Raf1 depletion attenuates BCR-ABL–induced leukemogenesis in a murine transfection/transplantation model. Mice transplanted with pMmiR^Raf1–BCR-ABL show delayed onset and slower progression of disease. (A) Raf1 knockdown in BCR-ABL–positive cells prolongs overall survival of mice in a BM transplantation model. Kaplan-Meier plot detailing survival times of mice transplanted with pMmiR^Ctrl–BCR-ABL (n = 23) or pMmiR^Raf1–BCR-ABL (n = 21) in 5 independent experiments. (B) Proportion of leukemic WBCs in the peripheral blood of mice that received transplants at indicated time points (day 15: pMmiR^Ctrl–BCR-ABL n = 10; others n = 9). P value was determined by Student t test. (C) White blood cell counts from peripheral blood of mice that received transplants of one experiment at indicated time points (n = 3 for each group). (D) p53 knockdown in BCR-ABL–positive cells has no significant impact on overall survival in a BM transplantation model. Kaplan-Meier plot detailing survival times of mice transplanted with pMmiR^Ctrl–BCR-ABL (n = 8) or pMmiR^p53–BCR-ABL (n = 8) in 2 independent experiments. (E-F) Target knockdown is durable in a BM transplantation model. qRT PCR (TaqMan) analysis of splenocytes isolated from moribund mice with > 80% EGFP-positive splenocytes. (E) Raf1 and (F) p53 mRNA levels were normalized to the housekeeping gene GAPDH. Values were determined from 2-3 mice per group measured in duplicates.