[LncRNA LINC-PINT regulating proliferation and apoptosis of osteosarcoma cells by targeting miR-524-5p].

To study the effect of long non-coding RNA LINC-PINT on proliferation and apoptosis of osteosarcoma cells. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect the expressions of LINC-PINT and miR-524-5p in normal osteoblast hFOB and human osteosarcoma cell lines HOS, MG63 and SAOS2 cells. The pcDNA plasmid, pcDNA-LINC-PINT plasmid, negative control siRNA (si-NC), si-LINC-PINT, negative control mimics (miR-NC), miR-524-5p mimics (miR-524-5p), pcDNA-LINC-PINT combined with miR-NC, pcDNA-LINC-PINT combined with miR-524-5p were transfected into HOS cells with liposome, respectively. The protein expressions of PCNA and cleaved-caspase-3 in the cells were detected by western blot. Cell proliferation ability was detected by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) assay. The apoptosis was detected by flow cytometry. The transcriptional activity was detected by double luciferase reporter assay. Compared with normal osteoblast hFOB cell (1.00±0.08 vs 1.00±0.06), the expressions of LINC-PINT were down-regulated (0.18±0.01; 0.33±0.01; 0.42±0.01), while the expressions of miR-524-5p were up-regulated (2.65±0.23; 1.68±0.14; 1.51±0.13) in human osteosarcoma cell lines HOS, MG63 and SAOS2 cells, respectively. Overexpression of LINC-PINT significantly inhibited the proliferation (0.41±0.05 vs. 0.62±0.05 for 48 h; 0.57±0.05 vs. 1.06±0.09 for 72 h, both <0.05) while promoted the apoptosis (25.28±2.15 vs. 9.01±0.17, <0.01) of HOS cells. Knockdown of LINC-PINT or overexpression of miR-524-5p can significantly promote the proliferation and inhibit apoptosis of HOS cells. Moreover, miR-524-5p inhibited the fluorescence activity of wild-type LINC-PINT (0.31±0.03) in HOS cells when comparred with miR-NC (1.00±0.03) and was negatively regulated by LINC-PINT. Overexpression of miR-524-5p reversed the proliferation inhibition and apoptosis-promotion effects of LINC-PINT in HOS cells. Long non-coding RNA LINC-PINT can inhibit the proliferation and promote apoptosis of osteosarcoma cells through targeting miR-524-5p, which will provide a new target for the treatment of osteosarcoma.