Project description:Purpose: The goals of this study are to compare transcriptomes after shutting off the CALM-AF10, MLL-AF10 and MLL-AF9 fusion proteins in mouse AML cells. Furthermore, we also perform transcriptomic experiments to assess the changes in transcripts upon JAK1 deletion in mouse CALM-AF10 AML. Methods: Mouse AMLs cells grown in Mouse leukemia medium (see below) were treated with DMSO (Tet-On) or 4ug/ul Doxycycline (Tet-Off) and RNA was isolated to perform RNA-seq. RNA for CALM-AF10, MLL-AF10 was poly-A selected and MLL-AF9, total RNA was used to make RNAseq libraries using the NEB RNAseq lbrary prep kit. The sequence reads that passed quality filters were analyzed at the transcript isoform level with two methods: Burrows–Wheeler Aligner (BWA) followed by ANOVA (ANOVA) and TopHat followed by Cufflinks. qRT–PCR validation was performed using TaqMan and SYBR Green assays Results: Using an optimized data analysis workflow, we mapped about 20 million sequence reads per sample to the mouse genome (build mm9) and 60 million reads for MLL-AF9 data. Data analysis with BWA and TopHat workflows revealed genes that are significantly changed after shutting off the fusions or after deleting Jak1 in CALM-AF10 Jak1 floxed cells using the Cre recombinase. Conclusions:
Project description:We report the genome wide distribution of the three states of H3K79 methylation (H3K79me1/me2/me3) and H3K27me3 in mouse lineage negative Sca-1 positive Kit positive cells (LSKs), granulocyte macrophage progenitors (GMPs) and LSK derived MLL-AF9 leukemias in the presence or absence of the Af10 OM-LZ domain. Legend- MIT:MSCV-IRES-tdTomato (Empty vector control) and CRE (MIT vector with the Cre recombinase). We examined the H3K79 me1,me2,me3 and H3K27me3 profiles by ChIP-seq in lineage negative Sca-1 positive, Kit positive (LSK) cells, granulocyte macrophage progenitors (GMPs) and bone marrow cells from sacrificed terminally ill secondary MLL-AF9 positive leukemic mice. In case of the MLL-AF9 leukemias, the ChIP-seq experiments were performed in 2 conditions in the presence or absence of the Dot1l interacing octapeptide-motif leucine zipper (OM-LZ) domain of Af10. For the leukemia experiments, leukemias derived from the Af10 OM-LZ homozygous floxed background were transduced with MSCV-IRES-tdTomato control vector (MIT) or its Cre-recombinase expressing counterparts (CRE). Subsequently, we sorted tdTomato positive cells and injected them into sub-lethally irradiated syngenic secondary recipient mice. Seconday leukemias obtained from these MIT or CRE expressing cells were used for ChIP -seq studies.
Project description:Analysis of H3K9me2 level in MLL-AF9 leukemia cells upon deletion of Jmjd1c. Jmjd1c has been shown to be a H3K9me1/2 demethylase and these results provide insight into its role in MLL-Af9 leukemia
Project description:Aberrant Hox gene activation is a recurrent feature in several different types of human leukemia, including leukemias with rearrangements of the mixed lineage leukemia (MLL) gene. In this study, we demonstrate that Hox gene expression is controlled by higher degree H3K79 methylation in acute myeloid leukemia (AML). We show that the deposition of progressive H3K79 methylation states at the genomic loci of critical Hox genes is dependent on the interaction of the H3K79 methyltransferase Dot1l with Af10, a protein that is found in the Dot1l complex isolated from diverse cell types. Furthermore, abrogation of the Dot1l-Af10 interaction reverses aberrant epigenetic profiles found in the leukemia epigenome and impairs the transforming ability of mechanistically distinct AML oncogenes. Primary MLL-AF9 leukemias in the AF10 floxed background (homozygous) were transduced with MSCV-IRES-tdTomato (MIT) or the Cre recombinase expressing MIT vector, cells were sorted and injected into secondary recipient mice to generate Af10 floxed (MIT) or deleted (CRE) leukemias. BM cells fresly harvested from these leukemias were sorted for tdTomato expression and used for microarrays. BM cells from Hoxa9-Meis1 transduced primary leukemias were used for comparison.
Project description:MIR139 is a critical tumor suppressor and commonly silenced in human cancer, including acute myeloid leukemia (AML). Here, we found that depletion of identified MIR139 targets affects AML outgrowth. We unraveled the mechanism of MIR139 gene inactivation in AML expressing the Mixed-Lineage Leukemia (MLL)-AF9 oncogene. Epigenetic analyses revealed two well-conserved putative enhancer regions in close proximity of transcriptional start sites (TSS) of MIR139. These regions were silenced by the Polycomb-Repressive Complex-2 (PRC2) downstream of MLL-AF9. Genomic deletion of these regions abolished MIR139 transcriptional regulation in normal and oncogenic conditions. Genome-wide knockout screens revealed the transcriptional pausing factor of RNA Polymerase-II, POLR2M, as a critical MIR139-silencing factor. Furthermore, direct POLR2M binding to the MIR139 TSS induced paused transcription, which was abrogated upon PRC2 inhibition. We present evidence for an oncogenic POLR2M-mediated MIR139 silencing mechanism, downstream of MLL-AF9 and PRC2. Together, our findings highlight the importance of POLR2M-mediated paused transcription in AML.
Project description:To identify such targets of leukemia-related miRNAs such as miR-196b, we conducted Affymetrix gene arrays of leukemic BM samples from 24 mice including 9 primary (including 3 each of negative control, MLL-AF9, and miR-196b+MLL-AF9) and 15 secondary (including 3 negative control, 6 MLL-AF9, and 6 miR-196b+MLL-AF9) recipient mice
Project description:To identify such targets of leukemia-related miRNAs such as miR-196b, we conducted Affymetrix gene arrays of leukemic BM samples from 24 mice including 9 primary (including 3 each of negative control, MLL-AF9, and miR-196b+MLL-AF9) and 15 secondary (including 3 negative control, 6 MLL-AF9, and 6 miR-196b+MLL-AF9) recipient mice A total of 24 mouse bone marrow samples including 9 primary (including 3 each of negative control, MLL-AF9, and miR-196b+MLL-AF9) and 15 secondary (including 3 negative control, 6 MLL-AF9, and 6 miR-196b+MLL-AF9) obtained from the in vivo mouse bone marrow reconstitution assays were analyzed by use of Affymetrix GeneChip Mouse Gene 1.0 ST Array (Affymetirx, Santa Clara, CA)
Project description:We investigated the role of the transcriptional regulator Id2 in the context of MLL-rearranged acute myeloid leukemia (AML). Using an AML mouse model driven by tet-regulated MLL-AF9 co-expressed with oncogenic NRASG12D (Tet-off MLL-AF9), we demonstrated that MLL-AF9 regulates the E protein pathway by suppressing Id2, while activating the expression of its target E2-2. Moreover, we found that Id2 over-expression in Tet-Off MLL-AF9 AML cells in vitro partially phenocopies MLL-AF9 depletion and results inhibition of leukemia growth, loss of leukemia stem cell-associated gene expression pattern and induction of differentiation. To compare gene expression changes associated with enforced Id2 expression and MLL-AF9 withdrawal, RNA sequencing analysis was performed on Tet-off MLL-AF9 cells transduced with an Id2 over-expressing or a control vector, or upon MLL-AF9 dox-inducible knock-down.