The transcription factor HIF2a partakes in the differentiation blockade of acute myeloid leukaemia [ChIP-seq]
Acute myeloid leukemia (AML) is characterized by an accumulation of aberrant myeloid cells arrested at different stages of differentiation. Therapeutic approaches that prompt AML blasts to differentiate represent an attractive opportunity in the landscape of AML therapies, as they aim to induce terminal maturation and leukemia debulking without intensive cytotoxic treatments. In the present study, we investigate the involvement of HIF1a and HIF2a transcription factors in AML pathogenesis, and position HIF2a as a novel regulator of the AML differentiation block. We performed a comparative analysis of HIF1a and HIF2a function in AML cell lines via their inhibition with genetic or pharmacological strategies and found that both factors promote AML proliferation and clonogenicity. Importantly, specific inhibition of HIF2a provokes AML cell differentiation in cell lines and patient-derived xenograft (PDX) models.  Additionally, we demonstrate that HIF2a is positively regulated by the pro-differentiation agent all-trans retinoic acid (ATRA), and its inhibition cooperates with ATRA in triggering AML cell differentiation. In conclusion, we report evidence of a new role of HIF2a in the pathogenesis of AML, and we propose that HIF2a inhibition may open new therapeutic avenues for AML treatment by licensing AML differentiation and synergizing with ATRA towards leukemia exhaustion. Overall design: ChIP-sequencing (ChIP-seq) analysis of H3K27me3 in Kasumi1 cells stably transfected with shRNA against HIF2a (shHIF2a) or a scramble shRNA as control (shCTRL). Each condition was conducted in experimental triplicate (6 samples).