The effect of caffeine on DAPI-inducible fragile sites

• Published in: Mutation research Vol. 282; no. 1; pp. 43 - 48
• Main Authors: Pelliccia, F., Rocchi, A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.05.1992; Elsevier
• Subjects: Biological and medical sciences; Caffeine; Caffeine - toxicity; Cells, Cultured; Chemical mutagenesis; Chi-Square Distribution; Chromosome Fragile Sites; Chromosome Fragility; DAPI; Drug Interactions; Female; Fragile sites; Humans; Indoles - toxicity; Male; Medical sciences; Mutagens - toxicity; Toxicology; DAPI; Fragile sites; Caffeine; Human; Chromosome fragility; Fragile site; Mutagenicity testing; Chromosome banding; Lymphocyte; Blood
• ISSN: 0165-7992; 0027-5107
• DOI: 10.1016/0165-7992(92)90072-P

DAPI is a non-intercalating compound which binds specifically to the AT bases of DNA. When leukocytes are grown in complete medium (RPMI 1640) DAPI induces the expression of three fragile sites on human chromosomes and if the medium is deficient in folic acid and thymidine (199M) it induces 19 fragile sites. Caffeine has been found by different authors to considerably enhance the expression of chromosome breaks which have been produced by other agents. When it is added to the complete medium after DAPI, it elicits almost all the sites that DAPI only induces in incomplete medium. When caffeine is added after DAPI to incomplete medium, it does not significantly or unidirectionally modify the capacity of the two subjects examined to elicit fragile sites. The analysis of these results, when correlated with that of the mitotic index, reveals a different sensitivity of the two subjects to the combined DAPI—caffeine treatment. The results are quite compatible with the hypothesis that the DAPI-induced fragile sites are DNA regions which are not accurately replicated during the S phase.