Abstract
Microarray technology (Human OneArray microarray, phylanxbiotech.com) was used to compare gene expression profiles of non-invasive MCF-7 and invasive MDA-MB-231 breast cancer cells exposed to dioscin (DS), a steroidal saponin isolated from the roots of wild yam, (Dioscorea villosa). Initially the differential expression of genes (DEG) was identified which was followed by pathway enrichment analysis (PEA). Of the genes queried on OneArray, we identified 4641 DEG changed between MCF-7 and MDA-MB-231 cells (vehicle-treated) with cut-off log2 |fold change|≧1. Among these genes, 2439 genes were upregulated and 2002 were downregulated. DS exposure (2.30 μM, 72 h) to these cells identified 801 (MCF-7) and 96 (MDA-MB-231) DEG that showed significant difference when compared with the untreated cells (p<0.05). Within these gene sets, DS was able to upregulate 395 genes and downregulate 406 genes in MCF-7 and upregulate 36 and downregulate 60 genes in MDA-MB-231 cells. Further comparison of DEG between MCF-7 and MDA-MB-231 cells exposed to DS identified 3626 DEG of which 1700 were upregulated and 1926 were down-regulated. Regarding to PEA, 12 canonical pathways were significantly altered between these two cell lines. However, there was no alteration in any of these pathways in MCF-7 cells, while in MDA-MB-231 cells only MAPK pathway showed significant alteration. When PEA comparison was made on DS exposed cells, it was observed that only 2 pathways were significantly affected. Further, we identified the shared DEG, which were targeted by DS and overlapped in both MCF-7 and MDA-MB-231 cells, by intersection analysis (Venn diagram). We found that 7 DEG were overlapped of which six are reported in the database. This data highlight the diverse gene networks and pathways in MCF-7 and MDA-MB-231 human breast cancer cell lines treated with dioscin.