NNMT and neuroblastoma: In a previous study, overexpressing NNMT in SH-SY5Y neuroblastoma cells or incubating the cells with 1-methylnicotinamide significantly decreased the cell death rate, which was found to correlate with increased intracellular ATP content, ATP/ADP ratio and complex I activity, and reduced the degradation of complex I inhibitors (28), thus suggesting that 1-methylnicotinamide may mediate the cellular effects of NNMT.