A novel long non-coding RNA MIR4500HG003 promotes tumor metastasis through miR-483-3p-MMP9 axis in triple-negative breast cancer.

Breast cancer (BC) is the most common cancer and the leading cause of cancer-related deaths in women worldwide. The 5-year survival rate is over 90% in BC patients, but once BC cells metastasis into distal organs, it is dramatically decreasing to less than 30%. Especially, triple-negative breast cancer (TNBC) patients usually lead to poor prognosis and survival because of metastasis. Understanding the underline mechanisms of TNBC metastasis is a critical issue. Non-coding RNAs, including of lncRNAs and microRNAs, are non-protein-coding transcripts and have been reported as important regulators in TNBC metastasis. However, the underline mechanisms for non-coding RNAs regulating TNBC metastasis remain largely unclear. Here, we found that lncRNA MIR4500HG003 was highly expressed in highly metastatic MDA-MB-231 TNBC cells and overexpression of MIR4500HG003 enhanced metastasis ability in vitro and in vivo and promoted MMP9 expression. Furthermore, we found MIR4500HG003 physically interacted with miR-483-3p and reporter assay showed miR-483-3p attenuated MMP9 expression. Importantly, endogenous high expressions of MIR4500HG003 were correlated with tumor recurrence in TNBC patients with tumor metastasis. Taken together, our findings suggested that MIR4500HG003 promotes metastasis of TNBC through miR-483-3p-MMP9 signaling axis and may be used as potential prognostic marker for TNBC patients.