Uptake and mutagenicity of AF‐2 in chinese hamster V‐79 spheroids under aerobic and hypoxic conditions

Abstract

Chinese hamster V-79 cells, when grown in suspension culture as multicell spheroids, display many of the features of organized tissue. AF-2, a known mutagen, was used to examine the influence of some of these factors on mutagenesis. Since AF-2 is fluorescent, FCM quantitation of intracellular drug content was performed after incubation of spheroids under either aerobic or hypoxic conditions. For the same level of toxicity, hypoxic spheroids accumulated twice as much AF-2 as aerobic spheroids, but showed less than half the number of mutants resistant to 6-thioguanine. Using velocity sedimentation techniques, a selective increase in the toxic and mutagenic effects of AF-2 was found for internal vs external cells of the spheroids. However, in mutagenicity experiments using all the cells from spheroids, the response of the external cycling cells predominated over the response of the internal cells. Thus, in addition to the demonstration that cellular environment can modify mutagenesis, these results also suggest that the growth fraction of the target cells can be an important consideration in mutation experiments.

Mutagenicity of nitrofuran derivatives: Review

“…However, unlike the XP cells, AT fibroblasts are not sensitive to nitrofurans [McCalla et al, 1978al. Olive andDurand [1981] have studied the action of AF2 on Chinese hamster V79 cell spheroids (balls of cells having diameters of several hundred microns). Since the sensitivity of cells to nitroheterocycles is known to depend on a variety of factors including cell crowding [Olive, 19811, spheroids provide an interesting model since they are intermediate in complexity between single cell cultures and organized tissue.…”

Patterns of mutagen binding and penetration in multicell spheroids

“…Adriamycin, 4NQ0, and Hoechst 33342 have previously been shown to penetrate poorly into spheroids [Durand, 1981b;Olive, 1981;Durand and Olive, 1982; Olive and Durand, 19831. Results shown here also indicate that acridine orange and monobromobimane are more toxic to external cells of spheroids.…”