title: Evaluation of wild yam (Dioscorea villosa) root extract as a potential epigenetic agent in breast cancer cells.
abstract: The present study was designed to evaluate the efficacy of wild yam root extract (WYRE) as a potential demethylating agent using two breast cancer cell lines, MCF-7 (estrogen receptor positive; ER(+)) and MDA-MB-231 (Estrogen receptor negative; ER(-)), and a methylated gene, GATA3, as a potential marker of breast cancer development. The cells were treated with WYRE (0-50 μg/mL) for 72 h and used for viability, mRNA, and methylation analyses. WYRE significantly reduced viability of both cell lines and enhanced mRNA content of GATA3 in a concentration-dependent manner; however, DNMT mRNAs (DNMT1, 3A, 3B) were found to increase significantly only in MDA-MB-231 cells. Global DNA methylation, analyzed as 5'-methyl-2'-deoxycytidine (5-mC) and 5-hydroxymethylcytosine (5-hmC), showed a concentration-dependent enhancement of 5-mC with no alteration in 5-hmC level in MCF-7 cells; however, in MDA-MB-231 cells, in contrast to MCF-7 cells, 5-mC remained unaltered but 5-hmC reduced significantly in all WYRE concentrations (10-50 μg/mL) used in this study. Since 5-hmC is generated from 5-mC by ten-eleven-translocation (TET) enzymes, analysis of TET mRNAs (TET1, TET2, and TET3) in MDA-MB-231 cells indicated a concentration-dependent reduction in TET1 and induction of TET3; however, TET2 remained unaltered. No alterations in any of the TET mRNAs were found in MCF-7 cells. Methylation analysis of GATA3 promoter at specific locus indicates probable demethylating activity of WYRE in MDA-MB-231 cells. We conclude that activation of GATA3 gene in ER(-) MDA-MB-231 cells may occur by altering DNA methylation pattern on the promoter region which may be different from the mechanisms operated in ER(+) MCF-7 cells.
authors.affiliation: National Center for Natural Product Research, School of Pharmacy, University of Mississippi, University, MS, 38677, USA.
authors.forename: Pranapda
authors.initials: P
authors.lastname: Aumsuwan
authors.forename: Shabana I
authors.initials: SI
authors.lastname: Khan
authors.forename: Ikhlas A
authors.initials: IA
authors.lastname: Khan
authors.forename: Bharathi
authors.initials: B
authors.lastname: Avula
authors.forename: Larry A
authors.initials: LA
authors.lastname: Walker
authors.forename: William G
authors.initials: WG
authors.lastname: Helferich
authors.forename: Benita S
authors.initials: BS
authors.lastname: Katzenellenbogen
authors.forename: Asok K
authors.initials: AK
authors.lastname: Dasmahapatra
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation / Q000187:drug effects / Q000235:genetics; D027742:Dioscorea / Q000737:chemistry*; D044127:Epigenesis, Genetic / Q000187:drug effects*; D005260:Female; D050990:GATA3 Transcription Factor / Q000235:genetics / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D056426:Genetic Loci; D006801:Humans; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D050990:GATA3 Transcription Factor; C494749:GATA3 protein, human; D009363:Neoplasm Proteins; D010936:Plant Extracts; D012333:RNA, Messenger; D004248:DNA (Cytosine-5-)-Methyltransferases