Identification and characterization of microRNAs expressed in human breast cancer T-47D cells in response to prolactin treatment by Solexa deep-sequencing technology

MicroRNAs (miRNAs) are key regulators of gene expression and perform critical roles in various biological processes. To investigate the functional roles of miRNAs in the prolactin receptor (PRLR) signaling pathway in breast cancer, we constructed two small RNA libraries from human breast cancer T-47D cells treated with or without prolactin (PRL). The miRNA expression profiles were systematically screened using Solexa deep-sequencing technology. More than 40 miRNAs were significantly differentially expressed, from which 4 miRNAs were chosen for validation by stem-loop real-time PCR. In addition, 3 novel miRNAs were selected for verification by PCR. Furthermore, upstream miRNA target genes were predicted using different algorithms, GO and KEGG analyses revealed that these targets were highly related to the PRLR signaling pathway. This study provides a reference for elucidating the complex miRNA-mediated regulatory networks of PRL/PRLR signaling pathway that affect breast cancer tumorigenesis and progression.

► Small RNA libraries were constructed from T-47D cells treated with PRL or without.
► The miRNA expression profiles were successfully screened using Solexa sequencing.
► Four known miRNAs and 3 novel miRNAs were verificated by stem-loop real-time PCR.
► Above 7 miRNAs were related with PRLR signaling pathway by GO and KEGG analysis.
► This study expanded understanding the role of miRNAs in PRL/PRLR signaling.