Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 318174
Title A physiological threshold for protection against menadione toxicity by human NAD(P)H : quinone oxidoreductase (NQO1) in Chinese hamster ovary (CHO) cells
Author(s) Haan, L.H.J. de; Boerboom, A.M.J.F.; Rietjens, I.M.C.M.; Capelle, D. van; Ruijter, A.J.M. de; Jaiswal, A.K.; Aarts, J.M.M.J.G.
Source Biochemical Pharmacology 64 (2002). - ISSN 0006-2952 - p. 1597 - 1603.
Department(s) Sub-department of Toxicology
Publication type Refereed Article in a scientific journal
Publication year 2002
Abstract NAD(P)H:quinone oxidoreductase 1 (NQO1) has often been suggested to be involved in cancer prevention by means of detoxification of electrophilic quinones. In the present study, a series of Chinese hamster ovary (CHO) cell lines expressing various elevated levels of human NQO1 were generated by stable transfection. The level of NQO1 over-expression ranged from 14 to 29 times the NQO1 activity in the wild-type CHO cells. This panel of cell lines, allowed investigation of the protective role of NQO1 in quinone cytotoxicity. It could be demonstrated that menadione toxicity was significantly reduced in all NQO1-transfected CHO clones compared to the wild-type cells, but the clones did not show differences in their level of protection against menadione. This observation pointed at a critical threshold concentration of NQO1 above which a further increase does not provide further protection against quinone cytotoxicity. Additional studies in which the NQO1 activity was inhibited by dicoumarol showed that only dicoumarol concentrations of about five times the 50 for NQO1 inhibition were able to reduce NQO1 levels below the apparent threshold, making the cells more sensitive. The level of this threshold was estimated to be in the range of base line NQO1 activities observed in several tissues and species. Thus, the results of the present study indicate that beneficial effects of NQO1 induction by, for example, cruciferous vegetables might be absent or present depending on the NQO1 activity threshold for optimal protection and the basal level of NQO1 expression in the tissue and species of interest.
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