Complementary effects of A1 and pim-1 in the BCR/ABL-mediated transformation of primary BMCs.

(A) A1 and pim-1 rescued transforming capacity of the BCR/ABLΔΔ mutant. Cells were infected with BCR/ABL WT-IRES-GFP (WT-GFP), BCR/ABL ΔΔ-IRES-GFP (ΔΔ-GFP) or with IRES-GFP (GFP) retroviruses. After 3 days in culture GFP⁺cells were isolated and coinfected with retroviruses carrying A1, pim-1, or with equivalent empty retroviruses (E). Groups are: 1, E+E+GFP; 2, A1+E+GFP; 3, E+pim-1+GFP; 4, A1+pim-1+GFP; 5, E+E+WT-GFP; 6, E+E+ΔΔ-GFP; 7, A1+E+ΔΔ-GFP; 8, E+pim-1+ΔΔ-GFP; 9, A1+pim-1+ΔΔ-GFP. (B) Simultaneous inhibition of A1 (by the AS cDNA) and pim-1 (by the dominant-negative K67M mutant) reduced transforming capacity of the BCR/ABL. Cells were infected with BCR/ABL WT-IRES-GFP retrovirus. GFP⁺ cells were coinfected with retroviruses containing A1 AS cDNA(AS), pim-1(K67M) dominant-negative mutant, or with equivalent empty retroviruses (E). Groups are: 1, WT-GFP+E+E; 2, WT-GFP+A1(AS)+E; 3, WT-GFP+E+pim-1(K67M); 4, WT-GFP+A1(AS)+pim-1(K67M). After infection 10⁴ cells were plated in methylcellulose in the absence (−) or presence (+) of the threshold concentration (0.1 U/mL) of murine recombinant IL-3. Results (mean ± SD) are from 3 experiments.