Expression of CBL-Y371H in TF-1 leukemic cell line enhances cytokine-independent as well as cytokine-dependent proliferation.
A, TF-1 cells were retrovirally infected with the vector or the indicated HA-tagged CBL constructs, the GFP+ population sorted and maintained continuously in GM-CSF-containing media. The expression of ectopic CBL constructs was verified using immunoprecipitation of cell lysates with anti-HA antibody. Reactivity with the culture medium-derived IgG heavy chain bands in the lysates provides a loading control. B and C, TF-1 cell lines expressing the indicated CBL constructs were GM-CSF deprived for 24 h, followed by culture in medium without GM-CSF (B) or supplemented with the indicated concentrations of GM-CSF (C). D, TF-1 cell lines expressing the indicated CBL constructs were GM-CSF deprived for 24 h, followed by culture in medium supplemented with the indicated concentrations of SCF. Proliferation was assessed after 72 h, using the Cell TiterGlo assay. B–D, left is one representative experiment with six replicates (mean ± S.D.); right is pooled data of three independent experiment shown as percentage to vector only control (mean ± S.E.). *, p < 0.05.