NAMPT and cancer: When NAD+ production is inhibited genetically by depleting NAMPT or pharmacologically with NAMPT inhibitors (e.g., FK866) (26) prior to β-lap treatment in NQO1-overexpressing cancer cells, a synergistic cell death due to compromised NAD+ production following PARP hyperactivation highlights the critical role of catastrophic NAD+ depletion in NAD+-Keresis (Figure 1A) (26).