Depletion of HIF-1α does not affect the number of focal contacts and cell spreading.

<p>(A) Two HIF-1α knock down cell clones (c1, c2) and a non-target control shRNA cell clone (shC) were stained for vinculin 24 hrs after normoxic (20% O₂) or hypoxic (1% O₂) incubation. Counting vinculin positive focal contacts showed a higher number of focal contacts in hypoxia in all three cell lines. (B) Flow cytometry analysis of the HIF-1α knock down cell clones c1 and c2 and the non-target control shRNA cell clone (shC) after 24 hrs of normoxia or hypoxia stained with integrin β1 antibodies. (C) Wt, shC, and the HIF-1α knock down cell clones c1 and c2 cells were lysed after 24 hrs of normoxia (20% O₂) or hypoxia (1% O₂). Cell extracts were analysed by Western blots. Note that vinculin and integrin β1 levels are not changed in hypoxia. (D) Cell spreading of the HIF-1α knock down cell clones c1 and c2 and the non-target control shRNA (shC) cell clone in normoxia and hypoxia. Cells were incubated at 20% O₂ and 1% O₂, trypsinised and replated for 20 min. Cells were fixed and stained with phalloidin-FITC and divided into three categories (a: round, barely spread; b: in the course of spreading; c: well spread). The percentage of cells in each category was determined. All three cell lines spread faster under hypoxic conditions. Numbers within the bars indicate the number of cells analysed. ** p<0.01, *** p<0.001. Bars represent mean values±SEM.