METTL3/MYCN cooperation drives neural crest differentiation and provides therapeutic vulnerability in neuroblastoma

Neuroblastoma (NB) is the most common extracranial childhood cancer, caused by the improper differentiation of developing trunk neural crest cells (tNCC) in the sympathetic nervous system. The N 6 -methyladenosine (m 6 A) epitranscriptomic modification controls post-transcriptional gene expression but the mechanism by which the m 6 A methyltransferase complex METTL3/METTL14/WTAP is recruited to specific loci remains to be fully characterized. We explored whether the m 6 A epitranscriptome could fine-tune gene regulation in migrating/differentiating tNCC. We demonstrate that the m 6 A modification regulates the expression of HOX genes in tNCC, thereby contributing to their timely differentiation into sympathetic neurons. Furthermore, we show that posterior HOX genes are m 6 A modified in MYCN -amplified NB with reduced expression. In addition, we provide evidence that sustained overexpression of the MYCN oncogene in tNCC drives METTL3 recruitment to a specific subset of genes including posterior HOX genes creating an undifferentiated state. Moreover, METTL3 depletion/inhibition induces DNA damage and differentiation of MYCN overexpressing cells and increases vulnerability to chemotherapeutic drugs in MYCN -amplified patient-derived xenografts (PDX) in vivo, suggesting METTL3 inhibition could be a potential therapeutic approach for NB. Synopsis Neuroblastoma (NB) childhood cancers, associated with amplification of the MYCN oncogene, present an undifferentiated phenotype and are challenging to treat. This study reports MYCN cooperation with the m 6 A methyltransferase METTL3 promoting epitranscriptome changes and a developmental, aggressive state in early trunk neural crest cells (tNCC). m 6 A deposition regulates HOX gene expression in tNCC, ensuring their proper differentiation into sympathetic neurons. Increased MYCN levels promote METTL3 recruitment and m 6 A deposition at specific genes in tNCC, including HOX genes, which maintain an undifferentiated state in NB. Depleting or inhibiting METTL3 in MYCN-driven NB promotes cell differentiation and triggers DNA damage. Inhibiting METTL3 increases NB sensitivity to chemotherapy in mice. MYCN oncogene drives METTL3 recruitment and m 6 A deposition at posterior HOX genes, creating an undifferentiated state in early neural crest cells.