ABSTRACT
Objective:To investigate the relationship between long non-coding RNA (lncRNA) DHRS4-AS1 and disease-free survival in osteosarcoma patients and the mechanisms of its effect on proliferation and migration of osteosarcoma cells in vitro.Methods:The data of DHRS4-AS1 transcriptome levels and survival status of osteosarcoma patients in GEPIA database were collected since the database was established, and the patients were divided into high DHRS4-AS1 expression group and low DHRS4-AS1 expression group based on the median DHRS4-AS1 transcriptome level, with 59 cases in each group, and the Kaplan-Meier method was used to analyze the disease-free survival of the two groups. Real-time fluorescence quantitative polymerase chain reaction (qRT-PCR) was used to detect the expression of DHRS4-AS1 in osteosarcoma cell lines MG-63, HOS, 143B, U-2OS, Saos2 and normal osteoblast cell line hFOB1.19, and the osteosarcoma cell line with the lowest DHRS4-AS1 expression level was selected for subsequent experiments. The plasmid carrying DHRS4-AS1 sequence and the plasmid carrying negative control sequence were transfected into the selected osteosarcoma cells as DHRS4-AS1 group and control group. CCK-8 method was used to detect the proliferation of each group of cells, and the absorbance value was used as the cell proliferation ability; cell scratch assay was used to detect the migration of each group of cells. The bioinformatics website starBase V2.0 was used to predict the target genes of DHRS4-AS1, and the dual luciferase reporter gene assay was used to verify the targeting relationship between DHRS4-AS1 and the target genes. The expression levels of target genes and downstream genes of osteosarcoma cells in control group and DHRS4-AS1 group were detected by qRT-PCR and Western blotting.Results:Survival analysis showed that the disease-free survival of osteosarcoma patients in the high DHRS4-AS1 expression group in GEPIA database was superior to that of the low DHRS4-AS1 expression group ( P < 0.001). Compared with normal osteoblastic hFOB1.19 cells, the expression level of DHRS4-AS1 was low in all osteosarcoma cells (all P < 0.01), with the lowest expression level of DHRS4-AS1 in U-2OS cells ( P < 0.001). Cell proliferation ability was reduced in U-2OS cells of the DHRS4-AS1 group after 1, 2, 3 and 4 d of culture compared with the control group (all P < 0.05). The migration rate of U-2OS cells in the DHRS4-AS1 group was lower than that in the control group [(31±6)% vs. (63±4)%, t = 4.38, P = 0.005]. starBase V2.0 website predicted that DHRS4-AS1 complementarily bound to miRNA-411-3p (miR-411-3p); dual luciferase reporter gene assay showed that miR-411-3p overexpression reduced the luciferase activity of the wild-type DHRS4-AS1 reporter gene ( P < 0.001), but had no effect on the luciferase activity of the mutant DHRS4-AS1 reporter gene ( P > 0.05). qRT-PCR showed that the relative expression of miR-411-3p in U-2OS cells of the DHRS4-AS1 group was low (0.22±0.06 vs. 1.06±0.23, t = 3.55, P = 0.012) and the relative expression of metastasis suppressor MTSS1 mRNA was high (5.58±1.03 vs. 1.06±0.22, t = 4.28, P = 0.005) compared with the control group; Western blotting showed that MTSS1 expression was elevated, and the expression levels of cell proliferation phenotype proteins CDK3 and cyclin C and cell migration phenotype proteins ZEB2 and KLF8 were low. Conclusions:Osteosarcoma patients with high expression of lncRNA DHRS4-AS1 have better disease-free survival, and its expression is low in osteosarcoma cell lines. DHRS4-AS1 may promote MTSS1 gene expression and inhibit cell proliferation and migration by targeting and down-regulating miR-411-3p expression in osteosarcoma cells.