NAMPT inhibition uncovers therapeutic vulnerabilities to venetoclax and chemotherapy in acute myelogenous leukemia.

Acute myeloid leukemia (AML) cells depend on nicotinamide adenine dinucleotide (NAD) biosynthesis via nicotinamide phosphoribosyltransferase (NAMPT) for survival. Single-cell RNA sequencing revealed robust NAMPT expression across diverse AML subtypes. Proteomic profiling showed that NAMPT inhibition with KPT-9274 induced adaptive upregulation of BCL2, an anti-apoptotic protein, highlighting a survival mechanism. BH3 profiling confirmed that AML cells hierarchically depend on BCL2, followed by MCL1 and BCLxL, for survival. Combining KPT9274 with the BCL2 inhibitor venetoclax synergistically enhanced mitochondrial dysfunction, cytochrome C release, and apoptotic death in AML blasts. Additionally, NAMPT inhibition reduced PARP activity and impaired DNA repair pathways, sensitizing AML cells to cytarabine and hypomethylating agents. Together, these results demonstrate that NAMPT inhibition both potentiates venetoclax activity and enhances the cytotoxic effects of standard chemotherapies by targeting metabolic and DNA repair vulnerabilities. These findings provide strong preclinical support for evaluating NAMPT and BCL2 dual inhibition strategies in future AML clinical trials.