Mutagenesis and carcinogenesis testing <i>in vitro</i>

Casto, Bruce C.

doi:10.1002/bit.260231203

Cited by 6 publications

(2 citation statements)

References 26 publications

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“…In addition, a quantitative relationship between chemical-DNA adduct formation and biological effect, as measured by increased virus transformation frequency, has been demonstrated [Theall et al, 19821. Positive test results in the SHE-SA7 system generally agree with those obtained in bacterial and mammalian cell rnutagenesis assays [Casto, 1981b;Hatch et al, 1982bl and in vivo carcinogenesis assays [Casto, 1981a,b;Hatch et al, 1983b;Heidelberger et al, 19831. To test the utility of the SHE-SA7 assay as a reliable system for screening potential genotoxic agents, it is necessary to demonstrate reproducibility in experimental results both within and between laboratories. Recently, the intra-and interlaboratory reproducibility of this assay was investigated by testing nine model carcinogenic and noncarcinogenic compounds Schechtman et al, 19861. In the present study, diverse chemicals received under code were evaluated by two independent commercial laboratories.…”

Section: Introductionsupporting

confidence: 71%

Chemical enhancement of SA7 virus transformation of hamster embryo cells: Evaluations by interlaboratory testing of diverse chemicals

Hatch¹,

Anderson²,

Lubet³

et al. 1986

Environ. mutagen

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Twelve chemicals from diverse structural classes were tested under code for their capacity to enhance the transformation of Syrian hamster embryo cells by simian adenovirus SA7 in two independent laboratories. Pretreatment of hamster cells with eight of those chemicals (reserpine, dichlorvos, methapyrilene hydrochloride, benzidine dihydrochloride, diphenylhydantoin, cinnamyl anthranilate, 11-aminoundecanoic acid, and 4,4'-oxydianiline) produced repeatable enhancement of SA7 transformation at two or more consecutive dose levels, which constitutes clear evidence of enhancing activity in this assay. Both toxic and nontoxic doses of each of these chemicals caused enhancement of virus transformation. Two chemicals (2,6-dichloro-p-phenylenediamine and cinnamaldehyde) produced some evidence of enhancing activity (repeatable transformation enhancement at one dose). Dose ranges for cytotoxicity and enhancement of SA7 transformation were similar in both laboratories for all chemicals producing activity. The final two chemicals, chloramphenicol sodium succinate and ethylene thiourea, failed to reproducibly demonstrate either significant cytotoxicity or enhancement of SA7 transformation at concentrations up to 10-20 mM. The test results for these 12 chemicals were combined with the test results for 9 known carcinogens and noncarcinogens in order to evaluate relationships between activity, dose response, and lowest effective enhancing concentration for these compounds, as well as to correlate them with rodent carcinogenesis classifications. The Syrian hamster embryo cell-SA7 system demonstrated reproducible test responses in both intra- and interlaboratory studies and detected 13 out of 15 known rodent carcinogens.

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Section: Introductionsupporting

confidence: 71%

Chemical enhancement of SA7 virus transformation of hamster embryo cells: Evaluations by interlaboratory testing of diverse chemicals

Hatch¹,

Anderson²,

Lubet³

et al. 1986

Environ. mutagen

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“…(days) 5 10 25 SOLVENT MMS 50pg/ml 0.1 1 .o In the experiment shown in Table 1, the percentage of cell5 that initially contained Ad5 DNA with (1 2.5-30.0%) or without (8.3%) MMS pretreatment was higher than the with (0.5-1.5%) or without (0.3%) MMS Dretreatment. These results suggest that the Ad5 DNA fo;nd early after jnfection Was free Viral DNA that had not been integrated into the cellular genome.…”

Section: Time Of Incubationmentioning

confidence: 88%

Early Events in Methyl Methanesulfonate Enhancement of Adenovirus Transformation of Cloned Rat Embryo Fibroblast Cells

Fisher

1989

Molecular Carcinogenesis

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Pretreatment of a cloned rat embryo fibroblast (CREF) cell line with methyl methanesulfonate (MMS) prior to infection with a specific host-range and cold-sensitive type 5 adenovirus mutant (H5hr1), results in a unique carcinogen enhancement of transformation (CET) phenotype (Carcinogenesis 8:967, 1987). By using low-density clonal assays and in situ hybridization techniques with 32P-labeled type 5 adenovirus (Ad5) probes, we demonstrated that 5-10 d following infection the proportion of CREF colonies containing H5hr1 DNA and RNA is increased two- to threefold as a result of pretreatment with MMS. Twenty-five days following infection of CREF cells, Ad5 DNA assays showed that both solvent and MMS-pretreated CREF colonies no longer contained detectable levels of viral DNA or RNA. Analysis of free viral DNA by the Hirt procedure suggested that more free viral DNA persisted in MMS-pretreated H5hr1-infected CREF cells than in solvent-pretreated H5hr1-infected CREF cells. The relative amount of free viral DNA in both types of cultures was directly related to the multiplicity of H5hr1 infection and decreased with time following infection. As observed using in situ hybridization techniques, by 25 d after infection no free viral DNA was detected in either MMS- or solvent-pretreated H5hr1-infected CREF cells. By using a protein synthesis inhibitor (cycloheximide) and an RNA transcription inhibitor (actinomycin D), it was further demonstrated that the ability of MMS to induce a unique CET in CREF cells following infection with H5hr1 was dependent on the synthesis of new protein and RNA. In contrast, inhibition of protein and RNA synthesis did not alter the de novo rate of H5hr1 transformation of CREF cells. Temporal kinetic studies indicated that the ability of MMS to enhance H5hr1 transformation of CREF cells and to increase the percentage of CREF colonies containing Ad5 genetic information is regulated in a strict temporal manner. The results of the present investigation suggest that the ability of MMS to enhance H5hr1 transformation of CREF cells is dependent on the induction of new protein(s) in CREF cells, and enhancement is associated with an increase in the proportion of cells in the infected CREF cell population that initially contain Ad5 DNA/RNA.

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Synergism in the transformation of hamster embryo cells treated with formaldehyde and adenovirus

et al. 1983

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Formaldehyde is a large production volume chemical widely distributed in research laboratories, industrial workplaces, and home and personal environments. Inhalation studies with formaldehyde have documented its ability to produce squamous cell carcinomas in rats. When primary hamster embryo cells were treated by gaseous exposure to formaldehyde or by incorporation into the medium, a dose-related increase in the frequency of SA7 virus transformation was produced. The length of chemical treatment and the time interval before subsequent addition of transforming virus was critical, with two-hr treatment times as the most efficient. Treatment by gaseous exposure permitted utilization of lower treatment concentrations. Determination of formaldehyde concentrations in culture media of bioassay dishes treated by this method documented that 2.2 micrograms/ml produced significantly enhanced viral transformation. Exposure of hamster embryo cells to formaldehyde by these methods produces reproducible and quantitative genotoxic effects.

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Mutagenesis and carcinogenesis testing in vitro

Cited by 6 publications

References 26 publications

Chemical enhancement of SA7 virus transformation of hamster embryo cells: Evaluations by interlaboratory testing of diverse chemicals

Chemical enhancement of SA7 virus transformation of hamster embryo cells: Evaluations by interlaboratory testing of diverse chemicals

Early Events in Methyl Methanesulfonate Enhancement of Adenovirus Transformation of Cloned Rat Embryo Fibroblast Cells

Synergism in the transformation of hamster embryo cells treated with formaldehyde and adenovirus

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