Abstract: Objective To investigate the effects of long non⁃coding RNA human proteasome α subunit type 3 antisense RNA1 (lncRNA PSMA3⁃AS1) on the proliferation, migration and invasion of neuroblastoma cells and the regulation mechanism of microRNA⁃186⁃5p (miR⁃186⁃5p)/sex⁃determining region Y box protein 4 (SOX4) axis. Methods si⁃PSMA3⁃AS1 and miR⁃186⁃5p inhibitor as well as their negative controls were transfected, respectively, into human neuroblastoma cells SH⁃SY5Y with LipofectamineTM 3000 reagent. The cells were randomly divided into the Control group (untransfected plasmid), the si⁃NC group (transfected with PSMA3⁃AS1 negative control), the si⁃PSMA3⁃AS1 group (transfected with si⁃PSMA3⁃AS1), the si⁃PSMA3⁃AS1+miR⁃NC group (co⁃transfected with si⁃PSMA3⁃AS1 and miR⁃186⁃5p inhibitor negative control), the si⁃PSMA3⁃AS1+miR⁃186⁃5p inhibitor group (co⁃transfected with si⁃PSMA3⁃AS1 and miR⁃186⁃5p inhibitor). The expression levels of PSMA3⁃AS1, miR⁃186⁃5p and SOX4 mRNA in each group were detected by qRT⁃PCR. The expression of SOX4 protein in each group were detected by Western blot. CCK⁃8 method and Transwell assay were used to detect the proliferation, migration and invasion ability of transfected cells in each group. The targeting relationship between miR⁃186⁃5p and PSMA3⁃AS1 and SOX4 was predicted by bioinformatics method and was verified by double luciferase reporter gene assay. Results Compared with the Control group and si⁃NC group, the si⁃PSMA3⁃AS1 group had a decreased PSMA3⁃AS1 expression level, cell survival rate, number of migration and invasion cells (all P<0.001). The results of double luciferase reporter gene assay showed that PSMA3⁃AS1 could target and negatively regulate miR⁃186⁃5p, while miR⁃186⁃5p could target and negatively regulate SOX4. After knocking down PSMA3⁃AS1, the expression level of miR⁃186⁃5p was increased, while the expression levels of SOX4 mRNA and protein were decreased (all P<0.001). In the recovery experiment, compared with the si⁃PSMA3⁃AS1+miR⁃NC group, the expression levels of SOX4 mRNA and protein, the cell survival rate, the number of migration and invasion cells in the si⁃PSMA3⁃AS1+miR⁃186⁃5p inhibitor group were increased (all P<0.001), and the expression level of miR⁃186⁃5p was decreased (all P<0.001). Conclusions Knockdown of PSMA3⁃AS1 can inhibit the proliferation, migration and invasion of neuroblastoma cells by regulating the miR⁃186⁃5p/SOX4 axis.

Key words:  Neuroblastoma, LncRNA PSMA3?AS1, miR?186?5p/SOX4 axis, Migration, Invasion, Proliferation