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Hopkins BT, Bame E, Bell N, Bohnert T, Bowden-Verhoek JK, Bui M, Cancilla MT, Conlon P, Cullen P, Erlanson DA, Fan J, Fuchs-Knotts T, Hansen S, Heumann S, Jenkins TJ, Marcotte D, McDowell B, Mertsching E, Negrou E, Otipoby KL, Poreci U, Romanowski MJ, Scott D, Silvian L, Yang W, Zhong M. Optimization of novel reversible Bruton's tyrosine kinase inhibitors identified using Tethering-fragment-based screens. Bioorg Med Chem 2019; 27:2905-2913. [PMID: 31138459 DOI: 10.1016/j.bmc.2019.05.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/09/2019] [Accepted: 05/13/2019] [Indexed: 01/06/2023]
Abstract
Since the approval of ibrutinib for the treatment of B-cell malignancies in 2012, numerous clinical trials have been reported using covalent inhibitors to target Bruton's tyrosine kinase (BTK) for oncology indications. However, a formidable challenge for the pharmaceutical industry has been the identification of reversible, selective, potent molecules for inhibition of BTK. Herein, we report application of Tethering-fragment-based screens to identify low molecular weight fragments which were further optimized to improve on-target potency and ADME properties leading to the discovery of reversible, selective, potent BTK inhibitors suitable for pre-clinical proof-of-concept studies.
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Affiliation(s)
- Brian T Hopkins
- Biogen Inc., 225 Binney Street, Cambridge, MA 02142, United States.
| | - Eris Bame
- Biogen Inc., 225 Binney Street, Cambridge, MA 02142, United States
| | - Noah Bell
- Sunesis Pharmaceuticals, Inc., 395 Oyster Point Boulevard, South San Francisco, CA 94080, United States
| | - Tonika Bohnert
- Biogen Inc., 225 Binney Street, Cambridge, MA 02142, United States
| | | | - Minna Bui
- Sunesis Pharmaceuticals, Inc., 395 Oyster Point Boulevard, South San Francisco, CA 94080, United States
| | - Mark T Cancilla
- Sunesis Pharmaceuticals, Inc., 395 Oyster Point Boulevard, South San Francisco, CA 94080, United States
| | - Patrick Conlon
- Biogen Inc., 225 Binney Street, Cambridge, MA 02142, United States
| | - Patrick Cullen
- Biogen Inc., 225 Binney Street, Cambridge, MA 02142, United States
| | - Daniel A Erlanson
- Sunesis Pharmaceuticals, Inc., 395 Oyster Point Boulevard, South San Francisco, CA 94080, United States
| | - Junfa Fan
- Sunesis Pharmaceuticals, Inc., 395 Oyster Point Boulevard, South San Francisco, CA 94080, United States
| | - Tarra Fuchs-Knotts
- Sunesis Pharmaceuticals, Inc., 395 Oyster Point Boulevard, South San Francisco, CA 94080, United States
| | - Stig Hansen
- Sunesis Pharmaceuticals, Inc., 395 Oyster Point Boulevard, South San Francisco, CA 94080, United States
| | - Stacey Heumann
- Sunesis Pharmaceuticals, Inc., 395 Oyster Point Boulevard, South San Francisco, CA 94080, United States
| | - Tracy J Jenkins
- Biogen Inc., 225 Binney Street, Cambridge, MA 02142, United States
| | - Douglas Marcotte
- Biogen Inc., 225 Binney Street, Cambridge, MA 02142, United States
| | - Bob McDowell
- Sunesis Pharmaceuticals, Inc., 395 Oyster Point Boulevard, South San Francisco, CA 94080, United States
| | | | - Ella Negrou
- Biogen Inc., 225 Binney Street, Cambridge, MA 02142, United States
| | - Kevin L Otipoby
- Biogen Inc., 225 Binney Street, Cambridge, MA 02142, United States
| | - Urjana Poreci
- Biogen Inc., 225 Binney Street, Cambridge, MA 02142, United States
| | - Michael J Romanowski
- Sunesis Pharmaceuticals, Inc., 395 Oyster Point Boulevard, South San Francisco, CA 94080, United States
| | - Daniel Scott
- Biogen Inc., 225 Binney Street, Cambridge, MA 02142, United States
| | - Laura Silvian
- Biogen Inc., 225 Binney Street, Cambridge, MA 02142, United States
| | - Wenjin Yang
- Sunesis Pharmaceuticals, Inc., 395 Oyster Point Boulevard, South San Francisco, CA 94080, United States
| | - Min Zhong
- Sunesis Pharmaceuticals, Inc., 395 Oyster Point Boulevard, South San Francisco, CA 94080, United States
