Tumor suppressive role of microRNA-4731-5p in breast cancer through reduction of PAICS-induced FAK phosphorylation

A wide array of microRNAs (miRNAs) is differentially expressed in breast tumors and also functions as tumor suppressors. Herein, the current study sought to unravel the function of miR-4731-5p in breast cancer progression. First, breast cancer-related miRNA and mRNA microarray data sets were retrieved for differential analyses. Subsequently, the expression patterns of miR-4731-5p, PAICS, and FAK in breast cancer tissues and cells were determined, in addition to analyses of their roles in glycometabolism, migration, invasion, epithelial–mesenchymal transition (EMT) analyzed through functional assays. Next, the targeting relation between miR-4731-5p and PAICS was validated. Xenograft tumors in nude mice were further established to reproduce and verify the in vitro findings. miR-4731-5p was poorly expressed and PAICS was highly expressed in breast cancer tissues and cells. PAICS was confirmed as a target of miR-4731-5p. Moreover, miR-4731-5p exerted an inhibitory effect on glycolysis, EMT, migration, and invasion in breast cancer cells via regulation of PAICS-dependent phosphorylation of FAK. In vivo assay further validated the significance of the miR-4731-5p/PAICS/FAK axis in vivo tumorigenesis and lung metastasis in breast cancer. Collectively, our findings indicated that miR-4731-5p inhibited breast cancer cell glycolysis and EMT through the reduction of PAICS-induced phosphorylation of FAK.