LINC00662 triggers malignant progression of chordoma by the activation of RNF144B via targeting miR-16-5p

C.-B. Wang, Y. Wang, J.-J. Wang, X.-L. Guo

Department of Orthopedics, Yantaishan Hospital, Yantai, Shandong, China. kjmxkw@163.com

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• Orthopedics

OBJECTIVE: Chordoma is a rare malignant tumor difficult to diagnose and treat. Long non-coding RNAs acting as novel biomarkers are frequently reported in numerous cancers. The purpose of this study was to investigate the role of long intergenic non-coding RNA 00662 (LINC00662) and its associated action mechanisms in chordoma.

MATERIALS AND METHODS: The expression of LINC00662, Ring finger protein 144B (RNF144B), and microRNA-16-5p (miR-16-5p) was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The protein levels of RNF144B, cell proliferation markers (Cyclin D1 and Ki67), epithelial-mesenchymal transition (EMT) markers (E-cadherin, Vimentin and N-cadherin), and glycolysis markers [glucose transporter 1 (GLUT1), hexokinase II (HK2), and lactic dehydrogenase A (LDHA)] were determined by Western blot. Cell proliferation, the number of colonies, migration, and invasion were investigated by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT), colony formation, and transwell assays, respectively. Glycolysis progress was evaluated by the glycolysis stress test, glucose consumption, lactate production, and ATP production. The relationship between miR-16-5p and LINC00662 or RNF144B was predicted by the online bioinformatics tool starBase and verified by Dual-Luciferase reporter assay. Xenograft tumor model was established to monitor the role of LINC00662 in vivo.

RESULTS: LINC00662 and RNF144B were aberrantly upregulated in chordoma tissues. Knockdown of LINC00662 or RNF144B impeded proliferation, colony formation, invasion, migration, EMT, and glycolysis in chordoma cells. Besides, RNF144B overexpression reversed the role of LINC00662 knockdown. It was confirmed that miR-16-5p was a target of LINC00662, and miR-16-5p could target RNF144B. The relationship between LINC00662 and RNF144B was established by miR-16-5p. In addition, LINC00662 stable knockdown inhibited tumor growth in vivo.

CONCLUSIONS: LINC00662 participated in the malignant progression of chordoma by the promotion of RNF144B by acting as a sponge of miR-16-5p, suggesting that LINC00662 was a promising therapeutic target for chordoma.

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