miR-192-5p regulated osteosarcoma cell proliferation, apoptosis, migration, invasion and chemo-sensitivity through USP1. (A) The USP1 mRNA expression was detected by reverse transcription-quantitative polymerase chain reaction. (B) The USP1 protein expression was detected by western blot analysis. (C-I) Ectopic expression of USP1 statistically enhanced cell (C and D) proliferation, decreased cell (E and F) chemo-sensitivity, promoted cell (G) migration and (H) invasion (magnification, ×100), and reduced cell (I) apoptosis in 143B and U2OS cells, which could be partially abolished by miR-192-5p following co-transfection with miR-192-5p mimics and USP1. Data are presented as the mean ± standard deviation of 3 independent assays. *P<0.05, **P<0.01 and ***P<0.001 vs. NC, or as indicated. miR-NC. miR, microRNA; NC, negative control; USP1, ubiquitin-specific protease 1; PI, propidium iodide.