PHF8 and neuroblastoma: Specifically, we found that Pon1 depletion downregulated histone demethylase Phf8 both at the protein and mRNA level, increased H4K20me1 binding at the mTOR promotor (Figure 4A), and upregulated mTOR expression and phosphorylation in the mouse brain (Figure 1C,D) and neuroblastoma N2a-APPswe cells (Figure 3D,E).