Flow injection analysis quantifies multidrug resistance phenotype

Flow injection analysis (FIA) of DNA damage, repair and drug accumulation was employed to examine the relation between DNA damage, drug resistance and cell survival. Resistant sublines to adriamycin (P388/ADR), mitoxantrone (P388/MTN) and drug sensitive (P388/S) leukemic cells were exposed to different concentrations of adriamycin. The subtle difference in tumor response between sensitive and resistant cells was well differentiated and the results were comparable with other methods of measuring DNA strand-break and repair. Drug concentrations as low as 5 × 10−11 M could be measured by FIA. In addition the method also enables assessment of cross-resistance/sensitivity. The speed, sensitivity and reproducibility make FIA a good technique for routine monitoring of tumor cell response to DNA damaging agents.