5-Azacytidine increases the total cellular copper content and basal level metallothionein mRNA accumulation of human Hep G2 cells.
In this study we have demonstrated the ability of 5-azacytidine to elevate the basal level expression of the metallothionein (MT)-IF and MT-IG genes and increase the basal level expression of the MT-IIA gene in Hep G2 cells, a cell line which exhibits heavy metal inducible MT gene expression. Atomic absorption analysis of 5-azacytidine treated Hep G2 cells detected a 2-fold increase in the total cellular copper content. Pretreatment of 5-azacytidine exposed cells with hydroxyurea and cycloheximide indicated that the increase in total cellular copper content was a direct response to 5-azacytidine treatment. S1 nuclease analysis illustrated that pretreatment of Hep G2 cells with KCN, a copper specific chelator and uptake inhibitor, suppressed 5-azacytidine- and copper-inducible MT-IG gene expression. Thus, the increase in MT gene expression in response to 5-azacytidine treatment can be correlated to an increase in the total cellular copper content. Possible mechanisms on how 5-azacytidine could alter the influx/efflux of copper in Hep G2 cells are discussed.
Foster
R
R
Department of Biological Sciences, University of Calgary, Canada.
Jahroudi
N
N
Gedamu
L
L
D000818:Animals; D001374:Azacitidine / Q000494:pharmacology*; D015152:Blotting, Northern; D003300:Copper / Q000378:metabolism*; D004790:Enzyme Induction / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008114:Liver Neoplasms, Experimental / Q000378:metabolism*; D008668:Metallothionein / Q000096:biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis*; D013054:Spectrophotometry, Atomic; D014407:Tumor Cells, Cultured
D012333:RNA, Messenger; D003300:Copper; D008668:Metallothionein; D001374:Azacitidine