LINC00355 triggers malignant progression of hepatocellular carcinoma via the sponge effect on miR-217-5p with the involvement of the Wnt/β-catenin signaling.

Purpose: To uncover the biological role of LINC00355 in regulating the proliferative and apoptotic potentials in hepatocellular carcinoma (HCC), and the underlying mechanism.

Methods: LINC00355 levels in HCC tissues and cell lines were detected by quantitative real-time polymerase chain reaction (qRT-PCR). After knockdown of LINC00355 or miR-217-5p in Hub7 and Hep3B cells, proliferative and apoptotic potentials were assessed by cell counting kit-8 (CCK-8), colony formation assay and flow cytometry. The interaction between LINC00355 and miR-217-5p was determined by dual-luciferase reporter assay and Pearson correlation test. Western blot analysis was conducted to illustrate the regulatory effects of LINC00355 and miR-217-5p on the Wnt/β-catenin signaling.

Results: LINC00355 was upregulated in HCC tissues and cell lines. Knockdown of LINC00355 reduced viability in Hub7 and Hep3B cells, which was much pronounced on days 3 and 4. Clonality was attenuated by transfection of shLINC00355 as well. In addition, apoptosis rate increased by knockdown of LINC00355 in HCC cells. Protein levels of β-catenin, GSK3β, c-myc and cyclin D1 were downregulated in Hub7 and Hep3B cells transfected with shLINC00355. MiR-217-5p was the target gene binding LINC00355. It displayed exactly opposite regulations on HCC cell phenotypes and protein levels of vital genes in the Wnt/β-catenin signaling to those of LINC00355.

Conclusions: LINC00355 is upregulated in HCC specimens, LINC00355 triggers proliferative rate and inhibits apoptosis in HCC cells by negatively regulating miR-217-5p and activating the Wnt/β-catenin signaling.