miR-106a-5p Suppresses the Proliferation, Migration, and Invasion of Osteosarcoma Cells by Targeting HMGA2.

We aim to investigate the effect of miR-106a-5p on the proliferation, migration, and invasion of osteosarcoma (OS) cells by targeting high-mobility group AT-hook 2 (HMGA2). Real-time fluorescent quantitative polymerase chain reaction (RT-qPCR) was used for detecting the expressions of miR-106-5p and HMGA2 in 137 OS and adjacent normal bone tissues. Immunohistochemistry was applied for the HMGA2 protein expression detection. Luciferase reporter gene assay was conducted for verifying whether miR-106-5p targeted HMGA2. MG63 and U2SO cells were respectively divided into five groups: Blank, miR-106a-5p, scramble, HMGA2-siRNA, and miR-106a-5p+HMGA2 groups. RT-qPCR and western blot were applied for detecting the expressions of miR-106a-5p and HMGA2 in five groups. Proliferation rate, cell cycle, invasion, and migration ability of OS cells were detected using methyl thiazolyl-tetrazolium, 5-ethynyl-2'-deoxyuridine (Edu) assay, flow cytometry, and Transwell.  Compared with adjacent normal tissues, OS tissues presented with decreased miR-106a-5p expressions, elevated HMGA2 mRNA, and positive expressions (all p < 0.05). The sensitivity and specificity of miR-106a-5p were 97.8%, 93.43%, and HMGA2 mRNA were 97.8%, 99.27%, separately. miR-106a-5p and HMGA2 expressions were associated with tumor size, Enneking stage, distant metastasis, and lung metastasis. Expressions of HMGA2 in OS cells in miR-106a-5p and HMGA2 siRNA groups were both significantly decreased with the same downregulation level, and the proliferation rates in both groups were obviously slowed down after 48 h (both p < 0.001). Edu positive cells, S phase cells (majority of cells blocked at G0/G1 phase), migratory and invasive cells were obviously decreased (all p < 0.05). Downregulation of miR-106a-5p was found in OS tissues, and upregulation of miR-106a-5p can inhibit the proliferation, migration, and invasion by targeting HMGA2 in OS cells.