The NAE inhibitor pevonedistat interacts with the HDAC inhibitor belinostat to target AML cells by disrupting the DDR

Abstract

• The NAE inhibitor pevonedistat induces Chk1/Wee1 activation and the intra-S checkpoint, limiting its anti-AML efficacy.• The HDAC inhibitor belinostat potentiates the in vitro and in vivo activity of pevonedistat in AML by disrupting the DDR.Two classes of novel agents, NEDD8-activating enzyme (NAE) and histone deacetylase (HDAC) inhibitors, have shown single-agent activity in acute myelogenous leukemia (AML)/myelodysplastic syndrome (MDS). Here we examined mechanisms underlying interactions between the NAE inhibitor pevonedistat (MLN4924) and the approved HDAC inhibitor belinostat in AML/MDS cells. MLN4924/belinostat coadministration synergistically induced AML cell apoptosis with or without p53 deficiency or FLT3-internal tandem duplication (ITD), whereas p53 short hairpin RNA (shRNA) knockdown or enforced FLT3-ITD expression significantly sensitized cells to the regimen. MLN4924 blocked belinostat-induced antiapoptotic gene expression through nuclear factor-kB inactivation. Each agent upregulated Bim, and Bim knockdown significantly attenuated apoptosis. Microarrays revealed distinct DNA damage response (DDR) genetic profiles between individual vs combined MLN4924/belinostat exposure. Whereas belinostat abrogated the MLN4924-activated intra-S checkpoint through Chk1 and Wee1 inhibition/downregulation, cotreatment downregulated multiple homologous recombination and nonhomologous end-joining repair proteins, triggering robust double-stranded breaks, chromatin pulverization, and apoptosis. Consistently, Chk1 or Wee1 shRNA knockdown significantly sensitized AML cells to MLN4924. MLN4924/belinostat displayed activity against primary AML or MDS cells, including those carrying next-generation sequencingdefined poor-prognostic cancer hotspot mutations, and CD34

Assessment of Drug Sensitivity in Hematopoietic Stem and Progenitor Cells from Acute Myelogenous Leukemia and Myelodysplastic Syndrome Ex Vivo

“…1C). These results are consistent with a recent report demonstrating lack of MLN4924 toxicity in normal human CD34 + cells [29]. In the present study, no decrease in survival was noted in normal HSCs, MPPs, CMPs, or GMPs during MLN4924 treatment (supplemental online Fig.…”

“…However, even in low risk MDS patients, cytogenetic and mutation profiling studies have previously demonstrated that the overwhelming majority of HSCs and progenitors are abnormal [], making it probable that MLN4924 reduction of these populations includes the mutated HSCs and progenitors. Moreover, our study as well as a recently published study from another group [] indicate that normal stem and progenitor cells are unaffected by the same concentrations of MLN4924 (Fig. 1C; supplemental online Fig.…”

“…Under the conditions of the ex vivo assay described in this study, MLN4924 is toxic to leukemic and myelodysplastic hematopoietic stem and progenitor cells, whereas cytarabine in general is not. The same assay shows that MLN4924 has limited toxicity in normal hematopoietic stem and progenitor cells, extending a recent report that assessed toxicity of MLN4924 in normal CD34 + cells [29]. Thus, the strategy described here might help inform development of future AML and MDS therapies aimed at targeting malignant stem and progenitor cell populations while sparing normal hematopoietic progenitors.…”

Combinatorial Screening of Pancreatic Adenocarcinoma Reveals Sensitivity to Drug Combinations Including Bromodomain Inhibitor Plus Neddylation Inhibitor

“…Moreover, reversible neddylation is an important and intrinsic component of DNA damage responses including nucleotide excision repair of double-strand DNA breaks through non-homologous end joining (NHEJ) (50). At least some of the anti-neoplastic effects of MLN4924 have been attributed to DNA damage (51,52)Through these mechanisms, inhibition of NAE leads to DNA damage, DNA re-replication, and S phase or G2 arrest (53). Furthermore, MLN4924 is effective at inhibiting growth of several cancer types including osteosarcoma (54-56).…”

NEDD8 and HDACs: promising cotargets in AML

“…In the studies reported in this issue of Blood, Zhou et al examined the preclinical activity of a combination of pevonedistat and belinostat. 1 They demonstrated that, compared with treatment with each agent alone, combined therapy with pevonedistat and belinostat exerts in vitro synergistic lethality against a variety of cultured AML cell types with diverse genetic backgrounds, including the presence of FLT3-ITD and MLL-AF4 (as in MV4-11 cells), as well as the deficiency of wild-type TP53 (see figure). The combination was also synergistically lethal against patient-derived primary AML cells.…”