The NEDD8-activating enzyme inhibitor MLN4924 disrupts nucleotide metabolism and augments the efficacy of cytarabine.
OBJECTIVE
New therapies are urgently needed for patients with acute myelogenous leukemia (AML). The novel NEDDylation inhibitor MLN4924 (pevonedistat) has demonstrated significant preclinical antileukemic activity and preliminary efficacy in patients with AML in a phase I trial. On the basis of its antimyeloid and DNA-damaging properties, we investigated the ability of MLN4924 to augment conventional cytarabine (ara-C) therapy.


METHODS
The effects of MLN4924/ara-C on viability, clonogenic survival, apoptosis, DNA damage, and relevant pharmacodynamic targets were determined. The efficacy and pharmacodynamics of MLN4924/ara-C were assessed in an AML xenograft model.


RESULTS
Cotreatment of AML cell lines and primary patient specimens with MLN4924 and ara-C led to diminished clonogenic survival, increased apoptosis, and synergistic levels of DNA damage. RNAi demonstrated that stabilization of CDT-1, an event previously shown to mediate the DNA-damaging effects of MLN4924, was not a key regulator of sensitivity to the MLN4924/ara-C combination. Global metabolic profiling revealed that MLN4924 disrupts nucleotide metabolism and depletes intracellular nucleotide pools in AML cells. Subsequent experiments showed that MLN4924 promoted increased incorporation of ara-C into the DNA of AML cells. This effect as well as the therapeutic benefit of the MLN4924/ara-C combination was antagonized by supplementation with the nucleotide building block ribose. Coadministration of MLN4924 and ara-C to mice bearing FLT3-ITD(+) AML xenografts stably inhibited disease progression and increased DNA damage in vivo.


CONCLUSIONS
Our findings provide strong rationale for clinical investigation of the MLN4924/ara-C combination and establish a new link between therapeutic inhibition of NEDDylation and alterations in nucleotide metabolism. Clin Cancer Res; 21(2); 439-47. ©2014 AACR.
Division of Hematology/Oncology, CTRC, The University of Texas Health Science Center, San Antonio, Texas.
Steffan T
ST
Nawrocki
USC Norris Comprehensive Cancer Center, Pasadena, California.
Kevin R
KR
Kelly
Millennium Pharmaceuticals, Cambridge, Massachusetts. H3 Biomedicine, Cambridge, Massachusetts.
Peter G
PG
Smith
Metabolon, Inc., Durham, North Carolina. Duke University, Durham, North Carolina.
Mignon
M
Keaton
Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio.
Hetty
H
Carraway
Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio.
Mikkael A
MA
Sekeres
Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio.
Jaroslaw P
JP
Maciejewski
Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio. carewj@ccf.org.
Jennifer S
JS
Carew
D000818:Animals; D017209:Apoptosis; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003517:Cyclopentanes / Q000494:pharmacology*; D003561:Cytarabine / Q000494:pharmacology*; D004357:Drug Synergism; D055785:Gene Knockdown Techniques; D006801:Humans; D008819:Mice, Nude; D000075687:NEDD8 Protein; D009711:Nucleotides / Q000378:metabolism*; D055550:Protein Stability; D011743:Pyrimidines / Q000494:pharmacology*; D014452:Ubiquitins / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays
C467199:CDT1 protein, human; D018797:Cell Cycle Proteins; D003517:Cyclopentanes; D000075687:NEDD8 Protein; C082860:NEDD8 protein, human; D009711:Nucleotides; D011743:Pyrimidines; D014452:Ubiquitins; D003561:Cytarabine; C539933:pevonedistat