RRR-α-tocopherol regulation of gene transcription in response to the cell oxidant status

A. Azzi, D. Boscoboinik, A. Fazzio, D. Marilley, P. Maroni, N. K. Özer, S. Spycher, A. Tasinato

Research output: Contribution to journalArticlepeer-review


RRR-α-Tocopherol, but not RRR-β-tocopherol, negative regulates proliferation of vascular smooth muscle cells at physiological concentrations. At the same concentrations RRR-α-tocopherol inhibits protein kinase C activity, whereas RRR-β-tocopherol is ineffective. Furthermore, RRR-β-tocopherol prevents the inhibition of cell growth and of protein kinase C activity caused by RRR-α-tocopherol. The negative regulation by RRR-α-tocopherol of protein kinase C activity appears to be the cause of smooth muscle cell growth inhibition. RRR-α-Tocopherol does not act by binding to protein kinase C directly but presumably by preventing protein kinase C activation. A second RRR-α-tocopherol effect has been found at the level of AP 1, the latter becoming activated by RRR-α-tocopherol under condition of protein kinase C inhibition or down regulation. AP-1 inhibition by RRR-α-tocopherol is seen, however, under condition of protein kinase C stimulation. Compositional changes of AP-1 have been found to be at the basis of the RRR-α-tocopherol effects. RRR-β-Tocopherol, provided with similar antioxidant properties, not only it does not affect AP 1 but it prevents the effects of RRR-α-tocopherol. Moreover, it has been observed that RRR-α- tocopherol is able to affect TRE regulated gene transcription. It is concluded that RRR-α-tocopherol acts specifically in vascular smooth muscle cells, by controlling a signal transduction pathway leading to cell proliferation by a non-antioxidant mechanism.

Original languageEnglish
Pages (from-to)21-28
Number of pages8
JournalZeitschrift fur Ernahrungswissenschaft
Issue numberSUPPL. 1
Publication statusPublished - 1998


  • Antioxidants
  • AP-1 transcription factor
  • Arteriosclerosis
  • Protein kinase C
  • RRR-α-tocopherol
  • Smooth muscle cell proliferation

ASJC Scopus subject areas

  • Biochemistry
  • Medicine (miscellaneous)
  • Food Science


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