BCR-ABL antiapoptotic signaling is dramatically different in ES-derived hematopoietic progenitors compared with BaF3 cells.
(A) Major antiapoptotic signaling molecules regulated by BCR-ABL expression in the pro-B BaF3 cell line are not in ES-derived hematopoietic progenitors. ES-derived hematopoietic progenitor and BaF3 cell lysates expressing BCR-ABL and control samples were prepared and equivalent protein amounts were immunoblotted with site-specific phospho-antibodies and total protein antibodies for STAT5 and AKT. IL-3–stimulated BaF3 cell lysates were included as positive controls for STAT5 and AKT activation. The levels of BCL-2 and BCR-ABL were measured with their respective antibodies, and for BCR-ABL activity a total phosphotyrosine antibody was used. Each molecular pathway was examined twice from 2 independent experiments with identical results. (B) BCL-XL is up-regulated on BCR-ABL induction in both ES-derived hematopoietic progenitors and BaF3 cells. Conditions are identical to panel A, with a BCL-XL antibody. This molecular pathway was analyzed 3 times from 3 separate experiment samples with identical results.
