Characterization of Human Leukemic HL-60 Sublines as a Model for Primary and Secondary Resistance Against Cytostatics

Resistance against cytostatics is a major problem in the therapy of hematologic malignancies. The intracellular alterations can be studied in vitro and several molecular mechanisms affecting all cellular levels like altered membrane transport rates (Pglycoprotein) [1], “trapping” of cytostatics in vesicles [2], detoxification (glutathione-S-transferase) [3], and alteration of nuclear target proteins (topoisomerases) [4] have been described. A special problem is the exhibition of a multidrug-resistant (MDR) phenotype, resulting in resistance against a broad spectrum of substances from different classes.