A regimen combining the Wee1 inhibitor AZD1775 with HDAC inhibitors targets human acute myeloid leukemia cells harboring various genetic mutations

Abstract

AZD1775 targets the cell cycle checkpoint kinase Wee1 and potentiates genotoxic agent cytotoxicity through p53-dependent or -independent mechanisms. Here, we report that AZD1775 interacted synergistically with histone deacetylase inhibitors (HDACIs e.g., Vorinostat), which interrupt the DNA damage response (DDR), to kill p53-wild type or -deficient as well as FLT3-ITD leukemia cells in association with pronounced Wee1 inhibition and diminished cdc2/Cdk1 Y15 phosphorylation. Similarly, Wee1 shRNA knock-down significantly sensitized cells to HDACIs. While AZD1775 induced Chk1 activation, reflected by markedly increased Chk1 S296/S317/S345 phosphorylation leading to inhibitory T14 phosphorylation of cdc2/Cdk1, these compensatory responses were sharply abrogated by HDACIs. This was accompanied by premature mitotic entry, multiple mitotic abnormalities, and accumulation of early S-phase cells displaying increased newly replicated DNA, culminating in robust DNA damage and apoptosis. The regimen was active against patient-derived AML cells harboring either wild type or mutant p53, and various NGS-defined mutations. Primitive CD34+/CD123+/CD38− populations enriched for leukemia-initiating progenitors, but not normal CD34+ hematopoietic cells, were highly susceptible to this regimen. Finally, combining AZD1775 with Vorinostat in AML murine xenografts significantly reduced tumor burden and prolonged animal survival. A strategy combining Wee1 with HDACI inhibition warrants further investigation in AML with poor prognostic genetic aberrations.

Synergistic anti-leukemic interactions between panobinostat and MK-1775 in acute myeloid leukemia ex vivo

“…While we were performing our studies, Zhou et al published their study investigating the combination of Vorinostat, a pan-HDACI, with MK-1775 in AML. 45 In their study, the authors found diminished p-CDK1 following Vorinostat or MK-1775 treatment and further decrease after combined drug treatment, 45 which are similar to our results with panobinostat and MK-1775 treatment (Fig. 5).…”

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

“…MLN4924 and belinostat interact synergistically in AML cell lines with various genetic backgrounds, whereas FLT3-ITD or p53 knockdown increase sensitivity MLN4924 interactions with belinostat in leukemia cell lines expressing wt or mutant p53 and/or FLT3-ITD, adverse prognostic markers in AML, 6 were first examined. Although sensitivity to MLN4924 alone varied between lines, MLN4924/belinostat coexposure significantly increased apoptosis in all AML lines (Figure 1A-B; supplemental Figure 1A), whereas p53-deficient cells (eg, U937; Figure 1B left panel) were more sensitive than wt p53 cells (eg, OCI-AML-3; Figure 1A left panel).…”

“…Primary AML (blasts .70% and viability .95%) or MDS samples and normal human cord blood (CB) CD34 1 cells were isolated as before. 6 Clinical, molecular, and cytogenetic characteristics of 6 selected patients are described in supplemental Table 1 (available on the Blood Web site).…”

“…6 Experiments used logarithmically growing cells (3-6 3 10 5 cells per mL). Bone marrow (BM) or peripheral blood samples were obtained with informed consent from patients with histologically documented AML undergoing routine diagnostic procedures (Virginia Commonwealth University Institutional Review Board approval #HM 12517).…”

“…3 Recently, attention has focused on HDACI-mediated DNA damage response (DDR) disruption. 4 For example, HDACIs downregulate genes involved in checkpoints 5,6 and DNA repair 7,8 including homologous recombination (HR) and nonhomologous end-joining (NHEJ) repair. 9 Several HDACIs, including vorinostat, romidepsin, and belinostat, have been approved for cutaneous T-cell lymphoma or peripheral T-cell lymphoma, 10 and pracinostat was granted orphan drug status in AML.…”