Figure 3.

Effects of treatment with As₂O₃, RA, or As₂O₃ + RA on the induction of apoptosis in leukemic cells sorted from the liver of transplanted NM. (A) The percentage of apoptotic cells in the sorted leukemic cells from the NM transplanted with PML-RARα (Left) or PLZF-RARα (Right) leukemic cells and treated as indicated was evaluated by scoring the number of TUNEL-positive cells. The results are expressed as -fold relative to the untreated animals. Mean percentage ± standard deviation (SD) of PML-RARα leukemic apoptotic cells in the liver: UN: 3.3% ± 0.5%; RA: 4.6% ± 0.8%; As₂O₃: 16% ± 4%; and As₂O₃ + RA: 18% ± 4.5%. Mean percentage ± SD of PLZF-RARα leukemic apoptotic cells in the liver: UN: 4% ± 1.1%; RA: 4.4% ± 1.2%; As₂O₃: 7.7% ± 1.5%; and As₂O₃ + RA: 8% ± 1.8%. (B) TUNEL-positive cells (green fluorescence) in sorted leukemic cells from the liver of NM transplanted with PML-RARα or PLZF-RARα cells and treated with As₂O₃ + RA for 3 days. Staining with 4′,6-diamidino-2-phenylindole was performed to reveal nuclei. (×1,000.)