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Uptake of radiolabelled modified fragment of human alfa-fetoptrotein by experimental mammary adenocarcinoma: in vitro and in vivo studies
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Abstract
MATERIAL AND METHODS: The 36-amino acid peptide (P149-QY) of 90% homology to 447–480 peptide fragment of hAFP was synthesised and radiolabelled with iodine-125. The biodistribution of P149-Q[125I]-Y was studied in experimental mammary tumours. For in vitro experiments, extract from mouse mammary tumours were prepared and incubated with radioiodinated P149-QY peptide in the presence of a cross-linking reagent.
RESULTS: The gel electrophoresis analysis (SDS-PAGE) showed that radioiodinated P149-QY peptide formed a complex with adenocarcinoma proteins of about 30 kDa. The biodistribution of P149-Q[125I]-Y studied in experimental mammary tumours revealed a higher pharmacokinetic rate in comparison with the whole radioiodinated AFP molecule. A moderate uptake of P149-Q[125I]-Y in the tumour tissue was observed (3.2% ID/g at 30-min p.i.v). However, a faster radioactivity clearance from blood and normal tissues resulted in an increase in the tumour/muscle (T/M) ratio, i.e. from 2.3 to 3.4 after 30 mins and 24 h p.i.v, respectively.
CONCLUSIONS: The present study shows that radioiodinated P149-QY peptide reveals some positive features as the AFP receptor radioligand, however, some additional structural modifications of the initial peptide molecule are necessary for full retention of the ligand-receptor interaction of its radiolabelled forms.
Abstract
MATERIAL AND METHODS: The 36-amino acid peptide (P149-QY) of 90% homology to 447–480 peptide fragment of hAFP was synthesised and radiolabelled with iodine-125. The biodistribution of P149-Q[125I]-Y was studied in experimental mammary tumours. For in vitro experiments, extract from mouse mammary tumours were prepared and incubated with radioiodinated P149-QY peptide in the presence of a cross-linking reagent.
RESULTS: The gel electrophoresis analysis (SDS-PAGE) showed that radioiodinated P149-QY peptide formed a complex with adenocarcinoma proteins of about 30 kDa. The biodistribution of P149-Q[125I]-Y studied in experimental mammary tumours revealed a higher pharmacokinetic rate in comparison with the whole radioiodinated AFP molecule. A moderate uptake of P149-Q[125I]-Y in the tumour tissue was observed (3.2% ID/g at 30-min p.i.v). However, a faster radioactivity clearance from blood and normal tissues resulted in an increase in the tumour/muscle (T/M) ratio, i.e. from 2.3 to 3.4 after 30 mins and 24 h p.i.v, respectively.
CONCLUSIONS: The present study shows that radioiodinated P149-QY peptide reveals some positive features as the AFP receptor radioligand, however, some additional structural modifications of the initial peptide molecule are necessary for full retention of the ligand-receptor interaction of its radiolabelled forms.
Keywords
alfa-fetoprotein; alfa-fetoprotein receptor; P149-QY peptide; radiolabelling; mammary adenocarcinoma
Title
Uptake of radiolabelled modified fragment of human alfa-fetoptrotein by experimental mammary adenocarcinoma: in vitro and in vivo studies
Journal
Issue
Article type
Research paper
Pages
6-10
Published online
2005-06-21
Page views
631
Article views/downloads
895
Bibliographic record
Nucl. Med. Rev 2005;8(1):6-10.
Keywords
alfa-fetoprotein
alfa-fetoprotein receptor
P149-QY peptide
radiolabelling
mammary adenocarcinoma
Authors
Piotr Garnuszek
Rafał Wiercioch
Helena Sztajer
Urszula Karczmarczyk
Marek Mirowski