Romidepsin induces caspase-dependent cell death in human neuroblastoma cells

[Display omitted] •Romidepsin is an FDA-approved small molecule drug and a selective HDAC1/2 inhibitor.•Romidepsin potently induces caspase-dependent cell death in human neuroblastoma cells.•MYCN-amplified neuroblastoma cells are more sensitive to Romidepsin-induced death.•The cytotoxic dose of Romidepsin can be lowered by combination with other cytotoxins.•Romidepsin may be a promising mono-/combination- chemotherapeutic for neuroblastoma. Neuroblastoma is the most common extracranial pediatric solid tumor, arising from the embryonic sympathoadrenal lineage of the neural crest, and is responsible for 15% of childhood cancer deaths. Although survival rates are good for some patients, those children diagnosed with high-risk neuroblastoma have survival rates as low as 35%. Thus, neuroblastoma remains a significant clinical challenge and the development of novel therapeutic strategies is essential. Given that there is widespread epigenetic dysregulation in neuroblastoma, epigenetic pharmacotherapy holds promise as a therapeutic approach. In recent years, histone deacetylase (HDAC) inhibitors, which cause selective activation of gene expression, have been shown to be potent chemotherapeutics for the treatment of a wide range of cancers. Here we examined the ability of the FDA-approved drug Romidepsin, a selective HDAC1/2 inhibitor, to act as a cytotoxic agent in neuroblastoma cells. Treatment with Romidepsin at concentrations in the low nanomolar range induced neuroblastoma cell death through caspase-dependent apoptosis. Romidepsin significantly increased histone acetylation, and significantly enhanced the cytotoxic effects of the cytotoxic agent 6-hydroxydopamine, which has been shown to induce cell death in neuroblastoma cells through increasing reactive oxygen species. Romidepsin was also more potent in MYCN-amplified neuroblastoma cells, which is an important prognostic marker of poor survival. This study has thus demonstrated that the FDA-approved chemotherapeutic drug Romidepsin has a potent caspase-dependent cytotoxic effect on neuroblastoma cells, whose effects enhance cell death induced by other cytotoxins, and suggests that Romidepsin may be a promising chemotherapeutic candidate for the treatment of neuroblastoma.