RETRACTED: Knockdown of lncRNA HULC inhibits proliferation, migration, invasion, and promotes apoptosis by sponging miR-122 in osteosarcoma (Retracted article. See vol. 122, pg. 599, 2021)

Osteosarcoma is a rare malignant bone tumor with high degree of malignancy. HULC (highly upregulated in liver cancer), a long noncoding RNA (lncRNA) was involved in hepatocellular carcinoma development and progression, but its underlying mechanism in osteosarcoma is unknown. The aim of this study was to explore the functional role of HULC in osteosarcoma. The study was conducted in human osteosarcoma cell lines and the expression of HULC in the cell lines was detected by qRT-PCR. Furthermore, the effects of HULC on tumorigenicity of osteosarcoma cells were evaluated by in vitro assays. Results revealed that HULC was highly expressed in osteosarcoma MG63 and OS-732 cells compared to osteoblast hFOB1.19 cells. Suppression of HULC in osteosarcoma cells inhibited cell viability, migration, invasion, and promoted apoptosis. HULC functioned as an endogenous sponge for miR-122, and its silence functioned through upregulating miR-122. HNF4G was a target of miR-122, and the effect of HNF4G on OS-732 cells was the same as HULC. Furthermore, overexpression of miR-122 inactivated PI3K/AKT, JAK/STAT, and Notch pathways by downregulation of HNF4G. These findings suggest that knockdown of HULC inhibited proliferation, migration, and invasion by sponging miR-122 in osteosarcoma cells. HULC may act as a novel therapeutic target for management of osteosarcoma.