[The down-regulation of miR-129 in breast cancer and its effect on breast cancer migration and motility].

To search the microRNAs (miRNA) which suppress metastasis of breast cancer, we utilize three well known micoRNA target prediction programs, Targetscan, Pictar and miRanda, to select the microRNAs that target the genes related to tumor metastasis. We chose MDA-MB-231 with high metastasis ability as the model to evaluate the effect of miRNAs on cell motility through Transwell migration assay. After the first round of screening, miR-129 is found to significantly inhibit the migration of MDA-MB-231 both in Transwell migration assay and wound healing assay. Furthermore, miR-129 also shows great suppressive ability to cell mobility and migration in another two breast cancer cell lines BT549 and MDA-MB-435s. Most importantly, miR-129 is down-regulated both in breast cancer tissues compared with the paired adjacent normal breast tissues, and in breast cancer cell lines compared with normal breast epithelial cell MCF10A (P < 0.05). These results indicate that over-expression of miR-129 could inhibit breast cancer motility and migration, and the down-regulation of miR-129 may participate in the breast cancer migration and metastasis.