Expression of Aur-A in CD34⁺CD38^low fractions of CML cells and normal hematopoietic progenitor cells, and cytotoxicity of AUR-1 against CD34⁺ CML cells and CD34⁺ normal hematopoietic stem cells. (A) Expression levels of Aur-A mRNA in CD34⁺ cells isolated from BMMCs of patients with CML, CD34⁺ cells isolated from normal BMMCs and CBMCs, and normal PBMCs. Expression levels of Aur-A mRNA in leukemic CD34⁺ cells, normal hematopoietic stem cells, and normal PBMCs were determined using 3 samples of CML BMMCs, 1 sample of normal BMMCs, 2 samples of CBMCs, and 4 samples of normal PBMCs. The level of Aur-A mRNA in normal PBMCs is shown as 1.0 and the expression levels in samples were calculated relative to this value. (B) Representative data of Aur-A mRNA expression in the CD34⁺CD38^low fraction of BMMCs, whole BMMCs, and PBMCs isolated from a patient with CML in chronic phase and PBMCs isolated from 4 healthy individuals. The CD34⁺CD38^low cells were collected using a cell sorter. (C) Representative data of Aur-A mRNA expression in the CD34⁺CD38^low fraction of CBMCs isolated from a normal donor and PBMCs isolated from 4 healthy individuals. The CD34⁺CD38^low cells were collected using a cell sorter. (D) Cytotoxicity of AUR-1 against CD34⁺ leukemia progenitor cells and normal CD34⁺ hematopoietic progenitor cells. The cytotoxicity of AUR-1 against CD34⁺ leukemia cells isolated from 2 HLA-A*0201–positive patients with CML and normal CD34⁺ hematopoietic progenitor cells isolated from an HLA-A*0201–positive cord blood donor was determined by ⁵¹Cr-release assays at E/T ratios of 20:1, 10:1, and 5:1. Expression levels of Aur-A mRNA in samples are also shown.