Jarid2 Functions as a Tumor Suppressor in Myeloid Neoplasms by Repressing Self-Renewal in Hematopoietic Progenitor Cells
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ABSTRACT: How specific genetic lesions contribute to transformation of non-malignant myeloproliferative neoplasms (MPN) and myelodysplastic syndromes (MDS) to secondary acute myeloid leukemia (sAML) are poorly understood. The JARID2 gene is lost by chromosomal deletions in a proportion of MPN/MDS patients who progress to sAML. In this study, genetic mouse models and patient-derived xenografts (PDX) demonstrated that Jarid2 acts as a tumor suppressor in chronic myeloid disorders. Genetic deletion of Jarid2 either reduced overall survival of MPN, or drove transformation to sAML, depending on the timing and context of co-operating mutations. Mechanistically, Jarid2 recruits PRC2 to epigenetically repress self-renewal pathways in hematopoietic progenitor cells. These studies establish Jarid2 as a bona fide hematopoietic tumor suppressor and highlight new therapeutic targets.
Project description:Myelodysplastic syndromes (MDS) are a heterogenous group of hematopoietic stem cell disorders characterized by dysplastic blood cell formation and peripheral blood cytopenias. Up to 30% of patients with MDS will progress to a highly chemotherapy-resistant secondary acute myeloid leukemia (sAML). We identified mutations in U2AF1 in MDS patients and patients with U2AF1 mutations are at an increased risk of developing sAML. We identified mutations in U2AF1 in patients with MDS and hypothesized that U2AF1 mutations may represent a novel mechanism that could alter gene expression in MDS. To elucidate gene expression changes associated with U2AF1 mutations, we analyzed the global mRNA expression profile obtained from bone marrow CD34+ cells purified from 5 MDS patients with a U2AF1 mutation, 10 MDS patients without a mutation, and 4 normal donors.
Project description:Myelodysplastic syndromes (MDS) are a heterogenous group of hematopoietic stem cell disorders characterized by dysplastic blood cell formation and peripheral blood cytopenias. Up to 30% of patients with MDS will progress to a highly chemotherapy-resistant secondary acute myeloid leukemia (sAML). We identified mutations in U2AF1 in MDS patients and patients with U2AF1 mutations are at an increased risk of developing sAML.
Project description:Transformation of post-myeloproliferative neoplasms into secondary (s) AML exhibit poor clinical outcome. In addition to increased JAK-STAT and PI3K-AKT signaling, post-MPN sAML blast progenitor cells (BPCs) demonstrate increased nuclear β-catenin levels and TCF7L2 (TCF4) transcriptional activity. Knockdown of β-catenin or treatment with BC2059 that disrupts binding of β-catenin to TBL1X (TBL1) depleted nuclear β-catenin levels. This induced apoptosis of not only JAKi-sensitive but also JAKi-persister/resistant post-MPN sAML BPCs, associated with attenuation of TCF4 transcriptional targets MYC, BCL-2 and Survivin. Co-targeting of β-catenin and JAK1/2 inhibitor ruxolitinib (rux) synergistically induced lethality in post-MPN sAML BPCs and improved survival of mice engrafted with human sAML BPCs. Notably, co-treatment with BET protein degrader ARV-771 and BC2059 also synergistically induced apoptosis and improved survival of mice engrafted with JAKi-sensitive or JAKi-persister/resistant post-MPN sAML cells. These preclinical findings highlight potentially promising anti-post-MPN sAML activity of combination of β-catenin and BETP antagonists against post-MPN sAML BPCs.
