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Author

Michal Bar-Natan

Other affiliations: Mount Sinai Hospital, Sheba Medical Center, Harvard University  ...read more
Bio: Michal Bar-Natan is an academic researcher from Icahn School of Medicine at Mount Sinai. The author has contributed to research in topics: Myeloid leukemia & Leukemia. The author has an hindex of 16, co-authored 38 publications receiving 1716 citations. Previous affiliations of Michal Bar-Natan include Mount Sinai Hospital & Sheba Medical Center.

Papers
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Journal ArticleDOI
TL;DR: It is demonstrated that CRLF2 is overexpressed in approximately 15% of adult and high-risk pediatric B-ALL that lack MLL, TCF3, TEL, and BCR/ABL rearrangements, but not in B-all with these rearrangement or other lymphoid malignancies.
Abstract: The prognosis for adults with precursor B-cell acute lymphoblastic leukemia (B-ALL) remains poor, in part from a lack of therapeutic targets. We identified the type I cytokine receptor subunit CRLF2 in a functional screen for B-ALL–derived mRNA transcripts that can substitute for IL3 signaling. We demonstrate that CRLF2 is overexpressed in approximately 15% of adult and high-risk pediatric B-ALL that lack MLL, TCF3, TEL, and BCR/ABL rearrangements, but not in B-ALL with these rearrangements or other lymphoid malignancies. CRLF2 overexpression can result from translocation with the IGH locus or intrachromosomal deletion and is associated with poor outcome. CRLF2 overexpressing B-ALLs share a transcriptional signature that significantly overlaps with a BCR/ABL signature, and is enriched for genes involved in cytokine receptor and JAK-STAT signaling. In a subset of cases, CRLF2 harbors a Phe232Cys gain-of-function mutation that promotes constitutive dimerization and cytokine independent growth. A mutually exclusive subset harbors activating mutations in JAK2. In fact, all 22 B-ALLs with mutant JAK2 that we analyzed overexpress CRLF2, distinguishing CRLF2 as the key scaffold for mutant JAK2 signaling in B-ALL. Expression of WT CRLF2 with mutant JAK2 also promotes cytokine independent growth that, unlike CRLF2 Phe232Cys or ligand-induced signaling by WT CRLF2, is accompanied by JAK2 phosphorylation. Finally, cells dependent on CRLF2 signaling are sensitive to small molecule inhibitors of either JAKs or protein kinase C family kinases. Together, these findings implicate CRLF2 as an important factor in B-ALL with diagnostic, prognostic, and therapeutic implications.

314 citations

Journal ArticleDOI
24 Mar 2011-Blood
TL;DR: Targeting STAT5 with pimozide and the kinase inhibitors imatinib or nilotinib shows enhanced effects in inhibiting STAT5 phosphorylation and in inducing apoptosis, suggesting that targeting STAT5 may be an effective strategy for the treatment of CML and other myeloproliferative diseases.

264 citations

Journal ArticleDOI
11 Jan 2019-Leukemia
TL;DR: The poor risk associated with CK-MDS is driven by its association with prognostically adverse TP53 mutations and can be refined by considering clinical and karyotype features.
Abstract: Risk stratification is critical in the care of patients with myelodysplastic syndromes (MDS). Approximately 10% have a complex karyotype (CK), defined as more than two cytogenetic abnormalities, which is a highly adverse prognostic marker. However, CK-MDS can carry a wide range of chromosomal abnormalities and somatic mutations. To refine risk stratification of CK-MDS patients, we examined data from 359 CK-MDS patients shared by the International Working Group for MDS. Mutations were underrepresented with the exception of TP53 mutations, identified in 55% of patients. TP53 mutated patients had even fewer co-mutated genes but were enriched for the del(5q) chromosomal abnormality (p 10%), abnormal 3q, abnormal 9, and monosomy 7 as having the greatest survival risk. The poor risk associated with CK-MDS is driven by its association with prognostically adverse TP53 mutations and can be refined by considering clinical and karyotype features.

156 citations

Journal ArticleDOI
TL;DR: Pimozide reduces the tumor burden in a mouse model of FLT3-driven AML and may provide a new avenue for the treatment of AML, and these may be effective alone or in combination with tyrosine kinase inhibitors.
Abstract: Activation of the transcription factor STAT5 is essential for the pathogenesis of acute myelogenous leukemia (AML) containing the FLT3 internal tandem duplication (ITD) mutation. FLT3 ITD is a constitutively active tyrosine kinase that drives the activation of STAT5, leading to the growth and survival of AML cells. Although there has been some success in identifying tyrosine kinase inhibitors that block the function of FLT3 ITD, there remains a continued need for effective treatment of this disease. We have identified the psychotropic drug pimozide as an effective inhibitor of STAT5 function. Pimozide inhibits the tyrosine phosphorylation of STAT5, leading to the death of AML cells through the induction of apoptosis. Pimozide shows a combinatorial effect with the tyrosine kinase inhibitors midostaurin (PKC412) and sunitinib in the inhibition of STAT5 tyrosine phosphorylation and the induction of apoptosis. Significantly, pimozide reduces the tumor burden in a mouse model of FLT3-driven AML. Therefore, identifying STAT5 inhibitors may provide a new avenue for the treatment of AML, and these may be effective alone or in combination with tyrosine kinase inhibitors.

