Fig. 4.

Endocytic pathways of HPMA copolymers containing different functional groups. Cells were pre-incubated with inhibitors for 30 min and 0.2 mg/ml fraction 3 (F3) of copolymers were added and incubation continued for 12 h in the presence of inhibitors. After incubation, cells were analyzed by flow cytometry. The data shown are averages (±SD) of three separate experiments. a) Clathrin-mediated endocytosis. Cells were exposed to CPZ (10 μM). b) Caveolae-mediated endocytosis. Cells were depleted of cholesterol by incubating with serum free medium for 30 min. Subsequently, cells were treated with filipin (2.5 μg/ml; full columns) or mevinolin (10 μM; empty columns) for 30 min prior to exposure to copolymers. c) Dynamin-dependent endocytosis. Cells were pre-incubated with dynasore (80 μM). d) Macropinocytosis. Cells were pre-treated with wortmannin (1 μM; grey columns), amiloride (10 μM; empty columns), or LY 294002 (10 μM; black columns). For molecular weight of F3 fractions see Table 2.