COMPARATIVE SUBCELLULAR-DISTRIBUTION OF THE COPPER-COMPLEXES OF BLEOMYCIN-A(2) AND DEGLYCOBLEOMYCIN-A(2)

We have compared the cellular uptake and subcellular localization of C-14-labeled bleomycin-A(2) (BLM) and deglycobleomycin-A(2) in living KB3 cells. Both drugs exhibit poor internalization into cells but reveal significantly different intracellular distribution, with tow and high accumulation into the cell nuclei for BLM and deglyco-BLM, respectively. The results indicate that the carbohydrate chain does not constitute a limiting factor for BLM permeation and is directly implicated in the intracellular distribution of the drug into cells.