toxicity evaluation of 6-mercaptopurine using accelerated cytotoxicity mechanism screening (acms) techniques

6- mercaptopurine (6-mp) is widely used in clinic as an immunosuppressive for treatment of acute lymphocytic leukemia, crohn's disease, and ulcerative colitis with documented unpredictable hepatotoxicity. the potential molecular cytotoxic mechanisms of 6-mp against isolated rat hepatocytes were searched in this study using “accelerated cytotoxicity mechanism screening (acms)” techniques. the concentration of 6-mp required to cause 50% cytotoxicity in 2 hour at 37∘c was detected to be 400 µm. a significant increase in 6-mp induced cytotoxicity and reactive oxygen species (ros) formation, % mitochondrial membrane potential (mmp), lysosomal damage was observed. the addition of chloroquine (lysosomotropic agent), l-carnitine (inhibitor of membrane permeability transition (mpt), diphenyleneiodonium (dpi) as an inhibitor of production of superoxide and h2o2 by mitochondria and dimethyl sulfoxide (dmso) as a radical scavenger decreased 6-mp-induced cytotoxicity, ros formation, collapse of mmp, lysosomal damage. results from this study suggest that 6-mp -induced cytotoxicity in isolated rat hepatocytes due to ros formation, mitochondrial and lysosomal damages that resulted in crosstalk toxicity between mitochondrial and lysosomal damage and finally cell death.