Abstract | UNLABELLED: METHODS:
DNA encoding hnTf, peptide linker (GGGGS)(3), and VEGF(165) genes were cloned into the Pichia pastoris vector pPICZalphaB to generate the pPICZalphaB-hnTF- VEGF plasmid. The expression vector was transformed into P. pastoris KM71H strain. The protein was purified using Co(2+) metal affinity resin. The growth-stimulatory effects of hnTf- VEGF on human umbilical vascular endothelial cells (HUVECs) and its binding to porcine aortic endothelial cells (PAECs) transfected with VEGF receptors were evaluated. hnTf- VEGF protein was labeled with (111)InCl(3) in 10 mmol/L HEPES/15 mmol/L NaHCO(3) buffer, pH 7.4 ( HEPES is N-(2-hydroxyethyl) piperazine-N'-(2- ethanesulfonic acid). The loss of (111)In in vitro from (111)In-hnTf- VEGF to transferrin in human plasma and to diethylenetriaminepentaacetic acid ( DTPA) in buffer was determined. Tumor and normal tissue distributions of (111)In-hnTf- VEGF were evaluated in athymic mice implanted subcutaneously with U87MG human glioblastoma xenografts. Tumor imaging was performed. RESULTS:
Sodium dodecylsulfate-polyacrylamine gel electrophoresis under reducing and nonreducing conditions showed bands for hnTf- VEGF monomer (M(r) of 65 kDa) and dimer (M(r) of 130 kDa). hnTf- VEGF stimulated the growth of HUVECs 3-fold and demonstrated binding to PAECs displaced by a 50-fold excess of VEGF(165) but not by apotransferrin. There was 21.3% +/- 3.4% loss of (111)In per day from (111)In-hnTf-VEGF to transferrin in plasma, but <5% loss to DTPA over 4 h. (111)In-hnTf-VEGF accumulated in U87MG tumors (6.7% injected dose per gram at 72 h after injection) and its tumor uptake decreased 15-fold by coadministration of a 100-fold excess of VEGF but not by apotransferrin. The tumor-to-blood ratio was 4.9:1 at 72 h after injection and tumors were imaged at 24-72 h after injection. CONCLUSION:
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Authors | Conrad Chan, Jasbir Sandhu, Abhijit Guha, Deborah A Scollard, Judy Wang, Paul Chen, Karen Bai, Lydia Lee, Raymond M Reilly |
Journal | Journal of nuclear medicine : official publication, Society of Nuclear Medicine
(J Nucl Med)
Vol. 46
Issue 10
Pg. 1745-52
(Oct 2005)
ISSN: 0161-5505 [Print] United States |
PMID | 16204726
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)
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Chemical References |
- Indium Radioisotopes
- Radiopharmaceuticals
- Recombinant Fusion Proteins
- Transferrin
- VEGFA protein, human
- Vascular Endothelial Growth Factor A
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Topics |
- Animals
- Binding Sites
- Cell Line, Tumor
- Female
- Glioblastoma
(blood supply, diagnostic imaging, metabolism)
- Humans
- Indium Radioisotopes
(chemistry, pharmacokinetics)
- Metabolic Clearance Rate
- Mice
- Mice, Nude
- Neovascularization, Pathologic
(diagnostic imaging, metabolism)
- Organ Specificity
- Protein Binding
- Radionuclide Imaging
- Radiopharmaceuticals
(pharmacokinetics)
- Recombinant Fusion Proteins
(chemistry, pharmacokinetics)
- Tissue Distribution
- Transferrin
(chemistry, genetics, pharmacokinetics)
- Vascular Endothelial Growth Factor A
(chemistry, genetics, pharmacokinetics)
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