Project description:To investigate the contribution of ENL YEATS domain and downstream sequences in MLL-ENL leukemogenesis program, we generated MLL-ENL and MLL-ENL ∆YEATS (ENL aa372-559) cell lines by retrovirally introducing these constructs into lineage negative hematopoietic stem and progenitor cells (HSPCs).
Project description:Recurrent chromosomal translocations involving the mixed lineage leukemia gene (MLL) give rise to highly aggressive acute leukemia associated with poor clinical outcomes. The preferential involvement of chromatin-associated factors in MLL rearrangements belies a dependency on transcriptional control. To identify new targets for therapeutic development in MLL, we performed a genome-scale CRISPR-Cas9 knockout screen in MLL-AF4 leukemia. Among validated targets, we identified the transcriptional regulator, ENL, as an unrecognized dependency particularly indispensable for proliferation. To explain the mechanistic role for ENL in leukemia pathogenesis and the dynamic role in transcription control, we pursued a chemical genetic strategy utilizing targeted protein degradation. ENL loss suppresses transcription initiation and elongation genome-wide, with pronounced effects at genes featuring disproportionate ENL load. Importantly, ENL-dependent leukemic growth was contingent upon an intact YEATS epigenomic reader domain. These findings reveal a novel dependency in acute leukemia and a first mechanistic rationale for disrupting YEATS domains in disease.
Project description:Recurrent chromosomal translocations involving the mixed lineage leukemia gene (MLL) give rise to highly aggressive acute leukemia associated with poor clinical outcomes. The preferential involvement of chromatin-associated factors in MLL rearrangements belies a dependency on transcriptional control. To identify new targets for therapeutic development in MLL, we performed a genome-scale CRISPR-Cas9 knockout screen in MLL-AF4 leukemia. Among validated targets, we identified the transcriptional regulator, ENL, as an unrecognized dependency particularly indispensable for proliferation. To explain the mechanistic role for ENL in leukemia pathogenesis and the dynamic role in transcription control, we pursued a chemical genetic strategy utilizing targeted protein degradation. ENL loss suppresses transcription initiation and elongation genome-wide, with pronounced effects at genes featuring disproportionate ENL load. Importantly, ENL-dependent leukemic growth was contingent upon an intact YEATS epigenomic reader domain. These findings reveal a novel dependency in acute leukemia and a first mechanistic rationale for disrupting YEATS domains in disease.
Project description:Transcriptional co-regulators, which mediate chromatin-dependent transcriptional signaling, represent tractable targets to modulate tumorigenic gene expression programs with small molecules. Genetic loss-of-function studies have recently implicated the transcriptional co-activator, ENL, as a selective requirement for the survival of acute leukemia – particularly those driven by multiple lineage leukemia (MLL)-fusion oncogenes. The YEATS domain of ENL, which binds to chromatin by interacting with acyl-lysine side chains, is critical for its pathogenic function in acute leukemiaand highlighted an essential role for its chromatin reader YEATS domain. Motivated by these recent discoveries, we executed a screen of nearly 300,000 small molecules to identify chromatin-competitiveand identified an amido-imidazopyridine inhibitors of the ENL YEATS domain (IC50 = 7 µM). Leveraging a SuFEx-based high-throughput approach to Optimizing an amido-imidazopyridine scaffold with highly parallelized, SuFEx-based medicinal chemistry optimization, we discovered SR-0813 (IC50 = 25 nM), a potent and selective ENL/AF9 YEATS domain inhibitor that exclusively inhibits the growth of ENL-dependent leukemia cell lines. Armed with this tool and a first-in-class ENL PROTAC, SR-1114, we detailed the response of AML cells to pharmacological ENL disruption for the first time. Most notably, displacement of In AML cells, SR-0813 evicts ENL from chromatin, by SR-0813 preferentially suppresseselicited a strikingly selective suppression of ENL target genes, including HOXA9/10, MYB, MYC and a number of other leukemia proto-oncogenes. Our study reproduces a number of key observations previously made by CRISPR/Cas9 loss of function and dTAG-mediated degradation, and therefore, both reinforces ENL as an emerging leukemia target and validates SR-0813 as a high-quality chemical probe.
