ZAP-70 enhances migration of malignant B lymphocytes toward CCL21 by inducing CCR7 expression via IgM-ERK1/2 activation

Blood. 2011 Oct 20;118(16):4401-10. doi: 10.1182/blood-2011-01-333682. Epub 2011 Aug 24.

Abstract

ZAP-70 in chronic lymphocytic leukemia (CLL) has been associated with enhanced B-cell receptor (BCR) signaling, survival, and migration. We investigated whether ZAP-70 can directly govern migration and the underlying mechanisms. In the ZAP-70 stably transfected Ramos cell line, IgM stimulation, but no IgD, enhanced phosphorylation of ERK1/2, Akt and Syk, and delayed IgM and CD79b internalization. In contrast, in the Raji cell line, where ZAP-70 was constitutively phosphorylated, ERK1/2, but not Akt, was phosphorylated, suggesting that MAPK pathway mediates ZAP-70 effects. BCR stimulation modulated the expression of CCR7, CXCR4, CXCR5, CD44, CD49d, and CD62L, which were up-regulated in ZAP-70-positive CLL primary subclones. The most dramatic change after BCR engagement in ZAP-70-transfected cells was CCR7 up-regulation, this being impaired by ERK1/2 inhibition and translating into both increased signaling and migration toward CCL21. Primary CLL subclones with high ZAP-70 expression showed increased migration toward CCL21. In conclusion, ZAP-70 ectopic expression led to enhanced BCR signaling after IgM stimulation and increased the expression of CCR7 predominantly via ERK1/2, increasing the response and migration toward CCL21. In primary CLL samples, cellular subsets with high ZAP-70 expression had increased expression of adhesion molecules and chemokine receptors in addition to an enhanced ability to migrate toward CCL21.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • B-Lymphocytes / cytology*
  • B-Lymphocytes / immunology
  • Burkitt Lymphoma / immunology*
  • Cell Line, Tumor
  • Chemokine CCL21 / immunology*
  • Chemotaxis*
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Immunoglobulin M / immunology
  • Leukemia, Lymphocytic, Chronic, B-Cell / immunology*
  • MAP Kinase Signaling System
  • Receptors, CCR7 / genetics
  • Receptors, CCR7 / immunology*
  • Tumor Cells, Cultured
  • ZAP-70 Protein-Tyrosine Kinase / immunology*

Substances

  • Chemokine CCL21
  • Immunoglobulin M
  • Receptors, CCR7
  • ZAP-70 Protein-Tyrosine Kinase
  • ZAP70 protein, human