Abstract
The soft agar tumor colony assay has been adapted for measurement of cytotoxicity of drugs such as cyclophosphamide whose antitumor activity depends upon biotransformation to active metabolites. The S-9 fraction of rat liver, MgCl2, KCl, glucose-6-phosphate and NADP in phosphate buffer was added to medium containing cells from various continuous human tumor cell lines in the presence and in the absence of drug. After incubation for 1 hour at 37°, cells were washed twice with medium, seeded into 0.3% agar, and plated onto 0.5% agar in petri dishes. Colonies were counted 7 to 21 days later under phase contrast microscopy. Incubation of cells from human lines with cyclophosphamide or heliotrine, an experimental antitumor agent, in the absence of complete activating system caused no or minimal inhibition of colony formation. Incubation of cell lines with cyclophosphamide or heliotrine in the presence of complete activating system markedly reduced colony formation. The cytotoxic effects of both drugs were NADP dependent. This simple technique extends the usefulness of the soft agar stem cell assay to drugs requiring microsomal activation.
Original language | English (US) |
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Pages (from-to) | 287-293 |
Number of pages | 7 |
Journal | Life Sciences |
Volume | 28 |
Issue number | 3 |
DOIs | |
State | Published - Jan 19 1981 |
ASJC Scopus subject areas
- General Biochemistry, Genetics and Molecular Biology
- Pharmacology, Toxicology and Pharmaceutics(all)