MicroRNA-137-3p regulates drug-resistance of osteosarcoma cells through downregulating PTN expression / 肿瘤

ABSTRACT

Objective: To investigate the effect of pleiotrophin (PTN) on the chemotherapy resistance of osteosarcoma cells, and its possible molecular mechanism. Methods: The expression levels of PTN and microRNA (miR)-137-3p in osteosarcoma drug-resistant MG63/ADR cells and parental MG63 cells were detected by real-time fluorescent quantitative PCR. SiRNA-PTN or miR-137-3p mimic was transfected into MG63/ADR cells, while the PTN recombinant plasmid or miR-137-3p inhibitor was transfected into MG63 cells. After the transfection efficiency was verified by real-time fluorescent quantitative PCR, the cell proliferation activity was detected by CCK-8 and clony formation assay. The interaction between miR-1373p and the target gene PTN was verified by dual luciferase reporter gene system. The miR-137-3p mimic, siRNA-PTN or miR-137-3p mimic+PTN recombinant plasmid was respectively transfected into osteosarcoma MG63/ADR cells, then the expressions of PTN mRNA and protein were detected by real-time fluorescent quantitative PCR and Western blotting, and the cell viability was detected by CCK-8 method. Results: PTN was significantly highly expressed in drug-resistant MG63/ ADR cells (P < 0.01), while miR-137-3p was significantly lowly expressed (P < 0.01). After transfection with siRNA-PTN or miR-137-3p mimic, the proliferation and clone formation abilities of MG63/ADR cells were significantly reduced (all P < 0.01). After transfection with PTN vector or miR-137-3p inhibitor, the proliferation and clone formation abilities of parental MG63 cells were significantly increased (all P < 0.01). PTN was a downstream target gene of miR-137-3p, and miR-137-3p negatively regulated the expression of PTN gene (P < 0.01). After transfection with siRNA-PTN or miR-137-3p mimic, the expression levels of PTN mRNA and protein in MG63/ADR cells were reduced (both P < 0.01), but the overexpression of PTN could reverse the effect of miR-137-3p on the viability of osteosarcoma drug-resistant cells (P < 0.01). Conclusion: PTN can regulate the chemotherapy resistance of osteosarcoma, and its mechanism may be related to miR-137-3p downregulating PTN expression.