The EOL-1 cell line as an in vitro model for the study of FIP1L1-PDGFRA-positive chronic eosinophilic leukemia.

We recently identified the chimeric kinase FIP1L1-platelet-derived growth factor receptor alpha (PDGFRalpha) as a cause of the hypereosinophilic syndrome and of chronic eosinophilic leukemia. To investigate the role of FIP1L1-PDGFRA in the pathogenesis of acute leukemia, we screened 87 leukemia cell lines for the presence of FIP1L1-PDGFRA. One cell line, EOL-1, expressed the FIP1L1-PDGFRA fusion. Three structurally divergent kinase inhibitors--imatinib (STI-571), PKC412, and SU5614--inhibited the growth of EOL-1 cells. These results indicate that the fusion of FIP1L1 to PDGFRA occurs rarely in leukemia cell lines, but they identify EOL-1 as an in vitro model for the study of FIP1L1-PDGFRA-positive chronic eosinophilic leukemia and for the analysis of small molecule inhibitors of FIP1L1-PDGFRalpha.