Inhibition of DNA synthesis by nitroheterocycles. II. Mechanisms of cytotoxicity

Olive, Peggy L.

doi:10.1038/bjc.1979.145

Cited by 29 publications

(7 citation statements)

References 11 publications

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“…The presence of the nitro group is required for this effect, as evidenced by the absence of effects onDNA synthesis by derivatives lacking the nitro group, as well as the correlation observed here between electron-affinity and inhibition of DNA synthesis. Also, as shown in the following paper (Olive (1979)), reduced products of nitrofurazone had no effect on DNA synthesis. This suggests that the nitro group must be intact for the compound to inhibit DNA synthesis.…”

Section: Resultsmentioning

confidence: 63%

Inhibition of DNA synthesis by nitroheterocycles I. Correlation with half-wave reduction potential

Olive¹

1979

Br J Cancer

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Summary.-Twenty-one nitroheterocycles, including metronidazole, misonidazole and AF-2, were tested for their ability to inhibit DNA synthesis in mouse L-929 cells growing in culture. All those tested inhibited the rate of incorporation of 3H -thymidine into L cells following drug treatment for 4 h under aerobic conditions. Only 4 drugs reached their limits of solubility before the uptake of 3H-thymidine was inhibited by 50%o or more. For the remaining 17, the log of the concentration producing 50%o inhibition of incorporation was directly correlated with the half-wave reduction potential of the compound.

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Section: Resultsmentioning

confidence: 63%

Inhibition of DNA synthesis by nitroheterocycles I. Correlation with half-wave reduction potential

Olive¹

1979

Br J Cancer

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“…DNA strand breakage was measured using the alkali-unwinding technique (1, 14) as previously described (11). Cells (2 X 10' cells/60 mm dish) were incubated overnight with ['4C]thymidine (80 mCi/mmole; 0.01 pCi/ml) followed by treatment with CPM.…”

Section: Methodsmentioning

confidence: 99%

Characterization of the uptake and toxicity of a fluorescent thiol reagent

Olive¹,

Biaglow

Varnes

et al. 1983

Cytometry

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3-(4-Maleimidylphenyl)-4-methyl-7-diethylamino coumarin (CPM), is a fluorescent thiol-binding agent. CPM is nontoxic toChinese hamster V-79 cells (2 x los cells/ milliliter) exposed to 2.5 pg/milliliter for 30 minutes. However, both toxicity and cellular binding were directly dependent on the drugxell ratio. Using flow cytometry, cellular binding of CPM correlated with inhibition of DNA synthesis. In cells pretreated with the thiol binding drugs N-ethylmaleimide, diamide and diethylmaleate or the carcinogens 4-nitroquinoline-1-oxide and AF-2 (furylfuramide), the subsequent binding of CPM was reduced by 40% or more. Key terms: DNA damage, flow cytometry, thiolsCellular thiols, especially glutathione, act as scavenger nucleophiles and can protect against toxicity, mutagenicity or transformation by radiation and many carcinogens (5,6,8, 10, 13, 19). While biochemical techniques are available to quantitate protein and nonprotein thiol levels within cells, these assays generally require in excess of lo6 cells. In addition, only population averages can be obtained and the degree of cellular heterogeneity in thio1,content cannot be determined. Therefore, the development of a rapid single cell assay to quantitate the intracellular content of thiols could be valuable in measuring differences in thiol content of cells and in the ability of drugs to bind cellular thiols.3-(4-maleimidylphenyl)-4-methyl-7-diethylamino coumarin (CPM, Molecular Probes Inc., Junction City, OR) is a thiolbinding fluorochrome which was recently developed for use in histopathology to stain protein sulphydryls (15). We have found that viable cultured cells can be stained by CPM and, at concentrations of CPM that produce minimal toxicity, the amount of intracellular fluorescence of CPM can be easily quantified intracellularly using flow cytometry (FCM). Cells pretreated with the carcinogens 4-nitroquinoline-1-oxide Materials and MethodsChinese hamster V-79 lung fibroblasts were grown in Eagle's minimal essential medium containing 15% fetal bovine serum. For experiments, cells were either incubated in suspension cultures in Bellco glass stirring vessels (Bellco Glass Inc., Vineland, N J ) or on Petri dishes. Incubation of cells with all drugs was carried out at 37°C in Gibco formulation phosphate-buffered saline, pH 7.4, containing Ca++ and Mg++ (Gibco, Grand Island, NY). Cells were released from plates using 0.1% trypsin (Gibco) in a citrate/saline buffer (1.5 mM sodium citrate, 0.135 M KCI, pH 7.6). Clonogenicity was determined by seeding approximately 800 surviving cells/100-mm Petri dish. Colonies were stained with malachite green and counted 8 days later.CPM was dissolved in ethanol a t a concentration of 1 mg/ml. DNA strand breakage was measured using the alkali-unwinding technique (1, 14) as previously described (11). Cells (2 X 10' cells/60 mm dish) were incubated overnight with ['4C]thymidine (80 mCi/mmole; 0.01 pCi/ml) followed by treatment with CPM. Cells were then released from plates using trypsin, and resuspended a t 5 X lob cells/ml.A...

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“…Although the mechanisms involved in radiosensitization with nitroimidazole are not clear, it has been reported that the nitroimidazole derivative has greater activity on the cytotoxic effects of radiation on hypoxic cells than aerobic cells (Stratford, 1982;Brown & Lee, 1980;Adams, 1981). Olive (1979) noted in in vitro experiments using mouse L cells that these two compounds had little effect on DNA damage, under aerobic conditions, but under anaerobic conditions both produced marked DNA damage and proliferation ceased.…”

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confidence: 99%

“…These inconsistent results are attributed to (1) the difference in mechanism of antitumour action between MMC and hyperthermia, (2) the time point at which DNA biosynthesis was measured. In mechanism of action, MMC acts directly on DNA by crosslinking (Iyer & Szybalski, 1963), while although hyperthermia results in marked inhibitions of DNA and protein synthesis (Palzer & Heidelberger, 1973), DNA repair is relatively fast following hyperthermic damage (Gerweck et al, 1975). Concerning the assay of DNA biosynthesis, in the combined hyperthermic treatments showing temporary tumour regression, DNA biosynthesis measurements should be performed daily.…”

mentioning

confidence: 99%

Enhancement of hyperthermochemotherapy for human gastric cancer in nude mice by thermosensitization with nitroimidazoles

Fujimoto

Ohta²,

Shrestha³

et al. 1988

Br J Cancer

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Summary Hyperthermia for human gastric cancer xenotransplanted into the hindlegs of nude mice was performed to determine whether misonidazole (MISO) 6.7, 8.0 and 7.9 days respectively, compared with 4.6 days for the control, but tumour regression occurred in the heat plus MISO group only. Tumour tripling times for MMC plus heat, MMC plus MTR plus heat, and MMC plus MISO plus heat were 9.6, 11.6 and 17.1 days respectively, compared to 4.6 days for the control and 6.7 days for heat alone. These data suggest that the antitumour activity of MMC plus MISO plus heat is an additive phenomenon.

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Inhibition of DNA synthesis by nitroheterocycles. II. Mechanisms of cytotoxicity

Cited by 29 publications

References 11 publications

Inhibition of DNA synthesis by nitroheterocycles I. Correlation with half-wave reduction potential

Inhibition of DNA synthesis by nitroheterocycles I. Correlation with half-wave reduction potential

Characterization of the uptake and toxicity of a fluorescent thiol reagent

Enhancement of hyperthermochemotherapy for human gastric cancer in nude mice by thermosensitization with nitroimidazoles

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