Toosendanin induces the apoptosis of human Ewing's sarcoma cells via the mitochondrial apoptotic pathway.

Toosendanin, a triterpenoid extracted from the root bark of Melia toosendan, has its origin from traditional Chinese medicine and has been used as a non‑polluting and pesticide‑free plant insecticide in China for fruit and vegetable production. In recent years, toosendanin has been found to inhibit tumor cell proliferation and promote tumor cell apoptosis. Ewing's sarcoma (ES) is the second most common primary malignant bone and soft tissue tumor in children and adolescents. Although the overall prognosis of ES has improved, the 5‑year survival rate has not significantly increased. To analyze the role of toosendanin on ES progression, CCK‑8 viability assay, flow cytometry, Hoechst 33258 staining and western blotting were performed. The present results suggested that toosendanin suppressed cell viability and induced apoptosis in human SK‑ES‑1 cells compared with DMSO treatment. In addition, in the present study, toosendanin was found to upregulate the expression of Bax and downregulate the expression of Bcl‑2, altering the Bax/Bcl‑2 ratio. Additionally, toosendanin promoted the release of cytochrome c, resulting in the activation of the mitochondrial apoptotic pathway, thus inducing the activation of caspase‑9 and caspase‑3, and the cleavage of PARP. Our results demonstrated that toosendanin inhibited the growth of ES cells in a dose‑dependent manner and triggered mitochondrial apoptotic pathway to induce apoptosis. Therefore, toosendanin can potentially be utilized as an anticancer botanical drug for the treatment of ES.