β1 integrin regulates cancer cell interaction with ECs. PC3 cells were transfected with the indicated siRNAs. (A) β1 integrin levels were analyzed by FACS. (B–D) Shown is the number of adherent cells on HUVECs (B) or fibronectin-coated dishes (C) for 15 min (D) TEM of PC3 cells. (E and F) Time of intercalation for individual cells. Values (B–F) are means ± SEM expressed as the percentage of the total number of cells (n ≥ 3); *, P < 0.05; **, P < 0.01; ***, P < 0.001; See also Fig. S7.