StarD13 3'-untranslated region functions as a ceRNA for TP53INP1 in prohibiting migration and invasion of breast cancer cells by regulating miR-125b activity.

Competitive endogenous messenger RNA (ceRNA) affects transcription of other RNA molecules by competitively binding common microRNAs. Previous studies have shown that TP53INP1 functions as a suppressor in tumor metastasis. Our study elucidated StarD13 messenger RNA as a ceRNA in regulating migration and invasion of breast cancer cells. MicroRNA-125b was identified to induce metastasis of MCF-7 cells and bind with both StarD13 3'UTR and TP53INP1 3'UTR. Therefore, a ceRNA interaction between StarD13 and TP53INP1 mediated by competitively binding to miR-125b was indicated. Importantly, a microRNA-125b binding site at 4546-4560 nt on StarD13 was verified more vital for this ceRNA interaction. Indirectly regulation of SPARC in inducing metastasis of breast cancer cells by StarD13 via competitively binding with TP53INP1 was further confirmed. In conclusion, our findings demonstrate a ceRNA regulatory network which could give a better understanding of metastatic mechanisms of breast cancer.