Figure 1.
Association of ST and DT liposomes with HUVECs.
HUVECs (2×104 cells) cultured for 48 h were incubated in the presence of DiIC18-labeled PEG-Lip (○), PRP-PEG-Lip (▴), RGD-PEG-Lip (♦) or Dual-PEG-Lip (•) for 4 h at 37°C. After washing, the amount of liposomes associated with the HUVECs was determined fluorometrically. Association of liposomes is presented as the amount of DiIC18 per cellular protein amount. Data are presented as the mean value and SD. Significant differences: *, P<0.05; **, P<0.01.
Table 1.
Characteristics of the liposomes examined.
Figure 2.
Binding of ST and DT liposomes to the immobilized target molecules of the liposomal ligands.
Liposomes (1 mM as DSPC) dissolved in HBS, pH 7.4, containing surfactant P20 were applied to a Biacore sensor chip, CM5, pre-coated with recombinant human VEGFR-1 (a), integrin αvβ3 (b) or both VEGFR-1 and integrin αvβ3 (c) for 3 min at a flow rate of 20 µl/min. Binding of PEG-Lip (thin solid lines), PRP-PEG-Lip (thick dotted lines), RGD-PEG-Lip (thin dotted lines),or Dual-PEG-Lip (thick solid lines) was evaluated by SPR.
Figure 3.
Biodistribution of ST and DT liposomes in tumor-bearing mice.
Radiolabeled PEG-Lip (open bar), PRP-PEG-Lip (light grey bar), RGD-PEG-Lip (dark grey bar), or Dual-PEG-Lip (closed bar) were injected into Colon26 NL-17-bearing mice (n = 5) via a tail vein at 10 days after the tumor inoculation. At 24 h after the injection, the radioactivity in each organ was determined. Data are shown as a percent of the injected dose per 100 mg tissue and SD. Significant differences: *, P<0.05; **, P<0.01; ***, P<0.001.
Figure 4.
Intratumoral distribution of ST and DT liposomes.
DiI fluorescence-labeled PEG-Lip (a–c), PRP-PEG-Lip (d–f), RGD-PEG-Lip (g–i) or Dual-PEG-Lip (j–l) were intravenously injected into Colon26 NL-17-bearing mice at day 10 after tumor implantation. At 3 h after injection, the tumors were dissected, and then frozen-sections (10-µm thickness) were prepared. Left panels (a, d, g, and j) show the distribution of endothelial cells as visualized by immunostained CD31 (green color); and middle panels (b, e, h, and k), the distribution of the liposomes (red color). Merged images are shown in the right panels (c, f, i, and l). Scale bars represent 20 µm.