Menin-MLL inhibitors block oncogenic transformation by MLL fusion proteins in a fusion partner independent manner
ABSTRACT: Chromosomal rearrangements of the Mixed Lineage Leukemia (MLL) gene result in fusion proteins which retain the N-terminal portion of MLL fused with one of more than 70 different fusion partners. The high diversity of MLL fusion partners raises a question whether it is possible to develop a general therapeutic strategy to block the oncogenic activity of MLL fusion proteins in a fusion partner independent manner. We have demonstrated that blocking the menin-MLL interaction using small molecule inhibitor inhibits oncogenic activity of different MLL fusion proteins according to a mechanism that is independent on the fusion partner. Overall design: MLL-AF9, MLL-AF6 and MLL-AF1P transformed cells were treated with the menin-MLL inhibitor MI-2-2
Project description:Acute Myeloid Leukemia (AML) with MLL gene rearrangements demonstrate unique gene expression profiles driven by MLL-fusion proteins. Here, we identify the circadian clock transcription factor SHARP1 as a novel oncogenic target in MLL-AF6 AML, which has the worst prognosis among all subtypes of MLL rearranged AMLs. SHARP1 is expressed solely in MLL-AF6 AML, and its expression is regulated directly by MLL-AF6 / DOT1L. Suppression of SHARP1 induces robust apoptosis of human MLL-AF6 AML cells. Genetic deletion in mice delays the development of leukemia and attenuated leukemia-initiating potential, while sparing normal hematopoiesis. Mechanistically, SHARP1 binds to transcriptionally active chromatin across the genome and activates genes critical for cell survival as well as key oncogenic targets of MLL-AF6. Our findings demonstrate the unique oncogenic role for SHARP1 in MLL-AF6 AML. Overall design: ChIP-seq and RNA-seq using ML-2 cells. ChIP-seq using SHI1 cells.
Project description:MLL-fusions represent a large group of leukemia drivers, whose diversity originates from the vast molecular heterogeneity of C-terminal fusion partners of MLL protein. While studies of selected MLL-fusions have revealed critical molecular pathways, unifying mechanisms across all MLL-fusions remain poorly understood. We present the first comprehensive survey of protein-protein interactions of seven distantly related MLL-fusion proteins: MLL-AF1p, MLL-AF4, MLL-AF9, MLL-CBP, MLL-EEN, MLL-ENL and MLL-GAS7.
Project description:Fusion of the N-terminus of the mixed-lineage-leukemia (MLL) gene with various partner genes drives acute lymphoblastic leukemia (ALL). Despite the fusion proteins sharing some common attributes, transcriptome heterogeneity of MLL-fusion ALL is observed and the underlying mechanism and biological consequences are unknown. We compared the genome-wide occupancy of MLL-Af4 and MLL-AF9 in human ALL cells expressing FLAG-tagged fusion proteins. Although both oncoproteins retain the same MLL N-terminal domains that mediate chromatin binding, the two fusion proteins displayed largely non-overlapping binding profiles, with MLL-AF9 showing preferential binding at repetitive elements. The binding specificity of each fusion protein was associated with differential global gene activation distinguishing the two ALLs. A subset of prednisolone response genes were among the differentially regulated targets, and the resistance related genes were specifically upregulated in MLL-Af4/AF4 cells. These studies provide evidence that distinct chromatin occupancy of different MLL-fusion proteins is one driving force for transcriptome heterogeneity of MLL-fusion ALL, which could potentially result in the disparate therapeutic outcome of the disease. Overall design: MLL-AF9 ChIP-seq expreiment has been used in this study
Project description:The purpose of this study is to investigate the transcriptional programs as it relates to disease latency initiated by different MLL fusion proteins, including: MLL-AF1p, MLL-AF6, MLL-Gas7, MLL-AF9 and MLL-ENL. Leukemia cell lines were established by transforming kit+ mouse bone marrow cells with retroviruses coding MLL-AF1p, MLL-AF6, MLL-Gas7, MLL-AF9 or MLL-ENL. At early phase after the cell lines were established, cells growing at exponential phase (cell density at 0.5~1x106/ml) were harvested for RNA extraction and sequencing purpose. Sequencing is performed on total RNA isolated from mouse leukemia cell lines generated from kit+ mouse bone marrow cells transduced with various MLL fusion proteins and is compared to control total RNA isolated from kit+ mouse bone marrow cells.