Project description:Transcriptional co-regulators, which mediate chromatin-dependent transcriptional signaling, represent tractable targets to modulate tumorigenic gene expression programs with small molecules. Genetic loss-of-function studies have recently implicated the transcriptional co-activator, ENL, as a selective requirement for the survival of acute leukemia – particularly those driven by multiple lineage leukemia (MLL)-fusion oncogenes. The YEATS domain of ENL, which binds to chromatin by interacting with acyl-lysine side chains, is critical for its pathogenic function in acute leukemiaand highlighted an essential role for its chromatin reader YEATS domain. Motivated by these recent discoveries, we executed a screen of nearly 300,000 small molecules to identify chromatin-competitiveand identified an amido-imidazopyridine inhibitors of the ENL YEATS domain (IC50 = 7 µM). Leveraging a SuFEx-based high-throughput approach to Optimizing an amido-imidazopyridine scaffold with highly parallelized, SuFEx-based medicinal chemistry optimization, we discovered SR-0813 (IC50 = 25 nM), a potent and selective ENL/AF9 YEATS domain inhibitor that exclusively inhibits the growth of ENL-dependent leukemia cell lines. Armed with this tool and a first-in-class ENL PROTAC, SR-1114, we detailed the response of AML cells to pharmacological ENL disruption for the first time. Most notably, displacement of In AML cells, SR-0813 evicts ENL from chromatin, by SR-0813 preferentially suppresseselicited a strikingly selective suppression of ENL target genes, including HOXA9/10, MYB, MYC and a number of other leukemia proto-oncogenes. Our study reproduces a number of key observations previously made by CRISPR/Cas9 loss of function and dTAG-mediated degradation, and therefore, both reinforces ENL as an emerging leukemia target and validates SR-0813 as a high-quality chemical probe.
Project description:To identify the target genes of Runx1 in MLL fusion leukemia, we performed microarray analysis using control and Runx1-deficient MLL-ENL leukemia cells. Runx1 intact and excised bone marrow cells were transduced with MLL-ENL and transplanted into congenic mice. Leukemic cells were harvested from moribund mice, and gene expression was compared using 3 independent leukemia cells for each genotype.
Project description:To identify the target genes of Runx1 in MLL fusion leukemia, we performed microarray analysis using control and Runx1-deficient MLL-ENL leukemia cells.
Project description:Chromosomal translocations encoding the MLL-AF9 and MLL-ENL fusion transcription factors are prevalent in infant acute leukaemia and therapy-related leukaemia. In order to conditionally express the MLL-fusion oncogene in primary haematopoietic progenitor cells (HPC), retroviral delivery of the Tet-off expression system was used (Horton et al., Cancer Res, 2005). Treatment of the conditional cells with Doxycycline caused a decrease in MLL-AF9/ENL mRNA and protein expression, and resulted in terminal differentiation of the cells. By analysing global changes in gene expression after treatment of cells with Doxycycline we were able to identify a number of potential transcriptional target genes of the MLL-AF9 and MLL-ENL fusion oncogenes.
Project description:We report the application of next-generation RNA and ATAC sequencing technology for high-throughput profiling of MLL-ENL transformed cell lines. According to our results, the C/EBP transcription factors coordinate the expression of the MLL-ENL/Hoxa target genes. Genetic removal of both Cebpa and Cebpb revealed a surrogate function of C/EBPε for myeloid MLL-ENL transformation.
Project description:We report the application of next-generation RNA and ATAC sequencing technology for high-throughput profiling of MLL-ENL transformed cell lines. According to our results, the C/EBP transcription factors coordinate the expression of the MLL-ENL/Hoxa target genes. Genetic removal of both Cebpa and Cebpb revealed a surrogate function of C/EBPε for myeloid MLL-ENL transformation.