Publikationsdatum:
2018-11-29
Beschreibung:
Introduction. Inhibition of Bromodomain and extraterminal (BET) proteins was effective against different acute myeloid leukemia (AML) subtypes in preclinical studies (Dawson et al. Nature 2011; Zuber et al. Nature 2011; Dawson et al. Leukemia 2013; Chen et al. Cancer Cell 2014; Gröschel et al. Cell 2014; Zhao et al. Cell Reports 2016). However, the drug had limited clinical activity, suggesting the need of ad hoc combination therapies able to target leukemia stem cells (LSCs) in their microenvironment. Hypoxia is an integral component of the bone marrow microenvironment and plays a crucial role in survival and chemoresistance of LSCs. Aims. The study aims to elucidate the consequences of BETi treatment in AML under hypoxic conditions and identify novel potential combination strategies. Methods. AML cell lines (OCI-AML3: NPM1- and DNMT3A-mutated, Kasumi-1: t(8;21), HL60: MYC-amplified, MOLM-13, NOMO-1: MLL-driven, KG-1: TP53-mutated) were treated with the BET inhibitor (i) GSK1215101A (250/500 nM, 48h) or the NRF2 activator omaveloxolone (NRF2a, 0.2-1 mM, 48h) and with the drug combination (72h) at 1% or 20% O2 concentration. Cell viability, apoptosis and cell cycle were evaluated by trypan blue dye exclusion assay, AnnexinV and PI staining, respectively. Gene expression profiling (HTA2.0, Affymetrix) was carried out on actively translated mRNAs isolated by polysome profiling after 16h of BETi treatment and on 61 primary AML. The TCGA AML dataset was analyzed on the cBioPortal. Gene expression correlation and enrichment analysis were performed by Pearson coefficient and GSEA, respectively. Kaplan-Meier survival curves were compared by Logrank test. Glutathione was quantified by mass spectrometry (Metabolon). Results. BETi induced a dose-dependent reduction of cell viability in AML cells lines under hypoxia (25%-65% decrease at 500 nM) except for HL-60. Under the same conditions, the treatment caused a significant arrest in the G0/G1 phase of the cell cycle in OCI-AML3, Kasumi-1, HL-60 and KG-1 models (p
Print ISSN:
0006-4971
Digitale ISSN:
1528-0020
Thema:
Biologie
,
Medizin
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