Reciprocal Potentiation of the Antitumoral Activities of FK866, an Inhibitor of Nicotinamide Phosphoribosyltransferase, and Etoposide or Cisplatin in Neuroblastoma Cells

Abstract

NAD is an essential coenzyme involved in numerous metabolic pathways. Its principal role is in redox reactions, and as such it is not heavily "consumed" by cells. Yet a number of signaling pathways that bring about its consumption have recently emerged. This has brought about the hypothesis that the enzymes that lead to its biosynthesis may be targets for anticancer therapy. In particular, inhibition of the enzyme nicotinamide phosphoribosyl transferase has been shown to be an effective treatment in a number of preclinical studies, and two lead molecules [N-[4-(1-benzoyl-4-piperidinyl)butyl]-3-(3-pyridinyl)-2E-propenamide (FK866) and (E)-1-[6-(4-chlorophenoxy)hexyl]-2-cyano-3-(pyridin-4-yl)guanidine (CHS 828)] have now entered preclinical trials. Yet, the full potential of these drugs is still unclear. In the present study we have investigated the role of FK866 in neuroblastoma cell lines. We now confirm that FK866 alone in neuroblastoma cells induces autophagy, and its effects are potentiated by chloroquine and antagonized by 3-methyladenine or by down-regulating autophagy-related protein 7. Autophagy, in this model, seems to be crucial for FK866-induced cell death. On the other hand, a striking potentiation of the effects of cisplatin and etoposide is given by cotreatment of cells with ineffective concentrations of FK866 (1 nM). The effect of etoposide on DNA damage is potentiated by FK866 treatment, whereas the effect of FK866 on cytosolic NAD depletion is potentiated by etoposide. Even more strikingly, cotreatment with etoposide/cisplatin and FK866 unmasks an effect on mitochondrial NAD depletion.

Intracellular NAD+ depletion enhances bortezomib-induced anti-myeloma activity

“…Because a previous study linked cell death induced by FK866 combined with cisplatin/etoposide to apoptosis in neuroblastoma cells, 12 we next examined whether FK866 added to bortezomib also triggered apoptosis in MM cells. Indeed, we observed that combining low doses of these drugs markedly increased proteolytic cleavage of caspase-3, caspase-8, caspase-9, and PARP in both bortezomib-sensitive and -resistant MM cell lines ( Figure 3A).…”

“…Remarkably, the combination of FK866 plus bortezomib dramatically reduced intracellular NAD 1 to undetectable levels in all MM cells analyzed, enhancing the metabolic consequences of FK866 treatment alone ( Figure 6A). Because intracellular NAD 1 and adenosine triphosphate (ATP) levels, whose depletion follows NAD 1 shortage, 12,27 share the capacity to affect proteasome enzymatic activity, we next turned our attention to a possible synergism at this level.…”

“…In vivo studies in murine xenograft models of human MM showed that FK866 is well tolerated, prolongs survival, and reduces tumor growth. Numerous studies in other cancers have also revealed promising results by combining NAD 1 -depleting agents with TRAIL, 9 DNA damaging agents (daunorubicin, cisplatin, Ara-C, and melphalan), [10][11][12] and ionizing radiation. 13 Proteasome inhibitor bortezomib has transformed therapy of relapsed MM, as well as prolonged event-free and overall survival when used as initial therapy for newly diagnosis disease.…”

On-Target Effect of FK866, a Nicotinamide Phosphoribosyl Transferase Inhibitor, by Apoptosis-Mediated Death in Chronic Lymphocytic Leukemia Cells

“…FK866 reduces intracellular NAD content, resulting in selective cancer cell death in solid tumors (22,(25)(26)(27), and emerging evidence suggests that it is also active in blood cancers (28)(29)(30)(31)(32)(33). FK866 has been demonstrated to be effective in blood cancer cell lines, where it leads to ATP reduction and delayed induction of cell death.…”

Synergy between the NAMPT Inhibitor GMX1777(8) and Pemetrexed in Non–Small Cell Lung Cancer Cells Is Mediated by PARP Activation and Enhanced NAD Consumption

“…GMX1777 is a soluble prodrug of GMX used for in vivo studies (5,6). NAMPT inhibitors, including GMX1778 (GMX) and FK866, have shown preclinical activity alone and in combination with several therapeutic DNA-damaging agents, but the mechanism of synergy has not been clearly elucidated (7)(8)(9)(10).…”