The NCOR-HDAC3 co-repressive complex modulates the leukemogenic potential of the transcription factor ERG

The ERG (ETS-related gene) transcription factor is linked to various types of cancer, including leukemia. However, the specific ERG domains and co-factors contributing to leukemogenesis are poorly understood. Drug targeting a transcription factor such as ERG is challenging. Our study reveals the critical role of a conserved amino acid, proline, at position 199, located at the 3' end of the PNT (pointed) domain, in ERG's ability to induce leukemia. P199 is necessary for ERG to promote self-renewal, prevent myeloid differentiation in hematopoietic progenitor cells, and initiate leukemia in mouse models. Here we show that P199 facilitates ERG's interaction with the NCoR-HDAC3 co-repressor complex. Inhibiting HDAC3 reduces the growth of ERG-dependent leukemic and prostate cancer cells, indicating that the interaction between ERG and the NCoR-HDAC3 co-repressor complex is crucial for its oncogenic activity. Thus, targeting this interaction may offer a potential therapeutic intervention

Metabolic adaptation of acute lymphoblastic leukemia to the central nervous system microenvironment depends on Stearoyl CoA desaturase

Metabolic reprogramming is a key hallmark of cancer, but less is known about metabolic plasticity of the same tumor at different sites. Here, we investigated the metabolic adaptation of leukemia in two different microenvironments, the bone marrow and the central nervous system (CNS). We identified a metabolic signature of fatty acid synthesis in CNS leukemia, highlighting stearoyl-CoA desaturase (SCD) as a key player. In vivo SCD overexpression increases CNS disease, whereas genetic or pharmacological inhibition of SCD decreases CNS load. Overall, we demonstrated that leukemic cells dynamically rewire metabolic pathways to suit local conditions and that targeting these adaptations can be exploited therapeutically

An instructive role for Interleukin-7 receptor α in the development of human B-cell precursor leukemia

© The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.Kinase signaling fuels growth of B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Yet its role in leukemia initiation is unclear and has not been shown in primary human hematopoietic cells. We previously described activating mutations in interleukin-7 receptor alpha (IL7RA) in poor-prognosis "ph-like" BCP-ALL. Here we show that expression of activated mutant IL7RA in human CD34+ hematopoietic stem and progenitor cells induces a preleukemic state in transplanted immunodeficient NOD/LtSz-scid IL2Rγnull mice, characterized by persistence of self-renewing Pro-B cells with non-productive V(D)J gene rearrangements. Preleukemic CD34+CD10highCD19+ cells evolve into BCP-ALL with spontaneously acquired Cyclin Dependent Kinase Inhibitor 2 A (CDKN2A) deletions, as commonly observed in primary human BCP-ALL. CRISPR mediated gene silencing of CDKN2A in primary human CD34+ cells transduced with activated IL7RA results in robust development of BCP-ALLs in-vivo. Thus, we demonstrate that constitutive activation of IL7RA can initiate preleukemia in primary human hematopoietic progenitors and cooperates with CDKN2A silencing in progression into BCP-ALL.This work was supported by the Israel Science Foundation (# 1178/12 to S.I.), Children with Cancer (UK) (S.I. and T.E.), Swiss Bridge Foundation (S.I.), WLBH Foundation (S.I.), Waxman Cancer Research Foundation (S.I.), US–Israel Binational Science Foundation, Israeli health ministry ERA-NET program (#CANCER11-FP-127 to S.I.), Hans Neufeld Stiftung, the International Collaboration Grant from the Jacki and Bruce Barron Cancer Research Scholars’ Program, a partnership of the Israel Cancer Research Fund and City of Hope (S.I. grants # 00161), the Nevzlin Genomic Center for Precision Medicine in Schneider Children’s Medical Center of Israel, The European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 813091 (S.I.) and the Israel Childhood Cancer Foundation (S.I.). I.G. was partially supported by Israeli ministry of Immigrant Absorption.info:eu-repo/semantics/publishedVersio

NOTCH1 Signaling Promotes Human T-Cell Acute Lymphoblastic Leukemia Initiating Cell Regeneration in Supportive Niches

