Radiosensitization by nickel lapachol.
The properties of interest in the radiosensitization of a metal complex, nickel lapachol, are compared with those of the 2-nitroimidazole, misonidazole. These very different compounds were found to be surprisingly similar in terms of their reduction potential (-370 mV), enhancement ratios for killing of hypoxic Chinese hamster ovary cells by X-irradiation, and enhancement of DNA breaks in hypoxia. For nitroimidazoles, the sensitization depends on 'electron affinity', reduction of the nitro group; for nickel lapachol it is the metal which is necessary for reduction, yet the sensitization efficiencies are remarkably close. However, the metal complex has additional activities (some sensitization in aerobic cells; increased sensitization with preincubation) which are as yet unexplained but are assumed to be related to the nature of the naphthoquinone ligand, rather than to the reduction of the metal.
Skov
K A
KA
B. C. Cancer Research Centre, Vancouver, Canada.
Adomat
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H
Farrell
N P
NP
D000818:Animals; D016466:CHO Cells; D002470:Cell Survival / Q000528:radiation effects; D006224:Cricetinae; D008920:Misonidazole / Q000494:pharmacology*; D009285:Naphthoquinones / Q000494:pharmacology*; D009942:Organometallic Compounds / Q000494:pharmacology*; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*
D009285:Naphthoquinones; D009942:Organometallic Compounds; D011838:Radiation-Sensitizing Agents; C084950:nickel lapachol; D008920:Misonidazole