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In many cancers, microRNA-193a (miR-193a) is a suppressor miRNA, but its underlying anti-oncogenic activity in breast cancer is not known. In this study, we found decreased miR-193a (specifically, miR-193a-5p) expression not only in breast cancer cell lines but also in breast cancer tissues as compared with the adjacent non-tumor tissues. Ectopic miR-193a overexpression inhibited the proliferation, colony formation, migration, and invasion of MDA-MB-231 and BT549 cells. miR-193a reduced Wilms’ tumor 1 (WT1) expression and repressed luciferase reporter activity by binding WT1 coding region sequences; mutation of the predicted miR-193a binding site abolished this effect. miR-193a and WT1 expression were significantly inversely correlated in breast cancer tissues. Importantly, the anti-cancer activity induced by miR-193a was partially reversed by WT1 overexpression, indicating an important role for WT1 in such activity related to miR-193a. Our results reveal that miR-193a-WT1 interaction plays an important role in breast cancer metastasis, and suggest that restoring miR-193a expression is a therapeutic strategy in breast cancer.

Long noncoding RNAs (lncRNAs) are considered as regulators of gene expression in cancers. However, cancer profiling has little focused on noncoding genes. Here, we reported that RP11–115N4.1 (here renamed novel lncRNA inhibiting proliferation and metastasis [NLIPMT]) was downregulated in breast cancer tissues. Ectopic expression of NLIPMT inhibited mammary cell proliferation, motility in vitro. Moreover, lnc‐NLIPMT reduced the growth of implanted MDA‐MB‐231 cells in vivo. Mechanistically, glycogen synthase kinase 3β (GSK3β) was identified as an effector protein regulated by lnc‐NLIPMT. Inhibition of GSK3β activity restored NLIPMT‐induced inhibition of proliferation and motility in breast cancer cells. These data reveal that lnc‐NLIPMT functions as a driver of breast cancer progression and might serve as a potential target for antimetastatic therapies.

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