Vitamin C transiently arrests cancer cell cycle progression in S phase and G2/M boundary by modulating the kinetics of activation and the subcellular localization of Cdc25C phosphatase

Christopher G. Thomas, Patra E. Vezyraki, Vicky P. Kalfakakou, Angelos M. Evangelou

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Regulation of cell cycle progression involves redox (oxidation-reduction)- dependent modification of proteins including the mitosis-inducing phosphatase Cdc25C. The role of vitamin C (ascorbic acid, ASC), a known modulator of the cellular redox status, in regulating mitotic entry was investigated in this study. We demonstrated that vitamin C inhibits DNA synthesis in HeLa cells and, mainly the form of dehydroascorbic acid (DHA), delays the entry of p53-deficient synchronized HeLa and T98G cancer cells into mitosis. High concentrations of Vitamin C caused transient S and G2 arrest in both cell lines by delaying the activation of the M-phase promoting factor (MPF), Cdc2/cyclin-B complex. Although vitamin C did not inhibit the accumulation of cyclin-B1, it may have increased the level of Cdc2 inhibitory phosphorylation. This was achieved by transiently maintaining Cdc25C, the activator of Cdc2, both in low levels and in a phosphorylated on Ser216 inactive form that binds to 14-3-3 proteins contributing thus to the nuclear exclusion of Cdc25C. As expected, vitamin C prevented the nuclear accumulation of Cdc25C in both cell lines. In conclusion, it seems that vitamin C induces transient cell cycle arrest, at least in part, by delaying the accumulation and the activation of Cdc25C.

Original languageEnglish (US)
Pages (from-to)310-318
Number of pages9
JournalJournal of Cellular Physiology
Volume205
Issue number2
DOIs
StatePublished - Nov 2005

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Cell Biology

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