Project description:Recent studies have shown that epigenetic regulator are mutated in myelodysplastic syndrome (MDS) patients. Ezh2 is frequently mutated in hematopoietic malignant patients, however, the pathophysiological role of Ezh2 mutations has not been elucidated yet. In this study, we examined the function of Ezh2 in murine hematopoietic disease. Ezh2 deleted mice with myeloid malignancies including MDS, Myelodysplasia/myeloneoplasm(MDS/MPN), Myelodysplasia/myeloneoplasm_thrombocytosis(MDS/MPN_TC)
Project description:Rising blast-percentage or secondary (s) AML transformation (sAML) in MPNs leads to JAK inhibitor (JAKi) therapy-resistance and poor survival. Here, we demonstrate that the CDK7 inhibitor (CDK7i) SY-5609 treatment depletes phenotypically-characterized post-MPN-sAML stem/progenitor cells. In the cultured post-MPN sAML SET2 and HEL as well as patient-derived (PD) post-MPN-sAML cells, SY-5609 treatment inhibited growth and induced lethality, while sparing normal cells. RNA-Seq analysis following SY-5609 treatment demonstrated reduced mRNA expressions of MYC, MYB, CDK4/6, PIM1, and CCND1, but increased mRNA levels of CDKN1A and BCL2L1. Mass spectrometry of SY-5609-treated MPN-sAML cells also demonstrated reduced c-Myc, c-Myb, PIM1, and CDK4/6 but increased p21, caspase 9 and BAD protein levels. CRISPR-mediated CDK7 depletion also reduced viability of HEL cells. CyTOF analysis of SY-5609-treated PD, post-MPN-sAML stem/progenitor cells showed reduced c-Myc, CDK6 and PU.1, but increased protein levels of CD11b, p21 and cleaved Caspase 3. Co-treatment with SY-5609 and ruxolitinib was synergistically lethal in HEL, SET2 and PD post-MPN-sAML cells. A CRISPR screen in SET2 and HEL cells revealed BRD4, CBP and p300 as co-dependencies with SY-5609 treatment. Accordingly, co-treatment with SY-5609 and the BETi OTX015 or pelabresib or with the CBP/p300 inhibitor GNE-049 was synergistically lethal in MPN-sAML cells (including those exhibiting TP53 loss). Finally, in the HEL-Luc/GFP xenograft model, compared to each agent alone, co-treatment with SY-5609 and OTX015 reduced post-MPN-sAML burden and improved survival without inducing host toxicity. These findings demonstrate promising preclinical activity of the CDK7i-based combinations with BETi or HATi against advanced-MPNs, including post-MPN-sAML.
Project description:Chronic myeloproliferative neoplasms (MPNs) exhibit a propensity for transformation to secondary acute myeloid leukemia (sAML), for which the underlying mechanisms remain poorly understood, resulting in limited treatment options and dismal clinical outcomes. Here, we performed bulk transcriptome profiling accompanied by single cell RNA-sequencing on CD34+ stem/progenitor cells from serial patient samples obtained at the chronic MPN and sAML phases, identifying aberrantly increased expression of dual-specificity phosphatase 6 (DUSP6) underlying disease transformation. Genetic and pharmacologic targeting of DUSP6 led to inhibition of S6 and JAK/STAT signaling, resulting in potent suppression of cell proliferation, while also reducing inflammatory cytokine production in primary samples. Furthermore, ectopic DUSP6 expression augmented proliferation and mediated JAK2 inhibitor resistance, while DUSP6 inhibition reduced colony-forming potential of JAK2 inhibitor-persistent patient cells. Mechanistically, DUSP6 perturbation dampened S6 signaling via inhibition of RSK1, which we identified as a second indispensable candidate associated with poor clinical outcome. Ectopic expression of DUSP6 in patient-derived xenograft (PDX) models exacerbated disease severity and led to early lethality, whereas DUSP6 knockdown suppressed leukemic engraftment. Finally, pharmacological inhibition of DUSP6 potently and specifically suppressed disease development across Jak2 V617F and MPL W515L MPN mouse models, as well as sAML PDXs, without inducing toxicity in healthy controls. These findings underscore DUSP6 in driving disease transformation and therapeutic resistance, and highlight the DUSP6-RSK1 axis as a novel, druggable pathway in myeloid malignancies.
