Beta1-integrins in part support adhesion and migration of NL CD34+ cells to BM stroma and fibronectin (FN). NL CD34+ cell adhesion /migration is also influenced by chemokines, such as SDF-1alpha. The molecular mechanism(s) underlying integrin and chemokine dependent adhesion and migration of NL CD34+ cells are not known. Preliminary studies from our lab suggest involvement of PI3-kinase and the GTPase Cdc42 in these processes. CML is a stem cell leukemia characterized clinically by premature circulation of a massively expanded malignant CD34+ cell population in the blood. CML is caused by the Bcr/Abl oncogene. Although numerous studies have described alterations in signal pathways induced by Bcr/Abl in cell lines, the mechanism(s) underlying the features characteristic for chronic phase CML are not understood. Our lab has shown that (a) CML CD34+ cells adhere less and migrate more over FN than NL CD34+ cells which is not caused by decreased beta1-integrin expression. (b) In CML, the cell cytoskeleton is constitutively activated which decreases the mobility of integrins in the cell membrane. (c) CML CD34+ cell adhesion nor migration is affected by chemokines, such as SDF-1alpha. (d) GTPases and PI3-K, thought to play a role in NL CD34+ cell adhesion and migration, may be constitutively activated in CML and contribute to the aberrant adhesion and migration of CML CD34+ cells. (e) In CML CD34+ cells we have detected abnormally spliced and potentially dominant negative, isoforms of the focal adhesion kinase Pyk2. (f) Suppression of Bcr/Abl with antisense ODNs reverses these abnormalities and transfer of Bcr/Abl cDNA in cell lines induces these anomalies, strongly suggesting that Bcr/Abl is responsible for decreased integrin mobility and affinity, adhesion and increased migration. These observations support the following hypotheses (l) Engagement of beta1-integrins and stimulation of CXCR4 via SDF-1alpha activates Pyk2- H. This leads to the activation of signal pathways such as PI3-K, which activates the GTPases Cdc42 and Rac2 responsible for adhesion and migration of CD34+ cells. (2) Constitutive phosphorylation and activation of some of these signal molecules as a result of Bcr/Abl in CML HPC underlies the aberrant adhesion and migration seen in CML. We will test these hypotheses in the following specific aims: SA l. Characterize expression and function of Pyk2-H in CD34+ HPC. SA 2. Examine role of Cdc42 and Rac1/2, PI3-K, and Pyk2 in beta1-integrin- and SDF-1alpha mediated adhesion and migration of CD34+ HPC. SA 3. Examine effect of p210-Bcr/Abl on the function and interactions of GTPases, PI3-K, and Pyk2 leading to the decreased adhesion and enhanced migration characteristic of CML.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL049930-08
Application #
6490701
Study Section
Hematology Subcommittee 2 (HEM)
Program Officer
Thomas, John
Project Start
1994-08-01
Project End
2003-12-31
Budget Start
2002-01-01
Budget End
2002-12-31
Support Year
8
Fiscal Year
2002
Total Cost
$277,977
Indirect Cost
Name
University of Minnesota Twin Cities
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
168559177
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
Jongen-Lavrencic, M; Salesse, S; Delwel, R et al. (2005) BCR/ABL-mediated downregulation of genes implicated in cell adhesion and motility leads to impaired migration toward CCR7 ligands CCL19 and CCL21 in primary BCR/ABL-positive cells. Leukemia 19:373-80
Melikova, Sofya; Dylla, Scott J; Verfaillie, Catherine M (2004) Phosphatidylinositol-3-kinase activation mediates proline-rich tyrosine kinase 2 phosphorylation and recruitment to beta1-integrins in human CD34+ cells. Exp Hematol 32:1051-6
Salesse, S; Dylla, S J; Verfaillie, C M (2004) p210BCR/ABL-induced alteration of pre-mRNA splicing in primary human CD34+ hematopoietic progenitor cells. Leukemia 18:727-33
Dylla, Scott J; Deyle, David R; Theunissen, Koen et al. (2004) Integrin engagement-induced inhibition of human myelopoiesis is mediated by proline-rich tyrosine kinase 2 gene products. Exp Hematol 32:365-74
Salesse, Stephanie; Verfaillie, Catherine M (2003) BCR/ABL-mediated increased expression of multiple known and novel genes that may contribute to the pathogenesis of chronic myelogenous leukemia. Mol Cancer Ther 2:173-82
Punzel, Michael; Gupta, Pankaj; Verfaillie, Catherine M (2002) The microenvironment of AFT024 cells maintains primitive human hematopoiesis by counteracting contact mediated inhibition of proliferation. Cell Commun Adhes 9:149-59
Prosper, F; Verfaillie, C M (2001) Regulation of hematopoiesis through adhesion receptors. J Leukoc Biol 69:307-16
Zhao, R C; Jiang, Y; Verfaillie, C M (2001) A model of human p210(bcr/ABL)-mediated chronic myelogenous leukemia by transduction of primary normal human CD34(+) cells with a BCR/ABL-containing retroviral vector. Blood 97:2406-12
Jiang, Y; Prosper, F; Verfaillie, C M (2000) Opposing effects of engagement of integrins and stimulation of cytokine receptors on cell cycle progression of normal human hematopoietic progenitors. Blood 95:846-54
Jiang, Y; Zhao, R C; Verfaillie, C M (2000) Abnormal integrin-mediated regulation of chronic myelogenous leukemia CD34+ cell proliferation: BCR/ABL up-regulates the cyclin-dependent kinase inhibitor, p27Kip, which is relocated to the cell cytoplasm and incapable of regulating cdk2 activity. Proc Natl Acad Sci U S A 97:10538-43

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