Mammalian gene mutation assays

The potential for interaction with genetic material (and therefore risk of carcinogenicity) can be investigated using bacterial and mammalian gene mutation assays and chromosomal aberration assays. The parent CDs do not exhibit mutagenic behavior in any of these assays, and there have been no reports of tumors in oral feeding studies or in the parenteral administration of any of the parent CDs. 

Styles JA and Cross MF, Activity of 2,4,6-trinitrotoluene in an in vitro mammalian gene mutation assay, Cancer Lett., 20, 103, 1983. 

Cole, J., Fox, M., Gamer, R.C., McGregor, D.B. and Thacker, J. (1990). Gene mutation assays in cultured mammalian cells. In UKEMS Subcommittee on Guidelines for Mutagenicity Testing. Report Part I rev. (Kirkland, D.J., Ed.). Cambridge University Press, pp. 87-114. 

In mammalian assays, glycidol has been tested in human lymphocytes and Chinese hamster cells in vitro for induction of chromosomal aberrations and sister chromatid exchanges. It was also tested in vivo in the mouse micronucleus assay. All test results were positive, as were those of gene mutation assays using Chinese hamster V79 cells and mouse lymphoma L5178Y cells. An in-vivo assay to detect chromosomal aberrations in mouse bone-marrow cells gave negative results. 

Twenty-seven out of 44 FDA-approved biopharmaceuticals have been tested in a battery of genotoxicity assays. Eighty-five different assays performed yielded negative results. The most commonly performed assays were the Ames test, the chromosomal aberration assay in human lymphocytes, the mouse lymphoma gene mutation assay, and the mammalian in vivo erythrocyte micronucleus test. Examples of the range of biopharmaceutical products tested include, domase alfa (deoxyribonuclease I-DNAse), trastuzumab (mAb to human epidermal growth factor receptor 2), alteplase (tissue plasminogen activator), infliximab (mAb to the human tumor necrosis factor a). 

Nickel compounds are generally negative in bacterial gene mutation assays, but positive responses have often been found in in vitro mammalian cell assays. 

Nitrobenzene was nongenotoxic in Salmonella ty-phimurium and mammalian cells in vitro and in mammalian cells in vivo. Studies reported included DNA damage and repair assays, gene mutation assays, chromosomal effects assays, and cell transformation assays. 

Johnson GE (2012) Mammalian cell HPRT gene mutation assay test methods. Methods Mol Biol 817 55-67... 

Aaron CS et al., Mammalian cell gene mutation assays Working group report, Mut. 

No genotoxic activity of European mistletoe was observed in a variety of assays, including a bacterial mutation assay, mammalian cell gene mutation assay, in vitro cytogenetic assay, cell transformation assay, and the Ames test (Mengs 1998 Mengs et al. 1997). 

ICH guidelines specifically require three genotoxicity assays for all devices (see Table 6.2). The assays should preferably evaluate DNA effects, gene mutations and chromosomal aberrations, and two of the assays should preferably use mammalian cells. Guidance for providing tests for selection to meet these needs are the OECD guidelines, which include 8 in vitro and 7 in vivo assays. 

Under Guideline S2B, the following standard test battery is recommended (1) a test for gene mutation in bacteria, (2) an in vitro test with cytogenetic evaluation of chromosomal damage with mammalian cells or an in vitro mouse lymphoma thymidine kinase (TK) assay, and (3) an in vivo test for chromosomal damage using rodent hematopoietic cells. 

Furfural was genotoxic in vitro in mammalian cells, causing chromosomal aberrations, gene mutations, and sister chromatid exchanges it was not mutagenic in a number of bacterial assays. ... 

In genotoxic assays, TDI has produced chromosomal aberrations, base pair substim-tion, firameshift mutations, and DNA stand breaks of human white blood cells in vitro It induced gene mutation and sister chromatid exchanges but not DNA damage or chromosomal aberrations in cultured rodent cells5° It did not induce micronuclei in mammalian eiythro-qn es in vivo. 

The bacterial and mammalian cell assays for gene mutation were developed to measure statistically significant increases in the numbers of mutant colonies derived from rare events many millions of exposed cells must be plated out to allow the assessment of mutation frequency. The Salmonella typhimurium reverse mutation assay ( Ames test) is carried out in a variety of different mutant strains selected to identify the various classes of mutation. The test generates many hundreds of Petri dishes for counting and is not practical for profiling. 

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