Analysis of migratory and prosurvival pathways induced by the homeostatic chemokines CCL19 and CCL21 in B-cell chronic lymphocytic leukemia.
OBJECTIVE
The CCR7 chemokine receptor has been reported to promote homing of B-cell chronic lymphocytic leukemia (CLL) cells into lymph nodes and support their survival, but the mechanisms mediating these effects are largely unknown. We investigated the role of different signaling pathways triggered by CCR7 engagement by its ligands, the chemokines CCL19 and CCL21, in the control of CLL migration and survival.


METHODS
Chemotaxis and apoptosis assays were performed in the presence of pharmacologic inhibitors and genetic mutants of the phosphatidylinositol-3-OH kinase (PI3K), Rho guanosine triphosphatase, and mitogen-activated protein kinase (MAPK) signaling cascades to assess the role of these pathways on primary CLL migration and survival in response to CCR7 activation. Kinase activation was determined by immunoblotting and pull-down experiments.


RESULTS
CLL chemotactic activity induced by CCL19 or CCL21 was markedly reduced by inhibitors of PI3K and the Rho effector molecule Rho-associated coiled-coil forming protein kinases (ROCK), and also by the expression of dominant negative forms of PI3K and RhoA, whereas constitutively activated PI3K and RhoA mutants strongly promoted CLL migration. In contrast, MAPKs were not significantly involved in CLL migration to CCL19/CCL21. Conversely, extracellular signal-regulated kinase and c-Jun-N-terminal kinase, along with PI3K, had a role in CCR7-mediated CLL cell survival. Biochemical experiments confirmed that CCL19/21 induced PI3K-dependent phosphorylation of Akt/protein kinase B, activation of the Rho/Rho-associated coiled-coil forming protein kinases/myosin light chain pathway and MAPKs phosphorylation.


CONCLUSIONS
The role of PI3K, Rho guanosine triphosphatases, and MAPKs in CCR7-mediated CLL cells migration and survival suggests that these signal transduction pathways could represent promising targets for CLL therapy.
Cuesta-Mateos
Carlos
C
Department of Immunology, Hospital Universitario de La Princesa, Madrid, Spain.
López-Giral
Sonia
S
Alfonso-Pérez
Manuel
M
de Soria
Valle Gómez García
VG
Loscertales
Javier
J
Guasch-Vidal
Sara
S
Beltrán
Amada Elia
AE
Zapata
Juan M
JM
Muñoz-Calleja
Cecilia
C
D001402:B-Lymphocytes / Q000378:metabolism* / Q000473:pathology; D002470:Cell Survival / Q000187:drug effects; D054415:Chemokine CCL19 / Q000378:metabolism* / Q000494:pharmacology; D054421:Chemokine CCL21 / Q000378:metabolism* / Q000494:pharmacology; D002633:Chemotaxis; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000378:metabolism* / Q000473:pathology; D020935:MAP Kinase Signaling System / Q000187:drug effects; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D054400:Receptors, CCR7 / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D014407:Tumor Cells, Cultured; D020742:rhoA GTP-Binding Protein
C515460:CCL19 protein, human; C515370:CCR7 protein, human; D054415:Chemokine CCL19; D054421:Chemokine CCL21; D054400:Receptors, CCR7; C066737:RHOA protein, human; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D048031:JNK Mitogen-Activated Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D020742:rhoA GTP-Binding Protein