title: Enhanced cytotoxicity of nucleoside analogs by overexpression of mitochondrial deoxyguanosine kinase in cancer cell lines.
abstract: The cytotoxic anti-cancer purine nucleoside analogs 2-chloro-2'-deoxyadenosine (CdA), 9-beta-D-arabinofuranosylguanine (araG), and 2',2'-difluorodeoxyguanosine (dFdG) are phosphorylated by human mitochondrial deoxyguanosine kinase (dGK) in vitro. We overexpressed dGK as a fusion protein to the green fluorescent protein in the human pancreatic cancer cell lines PanC-1 and MIA PaCa-2 to determine the importance of dGK-mediated nucleoside analog phosphorylation. The transfected cells showed mitochondrial fluorescence patterns, and the mitochondrial locations of endogenous and overexpressed dGK were verified by Western blot analysis of cell extracts with polyclonal anti-dGK antibodies. The increase of dGK activity in the overexpressing cells was approximately 4-fold. These cell lines exhibited increased sensitivity to CdA, araG, and dFdG as compared with the untransfected parent cell lines. This is, to our knowledge, the first demonstration of a correlation between the activity of a mitochondrial deoxyribonucleoside kinase and the cytotoxicity of nucleoside analogs. Our data imply that the dGK activity is rate-limiting for the efficacy of nucleoside analogs in the cell lines investigated.
authors.affiliation: Division of Clinical Virology, Karolinska Institute, Huddinge University Hospital, S-14186 Stockholm, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Zhu
authors.forename: M
authors.initials: M
authors.lastname: Johansson
authors.forename: J
authors.initials: J
authors.lastname: Permert
authors.forename: A
authors.initials: A
authors.lastname: Karlsson
mesh_terms: D000970:Antineoplastic Agents / Q000633:toxicity; D001087:Arabinonucleosides / Q000378:metabolism / Q000633:toxicity; D017338:Cladribine / Q000378:metabolism / Q000633:toxicity; D003561:Cytarabine / Q000378:metabolism / Q000633:toxicity; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism / Q000633:toxicity; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000201:enzymology*; D009705:Nucleosides / Q000378:metabolism / Q000633:toxicity; D010190:Pancreatic Neoplasms / Q000201:enzymology; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection / Q000235:genetics; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D001087:Arabinonucleosides; D008164:Luminescent Proteins; D009705:Nucleosides; D011993:Recombinant Fusion Proteins; D003561:Cytarabine; C096208:LY 223592; D049452:Green Fluorescent Proteins; C028771:9-arabinofuranosylguanine; D017338:Cladribine; D017853:Phosphotransferases (Alcohol Group Acceptor); C019165:deoxyguanosine kinase; D003849:Deoxyguanosine