Project description:Chromosomal translocations affecting Mixed Lineage Leukemia (MLL) gene result in acute leukemias resistant to therapy. The leukemogenic activity of MLL fusion proteins is dependent on their interaction with menin, providing basis for therapeutic intervention. Here we report development of novel, highly potent and orally bioavailable small molecule inhibitors of the menin-MLL interaction, MI-463 and MI-503, show their profound effects in MLL leukemia cells and substantial survival benefit in mice models of MLL leukemia. Finally, we demonstrate efficacy of these compounds in primary samples derived from MLL leukemia patients. Overall, we demonstrate for the first time that pharmacologic inhibition of the menin-MLL interaction represents an effective treatment for MLL leukemias in vivo and provide advanced molecular scaffold for clinical lead identification. Overall design: MV4;11 human MLL leukemia cells were treated with the menin-MLL inhibitor MI-389
Project description:MLL-fusions represent a large group of leukemia drivers, whose diversity originates from the vast molecular heterogeneity of C-terminal fusion partners of MLL. While studies of selected MLL-fusions have revealed critical molecular pathways, unifying mechanisms across all MLL-fusions remain poorly understood. We present the first comprehensive survey of protein-protein interactions of seven distantly related MLL-fusion proteins. Functional investigation of 128 conserved MLL-fusion-interactors identified a specific role for the lysine methyltransferase SETD2 in MLL-leukemia. SETD2 loss caused growth arrest and differentiation of AML cells, and led to increased DNA damage. In addition to its role in H3K36 tri-methylation, SETD2 was required to maintain high H3K79 di-methylation and MLL-AF9 binding to critical target genes, such as Hoxa9. SETD2 loss synergized with pharmacologic inhibition of the H3K79 methyltransferase DOT1L to induce DNA damage, growth arrest, differentiation and apoptosis. These results uncover a dependency for SETD2 during MLL-leukemogenesis, revealing a novel actionable vulnerability in this disease. Overall design: ChIP-Seq with spike in Drosophila Melanogaster chromatin of 3 different histone modifications: H3K4me3, H3K36me3, H3K79me2 after inducible knockdown of Setd2 or Renilla (negative control); RNA-Seq performed after inducible knockdown of Setd2 or Renilla (negative control)
Project description:We retrospectively analyzed AML patients enrolled in the AIEOP since 2000, 42 patients with 11q23 rearrangement were analyzed by gene expression profile Gene expression analyses were performed to compare AML MLL partner genes (AF9, AF10, AF6, ENL, ELL, Septin 6, and AF1q) Keywords: Expression data Class comparison between different AML MLL partner genes
Project description:We retrospectively analyzed AML patients enrolled in the AIEOP since 2000, 42 patients with 11q23 rearrangement were analyzed by gene expression profile Gene expression analyses were performed to compare AML MLL partner genes (AF9, AF10, AF6, ENL, ELL, Septin 6, and AF1q) Keywords: Expression data Overall design: Class comparison between different AML MLL partner genes
Project description:The t(4;11)(q21;q23) fuses MLL to AF4, the most common MLL fusion partner. Here we show that MLL fused to murine Af4, highly conserved with human AF4, produces high-titer retrovirus permitting efficient transduction of human CD34+ cells to generate a faithful model of t(4;11) proB ALL that fully recapitulates the immunophenotypic and molecular aspects of the disease. MLL-Af4 induces a distinct B-ALL from MLL-AF9 through differential DNA binding of the fusion proteins leading to specific gene expression patterns. MLL-Af4 cells can assume a myeloid state under environmental pressure but retain lymphoid-lineage potential. We observed this incongruity in t(4;11) patients who evaded CD19-directed therapy by undergoing myeloid-lineage switch. Our model provides a valuable tool to unravel the pathogenesis of MLL-AF4 leukemogenesis. Overall design: MLL-AF4 ChIP-seq expreiment has been used in this study
Project description:We report the genome wide distribution of H3K79 dimethylation in the human MLL-AF6 rearranged cell line ML2 as well as the human MOLM13 and HL60 cell lines Examination of H3K79 dimethylation in the MLL-AF6 fusion positive human leukemia cell line ML2 and control cell lines MOLM-13 and HL60. The MLL-AF6 positive ML2 cell line (obtained from DSMZ) and the cell lines HL60 and MOLM 13 were grown under standard conditions and 1 million cells were fixed/crosslinked and used for ChIP-seq with H3K79 dimethylation specific antibody Ab3594 (Abcam)