Abstract
We have characterized an assay for the quantitative measurement of the frequency of conversion to anchorage-independent growth of N-acetoxy-2-acetylaminofluorene-treated normal human diploid fibroblasts. We investigated the effects of the following parameters on the absolute number and on the frequency of anchorage-independent colonies scored: (a) the number of cells seeded per dish; (b) the type of posttreatment medium; (c) the number of population doublings allowed posttreatment prior to seeding in suspension; and (d) the carcinogen dose.
The assay was linear over the range of 1.9 × 103 to 3.8 × 104 cells seeded per 60-mm dish for both total colonies scored and the induced frequency of anchorage-independent growth. The medium used posttreatment affected both the frequency and the kinetics of appearance of the anchorage-independent phenotype. The number of population doublings and the number of days allowed posttreatment prior to assaying for anchorage-independent growth potential also influenced the frequency of recovery of this phenotype. Under standardized conditions, the assay yielded a dose-response relationship for transformation to anchorage independence over the concentration range of 0 to 10 µm N-acetoxy-2-acetylaminofluorene.
Footnotes
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↵1 Supported by Research Grant CA-11751, Training Grant CA09078, and Center Grant ES-00002 from the NIH.
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↵3 To whom requests for reprints should be addressed.
- Received July 30, 1981.
- Accepted February 9, 1983.
- ©1983 American Association for Cancer Research.
Volume 43, Issue 5
