Long noncoding RNA TTN-AS1 promotes breast cancer cell migration and invasion via sponging miR-140-5p

Objectives: Breast cancer (BC) is one of the most ordinary fatal cancers. Recent studies have identified the vital role of long noncoding RNAs (lncRNAs) in the development and progression of BC. In this research, lncRNA TTN-AS1 was studied to identify how it functioned in the metastasis of BC.Methods TTN-AS1 expression of tissues was detected by RT-qPCR in 56 BC patients. Wound healing assay and transwell assay were used to observe the biological behavior changes of BC cells through gain or loss of TTN-AS1. In addition, luciferase assays and RNA immunoprecipitation (RIP) assay were performed to discover the potential targets of TTN-AS1 in BC cells.Results TTN-AS1 expression level in BC samples was higher than that of adjacent ones. Besides, cell migrated ability and cell invaded ability of BC cells were inhibited after TTN-AS1 was silenced. Cell migrated ability and cell invaded ability of BC cells were promoted after TTN-AS1 was overexpressed. In addition, miR-140-5p was upregulated after silence of TTN-AS1 in BC cells, while miR-140-5p was downregulated after overexpression of TTN-AS1 in BC cells. Furthermore, luciferase assays and RNA immunoprecipitation assay (RIP) showed that miR-140-5p was a direct target of TTN-AS1 in BC.Conclusion Our study uncovers a new oncogene in BC and suggests that TTN-AS1 could enhance BC cell migration and invasion via sponging miR-140-5p, which provides a novel therapeutic target for BC patients.