Bufalin induces apoptosis in the U‑2OS human osteosarcoma cell line via triggering the mitochondrial pathway

Bufalin has been shown to induce apoptosis in osteosarcoma cells; however, the underlying mechanism has not been elucidated. The purpose of the present study was to investigate whether mitochondria‑mediated signaling pathways trigger the process of apoptosis in the U‑2OS osteosarcoma cell line. Bufalin inhibited the proliferation and induced apoptosis in U‑2OS cells in a time- and dose‑dependent manner. Bufalin‑induced apoptosis was accompanied with a significant reduction of the mitochondrial membrane potential, release of mitochondrial cytochrome c into the cytosol, activation of caspase‑3, caspase‑9 and poly(adenosine diphosphate ribose) polymerase, as well as downregulation of B-cell lymphoma 2 (Bcl-2)/Bcl-2-associated X protein. Cyclosporin A, a specific inhibitor of the mitochondrial permeability transition pore, attenuated bufalin-induced apoptosis. In conclusion, the present study revealed that bufalin induced apoptosis in the U‑2OS human osteosarcoma cell line via triggering of the mitochondrial pathway.