Detection of 1-beta-D-arabinofuranosylcytosine incorporation into DNA in vivo.
The incorporation of (1-beta-d-arabinofuranosylcytosine (ara-C) into the DNA of leukemic cells is highly correlated with cytotoxicity in vitro. However, the measurement of ara-C incorporation into leukemic cell DNA in vivo during ara-C therapy has been limited by the lack of a suitably sensitive method. A quantitative assay procedure has therefore been developed to determine incorporation of unlabeled ara-C into DNA. This method involves DNA isolation from patient myeloblasts, enzymatic digestion of the DNA, high pressure liquid chromatography separation of the nucleosides, and determination of ara-C in the eluate fractions by radioimmunoassay. Using this approach, incorporation of unlabeled ara-C into DNA of HL-60 cells is log linear over concentrations of 1 to 100 microM ara-C. Furthermore, the extent of ara-C incorporation into DNA as determined by this method correlates significantly with measurements of [3H]ara-C (DNA) formation under similar conditions. This approach has also been applied to clinical samples. Myeloblasts from 6 patients receiving high-dose continuous-infusion ara-C therapy incorporated 0.00-0.36 pmol ara-C/microgram DNA during 24 h of therapy. These findings thus suggest that this method can be used to monitor the in vivo incorporation of ara-C into leukemic cell DNA.
D000328:Adult; D000368:Aged; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D003561:Cytarabine / Q000032:analysis*; D004247:DNA / Q000378:metabolism*; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay; D014407:Tumor Cells, Cultured / Q000378:metabolism
D003561:Cytarabine; D004247:DNA