The Chip-Seq datasets generated and/or analysed during the current study are available in the NCBI’s GEO (https://www.ncbi.nlm.nih.gov/geo/query) through #”type”:”entrez-geo”,”attrs”:”text”:”GSE109377″,”term_id”:”109377″GSE109377 for RUNX1 in Nalm6 and patients [26] and #”type”:”entrez-geo”,”attrs”:”text”:”GSE117684″,”term_id”:”117684″GSE117684 for the other data. Declarations Ethics approval and consent to participateBone marrow cells from B cell precursor acute lymphoblastic leukemia (BCP-ALL) patients were collected at diagnosis after informed consent had been obtained in accordance with the declaration of Helsinki. involved in proliferation of BCP-ALL cells is crucial to propose new therapeutic targets. Runt Related Transcription Factor 1 (RUNX1) and Core-Binding Factor Runt Domain Indirubin Derivative E804 name Alpha Subunit 2 Translocated To 3 (CBFA2T3, ETO2, MTG16) are grasp regulators of hematopoiesis and are implicated in leukemia. Methods We worked with BCP-ALL mononuclear bone marrow patients cells and BCP-ALL cell lines, and performed Chromatin Immunoprecipitations followed by Sequencing (ChIP-Seq), co-immunoprecipitations (co-IP), proximity ligation assays (PLA), luciferase reporter assays and mouse xenograft models. Results We exhibited that transcript levels correlate with expression in the pediatric t(12;21) BCP-ALL. By ChIP-Seq in BCP-ALL patients cells and cell lines, we found that RUNX1 is usually recruited on its promoter and on an enhancer of located ??2?kb upstream promoter and that, subsequently, the transcription factor RUNX1 drives both and expression. We exhibited that, mechanistically, RUNX1 and CBFA2T3 can be part of the same complex allowing CBFA2T3 to strongly potentiate the activity of the transcription factor RUNX1. Finally, we characterized a CBFA2T3-mimicking peptide that inhibits the conversation between RUNX1 and CBFA2T3, abrogating the activity of this transcription complex and reducing BCP-ALL lymphoblast proliferation. Conclusions Altogether, our findings reveal a novel and important activation loop between the transcription regulator CBFA2T3 and the transcription factor RUNX1 that promotes BCP-ALL proliferation, supporting the development of an innovative therapeutic approach based on the NHR2 subdomain of CBFA2T3 protein. Supplementary Information The online version contains supplementary material available at 10.1186/s13045-021-01051-z. located ??2?kb upstream promoter and drives both and expression. CBFA2T3 strongly enhances the transcriptional activity of RUNX1. A CBFA2T3-truncated protein functions as a potent inhibitor of RUNX1 and CBFA2T3 proteinCprotein conversation. A CBFA2T3-truncated protein dramatically inhibits RUNX1 transcriptional activity and decreases BCP-ALL lymphoblast proliferation. The RUNX1 and CBFA2T3 self-activation loop is usually a BCP-ALL driver loop. Background RUNX1 (Runt Related Transcription Factor 1) Indirubin Derivative E804 is usually a major transcription factor of hematopoiesis. It belongs to the RUNX Itga4 family of transcriptional Indirubin Derivative E804 regulators, where users, RUNX1, RUNX2 and RUNX3, share a domain name that shows strong evolutionary conservation [1] and is responsible for DNA binding. RUNX1 is essential for definitive hematopoiesis in early development as well as in adulthood for megakaryocyte maturation, T- and B-cell lineage and neuronal development [2C5]. gene deregulation, either by genetic alterations (point mutation or chromosome abnormalities) or gene expression modification, is usually involved in many hematological malignancies, notably in ETV6-RUNX1 pre-B acute lymphoblastic leukemia (BCP-ALL) [6C9]. The Indirubin Derivative E804 transcriptional activity of RUNX1 depends on its hetero-dimerization with the non-DNA binding factor CBF, and on the recruitment of co-factors [10] that bind functional domains that negatively or positively modulate RUNX1 transcriptional activity [11]. CBFA2T3 (Core-Binding Factor Runt Domain name Alpha Subunit 2 Translocated To 3, also known as MTG16, ETO2) belongs to the eight-twenty-one (ETO) family of chromatin-associated proteins. This family also includes Myeloid Translocation Gene 1-Related (MTGR1) and Myeloid Translocation Gene 8 (MTG8, ETO) [12]. Each of these proteins contains four Nervy Homology Region (NHR) domains, and form homo- or hetero-oligomeric ETO complexes via the NHR2 domain name [13, 14]. CBFA2T3 is usually important for hematopoietic stem and progenitor cells self-renewal, lineage commitment and differentiated hematopoietic lineages including T-cell development or erythropoiesis [15C17]. CBFA2T3 participates in oncogenic recurrent translocations in acute myeloid leukemia (with the t(16;21)(q24;q22) giving rise to RUNX1-CBFA2T3) or acute megakaryoblastic leukemia (with inv [16] (p13q24) giving rise to CBFA2T3-GLIS2) [17]. Numerous binding partners have been reported for CBFA2T3, including transcription factors and chromatin modifiers[17], and it is generally believed that this ETO family members act as transcriptional repressor proteins Indirubin Derivative E804 via multiple binding to corepressors, such as nuclear receptor corepressor (NCOR), silencing-mediator for retinoid/thyroid hormone receptor (SMRT), mSin3a, and histone deacetylases (HDACs) [12, 18]. BCP-ALL is the most frequent type of pediatric malignancy. Several detailed studies have examined the expression of genes deregulated in ETV6-RUNX1 BCP-ALL compared to other types of leukemia and exhibited that and are specifically upregulated in ETV6-RUNX1 BCP-ALL [19] suggesting that these genes could be implicated in the onset and the maintenance of BCP-ALL [19C21]. Moreover, the RUNX1 and CBFA2T3 proteins were previously identified as potential partners in erythroid cells or in an overexpression model in HEK293T cells [22C24]. In this study, we aimed at delineating the functional and structural CBFA2T3 and RUNX1 relationship at the genome and protein levels. First, we exhibited that RUNX1 protein upregulates gene. Next, we characterized the proteinCprotein conversation domains between CBFA2T3 and RUNX1. At a mechanistic level, we recognized an activation loop between CBFA2T3 and RUNX1. Finally, at a functional level, we exhibited that a CBFA2T3-mimicking peptide, whose.