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Titolo:
In vitro characterization of the influx of 3-[I-125]iodo-L-alpha-methyltyrosine and 2-[I-125]iodo-L-tyrosine into U266 human myeloma cells: Evidence for System T transport
Autore:
Lahoutte, T; Caveliers, V; Dierickx, L; Vekeman, M; Everaert, H; Mertens, J; Bossuyt, A;
Indirizzi:
Free Univ Brussels, Acad Hosp, Dept Nucl Med, B-1090 Jette, Belgium Free Univ Brussels Jette Belgium B-1090 Nucl Med, B-1090 Jette, Belgium Free Univ Brussels, Acad Hosp, Cyclotron Unit, B-1090 Jette, Belgium Free Univ Brussels Jette Belgium B-1090 tron Unit, B-1090 Jette, Belgium
Titolo Testata:
NUCLEAR MEDICINE AND BIOLOGY
fascicolo: 2, volume: 28, anno: 2001,
pagine: 129 - 134
SICI:
0969-8051(200102)28:2<129:IVCOTI>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
AMINO-ACID-TRANSPORT; BRAIN-TUMORS; L-3-IODO-ALPHA-METHYL TYROSINE; PET; SPECT; FLUORODEOXYGLUCOSE; FEASIBILITY; GLIOMA;
Keywords:
3-[I-125]iodo-L-alpha-methyltyrosine; 2-[I-125]iodo-L-tyrosine; tumor imaging; single-photon emission tomography; System T;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
21
Recensione:
Indirizzi per estratti:
Indirizzo: Lahoutte, T Free Univ Brussels, Acad Hosp, Dept Nucl Med, Laarbeeklaan 101, B-1090 Jette, Belgium Free Univ Brussels Laarbeeklaan 101 Jette Belgium B-1090 gium
Citazione:
T. Lahoutte et al., "In vitro characterization of the influx of 3-[I-125]iodo-L-alpha-methyltyrosine and 2-[I-125]iodo-L-tyrosine into U266 human myeloma cells: Evidence for System T transport", NUCL MED BI, 28(2), 2001, pp. 129-134

Abstract

The aim of this study was to investigate the cellular uptake mechanisms responsible for the accumulation of 3-[I-125]iodo-L-alpha -methyltyrosine (I-125-3-IMT) and 2-[I-125]iodo-L-tyrosine (I-125-2-IT), two radiotracers for metabolic tumor imaging, using single-photon emission tomography, into U266human myeloma cancer cells. Time course and concentration dependency of I-125-3-IMT uptake was assessed. Kinetic parameters were calculated using an Eadie Hofstee plot. A set of competitive inhibitors of the main amino acid transport systems was used for the discrimination of the transporters responsible for the uptake of I-125-3-IMT and I-125-2-IT. Protein incorporation of both tracers was determined using acid precipitation. The measured maximum velocity for I-125-3-IMT transport was 4.199 nmol per mg protein 20 s(-1), and the Michaelis constant was 107.9 muM. Addition of 2-aminobicyclo[2,2,1]heptane-2-carboxylic acid (BCH), a competitive inhibitor of System L, reduced the influx by 39.0 +/- 3.3% for I-125-3-IMT and 66.3 +/- 0.9% for I-125-2-IT. The BCH-insensitive influx was further reduced by Tryptophan (Trp)by 43.8 +/- 3.5% for I-125-3-IMT and 15.3 +/- 1.3% for I-125-2-IT. This suggests involvement of System T transport. We measured <2% of radioactivity in the acid precipitable fractions of both tracers with no increase in time. We conclude that the influx of I-125-3-IMT and I-125-2-IT into U266 humanmyeloma cells is mediated by both System L and System T amino acid transporters. The kinetic parameters suggest that elevated plasma levels of aromatic amino acids will reduce I-123-3-IMT uptake in myeloma patients. Both tracers do not enter protein synthesis significantly. (C) 2001 Elsevier Science Inc. All rights reserved.

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Documento generato il 17/09/19 alle ore 22:37:24