Triptolide inhibits cell proliferation and tumorigenicity of human neuroblastoma cells

Triptolide is a diterpene triepoxide, extracted from the Chinese herb Tripterygium wilfordii Hook F, which has been shown to have antitumor activity in a number of cancers. Neuroblastoma is an aggressive extracranial pediatric solid tumor, with significant chemotherapeutic resistance. In this study, triptolide was hypothesized to be a potential therapeutic agent for neuroblastoma. The effects of triptolide on neuroblastoma cell growth and tumor development were investigated. Cell growth and proliferation were evaluated using a cell counting kit-8 assay and a 5-bromo-2-deoxyuridine staining assay. Cell cycle and apoptosis were detected by flow cytometry. Reverse transcription-quantitative polymerase chain reaction was conducted to detect the expression levels of the apoptosis-associated proteins, caspase-3 and caspase-9. The tumorigenicity of neuroblastoma cells was assessed by a soft agar clonogenic assay and an in vivo tumorigenic assay. The results demonstrated that exposure of BE(2)-C human neuroblastoma cells to triptolide resulted in a reduction in cell growth and proliferation, and the induction of cell death and apoptosis, together with cell cycle arrest in the S phase. A soft agar assay indicated that triptolide inhibited the colony-forming ability of BE(2)-C neuroblastoma cells. The xenograft experiment showed that triptolide significantly reduced tumor growth and development in vivo. The data suggested that this Chinese herb may be a potential novel chemotherapeutic agent for neuroblastoma.