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2
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Seo S, Nakamoto T, Takeshita M, Lu J, Sato T, Suzuki T, Kamikubo Y, Ichikawa M, Noda M, Ogawa S, Honda H, Oda H, Kurokawa M. Crk-associated substrate lymphocyte type regulates myeloid cell motility and suppresses the progression of leukemia induced by p210Bcr/Abl. Cancer Sci 2011; 102:2109-17. [PMID: 21848808 DOI: 10.1111/j.1349-7006.2011.02066.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The p210Bcr/Abl and p190Bcr/Abl fusion oncoproteins are known to cause chronic myelogenous leukemia (CML) and acute lymphoblastic leukemia (ALL). Bcr/Abl phosphorylates several proteins that can lead to leukemogenesis. Crk-associated substrate lymphocyte type (Cas-L)/human enhancer of filamentation-1 (HEF1)/neural precursor cell expressed, developmentally down-regulated 9 (NEDD9) is an adapter protein at focal adhesions known to be associated with solid tumor metastasis. Crk-associated substrate lymphocyte type has also been reported to be tyrosine phosphorylated by p190Bcr/Abl. We demonstrated that Cas-L was expressed in murine granulocytes, as well as in lymphocytes, and that Cas-L-deficient (Cas-L(-/-) ) granulocytes had increased migratory activity and decreased adhesiveness. To examine whether Cas-L was involved in leukemogenesis by p210Bcr/Abl, we generated Cas-L(-/-) p210Bcr/Abl transgenic mice. The mice displayed early development of myeloproliferative neoplasm seen in the chronic phase of CML, which resulted in the early death of the mice. Pathologically, increased infiltration of myeloid cells into several tissues was detected in the absence of Cas-L. In a hematopoietic reconstitution assay, Cas-L(-/-) p210Bcr/Abl transgenic cells showed a low population in the spleen, although only their myeloid cell population was normal. Thus, Cas-L seems to regulate the progression of CML in a negative way, presumably by attenuating extramedullary hyperplasia.
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Affiliation(s)
- Sachiko Seo
- Department of Hematology and Oncology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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3
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Yu L, Simonson OE, Mohamed AJ, Smith CIE. NF-kappaB regulates the transcription of protein tyrosine kinase Tec. FEBS J 2009; 276:6714-24. [PMID: 19843184 DOI: 10.1111/j.1742-4658.2009.07385.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The tyrosine kinase expressed in hepatocellular carcinoma (Tec) is a non-receptor protein tyrosine kinase (PTK) that is expressed in hematopoietic cells, such as B and T lymphocytes, myeloid lineage cells and neutrophils. Mutations in the human Btk gene cause X-linked agammaglobulinemia (XLA), but the corresponding mutation in mice results in a much milder defect. However, the combined inactivation of Btk and Tec genes in mice cause a severe phenotype resembling XLA. Tec is involved in the regulation of both B and T lymphocytes, fine-tuning of TCR/BCR signaling, and also activation of the nuclear factor of activated T cells. Previous work has shown that the transcription factors Sp1 and PU.1 can bind and regulate the Tec promoter. In this study, we demonstrate that NF-kappaB is an essential transcription factor for optimal expression of the Tec gene, and identify a unique functionally active NF-kappaB binding site in its promoter. The NF-kappaB subunit p65/RelA directly induced transcriptional activity of the Tec promoter. Moreover, we also found that proteasome inhibitors, including Bortezomib, repress Tec transcription through inactivation of the NF-kappaB signaling pathway. This study, together with our previous findings on the transcriptional regulation of Btk (Bruton's tyrosine kinase) by proteasome inhibitors, provides important insight into the molecular mechanism(s) underlying the role of NF-kappaB in Tec family kinase signaling and lymphocyte development.
