Effect of 5-azacytidine and congeners on DNA methylation and expression of deoxycytidine kinase in the human lymphoid cell lines CCRF/CEM/0 and CCRF/CEM/dCk-1.
The human lymphoid cell lines CCRF/CEM/0 and the deoxycytidine kinase (dCk)-deficient CCRF/CEM/dCk- were treated with various 5-azacytidine (5-aza-C) nucleosides and the effect on DNA methylation and dCk activity were examined. 5-Azacytidine (5-aza-C), 5,6-dihydro-5-azacytidine (DHAC), 5-aza-2'-deoxycytidine (5-aza-Cdr), and 1-beta-D-arabinofuranosyl-5-azacytidine (ara-AC) reduced the DNA 5-methylcytosine level in the CEM/0 cells, down to approximately 10% of the level in untreated cells. The dCk activity was increased after treatment with the 5-aza-C nucleosides approximately 10% compared to untreated cells. In CEM/dCk- cells DNA hypomethylation between 50 and 25% of control was seen only after treatment with DHAC and 5-aza-C. No decrease in the methylation level was seen after treatment with 5-aza-Cdr or ara-AC. The dCk activity was increased up to 37% after treatment with DHAC or 5-aza-C but no increase was observed after treatment with 5-aza-Cdr or ara-AC. CEM/dCk- cells treated with DHAC showed a revertant frequency to cells expressing dCk activity of between 0.1 and 0.6%. Cloned revertant CEM/dCk- cells isolated from soft agar had dCk activity between 31 and 113% compared to the activity in untreated CEM/0 cells. This in vitro study indicates that DHAC and 5-aza-C induced dCk re-expression in the CEM/dCk- cells whereas 5-aza-Cdr and ara-AC did not.
D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology*; D002460:Cell Line; D003561:Cytarabine / Q000494:pharmacology; D004247:DNA / Q000378:metabolism*; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism*; D000077209:Decitabine; D003842:Deoxycytidine Kinase / Q000378:metabolism*; D004351:Drug Resistance; D006801:Humans; D008221:Lymphoid Tissue / Q000201:enzymology* / Q000378:metabolism; D008745:Methylation; D010770:Phosphotransferases / Q000378:metabolism*
D003561:Cytarabine; C013938:5,6-dihydro-5-azacytidine; C022121:fazarabine; D000077209:Decitabine; D004247:DNA; D004248:DNA (Cytosine-5-)-Methyltransferases; D010770:Phosphotransferases; D003842:Deoxycytidine Kinase; D001374:Azacitidine