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Pirarubicin inhibits multidrug-resistant osteosarcoma cell proliferation through induction of G2/M phase cell cycle arrest.


ABSTRACT: AIM: Pirarubicin (THP) is recently found to be effective in treating patients with advanced, relapsed or recurrent high-grade osteosarcoma. In this study, the effects of THP on the multidrug-resistant (MDR) osteosarcoma cells were assessed, and the underlying mechanisms for the disruption of cell cycle kinetics by THP were explored. METHODS: Human osteosarcoma cell line MG63 and human MDR osteosarcoma cell line MG63/DOX were tested. The cytotoxicity of drugs was examined using a cell proliferation assay with the Cell Counting Kit-8 (CCK-8). The distribution of cells across the cell cycle was determined with flow cytometry. The expression of cell cycle-regulated genes cyclin B1 and Cdc2 (CDK1), and the phosphorylated Cdc2 and Cdc25C was examined using Western blot analyses. RESULTS: MG63/DOX cells were highly resistant to doxorubicin (ADM) and gemcitabine (GEM), but were sensitive or lowly resistant to THP, methotrexate (MTX) and cisplatin (DDP). Treatment of MG63/DOX cells with THP (200-1000 ng/mL) inhibited the cell proliferation in time- and concentration-dependent manners. THP (50-500 ng/mL) induced MG63/DOX cell cycle arrest at the G(2)/M phase in time- and concentration-dependent manners. Furthermore, the treatment of MG63/DOX cells with THP (200-1000 ng/mL) downregulated cyclin B1 expression, and decreased the phosphorylated Cdc2 at Thr(161). Conversely, the treatment increased the phosphorylated Cdc2 at Thr(14)/Tyr(15) and Cdc25C at Ser(216), which led to a decrease in Cdc2-cyclin B1 activity. CONCLUSION: The cytotoxicity of THP to MG63/DOX cells may be in part due to its ability to arrest cell cycle progression at the G(2)/M phase, which supports the use of THP for managing patients with MDR osteosarcoma.

SUBMITTER: Zheng SE 

PROVIDER: S-EPMC4010378 | biostudies-other | 2012 Jun

REPOSITORIES: biostudies-other

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