ACF impaired stem cell potential and reduced colony formation ability of primary CML cells, but not normal cells. (A) Total (left) or CD34⁺ (right) light-density BMMCs from CML patients or CD34⁺ light-density PBMCs from NHDs (right) were plated in methylcellulose-containing medium and treated as indicated from time 0 of incubation (PBS, vehicle for ACF or IM; DMSO, vehicle for DASA). Colony number was scored after 7 days. Values represent mean ± S.D. of data obtained from experiments performed in duplicate; vs PBS: *P ≤ .05, **P ≤ .01; vs DMSO: #P ≤ .05, ##P ≤ .01. (B-C) Light-density BMMCs from CML patients or light-density PBMCs from NHDs were treated as indicated (PBS, vehicle for ACF or IM; DMSO, vehicle for DASA) and incubated at 0.1% O₂ (LC1). (B) Viable cells from CML patients were counted at day 3 (n = 10) or day 7 (n = 12) of incubation at 0.1%O₂ (LC1). Values represent mean ± S.D.; *P ≤ .05, **P ≤ .01. (C) Cells were transferred from day 7 LC1 to drug-free normoxic LC2 to determine the maintenance of stem cell potential in LC1 via the counting of viable cells at the indicated times of incubation in LC2. Values represent results from single experiments or mean ± S.D. of data obtained in triplicate (CML #8).