Effects of oligonucleotides on TGFβ1-induced erythroid differentiation in wild-type K562 cells assayed by hemoglobin staining. Cells at an initial concentration of 0.2 × 106 cells/mL were preincubated for 24 hours with oligonucleotides at a concentration of 50 μmol/L. Cells were then induced with TGFβ1 (25 ng/mL). After 4 days of induction in the continuous presence of (▪) antisense Rb oligonucleotides, (▨) sense Rb oligonucleotides, or (□) buffer, respectively, cells were subjected to hemoglobin staining by the benzidine method, as described in the Materials and Methods. Simultaneously, noninduced cells were incubated with antisense Rb oligonucleotides, sense Rb oligonucleotides, or buffer, respectively, as controls. Two hundred cells from each incubation were counted and the percentage of benzidine-positive cells was determined. Results shown represent the mean values from three separate experiments, bars ± SEM.
