NAPRT and cancer: In order to confirm that the ability of our new inhibitors to sensitize NAPRT-proficient cancer cells to FK866 is on-target, i.e., due to NAPRT obstruction, we supplemented HCT116 and OVCAR-8 cells with NA or NAMN (at 10 μM) while treating them with our putative NAPRT inhibitors, in the presence or absence of FK866.