miRNAs were significantly regulated by myocardin and ERα

Using microarray, we compared miRNAs expression profiles of MDA-MB-231 cells transfected with myocardin and empty vector (pcDNA3.1) and found that 25 miRNAs were significantly changed in myocardin-transfected groups (17 up-regulated and 9 down-regulated miRNAs). Moreover, we showed that 18 of 25 miRNAs significantly regulated by myocardin were inhibited by ERα in MDA-MB-231 cells. In addition,through a microarray approach, we identify the subset of miRNAs modulated by ERα in MDA-MB-231 cells. Our results determined that ERα may function as tumor-promoter through down-regulating expression of 3 miRNAs (miR-26b, miR-146a and miR-331-3p) in MDA-MB-231 cells. There are 4 samples in this experiment (pcDNA3.1-transfected, myocardin-transfected, ERα-transfected, myocardin plus ERα co-transfecteded groups) and each sample was replicated 3 times. The vector-pcDNA3.1 was used as control.