Researchers at Children’s Hospital of Philadelphia (CHOP) found that combining a specialised diet with an approved medication interrupts the growth of high-risk neuroblastoma, a deadly paediatric cancer, by reprogramming tumour behaviour. The findings were published in the journal Nature.
Neuroblastoma originates from primitive cells meant to form nerve tissues but that remain “undifferentiated,” indicating cancer cells that haven’t specialized, often suggesting a more aggressive and unfavourable prognosis. These tumours rely on a steady supply of chemicals called polyamines that are essential for rapid cell growth and tumour progression. A medicine called difluoromethylornithine (DFMO) was approved by the Food and Drug Administration (FDA) to treat children with high-risk neuroblastoma, as DFMO blocks polyamine production. However, researchers sought to improve the effectiveness of the drug by using it at high doses and combining it with a diet that is depleted of the nutrients used by the body to make polyamines (arginine). This two-step approach was anticipated to lower polyamines substantially more than low dose DFMO alone.
“Our findings show that this treatment reduced polyamines in tumours to roughly 10% of their usual levels. This reduction greatly slowed tumour growth, and in many cases, completely eliminated the tumours,” said Michael D. Hogarty, MD, a lead author and an Attending Physician in the Division of Oncology at Children’s Hospital of Philadelphia. “Notably, the treatment altered the way the tumour cells make proteins, making it harder for them to grow and easier for them to mature, or differentiate.”
Hogarty and his team used a preclinical model to mimic MYCN-driven neuroblastoma, directly addressing the strong association between extra MYCN gene copies and aggressive neuroblastoma with poor prognosis. Animal models with tumours were divided into groups: one fed a normal diet and the other lacking amino acids for polyamine production. Each group either received DFMO in their drinking water or did not. The special diet or DFMO alone partially lowered polyamines and extended survival, but the combination had the most significant impact on tumours due to the profound polyamine depletion it caused.
The researchers plan to conduct additional preclinical studies, followed hopefully by clinical trials in children to determine the safety and efficacy of targeting this specific metabolic dependency of neuroblastoma cells. By complementing existing treatments, they hope to substantially improve patient outcomes, and because the therapy targets polyamines it may be effective in many other types of cancer that have frequent MYC gene activation.
