International Journal of Molecular Sciences Review Nicotinamide N-Methyltransferase in Acquisition of Stem Cell Properties and Therapy Resistance in Cancer Renata Novak Kujundži´c 1,*, Marin Prpi´c 2,3,4, Nikola Ðakovi´c 3,5, Nina Dabeli´c 2, Marko Tomljanovi´c 1, Anamarija Mojzeš 1, Ana Fröbe 2,4 and Koraljka Gall Trošelj 1 1 Laboratory for Epigenomics, Division of Molecular Medicine, Ruder¯ Boškovi´cInstitute, 10000 Zagreb, Croatia;
[email protected] (M.T.);
[email protected] (A.M.);
[email protected] (K.G.T.) 2 Department of Oncology and Nuclear Medicine, University Hospital Center Sestre Milosrdnice, 10000 Zagreb, Croatia;
[email protected] (M.P.);
[email protected] (N.D.);
[email protected] (A.F.) 3 Department of Clinical Oncology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
[email protected] 4 School of Dental Medicine, University of Zagreb, 10000 Zagreb, Croatia 5 Institute for Clinical Medical Research and Education, University Hospital Center Sestre Milosrdnice, 10000 Zagreb, Croatia * Correspondence:
[email protected]; Tel.: +385-1-456-0949 Abstract: The activity of nicotinamide N-methyltransferase (NNMT) is tightly linked to the mainte- nance of the nicotinamide adenine dinucleotide (NAD+) level. This enzyme catalyzes methylation of nicotinamide (NAM) into methyl nicotinamide (MNAM), which is either excreted or further me- tabolized to N1-methyl-2-pyridone-5-carboxamide (2-PY) and H2O2. Enzymatic activity of NNMT Citation: Novak Kujundži´c,R.; Prpi´c, is important for the prevention of NAM-mediated inhibition of NAD+-consuming enzymes poly– M.; Ðakovi´c,N.; Dabeli´c,N.; adenosine -diphosphate (ADP), ribose polymerases (PARPs), and sirtuins (SIRTs).