Ethidium bromide resistance in a rat liver epithelial cell line: Association with enhanced drug efflux

✍ Scribed by Jules J. Berman

• Publisher: Springer
• Year: 1988
• Tongue: English
• Weight: 561 KB
• Volume: 4
• Category: Article
• ISSN: 0742-2091
• DOI: 10.1007/bf00058740

✦ Synopsis

Ethidium bromide-resistant cell strains were obtained by continuous selection of an adult rat liver-derived cell line (ARL6 T) grown in the continuous presence of 200 ng/ml ethidium bromide. Comparison of resistant strains and parental (sensitive) cells was made for uptake and binding of ethidium bromide, visualized as fluorescent ethidium bromide-nucleic acid complexes. Although uptake of ethidium bromide was similar in parental and resistant cells, efflux kinetics were markedly different. Over a three-hour period, parental (sensitive) cells maintained fluorescence following a short ethidium bromide pulse (100 l~g/ ml ethidium bromide). In contrast, ethidium bromide-resistant cell lines eliminated photographically detectable fluorescent complexes within three hours following pulse exposure to ethidium bromide. The rapid elimination of ethidium bromide-fluorescent complexes in all (5) resistant cell strains examined supports an efflux mechanism as contributing to the resistance of ethidium bromide cytotoxicity in these cells.