The role of cytoplasmic deoxycytidine kinase in the mitochondrial effects of the anti-human immunodeficiency virus compound, 2',3'-dideoxycytidine.

Journal Article (Journal Article)

2',3'-Dideoxycytidine (ddC) is a potent inhibitor of human immunodeficiency virus replication in vitro and shows beneficial effects in AIDS therapy. The compound inhibits mitochondrial DNA (mtDNA) synthesis at a clinically relevant concentration, which could be responsible for the side effects of ddC observed in the clinic. Thymidine (dThd), one of the substrates of mitochondrial deoxypyrimidine kinase (dPyd kinase), was not able to reverse the mitochondrial toxicity of ddC in CEM cells. Furthermore, the cytoplasmic deoxycytidine kinase (dCyd kinase)-deficient CEM cells were highly resistant to the mitochondrial toxicity of ddC. These data suggest a critical role for cytoplasmic dCyd kinase in the mitochondrial toxicity of ddC. The metabolites of ddC, but not ddC itself, were able to inhibit mtDNA synthesis in isolated mitochondria. The potency of the inhibitory effect was in the order of ddCTP greater than ddCDP greater than ddCMP greater than ddC. The lack of inhibition by ddC of mtDNA synthesis could be due to the inefficient ddC phosphorylation in mitochondria. Although the mitochondrial dPyd kinase was reported to phosphorylate ddC, the phosphorylation of ddC in isolated mitochondria was not detectable. The data suggest that ddC is phosphorylated to ddCTP in the cytoplasm and then transported into mitochondria to exert its inhibitory effect on mtDNA synthesis.

Full Text

Duke Authors

Cited Authors

  • Chen, CH; Cheng, YC

Published Date

  • February 15, 1992

Published In

Volume / Issue

  • 267 / 5

Start / End Page

  • 2856 - 2859

PubMed ID

  • 1310674

International Standard Serial Number (ISSN)

  • 0021-9258


  • eng

Conference Location

  • United States