A Cdc25A antagonizing K vitamin inhibits hepatocyte DNA synthesis in vitro and in vivo

Brian I. Carr, Ziqiu Wang, Meifang Wang, Siddhartha Kar, Craig S. Wilcox, Katharyn Rosi, Eileen Southwick, John S. Lazo

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Thioalkyl containing K vitamin analogs have been shown to be potent inhibitors of hepatoma cell growth and antagonizers of protein tyrosine phosphatase activity. We now show that they inhibit the activity of specific protein tyrosine phosphatases (PTP) in cell-free conditions in vitro, particularly the dual specificity phosphatase Cdc25A. Using primary cultures of adult rat hepatocytes that are in G0/G1 phase until stimulated into DNA synthesis by epidermal growth factor, we found that 2-(2-mercaptoethanol)-3-methyl-1,4-naphthoquinone or Compound 5 (Cpd 5) inhibited hepatocyte DNA synthesis and PTP activity in cell culture and in vivo after a two-thirds partial hepatectomy. We found a selective inhibition of Cdc25A activity in vitro, using both synthetic substrates and authentic cellular substrate, immunoprecipitated phospho-Cdk4. Intact Cpd 5-treated cells had decreased cellular Cdc25A activity and increased tyrosine phosphorylation of Cdk4, resulting in decreased phosphorylation of retinoblastoma (Rb). Loss of Cdk4 activity was confirmed using Cdk4 immunoprecipitates from either Cpd 5-treated or untreated cells and measuring its kinase activity using GST-Rb as target. We found a similar order of activity for inhibition of growth and Cdc25A activity using several thiol-containing analogs. Cdc25A inhibitors may thus be useful for defining biochemical pathways involving protein tyrosine phosphorylation that mediate cell growth inhibition.

Original languageEnglish
Pages (from-to)721-735
Number of pages15
JournalJournal of Molecular Biology
Volume326
Issue number3
DOIs
Publication statusPublished - Feb 21 2003

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Vitamin K
Protein Tyrosine Phosphatases
Hepatocytes
Retinoblastoma
DNA
Phosphorylation
Tyrosine
cdc25 Phosphatases
Growth Inhibitors
Cell Cycle Resting Phase
G1 Phase
Hepatectomy
Growth
Sulfhydryl Compounds
Epidermal Growth Factor
Hepatocellular Carcinoma
Phosphotransferases
Cell Culture Techniques
In Vitro Techniques
Proteins

Keywords

  • Cdc25A
  • DNA synthesis
  • Hepatocytes
  • K vitamins
  • Protein phosphatase

ASJC Scopus subject areas

  • Virology

Cite this

Carr, B. I., Wang, Z., Wang, M., Kar, S., Wilcox, C. S., Rosi, K., ... Lazo, J. S. (2003). A Cdc25A antagonizing K vitamin inhibits hepatocyte DNA synthesis in vitro and in vivo. Journal of Molecular Biology, 326(3), 721-735. https://doi.org/10.1016/S0022-2836(02)01445-6

A Cdc25A antagonizing K vitamin inhibits hepatocyte DNA synthesis in vitro and in vivo. / Carr, Brian I.; Wang, Ziqiu; Wang, Meifang; Kar, Siddhartha; Wilcox, Craig S.; Rosi, Katharyn; Southwick, Eileen; Lazo, John S.

In: Journal of Molecular Biology, Vol. 326, No. 3, 21.02.2003, p. 721-735.

Research output: Contribution to journalArticle

Carr, BI, Wang, Z, Wang, M, Kar, S, Wilcox, CS, Rosi, K, Southwick, E & Lazo, JS 2003, 'A Cdc25A antagonizing K vitamin inhibits hepatocyte DNA synthesis in vitro and in vivo', Journal of Molecular Biology, vol. 326, no. 3, pp. 721-735. https://doi.org/10.1016/S0022-2836(02)01445-6
Carr, Brian I. ; Wang, Ziqiu ; Wang, Meifang ; Kar, Siddhartha ; Wilcox, Craig S. ; Rosi, Katharyn ; Southwick, Eileen ; Lazo, John S. / A Cdc25A antagonizing K vitamin inhibits hepatocyte DNA synthesis in vitro and in vivo. In: Journal of Molecular Biology. 2003 ; Vol. 326, No. 3. pp. 721-735.
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