96 citations


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TL;DR: This manuscript focuses on the NCCN Guidelines Panel recommendations for the workup, primary treatment, risk reduction strategies, and surveillance specific to DCIS.
Abstract: Ductal carcinoma in situ (DCIS) of the breast represents a heterogeneous group of neoplastic lesions in the breast ducts. The goal for management of DCIS is to prevent the development of invasive breast cancer. This manuscript focuses on the NCCN Guidelines Panel recommendations for the workup, primary treatment, risk reduction strategies, and surveillance specific to DCIS.

1,545 citations

Journal ArticleDOI
TL;DR: Treatments that target the IL-6/JAK/STAT3 pathway in patients with cancer are poised to provide therapeutic benefit by directly inhibiting tumour cell growth and by stimulating antitumour immunity.
Abstract: The IL-6/JAK/STAT3 pathway is aberrantly hyperactivated in many types of cancer, and such hyperactivation is generally associated with a poor clinical prognosis In the tumour microenvironment, IL-6/JAK/STAT3 signalling acts to drive the proliferation, survival, invasiveness, and metastasis of tumour cells, while strongly suppressing the antitumour immune response Thus, treatments that target the IL-6/JAK/STAT3 pathway in patients with cancer are poised to provide therapeutic benefit by directly inhibiting tumour cell growth and by stimulating antitumour immunity Agents targeting IL-6, the IL-6 receptor, or JAKs have already received FDA approval for the treatment of inflammatory conditions or myeloproliferative neoplasms and for the management of certain adverse effects of chimeric antigen receptor T cells, and are being further evaluated in patients with haematopoietic malignancies and in those with solid tumours Novel inhibitors of the IL-6/JAK/STAT3 pathway, including STAT3-selective inhibitors, are currently in development Herein, we review the role of IL-6/JAK/STAT3 signalling in the tumour microenvironment and the status of preclinical and clinical investigations of agents targeting this pathway We also discuss the potential of combining IL-6/JAK/STAT3 inhibitors with currently approved therapeutic agents directed against immune-checkpoint inhibitors

1,528 citations

Journal ArticleDOI
02 Jul 2015-Blood
TL;DR: The nature and prevalence of CHIP, distinction of this state from MDS, and current areas of uncertainty regarding diagnostic criteria for myeloid malignancies are discussed.

1,412 citations

Journal ArticleDOI
TL;DR: The Janus kinase (JAK)-signal transducer of activators of transcription (STAT) pathway is now recognized as an evolutionarily conserved signaling pathway employed by diverse cytokines, interferons, growth factors, and related molecules.
Abstract: The Janus kinase (JAK)–signal transducer of activators of transcription (STAT) pathway is now recognized as an evolutionarily conserved signaling pathway employed by diverse cytokines, interferons, growth factors, and related molecules. This pathway provides an elegant and remarkably straightforward mechanism whereby extracellular factors control gene expression. It thus serves as a fundamental paradigm for how cells sense environmental cues and interpret these signals to regulate cell growth and differentiation. Genetic mutations and polymorphisms are functionally relevant to a variety of human diseases, especially cancer and immune-related conditions. The clinical relevance of the pathway has been confirmed by the emergence of a new class of therapeutics that targets JAKs.

995 citations

Journal ArticleDOI
TL;DR: As epigenetic drugs target the epigenome as a whole, these true 'genomic medicines' lessen the need for precision approaches to individualized therapies.
Abstract: Next-generation sequencing has revealed that more than 50% of human cancers harbour mutations in enzymes that are involved in chromatin organization. Tumour cells not only are activated by genetic and epigenetic alterations, but also routinely use epigenetic processes to ensure their escape from chemotherapy and host immune surveillance. Hence, a growing emphasis of recent drug discovery efforts has been on targeting the epigenome, including DNA methylation and histone modifications, with several new drugs being tested and some already approved by the US Food and Drug Administration (FDA). The future will see the increasing success of combining epigenetic drugs with other therapies. As epigenetic drugs target the epigenome as a whole, these true 'genomic medicines' lessen the need for precision approaches to individualized therapies.

837 citations