Cytotoxicity of 2-chlorodeoxyadenosine and arabinosylcytosine in leukaemic lymphoblasts from paediatric patients: significance of cellular nucleoside transporter content.

2-chlorodeoxyadenosine (2-CdA) and arabinosylcytosine (araC) are nucleoside drugs that are used to treat various leukaemias, although 2-CdA has not been tested extensively in children with acute lymphoblastic leukaemia (ALL). Nucleoside cytotoxicity depends on the conversion of these agents to 5'-phosphate derivatives, following drug entry into cells via nucleoside transport (NT) processes. This study compared es nucleoside transporter content, determined using a flow cytometric assay with SAENTA [5'-S-(2-aminoethyl)-N6-(4-nitrobenzyl)-5'-thioadenosine] fluorescein, and cytotoxicities of 2-CdA and araC in fresh lymphoblasts from previously untreated paediatric ALL patients and the human T-lymphoblast cell line, CCRF-CEM.