Project description:Chronic myeloproliferative neoplasms (MPNs) exhibit a propensity for transformation to secondary acute myeloid leukemia (sAML), for which the underlying mechanisms remain poorly understood, resulting in limited treatment options and dismal clinical outcomes. Here, we performed bulk transcriptome profiling accompanied by single cell RNA-sequencing on CD34+ stem/progenitor cells from serial patient samples obtained at the chronic MPN and sAML phases, identifying aberrantly increased expression of dual-specificity phosphatase 6 (DUSP6) underlying disease transformation. Genetic and pharmacologic targeting of DUSP6 led to inhibition of S6 and JAK/STAT signaling, resulting in potent suppression of cell proliferation, while also reducing inflammatory cytokine production in primary samples. Furthermore, ectopic DUSP6 expression augmented proliferation and mediated JAK2 inhibitor resistance, while DUSP6 inhibition reduced colony-forming potential of JAK2 inhibitor-persistent patient cells. Mechanistically, DUSP6 perturbation dampened S6 signaling via inhibition of RSK1, which we identified as a second indispensable candidate associated with poor clinical outcome. Ectopic expression of DUSP6 in patient-derived xenograft (PDX) models exacerbated disease severity and led to early lethality, whereas DUSP6 knockdown suppressed leukemic engraftment. Finally, pharmacological inhibition of DUSP6 potently and specifically suppressed disease development across Jak2 V617F and MPL W515L MPN mouse models, as well as sAML PDXs, without inducing toxicity in healthy controls. These findings underscore DUSP6 in driving disease transformation and therapeutic resistance, and highlight the DUSP6-RSK1 axis as a novel, druggable pathway in myeloid malignancies.
Project description:Chronic myeloproliferative neoplasms (MPNs) exhibit a propensity for transformation to secondary acute myeloid leukemia (sAML), for which the underlying mechanisms remain poorly understood, resulting in limited treatment options and dismal clinical outcomes. Here, we performed bulk transcriptome profiling accompanied by single cell RNA-sequencing on CD34+ stem/progenitor cells from serial patient samples obtained at the chronic MPN and sAML phases, identifying aberrantly increased expression of dual-specificity phosphatase 6 (DUSP6) underlying disease transformation. Genetic and pharmacologic targeting of DUSP6 led to inhibition of S6 and JAK/STAT signaling, resulting in potent suppression of cell proliferation, while also reducing inflammatory cytokine production in primary samples. Furthermore, ectopic DUSP6 expression augmented proliferation and mediated JAK2 inhibitor resistance, while DUSP6 inhibition reduced colony-forming potential of JAK2 inhibitor-persistent patient cells. Mechanistically, DUSP6 perturbation dampened S6 signaling via inhibition of RSK1, which we identified as a second indispensable candidate associated with poor clinical outcome. Ectopic expression of DUSP6 in patient-derived xenograft (PDX) models exacerbated disease severity and led to early lethality, whereas DUSP6 knockdown suppressed leukemic engraftment. Finally, pharmacological inhibition of DUSP6 potently and specifically suppressed disease development across Jak2 V617F and MPL W515L MPN mouse models, as well as sAML PDXs, without inducing toxicity in healthy controls. These findings underscore DUSP6 in driving disease transformation and therapeutic resistance, and highlight the DUSP6-RSK1 axis as a novel, druggable pathway in myeloid malignancies.
Project description:In recent years fatty acid metabolism has gained greater attention in haematological cancers, such as myeloid dysplastic syndrome (MDS) and secondary acute myeloid leukaemia (sAML), and has been implicated in increased proliferation and drug resistance. We have characterised two populations of FACS-sorted MDS/sAML cells - SKK-1LOW and SKK-1HIGH - that retain distinct fatty acid uptake phenotypes that are stable over time. Transcriptomic analysis of SKK-1LOW and SKK-1HIGH confirmed differentially expressed genes. Gene ontology analysis revealed gene expression differences principally in fatty acid transport genes and receptor tyrosine kinases, of which KIT was associated with low fatty acid uptake. SKK-1LOW resembled a leukaemic stem cell sub-population on the level of its immunophenotype and exhibited greater resistance to the hypomethylating agent, azacitadine. Overall, this study sheds new light on the relatively under-characterised SKK-1 cell line, which may be useful for the study of MDS-to-sAML transformation.
Project description:DNMT3A mutations are observed in myeloid malignancies, including myeloproliferative neoplasms (MPN), myelodysplastic syndromes (MDS), and acute myeloid leukemia (AML). Here we investigated the impact of conditional hematopoietic Dnmt3a loss on disease phenotype in primary mice. Dnmt3a ablation led to a lethal, fully penetrant myeloproliferative neoplasm with myelodysplasia (MDS/MPN) characterized by marked, progressive hepatomegaly that was transplantable. We detected expanded stem/progenitor populations in the liver of Dnmt3a-ablated mice. Homing studies showed that Dnmt3a-deleted bone marrow cells preferentially migrated to the liver. Hence, in addition to the established role of Dnmt3a in regulating self-renewal, Dnmt3a regulates tissue tropism and limits myeloid progenitor expansion in vivo.