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Florofangchinoline inhibits proliferation of osteosarcoma cells via targeting of histone H3 lysine 27 trimethylation and AMPK activation

Liyan Zhao
Xiongtao Liu
Weina Zhu
Pei Yang
Jie Qin
Ru Gu
Zhili Zhao


Purpose: To investigate the effect of florofangchinoline on osteosarcoma cell growth in vitro, and the underlying mechanism of action.
Methods: Changes in the viability of KHOS and Saos-2 cells were measured using water soluble tetrazolium salt (WST) assay, while apoptosis was determined using Annexin V/PI staining and flow cytometry. Increases in mtDNA, and expressions of PGC-1α and TFAM were assayed with immunoblot analysis and quantitative real-time polymerase chain reaction (qPCR), respectively.
Results: Microscopic examination of florofangchinoline-treated cells showed significant decrease in cell density, relative to control cells (p < 0.05). Treatment with 10 μM florofangchinoline increased apoptosis in KHOS and Saos-2 cells to 56.32 and 63.75 %, respectively (p < 0.05). Florofangchinoline treatment markedly enhanced cleavage of caspase-3, caspase-8, caspase-9 and PARP. It elevated Bax level and reduced Bcl-2 in KHOS and Saos-2 cells. Moreover, florofangchinoline increased p21 and p-AMPKα levels, and mtDNA counts in KHOS and Saos-2 cells (p < 0.05). Moreover, in florofangchinoline-treated KHOS cells, the expressions of EED, EZH2 and SUZ12 were significantly suppressed (p < 0.05).
Conclusion: Florofangchinoline inhibits osteosarcoma cell viability by activation of apoptosis. Moreover, it activates AMPK and down-regulates  histone H3 lysine 27 trimethylation in osteosarcoma cells. Therefore, florofangchinoline has potentials for development as a therapeutic drug for

Keywords: Osteosarcoma, Histone H3, Florofangchinoline, Apoptosis, Chemotherapeutic