Abstract
BACKGROUND: The holistic approach of traditional medicine renders the identification of its mechanisms of action difficult. Microarray technology provides an efficient way to analyze the complex genome-wide gene expression of cells treated with mixtures of medicinal ingredients. We performed transcriptional profiling of MCF-7 cells treated with Nam Dia Long (NDL), a Vietnamese traditional formula, to explore the mechanism of action underlying the apoptosis inducing effect of this formula reported in a previous study. METHODS: MCF-7 cells were treated with aqueous extracts of NDL at the IC(50) concentration for 24, 36 and 48 h. Total RNAs at 24 h and 48 h were subsequently extracted, reverse transcribed and submitted to microarray expression profiling using the Human HT-12 v4.0 Expression Bead Chip (Illumina). Functional analyses were performed using the Database for Annotation, Visualization and Integrated Discovery and the Ingenuity Pathways Analysis. The expression level from selected genes at the three time points were assessed by quantitative real-time RT-PCR and Western blot. RESULTS: Fifty-four and 601 genes were differentially expressed at 24 and 48 h of NDL treatment, respectively. Genes with altered expression at 24 h were mostly involved in cell responses to xenobiotic stress whereas genes differentially expressed at 48 h were related to endoplasmic reticulum stress, DNA damage and cell cycle control. Apoptosis of NDL treated MCF-7 cells resulted from a combination of different mechanisms including the intrinsic and extrinsic pathways, cell cycle arrest- and oxidative stress-related cell death. CONCLUSION: NDL elicited a two-stage response in MCF-7 treated cells with apoptosis as the ultimate result. The various mechanisms inducing apoptosis reflected the complexity of the formula composition.