Comparable cell cycle, survival, and drug sensitivity in wild-type and Pik3r1 null cell lines.BCR-ABL- or v-ABL-transformed cells of the indicated genotypes were cultured for 24 hours in either diluent alone (0.1% EtOH) (A), or treated with LY294002 (B) or rapamycin (C), then fixed and stained with propidium iodide to determine DNA content. The percentages of live cells in G₀/G₁, S, and G₂/M stages of cell cycle were calculated using ModFit LT software. (D) The percentages of apoptotic cells under the indicated conditions were assessed by subdiploid DNA content using Cell Quest plots (BD Biosciences, San Diego, CA) of propidium iodide fluorescence. Graphs are representative of at least 3 experiments per condition and at least 3 different cell lines per genotype. (E) Cell lines were retrovirally infected with pMIT or pMIT-Δp85, then cultured in the presence of LY294002 (LY) or EtOH before analysis by FACS 20 hours after infection. The extent of apoptosis in cells with different levels of Thy1.1 expression was determined by Annexin V staining. The number in the upper-right quadrant represents the percentage of dying cells among the population expressing high levels of the Thy1.1 marker.