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Affiliation(s)
- Liang Yu
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden.
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4
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Enhanced expression of p210BCR/ABL and aberrant expression of Zfp423/ZNF423 induce blast crisis of chronic myelogenous leukemia. Blood 2009; 113:4702-10. [DOI: 10.1182/blood-2007-05-088724] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Abstract
Chronic myelogenous leukemia (CML) is a hematopoietic disorder originating from p210BCR/ABL-transformed stem cells, which begins as indolent chronic phase (CP) but progresses into fatal blast crisis (BC). To investigate molecular mechanism(s) underlying disease evolution, CML-exhibiting p210BCR/ABL transgenic mice were crossed with BXH2 mice that transmit a replication-competent retrovirus. Whereas nontransgenic mice in the BXH2 background exclusively developed acute myeloid leukemia, p210BCR/ABL transgenic littermates developed nonmyeloid leukemias, in which inverse polymerase chain reaction detected 2 common viral integration sites (CISs). Interestingly, one CIS was transgene's own promoter, which up-regulated p210BCR/ABL expression. The other was the 5′ noncoding region of a transcription factor, Zfp423, which induced aberrant Zfp423 expression. The cooperative activities of Zfp423 and p210BCR/ABL were demonstrated as follows: (1) introduction of Zfp423 in p210BCR/ABL transgenic bone marrow (BM) cells increased colony-forming ability, (2) suppression of ZNF423 (human homologue of Zfp423) in ZNF423-expressing, p210BCR/ABL-positive hematopoietic cells retarded cell growth, (3) mice that received a transplant of BM cells transduced with Zfp423 and p210BCR/ABL developed acute leukemia, and (4) expression of ZNF423 was found in human BCR/ABL-positive cell lines and CML BC samples. These results demonstrate that enhanced expression of p210BCR/ABL and deregulated expression of Zfp423/ZNF423 contribute to CML BC.
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5
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Nishida S, Hosen N, Shirakata T, Kanato K, Yanagihara M, Nakatsuka SI, Hoshida Y, Nakazawa T, Harada Y, Tatsumi N, Tsuboi A, Kawakami M, Oka Y, Oji Y, Aozasa K, Kawase I, Sugiyama H. AML1-ETO rapidly induces acute myeloblastic leukemia in cooperation with the Wilms tumor gene, WT1. Blood 2005; 107:3303-12. [PMID: 16380455 DOI: 10.1182/blood-2005-04-1656] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AML1-ETO, a chimeric gene frequently detected in acute myelogenous leukemia (AML), inhibits the differentiation of myeloid progenitors by suppressing genes associated with myeloid differentiation and increases the replating ability of clonogenic myeloid progenitors. However, AML1-ETO alone cannot induce AML and thus additional genetic events are required for the onset of AML. The Wilms tumor gene (WT1), which has been identified as the gene responsible for Wilms tumor, is expressed at high levels in almost all human leukemias. In this study, we have generated transgenic mice (WT1-Tg) that overexpress WT1 in hematopoietic cells to investigate the effects of WT1 on AML1-ETO-associated leukemogenesis. AML1-ETO-transduced bone marrow (BM) cells from WT1-Tg mice exhibited inhibition of myeloid differentiation at more immature stages and higher in vitro colony-forming ability compared with AML1-ETO-transduced BM cells from wild-type mice. Most importantly, all of the mice that received a transplant of AML1-ETO-transduced BM cells from the WT1-Tg mice rapidly developed AML. These results demonstrate that AML1-ETO may exert its leukemogenic function in cooperation with the expression of WT1.
