Preliminary in vivo evaluation of [131I]-2-iodo-D-phenylalanine as a potential radionuclide therapeutic agent in R1M-fluc rhabdomyosarcoma tumor-bearing NuNu mice using bioluminescent imaging.
BACKGROUND
Carrier-added [(123)I]-2-iodo-D-phenylalanine (CA [(123)I]-2-I-D-Phe) was previously found to have a preferential retention in tumors with a high tumor background contrast in animal models. A previous human dosimetry study demonstrated a favorable biodistribution and radiation burden in human subjects.


OBJECTIVE
The aim of this study was to investigate the potential of CA [(131)I]-2-I-D-Phe as an agent for radionuclide therapy.


METHODS
Sixty (60) nude athymic mice were inoculated subcutaneously with firefly luciferase-transduced R1M rhabdomyosarcoma cells. The mice in the therapy group were injected intravenously (i.v.) with 148 MBq [(131)I]-2-I-D-Phe (432 GBq/mmol) in kit solution. Controls were injected with kit solution without radioactivity, with physiological saline, or with 148 MBq [(131)I](-) in physiological saline. Tumor growth was quantified using bioluminescent imaging and caliper measurements.


RESULTS
[(131)I]-2-I-D-Phe clearly reduced tumor growth in the treated mice compared with the control groups. A tumor growth-rate reduction of at least 33% was found for mice receiving a therapeutic dose. There were no serious adverse side-effects of the therapy.


CONCLUSIONS
In conclusion, i.v. injection of CA 148 MBq [(131)I]-2-I-D-Phe specifically reduces tumor growth in athymic nude mice without relevant side-effects on the animals' health.
Bauwens
Matthias
M
Laboratory of Radiopharmacy, KUL, Leuven, Belgium. matthias.bauwens@pharm.kuleuven.be
Wimana
Lena
L
Keyaerts
Marleen
M
Peleman
Cindy
C
Lahoutte
Tony
T
Kersemans
Ken
K
Snykers
Sarah
S
Vinken
Mathieu
M
Mertens
John
J
Bossuyt
Axel
A
D000818:Animals; D006801:Humans; D007457:Iodine Radioisotopes; D008156:Luciferases / Q000378:metabolism*; D008163:Luminescent Measurements; D051379:Mice; D008819:Mice, Nude; D010649:Phenylalanine / Q000031:analogs & derivatives*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012208:Rhabdomyosarcoma / Q000000981:diagnostic imaging*; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
C496694:2-iodophenylalanine; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D010649:Phenylalanine; D008156:Luciferases