[Differential expression profiles of microRNAs between breast cancer cells and mammary epithelial cells]

Aberrant expression of microRNAs (miRNAs) is involved in the development of breast cancer. This study was to explore differential expression of miRNAs between breast cancer cells and mammary epithelial cells, and to predict potential targets of the differentially expressed miRNAs.

Human breast cancer MCF-7 cells and normal human mammary epithelial HBL-100 cells were cultured. The total RNA was isolated and examined. The expression profiles of miRNAs in MCF-7 and HBL-100 cells were detected with a miRNA microarray chip and compared. Array results were confirmed by real-time polymerase chain reaction (PCR). Potential mRNA targets were predicted by MiRanda, TargetScan, PicTar, and DIANA-microT software.

The purification of total RNA from MCF-7 and HBL-100 cells was relatively high. According to a microarray-based screening, 173 breast cancer-related miRNAs were identified. Of the 173 miRNAs, 113 were up-regulated and 60 were down-regulated in MCF-7 cells (P<0.01). Real-time PCR showed that mir-18a and mir-195 were highly expressed in MCF-7 cells. Sixty-eight potential target genes of mir-200b were predicted by informatics analysis.

The miRNA expression profiles of breast cancer cells and mammary epithelial cells are obtained. Some miRNAs may be involved in the pathogenesis of breast cancer by regulating their target genes.