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MESH Headings
- Animals
- Bone Marrow Transplantation/methods
- Cell Differentiation/genetics
- Cell Transformation, Neoplastic/genetics
- Core Binding Factor Alpha 2 Subunit/genetics
- Core Binding Factor Alpha 2 Subunit/metabolism
- Humans
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/metabolism
- Leukemia, Myeloid, Acute/pathology
- Mice
- Mice, Transgenic
- Myeloid Progenitor Cells/metabolism
- Myeloid Progenitor Cells/pathology
- Neoplastic Stem Cells/metabolism
- Neoplastic Stem Cells/pathology
- Oncogene Proteins, Fusion/genetics
- Oncogene Proteins, Fusion/metabolism
- RUNX1 Translocation Partner 1 Protein
- Transduction, Genetic
- WT1 Proteins/genetics
- WT1 Proteins/metabolism
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Affiliation(s)
- Sumiyuki Nishida
- Department of Molecular Medicine, Osaka University Graduate School of Medicine, 1-7, Yamada-Oka, Suita City, Osaka 565-0871, Japan
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6
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Kuribara R, Honda H, Matsui H, Shinjyo T, Inukai T, Sugita K, Nakazawa S, Hirai H, Ozawa K, Inaba T. Roles of Bim in apoptosis of normal and Bcr-Abl-expressing hematopoietic progenitors. Mol Cell Biol 2004; 24:6172-83. [PMID: 15226421 PMCID: PMC434248 DOI: 10.1128/mcb.24.14.6172-6183.2004] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bcr-Abl kinase is known to reverse apoptosis of cytokine-dependent cells due to cytokine deprivation, although it has been controversial whether chronic myeloid leukemia (CML) progenitors have the potential to survive under conditions in which there are limited amounts of cytokines. Here we demonstrate that early hematopoietic progenitors (Sca-1(+) c-Kit(+) Lin(-)) isolated from normal mice rapidly undergo apoptosis in the absence of cytokines. In these cells, the expression of Bim, a proapoptotic relative of Bcl-2 which plays a key role in the cytokine-mediated survival system, is induced. In contrast, those cells isolated from our previously established CML model mice resist apoptosis in cytokine-free medium without the induction of Bim expression, and these effects are reversed by the Abl-specific kinase inhibitor imatinib mesylate. In addition, the expression levels of Bim are uniformly low in cell lines established from patients in the blast crisis phase of CML, and imatinib induced Bim in these cells. Moreover, small interfering RNA that reduces the expression level of Bim effectively rescues CML cells from apoptosis caused by imatinib. These findings suggest that Bim plays an important role in the apoptosis of early hematopoietic progenitors and that Bcr-Abl supports cell survival in part through downregulation of this cell death activator.
