Background: Long non-coding RNAs exert vital roles in several types of cancer. The objective of this study was to explore the role of LINC_00355 in gastric cancer (GC) progression and its potential mechanism.
Methods: The expression levels of LINC_00355 in GC tissues and cells were detected by quantitative real-time PCR, followed by assessing the effects of LINC_00355 knockdown or overexpression on cell properties. Dual-luciferase reporter assay was utilized to identify the relationship between LINC_00355 and microRNA (miR)-15a-5p and miR-15a-5p and PHD finger protein 19 (PHF19), followed by the rescue experiments.
Results: The results showed that LINC_00355 was highly expressed in GC tissues and cells compared with the corresponding control. LINC_00355 knockdown decreased the viability, migration, and invasion and increased the accumulation of GC cells in G1 phase and apoptosis. Meanwhile, LINC_00355 downregulation markedly increased cleaved caspase 3 and cleaved poly (ADP-ribose) polymerase protein levels, whereas decreased cyclin D1, cyclin E, matrix metalloproteinase (MMP) 9, MMP2, and N-cadherin protein levels in GC cells. However, LINC_00355 overexpression had the opposite effects. It was verified that LINC_00355 upregulated the expression of PHF19 through sponging miR-15a-5p. Furthermore, PHF19 overexpression reversed the effect of LINC_00355 knockdown on GC cell properties, including cell viability, migration, invasion, and apoptosis.
Conclusions: Collectively, these results suggest that LINC_00355 promotes GC progression by up-regulating PHF19 through sponging miR-15a-5p. Our findings may provide an important clinical basis for reversing the malignant phenotype of GC.
Keywords: Gastric cancer; LINC_00355; PHD finger protein 19; miR-15a-5p.