Relationship of miR-31 and GNA13 in breast cancer cells. (A) Immunoblot analysis of GNA13 protein expression in breast and prostate cancer cell lines. Tubulin is used as loading control. (B) Relative basal expression of the microRNAs predicted to bind to the GNA13-3′-UTR in breast and prostate cancer cells. Relative microRNA expression is plotted in the y-axis. All values were calibrated to basal miR-31 expression in MDA-MB-231 cells.