Development of new markers for hypoxic cells: [131I]Iodomisonidazole and [131I]Iodoerythronitroimidazole.
This study was aimed at developing ligands to evaluate tumor hypoxia by planar scintigraphy. Two 2-nitroimidazole analogues were developed as precursor compounds to image hypoxic tumors. Both tosylmisonidazole (Ts MISO) and tosylerythronitroimidazole (Ts ETNIM) were labeled with 131I. The biodistribution and autoradiographic evaluations by planar scintigraphy of 131I-IMISO and 131I-IETNIM were conducted at 1, 2 and 4 hours after administration to rats bearing 13762 breast tumors. Biodistribution of 131I-IMISO was also evaluated in Madison lung tumor-bearing mice. Intratumoral oxygen tension was measured by the Eppendorf system. Biodistribution showed similar tumor/blood and tumor/muscle count density ratios for both compounds. The thyroid uptake of both analogues was increased with time, suggesting in vivo deiodination probably occurred. Autoradiographs of 131I-IMISO and 131I-IETNIM revealed good visualization of the neoplasms. The tumor oxygen tension was 3-6 mmHg as compared to the normal tissue oxygenation of 30-40 mmHg. The findings indicate that these analogues can localize in the hypoxic region of solid tumors and may assist with quantitation of the hypoxic fraction of tumor for proper selection and evaluation of appropriate radiotherapy and chemotherapy.
Cherif
A
A
Division of Diagnostic Imaging, The University of Texas M.D. Anderson Cancer Center, Houston 77030, USA.
Wallace
S
S
Yang
D J
DJ
Newman
R A
RA
Harrod
V L
VL
Nornoo
A
A
Inoue
T
T
Kim
C G
CG
Kuang
L R
LR
Kim
E E
EE
Podoloff
D A
DA
D000818:Animals; D001943:Breast Neoplasms / Q000000981:diagnostic imaging; D015687:Cell Hypoxia; D005260:Female; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D008175:Lung Neoplasms / Q000000981:diagnostic imaging; D051379:Mice; D008807:Mice, Inbred BALB C; D008920:Misonidazole / Q000493:pharmacokinetics; D009369:Neoplasms / Q000000981:diagnostic imaging*; D009593:Nitroimidazoles / Q000493:pharmacokinetics; D011838:Radiation-Sensitizing Agents / Q000493:pharmacokinetics; D011877:Radionuclide Imaging; D051381:Rats; D011916:Rats, Inbred F344; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured
D007457:Iodine Radioisotopes; D009593:Nitroimidazoles; D011838:Radiation-Sensitizing Agents; D008920:Misonidazole