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MESH Headings
- Animals
- Apoptosis/physiology
- Benzamides
- Biomarkers
- Bone Marrow Cells/cytology
- Bone Marrow Cells/metabolism
- Cell Line, Tumor
- Cell Survival
- Cells, Cultured
- Cytokines/metabolism
- Enzyme Inhibitors/pharmacology
- Fusion Proteins, bcr-abl/genetics
- Fusion Proteins, bcr-abl/metabolism
- Gene Expression Regulation
- Hematopoietic Stem Cells/cytology
- Hematopoietic Stem Cells/drug effects
- Hematopoietic Stem Cells/physiology
- Humans
- Imatinib Mesylate
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive
- Mice
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Mitogen-Activated Protein Kinases/metabolism
- Piperazines/pharmacology
- Proto-Oncogene Proteins c-bcl-2/genetics
- Proto-Oncogene Proteins c-bcl-2/metabolism
- Pyrimidines/pharmacology
- RNA, Small Interfering/metabolism
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Affiliation(s)
- Ryoko Kuribara
- Department of Hematology, Jichi Medical School, Tochigi, Japan
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7
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Abstract
p210bcr/abl is detected in almost all chronic myelogenous leukemia (CML) patients and a significant number of acute lymphoblastic leukemia (ALL) cases. It is generated by a reciprocal chromosomal translocation, t(9;22) (q34;q11), and the enhanced kinase activity of the protein is believed to be implicated in the pathogenesis of the diseases. To examine its oncogenicity in vivo and to create an animal model for BCR/ABL-positive leukemias, we generated transgenic mice expressing p210bcr/abl driven by the promoter of the mouse tec gene, a cytoplasmic tyrosine kinase preferentially expressed in early hematopoietic progenitors. While the founder mice showed excessive proliferation of lymphoblasts shortly after birth and were diagnosed as ALL, the transgenic progeny reproducibly exhibited marked granulocyte hyperplasia with thrombocytosis after a long latent period, which closely resembles the clinical course of human CML. In addition, to investigate whether loss of p53 would play a role in the transition from chronic phase to blast crisis of CML, we crossmated p210bcr/abl transgenic (BCR/ABLtg/-) mice with p53 heterozygous (p53+/-) mice and generated p210bcr/abl transgenic, p53 heterozygous (BCR/ABLtg/- p53+/-) mice, in which a somatic alteration in the residual p53 allele directly abrogates p53 function. The BCR/ABLtg/- p53+/- mice exhibited rapid proliferation of blast cells and died in a short period compared with their wild-type (BCR/ABL-/- p53+/+), p53 heterozygous (BCR/ABL-/- p53+/-), and p210bcr/abl transgenic (BCR/ABLtg/- p53+/+) littermates. Interestingly, the normal p53 allele was frequently and preferentially lost in the tumor tissues, providing in vivo evidence that acquired loss of p53 contributes to the blastic transformation of p210bcr/abl-expressing hematopoietic cells. Our transgenic mice will be a useful model for investigating oncogenic properties of p210bcr/abl in vivo and will provide insights into the molecular mechanism(s) underlying the progression from chronic phase to blast crisis of CML.
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MESH Headings
- Animals
- Disease Models, Animal
- Female
- Fusion Proteins, bcr-abl/genetics
- Genotype
- Humans
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/etiology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Lymphocyte Activation
- Male
- Mice
- Mice, Transgenic/genetics
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/etiology
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/pathology
- Promoter Regions, Genetic
- Survival Rate
- Tumor Suppressor Protein p53/genetics
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Affiliation(s)
- H Honda
- Third Department of Internal Medicine, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
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8
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Acquired loss of p53 induces blastic transformation in p210bcr/abl-expressing hematopoietic cells: a transgenic study for blast crisis of human CML. Blood 2000. [DOI: 10.1182/blood.v95.4.1144.004k04_1144_1150] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chronic myelogenous leukemia (CML) begins with an indolent chronic phase but inevitably progresses to a fatal blast crisis. Although the Philadelphia chromosome, which generates p210bcr/abl, is a unique chromosomal abnormality in the chronic phase, additional chromosomal abnormalities are frequently detected in the blast crisis, suggesting that superimposed genetic events are responsible for disease progression. To investigate whether loss of p53 plays a role in the evolution of CML, we crossmated p210bcr/abl-transgenic (BCR/ABLtg/−) mice with p53-heterozygous (p53+/−) mice and generated p210bcr/abl-transgenic, p53-heterozygous (BCR/ABLtg/−p53+/−) mice, in which a somatic alteration in the residual normal p53 allele directly abrogates p53 function. TheBCR/ABLtg/−p53+/− mice died in a short period compared with their wild-type (BCR/ABL−/−p53+/+), p53 heterozygous (BCR/ABL−/−p53+/−), and p210bcr/abl transgenic (BCR/ABLtg/−p53+/+) litter mates. They had rapid proliferation of blast cells, which was preceded by subclinical or clinical signs of a myeloproliferative disorder resembling human CML. The blast cells were clonal in origin and expressed p210bcr/abl with an increased kinase activity. Interestingly, the residual normal p53 allele was frequently and preferentially lost in the tumor tissues, implying that a certain mechanism facilitating the loss of p53 allele exists in p210bcr/abl-expressing hematopoietic cells. Our study presents in vivo evidence that acquired loss of p53 contributes to the blastic transformation of p210bcr/abl-expressing hematopoietic cells and provides insights into the molecular mechanism for blast crisis of human CML.
