Effect of mir-129 on the Sensitivity Enhancement of Methotrexate and Migration Inhibition in Osteosarcoma Cancer Cells

Abstract

Background: MicroRNAs have been recently declared to be contributed to the various aspects of osteosarcoma cells, including growth and survival, apoptosis, invasion, and chemoresistance. Objectives: The present study aimed to investigate the potentiating effects of miR-129 on the chemosensitivity of Saose-2 osteosarcoma cells to methotrexate (MTX) and underlying mechanisms. Methods: Saose-2 cells were transfected with miR-129 mimics using Lipofectamine. The cytotoxic effects of miR-129 and MTX on Saose-2 cells were measured using MTT assay. Scratch wound healing assay was used to evaluate cell migration. The apoptosis rate of cancer cells was also measured using ELISA Cell Death Assay and flow cytometry. The mRNA expression levels of target genes were measured using quantitative RT-PCR. Results: miR-129 mimic transfection significantly increased the expression levels of this miRNA in Saose-2 cells (P<0.05). The combination of MTX with miR-129 transfection led to enhanced cytotoxic effects of MTX in lower concentrations. In addition, miR-129 significantly increased MTX-induced apoptosis levels and decreased invasion behavior in Saose-2 cells. The mRNA expression levels of c-Myc, K-Ras, CXCR4, MMP9, and ADAMTS, as main genes involved in chemoresistance and invasion, were downregulated in miR-129 transfected cells. Conclusion: The obtained results revealed the importance of miR-129 in the sensitivity of osteosarcoma cells to MTX and its underlying mechanisms. Therefore, miR-129 might be an appropriate candidate for reversing MTX resistance in osteosarcoma cells.