Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2-3
pubmed:dateCreated
1997-7-30
pubmed:abstractText
The role of enzymes in the reductive activation of various chemotherapeutic agents is an area of considerable interest in studies to better understand the selective toxicities of these agents. Xanthine dehydrogenase (XDH) is an enzyme capable of reductive activation of chemotherapeutic agents. Previously, this enzyme has not been extensively studied because of difficulties in its isolation. We recently isolated this enzyme from EMT6 mouse mammary carcinoma cells and showed that this enzyme is capable of activating mitomycin C. In this study, we examined whether XDH could activate the clinically important antineoplastic agent, doxorubicin. Drug activation was determined under aerobic and hypoxic conditions and at various pHs in order to simulate the different environments found in solid tumors. The results of these studies show that XDH reacts with doxorubicin via a two-electron reduction. This reduction is different from the modified and more extensively studied form of the enzyme, xanthine oxidase (XO), which reacts with doxorubicin via a one-electron reduction. Under hypoxic conditions, the formation of large quantities of 7-deoxydoxorubicin aglycone, a deactivation product of doxorubicin metabolism, may serve to moderate doxorubicin's antineoplastic activity. Under aerobic conditions, however, XDH activation led to a greater rate of formation of oxygen radicals than XO thereby possibly potentiating doxorubicin's cytotoxicity to aerobic tumor cells. Kinetic constants were determined for doxorubicin activation by XDH.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0009-2797
pubmed:author
pubmed:issnType
Print
pubmed:day
2
pubmed:volume
104
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
87-101
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:9212777-Animals, pubmed-meshheading:9212777-Antibiotics, Antineoplastic, pubmed-meshheading:9212777-Carcinoma, pubmed-meshheading:9212777-Chromatography, High Pressure Liquid, pubmed-meshheading:9212777-Doxorubicin, pubmed-meshheading:9212777-Electrons, pubmed-meshheading:9212777-Female, pubmed-meshheading:9212777-Hydrogen-Ion Concentration, pubmed-meshheading:9212777-Kinetics, pubmed-meshheading:9212777-Mammary Neoplasms, Experimental, pubmed-meshheading:9212777-Mice, pubmed-meshheading:9212777-NAD, pubmed-meshheading:9212777-Naphthacenes, pubmed-meshheading:9212777-Oxidation-Reduction, pubmed-meshheading:9212777-Oxygen Consumption, pubmed-meshheading:9212777-Reactive Oxygen Species, pubmed-meshheading:9212777-Xanthine Dehydrogenase, pubmed-meshheading:9212777-Xanthine Oxidase
pubmed:year
1997
pubmed:articleTitle
Reductive activation of doxorubicin by xanthine dehydrogenase from EMT6 mouse mammary carcinoma tumors.
pubmed:affiliation
Department of Nutrition, University of Nevada, Reno 89557, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't