Abstract
ZAP-70 in chronic lymphocytic leukemia (CLL) is associated with enhanced response to microenvironmental stimuli. We analyzed the functional consequences of ZAP-70 ectopic expression in malignant B-cells in a xenograft mouse model of disseminated B-cell leukemia. Mice injected with B-cells expressing ZAP-70 showed a prominently higher infiltration of the bone marrow. In vitro analysis of the response of malignant B-cells to CXCL12, the main attracting chemokine regulating trafficking of lymphocytes to the bone marrow, or to bone marrow stromal cells, revealed that ZAP-70 induces an increased response in terms of signaling and migration. These effects are probably mediated by direct participation of ZAP-70 in CXCL12-CXCR4 signaling since CXCR4 stimulation led to activation of ZAP-70 and downstream signaling pathways, such as MAPK and Akt, whereas ZAP-70 did not alter the expression of the CXCR4 receptor. In addition, subclones of primary CLL cells with high expression of ZAP-70 also showed increased migrative capacity toward CXCL12. Neutralization of CXCR4 with a monoclonal antibody resulted in impaired in vitro responses to CXCL12 and bone marrow stromal cells. We conclude that ZAP-70 enhances the migration of malignant B-cells into the supportive microenvironment found in the bone marrow mainly by enhancing signaling and migration after CXCR4 stimulation.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Animals
-
B-Lymphocytes / metabolism*
-
B-Lymphocytes / pathology
-
Bone Marrow / metabolism*
-
Bone Marrow / pathology
-
Cell Movement*
-
Chemokine CXCL12 / genetics
-
Chemokine CXCL12 / metabolism
-
Humans
-
Jurkat Cells
-
Leukemia, B-Cell / genetics
-
Leukemia, B-Cell / metabolism*
-
Leukemia, B-Cell / pathology
-
Mice
-
Mice, SCID
-
Neoplasm Proteins / genetics
-
Neoplasm Proteins / metabolism*
-
Receptors, CXCR4 / genetics
-
Receptors, CXCR4 / metabolism*
-
Stromal Cells / metabolism
-
Stromal Cells / pathology
-
ZAP-70 Protein-Tyrosine Kinase / genetics
-
ZAP-70 Protein-Tyrosine Kinase / metabolism*
Substances
-
CXCL12 protein, human
-
CXCR4 protein, human
-
CXCR4 protein, mouse
-
Chemokine CXCL12
-
Cxcl12 protein, mouse
-
Neoplasm Proteins
-
Receptors, CXCR4
-
ZAP-70 Protein-Tyrosine Kinase
-
ZAP70 protein, human
-
Zap70 protein, mouse
Grants and funding
This work was supported by a grant from the Instituto de Salut Carlos III, Fondo de Investigaciones Sanitarias (PI 11/00792). N.P is supported by a fellowship from Vall d'Hebron Institut de Recerca. C.C is supported by a grant from Sociedad Española de Hematología y Hemoterapia (SEHH). M.C holds a contract from Ministerio de Economía y Competitividad (MINECO) (RYC-2012-12018), Spain. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.