-invasive agent in breast cancer.