title: Synthetic lethality of PARP and NAMPT inhibition in triple-negative breast cancer cells.
abstract: PARP inhibitors have been proposed as a potential targeted therapy for patients with triple-negative (ER-, PR-, HER2-negative) breast cancers. However, it is as yet unclear as to whether single agent or combination therapy using PARP inhibitors would be most beneficial. To better understand the mechanisms that determine the response to PARP inhibitors, we investigated whether enzymes involved in metabolism of the PARP substrate, β-NAD(+) , might alter the response to a clinical PARP inhibitor. Using an olaparib sensitization screen in a triple-negative (TN) breast cancer model, we identified nicotinamide phosphoribosyltransferase (NAMPT) as a non-redundant modifier of olaparib response. NAMPT is a rate-limiting enzyme involved in the generation of the PARP substrate β-NAD(+)  and the suppression of β-NAD(+)  levels by NAMPT inhibition most likely explains these observations. Importantly, the combination of a NAMPT small molecule inhibitor, FK866, with olaparib inhibited TN breast tumour growth in vivo to a greater extent than either single agent alone suggesting that assessing NAMPT/PARP inhibitor combinations for the treatment of TN breast cancer may be warranted.
authors.affiliation: The Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London, UK.
authors.forename: Ilirjana
authors.initials: I
authors.lastname: Bajrami
authors.forename: Asha
authors.initials: A
authors.lastname: Kigozi
authors.forename: Antoinette
authors.initials: A
authors.lastname: Van Weverwijk
authors.forename: Rachel
authors.initials: R
authors.lastname: Brough
authors.forename: Jessica
authors.initials: J
authors.lastname: Frankum
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Lord
authors.forename: Alan
authors.initials: A
authors.lastname: Ashworth
mesh_terms: D000178:Acrylamides / Q000008:administration & dosage / Q000378:metabolism*; D000818:Animals; D001943:Breast Neoplasms / Q000188:drug therapy*; D045744:Cell Line, Tumor; D016207:Cytokines / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005260:Female; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D054409:Nicotinamide Phosphoribosyltransferase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010793:Phthalazines / Q000008:administration & dosage / Q000378:metabolism*; D010879:Piperazines / Q000008:administration & dosage / Q000378:metabolism*; D010880:Piperidines / Q000008:administration & dosage / Q000378:metabolism*; D000071137:Poly (ADP-Ribose) Polymerase-1; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D014183:Transplantation, Heterologous / Q000473:pathology
chemical_list: D000178:Acrylamides; D016207:Cytokines; C480543:N-(4-(1-benzoylpiperidin-4-yl)butyl)-3-(pyridin-3-yl)acrylamide; D010793:Phthalazines; D010879:Piperazines; D010880:Piperidines; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D054409:Nicotinamide Phosphoribosyltransferase; C085455:nicotinamide phosphoribosyltransferase, human; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; C531550:olaparib