MYCN and HIF-1 Directly Regulate Expression to Control 5-hmC Gains and Enhance Neuroblastoma Cell Migration in Hypoxia

Ten-Eleven-Translocation 5-methylcytosine dioxygenases 1-3 (TET1-3) convert 5-methylcytosine to 5-hydroxymethylcytosine (5-hmC), using oxygen as a co-substrate. Contrary to expectations, hypoxia induces 5-hmC gains in -amplified neuroblastoma (NB) cells via upregulation of . Here, we show that MYCN directly controls expression in normoxia, and in hypoxia, HIF-1 augments expression and TET1 protein stability. Through gene-editing, we identify two MYCN and HIF-1 binding sites within that regulate gene expression. Bioinformatic analyses of 5-hmC distribution and RNA-sequencing data from hypoxic cells implicate hypoxia-regulated genes important for cell migration, including . We show that hypoxic cells lacking the two MYCN/HIF-1 binding sites within migrate slower than controls. Treatment of amplified NB cells with a CXCR4 antagonist results in slower migration under hypoxic conditions, suggesting that inclusion of a CXCR4 antagonist into NB treatment regimens could be beneficial for children with amplified NBs.