Arnicolide D Inhibits Proliferation and Induces Apoptosis of Osteosarcoma Cells through PI3K/Akt/mTOR Pathway

Background Osteosarcoma is considered as the most prevalent form of primary malignant bone cancer, prompting a pressing need for novel therapeutic options. Arnicolide D, a sesquiterpene lactone derived from the traditional Chinese herbal medicine Centipeda minima (known as E Bu Shi Cao in Chinese), showed anticancer efficacy against several kinds of cancers. However, its effect on osteosarcoma remains unclear.Objective This study aimed to investigate the anticancer activity of arnicolide D and the underlying molecular mechanism of its action in osteosarcoma cells, MG63 and U2OS.Methods Cell viability and proliferation were evaluated through MTT assay and colony formation assay following 24 h and 48 h treatment with different concentrations of arnicolide D. Flow cytometry was employed to examine cell cycle progression and apoptosis after 24 h treatment of arnicolide D. Western blotting was performed to determine the expression of the PI3k, Akt and m-TOR and their phosphorylated forms.Results Our findings revealed that arnicolide D treatment resulted in a significant reduction in cell viability, the inhibition of proliferation, and the induction of apoptosis and cell cycle arrest in the G2/M phase. Furthermore, arnicolide D could inhibit the activation of PI3K/Akt/mTOR pathway in osteosarcoma cells.Conclusion Based on our results, arnicolide D demonstrated significant anti-osteosarcoma activity and held the potential to be considered as a therapeutic candidate for osteosarcoma in the future.