NUSAP1 Accelerates Osteosarcoma Cell Proliferation and Cell Cycle Progression Via Upregulating CDC20 and Cyclin A2

Purpose: Nucleolar and spindle-associated protein 1 (NUSAP1) is a significant mitotic regulator and has been found to be implicated in carcinogenesis of several cancers. The aim of this study was to explore the functional role and underlying mechanisms of NUSAP1 in osteosarcoma.

Methods: Western blot assay and Real-time fluorescent quantitative polymerase chain reaction (RT-qPCR) were employed to assess the expressions of NUSAP1, cell division cycle 20 homologue (CDC20) and cyclin A2 (CCNA2) in osteosarcoma cells. Cell proliferation was evaluated by Cell Counting Kit-8 (CCK-8) assay and 5-ethynyl-2'-deoxyuridine (EdU) assay, and flow cytometry was applied for exploring cell cycle. In addition, an osteosarcoma tumor-bearing mouse model was established by injection of transfected osteosarcoma cells. Tumor volume and protein expressions of Ki67 and PCNA were examined. Bioinformatics analysis and immunoprecipitation were used to identify the combination of NUSAP1 with CDC20 and CCNA2.

Results: The mRNA and protein expression of NUSAP1 were extremely upregulated in osteosarcoma cells. Overexpression of NUSAP1 promoted whereas NUSAP1 silencing suppressed cell proliferation and cell cycle progression in transfected osteosarcoma cells. In osteosarcoma mouse model, NUSAP1 expression affected tumor volume and levels of Ki67 and PCNA. Moreover, CDC20 or CCNA2 silencing inhibited NUSAP1-induced cell proliferation and cell cycle in osteosarcoma cells.

Conclusion: Our data demonstrated that upregulated NUSAP1 may exacerbate the development of osteosarcoma by accelerating the proliferation and cell cycle process of osteosarcoma cells by binding to CDC20 and CCNA2, suggesting NUSAP1 as a possible therapeutic target for treatment of osteosarcoma.