Calpe Eva, Purroy Noelia, Carpio Cecilia, Abrisqueta Pau, Carabia Júlia, Palacio Carles, Castellví Josep, Crespo Marta, Bosch Francesc
Laboratory of Experimental Hematology, Department of Hematology, Vall d'Hebron University Hospital, Universitat Autònoma de Barcelona, Barcelona, Spain.
PLoS One. 2013 Dec 3;8(12):e81221. doi: 10.1371/journal.pone.0081221. eCollection 2013.
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.
ZAP-70在慢性淋巴细胞白血病（CLL）中与对微环境刺激的反应增强有关。我们在播散性B细胞白血病的异种移植小鼠模型中分析了ZAP-70在恶性B细胞中异位表达的功能后果。注射表达ZAP-70的B细胞的小鼠骨髓浸润明显更高。对恶性B细胞对CXCL12（调节淋巴细胞向骨髓迁移的主要趋化因子）或骨髓基质细胞反应的体外分析表明，ZAP-70在信号传导和迁移方面诱导了增强的反应。这些效应可能是由ZAP-70直接参与CXCL12-CXCR4信号传导介导的，因为CXCR4刺激导致ZAP-70和下游信号通路（如MAPK和Akt）的激活，而ZAP-70并未改变CXCR4受体的表达。此外，ZAP-70高表达的原发性CLL细胞亚克隆对CXCL12的迁移能力也增强。用单克隆抗体中和CXCR4导致对CXCL12和骨髓基质细胞的体外反应受损。我们得出结论，ZAP-70主要通过增强CXCR4刺激后的信号传导和迁移，增强恶性B细胞向骨髓中支持性微环境的迁移。
