Transcript L - ULB

Preload and afterload with L-amino acids to
enhance the differentiation between tumor and
inflammation by labelled amino acids PET imaging
Laïque Salma [1], Egrise Dominique [1], Lemaire Christian [2], Monclus Michel [1], Schmitz Frédéric [1], Luxen André [2], Goldman Serge [1]
[1]
PET/Biomedical Cyclotron Unit, ULB, Hopital Erasme, Route de Lennik 808, 1070 Anderlecht, BELGIUM
[2] Cyclotron Research Center, ULG, B 30 Building, 4000 Liège, BELGIUM
Aim : Among labelled amino-acids, FET and FT are transported across the cellular membrane by the exchanger l–system. In vitro
utilisation of FET and FT, after preload or prior to postload of non-radioactive L-amino-acids, was evaluated to measure the effects
of intra- and extra cellular amino-acid content on the differential tracers uptake in tumor (ROS 17/2.8) and inflammatory cells (human
leukocytes).
FET : O-(2-[18F] fluoroethyl)-L-Tyrosine :
not incorporated into proteins
HO
O
NH2
FT : 2-[18F] fluoro-L-Tyrosine :
incorporated into proteins
HO
O
NH2
O
F
Figure 1 : principle of PET
Scan imaging
OH
Figure 2 : FDG-PET revealing, an
inflammatory lesion in the
mediastinum, in a patient suffering
from sarcoidosis
F
FET Chemistry (1):
FT Chemistry (2) :
FET Biology :
FT Biology : L-tyrosine preload prior to FT administration on ROS 17/2.8 : figure 5
L-tyrosine preload prior to FET administration on ROS 17/2.8 and leukocytes : figure 3
Figure 5 : preload effect = ratio between the tracer uptake into
preloaded cells and control cells
Figure 3 : preload effect = ratio between the tracer uptake
into preloaded cells and control cells
L-methionine preload prior to FET administration on ROS 17/2.8 and leukocytes : figure 4
Conclusions : L–tyrosine preload, prior to FET administration, can help in the
differentiation between tumours and inflammatory lesions : see figure 6
Figure 4 : preload effect = ratio between the tracer
uptake into preloaded cells and control cells
Figure 6 : tracer uptake = % of loaded activity
L-phenylalanine load after FET administration on ROS 17/2.8 and leukocytes : table 1
References :
(1) Wester HJ, Herz M, Weber W, Heiss P, Senekowitsh-Schmidtke R, Schwaiger M, Stöcklin G.
Synthesis and radiopharmacology of O-(2-[18F]fluoroethyl)-L-tyrosine for tumor imaging. The Journal of
Nuclear Medecine (1999), 40 (1) : 205-212.
(2) Lemaire C, Gillet S, Guillouet S, Plenevaux A, Aerts J, Luxen A.
Highly enantioselective synthesis of no-carrier-added 6-[18F]fluoro-L-dopa by chiral phase transfer
alkylation. European Journal of Organic Chemistry (2004), (13) : 2899-2904.
(3) Ooi Takashi, Takeuchi Mifune, Kameda Minoru, Maruoka Keiji.
Practical catalytic enantioselective synthesis of a a -dialkyl-a-amino acids by chiral phase-transfer
catalysis. Journal of the American Chemical Society (2000), 122 (21) : 5228-5229.
Contact :  : [email protected]
: 0032-2-555.47.11
Table 1 : differenciation between ROS 17/2.8 and leukocytes = ratio
between FET content in ROS 17/2.8 and in the inflammatory cells