Effect of imatinib mesylate on responsiveness of 32D_Bcr-Ablwt cells to IL-3 and G-CSF stimulation.

Imatinib mesylate restores responsiveness of 32D_Bcr-Ablwtcells to IL-3 and G-CSF stimulation. (A) The 32Dcl3 and 32D_Bcr-Ablwt cells were grown in the presence or absence of IL-3, G-CSF, and imatinib mesylate as indicated. The amount of apoptosis in the individual cultures after 48 hours was determined by means of FACS analysis. Both IL-3 and G-CSF led to a rescue of apoptosis induced by 1 μM imatinib mesylate in 32D_Bcr-Ablwt cells in the absence of cytokines, suggesting that 32D_Bcr-Ablwt cells express functional IL-3 and G-CSF receptors. (B) Proliferation of 32Dcl3 and 32D_Bcr-Ablwtcells grown in the presence or absence of IL-3, G-CSF, and imatinib mesylate as indicated. Cell counts were determined by trypan blue exclusion. Imatinib mesylate restored the responsiveness of 32D_Bcr-Ablwt cells to both IL-3 and G-CSF. Cell counts of 32D_Bcr-Ablwt cells grown in the presence of 1 μM imatinib mesylate and G-CSF were slightly retarded when compared with the proliferation of 32Dcl3 cells grown in the presence of G-CSF.