Objective To detect the effect of Skp2 knockdown on the proliferation, cell cycle, apoptosis and migration of osteosarcoma cells, and explore the molecular mechanism.

Methods U2OS cells were transfected with control siRNA or human Skp2 siRNAs. The gene silence efficiency was verified by RT- qPCR and Western blot, respectively. MTT assay was performed to detect the proliferation of OS cells. Cells were stained with propidium iodide (PI), and flow cytometry analysis was conducted to measure the cell cycle distribution. Annexin V/PI double staining and flow cytometry analyses were performed to detect cell apoptosis. Transwell assay and Calcein-AM staining were carried out to detect the invasion and migration abilities of U2OS cells. The expression of p21, p27, E-cadherin and p-Akt were examined by Western blot.

Results The expression of Skp2 was effectively knocked down in U2OS cells by Skp2 siRNA. The depletion of Skp2 significantly inhibited the proliferation of U2OS cells, with a typical G₀/G₁ arrest pattern and increased cell apoptosis. The inhibition of Skp2 remarkably suppressed the migration and invasion abilities of U2OS cells. The depletion of Skp2 in U2OS cells upregulated the expression of p21, p27 and E-cadherin, while the expression of p-Akt was decreased.

Conclusion Skp2 affects the proliferation, cell cycle arrest, apoptosis, and migration ability of U2OS cells by regulating p21, p27, p-Akt and E-cadherin expression in its signalling pathway.