An investigation of micronucleus and mutation induction by oxazepam in mammalian cells

Stopper, Helga; Körber, C.; Spencer, Diane L.; Kirchner, Stephan; Caspary, William J.; Schiffmann, Dietmar

doi:10.1093/mutage/8.5.449

Cited by 23 publications

(9 citation statements)

References 29 publications

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“…A number of investigators have monitored trifluorothymidine (TFT) resi.stance in L5178Y mouse cells to identify the mutagenic activity of chemieals (Cl ive et al , 1972;Amacher et al , 1980;Oberly etal., 1984;Caspary and Myhr, 1986;McGregoretal., 1989McGregoretal., , 1991Myhr et al, 1990;Stopper et al, 1993b). The L5178Y mouse cell line, clone 3.7.2c, is heterozygous at the thymidine kinase (tk) locus.…”

Section: Introductionmentioning

confidence: 99%

Is micronucleus induction by aneugens an early event leading to mutagenesis?

Stopper¹,

Eckert²,

Schiffmann³

et al. 1994

Mutagenesis

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Section: Introductionmentioning

confidence: 99%

Is micronucleus induction by aneugens an early event leading to mutagenesis?

Stopper¹,

Eckert²,

Schiffmann³

et al. 1994

Mutagenesis

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“…Fritzenschaf et al (1993) also concluded that DES was positive in Syrian hamster embryo (SHE) cells. These first findings are interesting in that Stopper et al (1993aStopper et al ( ,b, 1994) also worked on L5178Y cells. The micromethod seems to be as sensitive as the classical method even if the times of treatment are different (24 h in our study versus 4 h in Stopper's work).…”

Section: Results For Aneugensmentioning

confidence: 82%

“…In parallel, we treated the cells for a shorter time (4 h) and a longer time (48 h): on the one hand, we found that 4 h, which is the treatment time used by Stopper et al (1993aStopper et al ( ,b, 1994, was insufficient to demonstrate the genotoxic activity of DES (Table III); on the other hand, a 48 h continuous treatment appeared to be very toxic. Thus, we retained two different harvesting times without metabolic activation: the first one without recovery time (immediate harvest) and the second one with 20 h of reculture.…”

mentioning

confidence: 87%

“…L5178Y cells, used in the mouse lymphoma assay (MLA), a test in which the effect of genotoxic compounds inducing gene mutation and chromosomal aberrations has been well validated (Sofuni et al, 1996), can also be used for the in vitro MN test because this cell line fulfils all of the above conditions. Indeed, Stopper et al (1993aStopper et al ( ,b, 1994 demonstrated the suitability of this cell line for the measurement of in vitro chemically induced MN.…”

Section: Introductionmentioning

confidence: 99%

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A micromethod for the in vitro micronucleus assay

Nesslany

Marzin

1999

Mutagenesis

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A micromethod for the in vitro micronucleus assay was developed using L5178Y cells to enable the rapid screening of a large number of molecules. The method is quick, simple to perform and needs very small amounts of compound, i.e. <10 mg. In this methodology, three types of treatment were carried out in parallel, enabling an optimal detection of both aneugenic and clastogenic compounds: two treatments without metabolic activation with or without a recovery period after a 24 h continuous treatment and one treatment with metabolic activation by Aroclor 1254-induced rat or hamster liver S9 mix. Seventeen known genotoxins (12 clastogens and five aneugens) and seven known non-genotoxins were tested. The in vitro micronucleus micromethod using L5178Y cells exhibited good sensitivity (16 positive/ 17 known genotoxins tested) and specificity (7 negative/7 known non-genotoxins tested) for the 24 test compounds studied with or without metabolic activation. Furthermore, this test showed a good correlation with other in vitro micronucleus tests performed using macromethods with various mammalian cell cultures. We conclude that the in vitro micronucleus micromethod with L5178Y cells could be used in the earliest stages of development of new molecules as a preliminary short-term screening assay before starting regulatory tests. IntroductionThe increasing numbers of new molecules synthesized in the pharmaceutical, chemical and cosmetic industries requires the use of assays providing rapid results and requiring small amounts of test material. As regulatory tests cannot reasonably be performed at an early stage of chemical development due to their complex protocols (duration, cost and need for large amounts of compound), we tried to miniaturize a chromosomal mutation assay, the in vitro micronucleus (MN) test. In fact, the in vitro MN test is known to be well adapted to the prescreening stage as it requires lower quantities of compound (500 mg are generally sufficient for the evaluation) and slide reading is easily and quickly performed. Moreover, it is able to demonstrate structural and numerical chromosomal aberrations in the same assay (Marzin, 1997). In fact, this methodology can simultaneously detect mitotic delay, apoptosis, chromosome breakage, chromosome loss and nondisjunction .The first requirement was to use microplates in order to decrease the amount of test compound. Thus, cells growing in suspension, which do not need trypsinization, were chosen. It

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“…This cell line has been shown to be suitable for analysis of micronucleus induction (10,11 ). The main question was whether the genotoxicity of 5-FU could be enhanced in vitro by inhibiting 5-FU catabolism.…”

mentioning

confidence: 99%

Combination of the Chemotherapeutic Agent 5-Fluorouracil with an Inhibitor of Its Catabolism Results in Increased Micronucleus Induction

Stopper

Kühnel

Podschun

1994

Biochemical and Biophysical Research Communications

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The rate limiting step in 5-fluorouracil catabolism is catalyzed by the enzyme dihydropyrimidine dehydrogenase. Since degradation of 5-fluorouracil decreases its efficacy in chemotherapy, the inhibition of its catabolism is a promising tool. We investigated the formation of micronuclei in vitro in mouse L5178Y cells. 5-fluorouracil induced an increase in micronucleus frequency, which could significantly be enhanced by the concurrent application of 2,6-dihydroxypyridine, an inhibitor of dihydropyrimidine dehydrogenase. The 5-fluorouracil concentration necessary to reach maximal genotoxic effects could be reduced to half in the presence of inhibitor. 2,6-Dihydroxypyridine alone and the naturally occuring enzyme substrate uracil did not induce micronucleus formation. Combined application of the chemotherapeutic agent 5-fluorouracil and an inhibitor of its could reduce side-effects by lowering the effective dose of the active drug. With this study we provide further support for the usefulness of this concept. "

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An investigation of micronucleus and mutation induction by oxazepam in mammalian cells

Cited by 23 publications

References 29 publications

Is micronucleus induction by aneugens an early event leading to mutagenesis?

Is micronucleus induction by aneugens an early event leading to mutagenesis?

A micromethod for the in vitro micronucleus assay

Combination of the Chemotherapeutic Agent 5-Fluorouracil with an Inhibitor of Its Catabolism Results in Increased Micronucleus Induction

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