Osteosarcoma (OS) is the most common primary malignancy of the bone in teenagers and accounts for 20‑35% of all malignant primary bone tumors. Increasing evidence shows that microRNAs (miRNAs) are abnormally expressed in several types of human cancer. miRNAs are necessary to maintain the malignant phenotype of cancer cells and can function as either tumor suppressors or oncogenes. The present study aimed to measure the expression of miRNA‑129‑5p (miR‑129‑5p) in OS, determine the effects of miR‑129‑5p on the malignant behaviors of OS cells, and elucidate the molecular mechanism underlying the oncogenesis and progression of OS. The expression levels of miR‑129‑5p in OS tissues and cell lines were measured using reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analysis. SAOS‑2 and U2OS cells were then transfected with miR‑129‑5p mimics or miR‑negative control. The effects of miR‑129‑5p on the proliferation, migration and invasion of SAOS‑2 and U2OS cells in vitro were then evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, Transwell migration assay and invasion assays, respectively. In addition, bioinformatics analysis, a luciferase reporter assay, and RT‑qPCR and western blot analyses were used to examine whether Rho‑associated protein kinase 1 (ROCK1) was a direct target of miR‑129‑5p. The mRNA expression of ROCK1 in OS tissues was detected using RT‑qPCR analysis, and the biological roles of ROCK1 in OS cells were also evaluated. The results showed that miR‑129‑5p was significantly downregulated in the OS tissues and cell lines. The re‑expression of miR‑129‑5p suppressed the cell proliferation, migration and invasion of OS cells. In addition, ROCK1 was confirmed as a direct target of miR‑129‑5p. The mRNA expression of ROCK1 was high in OS tissues and inversely correlated with the expression of miR‑129‑5p. The downregulation of ROCK1 inhibited the proliferation, migration and invasion of OS cells. These findings suggested that miR‑129‑5p inhibited cell proliferation, migration and invasion in the development of OS via the negative regulation of ROCK1. The miR‑129‑5p/ROCK1 axis may serve as an efficient target in cancer therapy.
Keywords: microRNA-129-5p; osteosarcoma; Rho-associated protein kinase 1; invasion; proliferation; migration.