Targeting TNF/IL-17/MAPK pathway in h<i>E2A-PBX1</i> leukemia: effects of OUL35, KJ-Pyr-9, and CID44216842

Abstract

t(1;19)(q23;p13) is one of the most common translocation genes in childhood acute lymphoblastic leukemia (ALL) and is also present in acute myeloid leukemia (AML) and mixed-phenotype acute leukemia (MPAL). This translocation results in the formation of the oncogenic E2A-PBX1 fusion protein, which contains a trans-activating domain from E2A and a DNA-binding homologous domain from PBX1. Despite its clear oncogenic potential, the pathogenesis of E2A-PBX1 fusion protein is not fully understood (especially in leukemias other than ALL), and effective targeted clinical therapies have not been developed. To address this, we established a stable and heritable zebrafish line expressing human E2A-PBX1 (hE2APBX1) for high-throughput drug screening. Blood phenotype analysis showed that hE2APBX1 expression induced myeloid hyperplasia by increasing myeloid differentiation propensity of hematopoietic stem cells (HSPCs) and myeloid proliferation in larvae, and progressed to AML in adults. Mechanistic studies revealed that hE2A-PBX1 activated the TNF/IL-17/MAPK signaling pathway in blood cells and induced myeloid hyperplasia by upregulating the expression of the runx1. Interestingly, through high-throughput drug screening, three small molecules targeting the TNF/IL-17/MAPK signaling pathway were identified, including OUL35, KJ-Pyr-9, and CID44216842, which not only alleviated the hE2A-PBX1- induced myeloid hyperplasia in zebrafish but also inhibited the growth and oncogenicity of human pre-B ALL cells with E2A-PBX1. Overall, this study provides a novel hE2A-PBX1 transgenic zebrafish leukemia model and identifies potential targeted therapeutic drugs, which may offer new insights into the treatment of E2A-PBX1 leukemia.