Figure 5. Inhibition of leukemic cell growth via β-arrestin 2 inhibition.

(A–B) K562 cells (1000 cells per well) were plated in triplicate in methylcellulose and treated with 40 nM of the indicated aptamer chimera. Cells were incubated for 14 days, and then colonies were counted. n = 5 (C) K562 cells were treated with 400 nM, 40 nM or 4 nM of the indicated aptamer constructs. Cells were plated in duplicate and incubated for 14 days, and colonies were counted. n = 4. (D) Mice were infected with the BCR-ABL transgene and allowed to develop CML as described [18]. Leukemic cells were purified from mouse spleens and treated with the indicated aptamer chimeras at 40 nM. Cells were plated triplicate in methylcellulose and incubated for 14 days before colony forming units were counted. n = 5 animals. (E) Blood samples from human patients were collected and enriched for CD34+ leukemia cells. Cells were treated with the indicated aptamer chimeras at 400 nM and plated in triplicate. After a14 day incubation, colonies were counted. n = 4 patients. All p-values generated using one-way ANOVA with Bonferroni correction.