HIF-1α silencing inhibits SDF-1-mediated chemotaxis and adhesion to stroma in CLL. (A) SDF-1α-mediated migration of MEC-1 cells is inhibited upon chronic silencing of HIF-1α cells (shHIF-1α) compared with control cells (shCTRL). Where indicated, cells were pretreated with the CXCR4 inhibitor AMD3100 as a control. Data are represented as mean values ± SEM of 3 independent experiments. (B) Cell adhesion of MEC-1 cells to Hs5 stromal cells is inhibited upon chronic silencing of HIF-1α cells (shHIF-1α) compared with control cells (shCTRL). MEC-1 cell adhesion was calculated as the percentage of MEC-1 cells adhering to Hs5 cells over total MEC-1 cells in coculture. Data are represented as mean values ± SEM of triplicates from 1 of 3 experiments with similar results. (C) SDF-1α-mediated migration of primary CLL B cells is inhibited after electroporation with a HIF-1α-targeting oligonucleotide (HIF-1α) compared with control oligonucleotide (CTRL). Data represent mean values ± SEM (n = 10). (D) Primary CLL B cells viability after electroporation with control oligonucleotide (CTRL) or HIF-1α-targeting oligonucleotide (HIF-1α). Data are expressed as percentages of total population and represent mean values ± SEM (n = 14). NT, untreated.