PET of Vascular Endothelial Growth Factor Receptor Expression

MicroPET of ⁶⁴Cu-DOTA-VEGF₁₂₁ in U87MG tumor-bearing mice. (A) Serial microPET scans of large and small U87MG tumor-bearing mice injected intravenously with 5–10 MBq of ⁶⁴Cu-DOTA-VEGF₁₂₁ (∼2–4 μg of VEGF₁₂₁). Mice injected with ⁶⁴Cu-DOTA-VEGF₁₂₁ 30 min after injection of 100 μg VEGF₁₂₁ are also shown (denoted as “Small tumor + block”). (B) Two-dimensional whole-body projection of the 3 mice shown in A at 16 h after injection of ⁶⁴Cu-DOTA-VEGF₁₂₁. Tumors are indicated by arrows.

MicroPET and biodistribution results. (A) Comparison of ⁶⁴Cu-DOTA-VEGF₁₂₁ uptake in small and large U87MG tumors (3 mice per group). (B) Time–activity curves of ⁶⁴Cu-DOTA-VEGF₁₂₁ uptake in the kidney, liver, and muscle (n = 6). (C) Comparison of ⁶⁴Cu-DOTA-VEGF₁₂₁ uptake in small U87MG tumors with those injected previously with 100 μg of VEGF₁₂₁ (3 mice per group). (D) Comparison of ⁶⁴Cu-DOTA-VEGF₁₂₁ uptake in kidneys (n = 6) with those injected previously with 100 μg of VEGF₁₂₁ (n = 3). (E) Biodistribution at 23 h after injection of ⁶⁴Cu-DOTA-VEGF₁₂₁ in mice injected previously with 100 μg of VEGF₁₂₁ (n = 3). (F) Comparison of quantification results obtained from biodistribution and microPET studies (n = 3). (G) Time–activity curves of liver, blood, kidney, and muscle in Sprague–Dawley rats injected with ⁶⁴Cu-DOTA-VEGF₁₂₁ (n = 3). *P < 0.05; **P < 0.01.

Immunofluorescence staining of VEGFR1, VEGFR2, and CD31 for kidney, small U87MG tumor, and large U87MG tumor. For VEGFR1 staining, frozen tissue slices (5-μm thick) were stained with a rabbit antimouse VEGFR1 primary antibody and a Cy3-conjugated donkey antirabbit secondary antibody. For VEGFR2 staining, tissue slices were stained with a rat antimouse VEGFR2 primary antibody and a Cy3-conjugated donkey antirat secondary antibody. For CD31 staining, slices were stained with a rat antimouse CD31 primary antibody and a Cy3-conjugated donkey antirat secondary antibody.