LncRNA HEIH regulates cell proliferation and apoptosis through miR-4458/SOCS1 axis in triple-negative breast cancer.

Hepatocellular carcinoma up-regulated EZH2-associated long non-coding RNA (HEIH) is a newly discovered lncRNA and has been suggested to be dysregulated in human cancers. However, the role of HEIH in triple-negative breast cancer (TNBC) was still unknown. Thus, the aim of our study was to investigate the clinical significance and biological function of HEIH in TNBC. In our study, we found that HEIH was overexpressed in TNBC tissues and cell lines compared with adjacent normal mammary tissues and normal mammary epithelial cell line, respectively. In addition, we conducted bioinformatic analysis, and found that HEIH harbors a potential miR-4458-binding site. Furthermore, we observed that HEIH and miR-4458 had a high correlation score in TNBC tissues, and HEIH directly binds to miR-4458, and negatively regulates miR-4458 expression in TNBC cells. The in vitro cell proliferation and apoptosis assays suggested down-regulation of HEIH inhibited TNBC cell proliferation and promoted apoptosis through regulating miR-4458/SOCS1 axis. Finally, we found that TNBC patients with tumor size ≥ 5 cm or advanced clinical stage had higher levels of HEIH expression than patients with tumor size < 5 cm or early clinical stage. In conclusion, HEIH functions as an oncogenic lncRNA that is overexpressed in TNBC and associated with clinical progression, and regulates TNBC cell proliferation and apoptosis through miR-4458/SOCS1 axis.