0185194 - UJF-V 20000368 RIV GB eng J - Journal Article
Orlova, A. - Sjöström, A. - Lebeda, Ondřej - Lundquist, H. - Tolmachev, V.
Intracellular retention of iodine-125 and astatine-211 labelled epidermal growth factor (EGF) in cultured A431 carcinoma cells.
Nuclear Medicine Communications. Roč. 21, - (2000), s. 577. ISSN 0143-3636. E-ISSN 1473-5628
Institutional research plan: CEZ:AV0Z1048901
Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders
Impact factor: 1.039, year: 2000

The fact, that many tumours over-express receptors to epidermal growth factor (EGF), has led us to considered this molecule in targeted radionuclide therapy. In this study different radiohalogens and labelling methods were applied, the binding pattern and the intracellular retention in carcinoma A431 cells of .sup.125I-EGF, .sup.125I-para-iodo-benzoate-EGF (.sup.125I-PIB-EGF), and .sup.211 At-para-astato-benzoate-EGF (.sup.211At-PAB-EGF), were studied. All labelled molecules bound specifically to the A431 cells. The intracellular retention of radioactivity, after pulse labelling, was found to be about the same for the two iodine labels with biological half-life of 1.5-2h. The astatine label gave a prolonged intracellular retention (biological half-life about 3.5 h) in comparison with radioiodine. Whenthe cells where incubated continuously with the labelled ligands, maximum accumulation was obtained later for the astatine label (about 6h) than for both iodine labels (2-4h).=Since the maximum accumulation is reached when the rate ofbinding is equal to the rate of efflux of degraded conjugate, the shift of the maximum position indicates that the excretion of astatine is slower than iodine labels. In conclusion, the use of non-phenolic linker did not improve intracellular retention of radioactivity. The improved intracellular retention of the astatine might be attributed to binding of radioactive catabolites to cellular proteins.
Permanent Link: http://hdl.handle.net/11104/0081605