Leukemia initiating cells (LIC) contribute to therapeutic resistance through acquisition of mutations in signaling pathways, such as NOTCH1, that promote self-renewal and survival within supportive niches. Activating mutations in NOTCH1 occur commonly in T cell acute lymphoblastic leukemia (T-ALL) and have been implicated in therapeutic resistance. However, the cell type and context specific consequences of NOTCH1 activation, its role in human LIC regeneration, and sensitivity to NOTCH1 inhibition in hematopoietic microenvironments had not been elucidated.We established humanized bioluminescent T-ALL LIC mouse models transplanted with pediatric T-ALL samples that were sequenced for NOTCH1 and other common T-ALL mutations. In this study, CD34(+) cells from NOTCH1(Mutated) T-ALL samples had higher leukemic engraftment and serial transplantation capacity than NOTCH1(Wild-type) CD34(+) cells in hematopoietic niches, suggesting that self-renewing LIC were enriched within the NOTCH1(Mutated) CD34(+) fraction. Humanized NOTCH1 monoclonal antibody treatment reduced LIC survival and self-renewal in NOTCH1(Mutated) T-ALL LIC-engrafted mice and resulted in depletion of CD34(+)CD2(+)CD7(+) cells that harbor serial transplantation capacity.These results reveal a functional hierarchy within the LIC population based on NOTCH1 activation, which renders LIC susceptible to targeted NOTCH1 inhibition and highlights the utility of NOTCH1 antibody targeting as a key component of malignant stem cell eradication strategies

The role of TSLP pathway in the development of B-Cell Acute Lymphoblastic Leukemia

B-Cell precursor acute lymphoblastic leukemia (B-ALL) is the most common malignancy in children. Recently, we and others described a new subtype of the disease, affecting 60% of children with Down Syndrome (DS) and about 10% of patients with sporadic ALL, in which chromosomal rearrangements result in over-expression of the cytokine receptor-like factor 2 (CRLF2) receptor1-4. This over-expression is often accompanied by mutations in additional proteins in the CRLF2 pathway, such as JAK2, a downstream effector in the pathway5-9, and IL7RA, the second subunit in the TSLP receptor10. Based on mutation analyses, aberrant CRLF2 expression was thought to play a causal role in the development of B-ALL. While some data obtained in mouse systems support this assertion2,3,6, no studies have been performed in human cells to ascertain whether or not CRLF2 contributes to B-ALL pathogenesis. Due to the prominent difference between mouse and human B lymphoid development, particularly in the TSLP/IL7 pathways, it is important to study the contribution of activation of the TSLP pathway to the development of B-ALL in human cells. In the research described here, I hypothesized that aberrant expression of CRLF2 in cooperation with secondary mutations in the TSLP pathways contributes to B-ALL initiation.This hypothesis was tested primarily by utilizing cord-blood (CB) hematopoietic-progenitors transduced with a set of lentiviral vectors carrying CRLF2 alone or in combination with JAK2 or IL7RA mutations. Outcome of forced TSLP pathway activation was cell context specific. Expression of CRLF2 in CB hematopoietic-progenitors from a ubiquitous promoter resulted in skewed differentiation towards the myeloid lineage while transcription of the same genes from a B-cell-specific promoter accelerated B-lymphoid differentiation in vitro, underscoring the importance of expressing the genes of interest in the right cellular context for B-ALL pathogenesis.Transduced CB cells were transplanted in NOD/LtSz-scid IL2Rγnull (NSG) mice, which are known to support human B-Cell differentiation. Transplanted cells expressing CRLF2 with mutant IL7RA exhibited population expansion, enhanced B-cell differentiation, and a significant block in differentiation at the pro-pre B-cell stage, resembling the stage of differentiation of leukemic blast cells

The role of TSLP pathway in the development of B-Cell Acute Lymphoblastic Leukemia

B-Cell precursor acute lymphoblastic leukemia (B-ALL) is the most common malignancy in children. Recently, we and others described a new subtype of the disease, affecting 60% of children with Down Syndrome (DS) and about 10% of patients with sporadic ALL, in which chromosomal rearrangements result in over-expression of the cytokine receptor-like factor 2 (CRLF2) receptor1-4. This over-expression is often accompanied by mutations in additional proteins in the CRLF2 pathway, such as JAK2, a downstream effector in the pathway5-9, and IL7RA, the second subunit in the TSLP receptor10. Based on mutation analyses, aberrant CRLF2 expression was thought to play a causal role in the development of B-ALL. While some data obtained in mouse systems support this assertion2,3,6, no studies have been performed in human cells to ascertain whether or not CRLF2 contributes to B-ALL pathogenesis. Due to the prominent difference between mouse and human B lymphoid development, particularly in the TSLP/IL7 pathways, it is important to study the contribution of activation of the TSLP pathway to the development of B-ALL in human cells. In the research described here, I hypothesized that aberrant expression of CRLF2 in cooperation with secondary mutations in the TSLP pathways contributes to B-ALL initiation.This hypothesis was tested primarily by utilizing cord-blood (CB) hematopoietic-progenitors transduced with a set of lentiviral vectors carrying CRLF2 alone or in combination with JAK2 or IL7RA mutations. Outcome of forced TSLP pathway activation was cell context specific. Expression of CRLF2 in CB hematopoietic-progenitors from a ubiquitous promoter resulted in skewed differentiation towards the myeloid lineage while transcription of the same genes from a B-cell-specific promoter accelerated B-lymphoid differentiation in vitro, underscoring the importance of expressing the genes of interest in the right cellular context for B-ALL pathogenesis.Transduced CB cells were transplanted in NOD/LtSz-scid IL2Rγnull (NSG) mice, which are known to support human B-Cell differentiation. Transplanted cells expressing CRLF2 with mutant IL7RA exhibited population expansion, enhanced B-cell differentiation, and a significant block in differentiation at the pro-pre B-cell stage, resembling the stage of differentiation of leukemic blast cells

