Constitutive Stat1HAY701F expression inhibits ATRA-induced growth arrest.
(A) Proliferation of pCIneo, Stat1(HA).7, and Y701F.8 cells after ATRA treatment. The cells were seeded at 150 000 cells/mL and counted on days 1, 2, 3, and 4. Results are shown as percent of uninduced control cells. Mean ± SD (n = 3). (B) DNA synthesis, as determined by the incorporation of 3H-TdR, was measured after 48 hours of ATRA stimulation and correlated to the total cell number. Data for incorporated 3H-TdR per cell are shown. Mean ± SD (n = 3). (C) Cell cycle analysis of U-937 sublines showing the percentage of cells in the S, G2, and M phases during ATRA differentiation. Cells were stimulated by ATRA, collected at the indicated time points, and the distribution of cells in different cell cycle phases was determined by flow cytometry of PI-stained nuclei. Mean ± SD (n = 3-4). The asterisks indicate significant differences to the corresponding pCIneo controls (P < .05).
