Neuroblastoma (NB) is an extracranial tumor of the peripheral nervous system arising from neural crest cells. It is the most common malignancy in infants and the most common extracranial solid tumor in children. The current treatment for high-risk NB involves chemotherapy and surgical resection followed by high-dose chemotherapy with autologous stem-cell rescue and radiation treatment. However, those with high-risk NB are susceptible to relapse and the long-term side effects of standard chemotherapy. Polyphenols, including the sub-class of flavonoids, contain more than one aromatic ring with hydroxyl groups. The literature demonstrates their utility in inducing the apoptosis of neuroblastoma cells, mostly in vitro and some in vivo. This review explores the use of various polyphenols outlined in primary studies, underlines the pathways involved in apoptotic activity, and discusses the dosage and delivery of these polyphenols. Primary studies were obtained from multiple databases with search the terms "neuroblastoma", "flavonoid", and "apoptosis". The in vitro studies showed that polyphenols exert an apoptotic effect on several NB cell lines. These polyphenols include apigenin, genistein, didymin, rutin, quercetin, curcumin, resveratrol, butein, bisphenols, and various plant extracts. The mechanisms of the therapeutic effects include calpain-dependent pathways, receptor-mediated apoptosis, and, notably, and most frequently, mitochondrial apoptosis pathways, including the mitochondrial proteins Bax and Bcl-2. Overall, polyphenols demonstrate potency in decreasing NB proliferation and inducing apoptosis, indicating significant potential for further in vivo research.
Keywords: apoptosis; cancer; flavonoids; neuroblastoma; polyphenols.