The broad objectives of this proposal are to understand how the Bcr/Abl protein induces chronic myeloid leukemia (CML), to create improved murine model systems that will facilitate the study of CML, and to develop an experimental framework for identifying and studying genes responsible for related myeloproliferative disorders.
The specific aims outlined below will address how Bcr/Abl induces bone marrow proliferation by activating cytokine-signaling pathways. Normal hematopoiesis is regulated by cytokines, but the hallmark of myeloproliferative disease is autonomous hematopoiesis, a pathology most clearly documented for erythroid progenitors, which form colonies in culture in the absence of erythropoietin (EPO). A prevailing hypothesis to explain the origin of this autonomous hematopoiesis is that somatic mutations arise in post-receptor signaling proteins, deregulating mitogenic pathways normally controlled by cytokine receptor signal transduction. Of the four adult myeloproliferative disorders, CML is the only one for which the activated signaling molecule is known. The CML-specific Bcr/Abl oncoprotein can abrogate growth factor requirements for established cell lines in culture and induce a CML-like myeloproliferative syndrome in mouse models, but which pathways are crucial to disease in vivo is unknown. The observation the EPO-independent erythropoiesis in CML patients requires stem cell factor (SCF), and recent insights into the cooperation of the EPO and SCF receptor pathways, suggest that Bcr/Abl functionally substitutes for the EPOR requirement in the SCF signaling pathway. Preliminary data confirm this by demonstrating that Bcr/Abl expression can rescue erythropoiesis in fetal liver progenitors of mice lacking the EPOR. This system affords a very direct assessment of the role of Bcr/Abl in a defined cytokine pathway. He proposes to determine which disease-related forms of Abl (P210 and P185 Bcr/Abl, Tel/Abl, and v-Abl) will rescue erythropoiesis from fetal liver progenitors and embryonic stem cells from EPOR(-/-) mice, using in vitro hematopoietic colony assays and in vivo reconstitution experiments. Through mutational analysis of Bcr/Abl and strategies for inhibiting the function of downstream signaling molecules, the p.i. will determine which domains of Bcr/Abl mediate signaling and what pathways are critical for rescue of erythropoiesis. He will then extend these studies to determine whether Bcr/Abl will induce myeloid colony formation in mice deficient in the IL-3, GM-CSF, and thrombopoietin receptors. Longer term objectives include expressing Bcr/Abl in ES cells under conditional promoters to develop a breedable strain of mice with regulated Bcr/Abl expression, and identifying genes relevant to other myeloproliferative disorders through expression cDNA cloning.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29CA076418-03
Application #
6124446
Study Section
Pathology B Study Section (PTHB)
Program Officer
Finerty, John F
Project Start
1997-12-02
Project End
2002-11-30
Budget Start
1999-12-01
Budget End
2000-11-30
Support Year
3
Fiscal Year
2000
Total Cost
$87,000
Indirect Cost
Name
Whitehead Institute for Biomedical Research
Department
Type
DUNS #
120989983
City
Cambridge
State
MA
Country
United States
Zip Code
02142
Lensch, M William; Daley, George Q (2004) Origins of mammalian hematopoiesis: in vivo paradigms and in vitro models. Curr Top Dev Biol 60:127-96
Koh, Eugene Y; Chen, Tong; Daley, George Q (2004) Genetic complementation of cytokine signaling identifies central role of kinases in hematopoietic cell proliferation. Oncogene 23:1214-20
Kyba, Michael; Daley, George Q (2003) Hematopoiesis from embryonic stem cells: lessons from and for ontogeny. Exp Hematol 31:994-1006
Perlingeiro, Rita C R; Kyba, Michael; Bodie, Susan et al. (2003) A role for thrombopoietin in hemangioblast development. Stem Cells 21:272-80
Azam, Mohammad; Latek, Robert R; Daley, George Q (2003) Mechanisms of autoinhibition and STI-571/imatinib resistance revealed by mutagenesis of BCR-ABL. Cell 112:831-43
Daley, George Q (2003) From embryos to embryoid bodies: generating blood from embryonic stem cells. Ann N Y Acad Sci 996:122-31
Larson, R A; Daley, G Q; Schiffer, C A et al. (2003) Treatment by design in leukemia, a meeting report, Philadelphia, Pennsylvania, December 2002. Leukemia 17:2358-82
Hoover, Russell R; Mahon, Francois-Xavier; Melo, Junia V et al. (2002) Overcoming STI571 resistance with the farnesyl transferase inhibitor SCH66336. Blood 100:1068-71
Koh, Eugene Y; Chen, Tong; Daley, George Q (2002) Novel retroviral vectors to facilitate expression screens in mammalian cells. Nucleic Acids Res 30:e142
Jena, Nilamani; Deng, Ming; Sicinska, Eva et al. (2002) Critical role for cyclin D2 in BCR/ABL-induced proliferation of hematopoietic cells. Cancer Res 62:535-41

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