Calcium flux analysis of untransformed and BCR/ABL-transformed hematopoietic cells in response to SDF-1. Analysis of calcium flux of Ba/F3 and BCR/ABL−transformed Ba/F3 cells, as described in Materials and Methods. Ba/F3, Ba/F3.p210^BCR/ABL (panel A, graphs 1 and 1′, respectively), and TonB210.1 (with and without doxycycline, panel B, graphs 1 and 1′) had equal basal levels of calcium fluxes. When SDF-1 (100 ng/mL) was added to Ba/F3 (A, graph 2) and TonB210.1 (without doxycycline; B, graph 2), an increase flux of calcium was observed. Unlike the wild-type Ba/F3 and uninduced TonB210.1, the BCR/ABL-transformed cell line Ba/F3.p210^BCR/ABL (A, graph 2′) and activated BCR/ABL TonB210.1 (with doxycycline; B, graph 2′) showed no calcium flux in response to SDF-1. Similar to the baseline levels of calcium fluxes of Ba/F3 and Ton B210.1, cells that were pretreated with pertussis toxin lacked a response to SDF-1 (A, graph 3 and B, graph 3, respectively). As a positive control for the Ba/F3 and Ba/F3.p210^BCR/ABL cell lines (A, graphs 4 and 4′, respectively), we measured calcium fluxes in response to ionomycin (5 μg/mL). The arrow in each panel represents the time of addition of SDF-1.