Divergent Effects of Ultra-High Dose Arachidonic Acid versus Docosahexaenoic Acid on MYCN-Driven Neuroblastoma Progression in a Syngeneic Mouse Model

Neuroblastoma (NB) represents the most common extracranial solid tumor in children, where high-risk cases have particularly poor prognosis. We used a syngeneic mouse model to investigate the effects of ultra-high dose highly unsaturated fatty acids (HUFA) on NB progression. Following tumor establishment, mice were randomized to receive daily oral gavage with omega-6 ({omega}6) arachidonic acid (ARA) at 4.7 g/d human equivalent (hEq), or omega-3 ({omega}3) docosahexaenoic acid (DHA) at 24 g/d hEq, and controls did not receive gavage. We observed strikingly divergent effects: ARA significantly promoted tumor growth, resulting in 100% tumor survival and 4-fold larger tumors compared to controls, with enhanced vascularization and invasive morphology. In contrast, DHA administration reduced tumor survival (40% versus 92% in controls) and significantly suppressed the progression of remaining tumors, with remaining DHA-treated tumors approximately 4.5-fold smaller than controls and 18-fold smaller than ARA-treated tumors. In a separate lipid mediator analysis, ARA supplementation significantly increased pro-inflammatory/pro-tumorigenic mediators including PGE2, TXB2, and epoxyeicosatrienoic acids in liver, spleen, brain and skeletal muscle. DHA supplementation increased anti-inflammatory/anti-tumor mediators, particularly EPA-derived 17,18-EpETE, 18-HEPE, and DHA-derived 14-HDHA in these same tissues. No significant differences in body weight were observed among treatment groups, indicating the treatments were well-tolerated. These findings build upon our previous research demonstrating that ultra-high dose {omega}3 supplementation can completely block tumor formation in MYCN-driven NB. The profound tumor-suppressive effects of DHA suggest that dietary modulation of {omega}3 and {omega}6 HUFA intake may offer a complementary, low-toxicity approach to high-risk NB standard of care (SoC). Our findings suggest that dietary intervention may be an effective primary or adjunctive strategy in pediatric oncology, enabling reduced SoC dosing while improving outcomes and survivorship.