Gadolinium(III) texaphyrin: a tumor selective radiation sensitizer that is detectable by MRI.
Gadolinium(III) texaphyrin (Gd-tex2+) is representative of a new class of radiation sensitizers detectable by magnetic resonance imaging (MRI). This porphyrin-like complex has a high electron affinity [E1/2 (red.) approximately = -0.08 V versus normal hydrogen electrode] and forms a long-lived pi-radical cation upon exposure to hydrated electrons, reducing ketyl radicals, or superoxide ions. Consistent with these chemical findings, Gd-tex2+ was found to be an efficient radiation sensitizer in studies carried out with HT29 cells in in vitro as well as in in vivo single and multifraction irradiation studies with a murine mammary carcinoma model. Selective localization of Gd-tex2+ in tumors was confirmed by MRI scanning.
Young
S W
SW
Pharmacyclics, Inc., Sunnyvale, CA 94086, USA.
Qing
F
F
Harriman
A
A
Sessler
J L
JL
Dow
W C
WC
Mody
T D
TD
Hemmi
G W
GW
Hao
Y
Y
Miller
R A
RA
D000818:Animals; D006801:Humans; D008279:Magnetic Resonance Imaging; D008325:Mammary Neoplasms, Experimental / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000532:radiotherapy; D008665:Metalloporphyrins / Q000378:metabolism* / Q000627:therapeutic use; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D011838:Radiation-Sensitizing Agents / Q000378:metabolism* / Q000627:therapeutic use; D011859:Radiography; D012513:Sarcoma, Experimental / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000532:radiotherapy; D014407:Tumor Cells, Cultured
D008665:Metalloporphyrins; D011838:Radiation-Sensitizing Agents; C437683:motexafin gadolinium