Effect of aggretin on HUVEC proliferation and migration. (A) HUVECs (4 × 10⁴/mL) were seeded on 24-well plates. After attachment, cells were treated with indicated concentration of aggretin or aggretin in combination with PD98059 (30 μM), LY294002 (10 μM), or anti–integrin α₂ mAb, A2-IIE10 (50 μg/mL), for 48 hours and then assayed by MTT. Results are expressed as fold of cell proliferation compared to control cells in the absence of serum (M199). Data are presented as mean ± SEM (n = 4). *P < .05 as compared with control (M199). (B) HUVECs (5 × 10⁴/mL) incubated with or without anti–integrin α₂ mAb, A2-IIE10 (AII, 25 μg/ml), were placed in the upper chamber of Transwell containing a gelatin-coated filter membrane. Haptotaxis was conducted by using a collagen-(col, 0.2 μg), aggretin-(agg, 0.6 μg), or BSA-coated (20 μg) filter for 16 hours. After fixation and removal of the nonmigrated cells of the upper filter, cells that migrated to the lower filter membrane were quantified by phase-contrast light microscopy under high-power field (HPF; original magnification × 100). All experiments were conducted in triplicate at least 4 times and similar results were obtained. Data are presented as mean ± SEM (n = 4-5). *P < .05 as compared with the respective control.