Knockdown of HIF1-α reduces clonogenicity of CML progenitors. (A) Schematic showing the procedure for lentiviral transduction of HIF1-α shRNA vectors. (B) Relative expression of HIF1-α, BNIP3, WT1, HIF2-α, and VEGFA normalized against the housekeeping gene TBP in lentiviral-transduced cells (n = 2). (C) Lentiviral-transduced cells were treated with 21% or 0.5% oxygen, with or without 1 µM imatinib for 96 hours and plated for colony formation. The number of colonies was normalized against the number of cells plated on methylcellulose (1400, 7333, 2100, and 1400 puromycin-selected cells for CML#1, CML#3, CML#4, and CML#5, respectively). The data show the results of 4 independent samples. Colony numbers are indicated on the top of each column.