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9
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Development of Acute Lymphoblastic Leukemia and Myeloproliferative Disorder in Transgenic Mice Expressing p210bcr/abl: A Novel Transgenic Model for Human Ph1-Positive Leukemias. Blood 1998. [DOI: 10.1182/blood.v91.6.2067] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractThe Philadelphia (Ph1) chromosome can be detected in chronic myelogenous leukemia (CML) and a significant number of acute lymphoblastic leukemia (ALL) cases. Generation of p210bcr/abl, a chimeric protein with enhanced kinase activity, is thought to be involved in the pathogenesis of these diseases. To elucidate the biological properties of p210bcr/abl and to create an animal model for human Ph1-positive leukemias, we generated transgenic mice expressing p210bcr/abl driven by the promoter of the tec gene, a cytoplasmic tyrosine-kinase preferentially expressed in the hematopoietic lineage. The founder mice showed excessive proliferation of lymphoblasts shortly after birth and were diagnosed as suffering from ALL based on surface marker and Southern blot analyses. Expression and enhanced kinase activity of the p210bcr/abl transgene product were detected in the leukemic tissues. In contrast, transgenic progeny exhibited marked granulocyte hyperplasia with thrombocytosis after a long latent period and developed myeloproliferative disorders (MPDs) closely resembling human CML. Expression of p210bcr/abl mRNA in the proliferating granulocytes was detected by RT-PCR. In particular, one MPD mouse showed remarkable proliferation of blast cells in the lung, which might represent an extramedullar blast crisis. The results demonstrate that the expression of p210bcr/abl in hematopoietic progenitor cells in transgenic mice can contribute to two clinically distinct hematopoietic malignancies, CML and ALL, indicating that this transgenic system provides a novel transgenic model for human Ph1-positive leukemias.
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10
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Development of Acute Lymphoblastic Leukemia and Myeloproliferative Disorder in Transgenic Mice Expressing p210bcr/abl: A Novel Transgenic Model for Human Ph1-Positive Leukemias. Blood 1998. [DOI: 10.1182/blood.v91.6.2067.2067_2067_2075] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Philadelphia (Ph1) chromosome can be detected in chronic myelogenous leukemia (CML) and a significant number of acute lymphoblastic leukemia (ALL) cases. Generation of p210bcr/abl, a chimeric protein with enhanced kinase activity, is thought to be involved in the pathogenesis of these diseases. To elucidate the biological properties of p210bcr/abl and to create an animal model for human Ph1-positive leukemias, we generated transgenic mice expressing p210bcr/abl driven by the promoter of the tec gene, a cytoplasmic tyrosine-kinase preferentially expressed in the hematopoietic lineage. The founder mice showed excessive proliferation of lymphoblasts shortly after birth and were diagnosed as suffering from ALL based on surface marker and Southern blot analyses. Expression and enhanced kinase activity of the p210bcr/abl transgene product were detected in the leukemic tissues. In contrast, transgenic progeny exhibited marked granulocyte hyperplasia with thrombocytosis after a long latent period and developed myeloproliferative disorders (MPDs) closely resembling human CML. Expression of p210bcr/abl mRNA in the proliferating granulocytes was detected by RT-PCR. In particular, one MPD mouse showed remarkable proliferation of blast cells in the lung, which might represent an extramedullar blast crisis. The results demonstrate that the expression of p210bcr/abl in hematopoietic progenitor cells in transgenic mice can contribute to two clinically distinct hematopoietic malignancies, CML and ALL, indicating that this transgenic system provides a novel transgenic model for human Ph1-positive leukemias.
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