Growth characteristics of cells expressing gag-akt, RafCAAX, or both, versus the parental H7 cells and versus BCR-ABL.A54 cells.
p210BCR-ABL confers rapid growth of H7 cells in the absence of IL-3, and in medium supplemented with low serum (1% FCS; A top) and in 10% FCS (B; bottom), whereas the combination of gag-akt/RafCAAX, but neither gag-akt nor RafCAAX alone, allows for slower but continuous cell growth. Cells were washed with phosphate-buffered saline and plated at 1 × 106 viable cells/mL, and viability counting (trypan blue) was performed at 24-hour intervals. Note that cells with BCR-ABL rapidly overgrow the supplied medium after reaching plateau viable cell concentrations at 1.5 to 2 × 106 viable cells/mL. These cells subsequently die off after overgrowth. Also, cell lines other than those expressing RafCAAX or coexpressing gag-akt/RafCAAX die off. Slow, continuous cell growth is observed in H7gag-akt/RafCAAX1 in the presence of 10% FCS (B), but viability of these cells is maintained at a stable level in 1% FCS (A). H7RafCAAX cells maintain viability for a prolonged period, but are not capable of proliferation.