Islet Specific Wnt Activation in Human Type II Diabetes

The Wnt pathway effector gene TCF7L2 has been linked to type II diabetes, making it important to study the role of Wnt signaling in diabetes pathogenesis. We examined the expression of multiple Wnt pathway components in pancreases from normal individuals and type II diabetic individuals. Multiple members of the Wnt signaling pathway, including TCF7L2, Wnt2b, β-catenin, pGSK3β, TCF3, cyclinD1, and c-myc, were undetectable or expressed at low levels in islets from nondiabetic individuals, but were also upregulated specifically in islets of type II diabetic patients. Culture of pancreatic tissue and islet isolation led to Wnt activation that was reversed by the Wnt antagonist sFRP, demonstrating that Wnt activation in that setting was due to soluble Wnt factors. These data support a model in which the Wnt pathway plays a dynamic role in the pathogenesis of type II diabetes and suggest manipulation of Wnt signaling as a new approach to β-cell-directed diabetes therapy

Cellular and metabolic characteristics of pre-leukemic hematopoietic progenitors with GATA2 haploinsuficiency

Mono-Allelic germline disruptions of the transcription factor GATA2 result in a propensity for developing myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) affecting more than 85% of carriers. How a partial loss of GATA2 functionality enables leukemic transformation occurring years later in life, is unclear. This question is unsolved mainly due to lack of informative models, as Gata2 heterozygote mice do not develop hematologic malignancies. Here we show that two different germline Gata2 mutations (tgERG/GATA2het and tgERG/Gata2L359V) accelerate AML in mice expressing the human hematopoietic stem cell regulator ERG. Analysis of ERG/Gata2het fetal liver and bone marrow derived hematopoietic cells revealed a distinct pre-leukemic phenotype. This was characterized by enhanced transition from stem to progenitor state, increased proliferation, and a striking mitochondrial phenotype, consisting of highly expressed Oxidative- Phosphorylation related gene-sets, elevated oxygen consumption rates, and notably, markedly distorted mitochondrial morphology. Importantly, the same mitochondrial gene-expression signature was observed in human AMLs harboring GATA2 aberrations. Similar to the observations in mice, non-leukemic bone marrows from children with germline GATA2 mutation demonstrated marked mitochondrial abnormalities. Thus, we observed the tumor suppressive effects of GATA2 in two germline Gata2 genetic mouse models. As oncogenic mutations often accumulate with age, Gata2 deficiency mediated priming of hematopoietic cells for oncogenic transformation may explain the earlier occurrence of MDS/AML in patients with GATA2 germline mutation. The mitochondrial phenotype is a potential therapeutic opportunity for prevention of leukemic transformation in these patients

Cellular and metabolic characteristics of pre-leukemic hematopoietic progenitors with GATA2 haploinsuficiency.

Mono-Allelic germline disruptions of the transcription factor GATA2 result in a propensity for developing myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) affecting more than 85% of carriers. How a partial loss of GATA2 functionality enables leukemic transformation occurring years later in life, is unclear. This question is unsolved mainly due to lack of informative models, as Gata2 heterozygote mice do not develop hematologic malignancies. Here we show that two different germline Gata2 mutations (tgERG/GATA2het and tgERG/Gata2L359V) accelerate AML in mice expressing the human hematopoietic stem cell regulator ERG. Analysis of ERG/Gata2het fetal liver and bone marrow derived hematopoietic cells revealed a distinct pre-leukemic phenotype. This was characterized by enhanced transition from stem to progenitor state, increased proliferation, and a striking mitochondrial phenotype, consisting of highly expressed Oxidative- Phosphorylation related gene-sets, elevated oxygen consumption rates, and notably, markedly distorted mitochondrial morphology. Importantly, the same mitochondrial gene-expression signature was observed in human AMLs harboring GATA2 aberrations. Similar to the observations in mice, non-leukemic bone marrows from children with germline GATA2 mutation demonstrated marked mitochondrial abnormalities. Thus, we observed the tumor suppressive effects of GATA2 in two germline Gata2 genetic mouse models. As oncogenic mutations often accumulate with age, Gata2 deficiency mediated priming of hematopoietic cells for oncogenic transformation may explain the earlier occurrence of MDS/AML in patients with GATA2 germline mutation. The mitochondrial phenotype is a potential therapeutic opportunity for prevention of leukemic transformation in these patients