Positive Health Online

Abstract

VENKATESWARAN and colleagues, Division of Urology, Sunnybrook and Women's College Health Science Centre, Toronto, Ontario, Canada, describe the modulation of cell proliferation and cell cycle regulators by vitamin E in human prostate carcinoma cells.

Background

Vitamin E has been put forward as a candidate for the prevention of prostate cancer . This effect may be in part due to inhibition of the cell cycle rather than only due to vitamin E's action as an antioxidant . The study aimed to test whether vitamin E induces an arrest of the cell cycle mediated by alterations in cell cycle regulatory proteins including cyclin E, cdk2 and p27 .

Methodology

Cells in culture were incubated with and without alpha- tocopherol (vitamin E) succinate at 20 micrograms per millilitre, then fixed and stained with propidium iodide for flow cytometry analysis . In parallel experiments, total protein was extracted and analyzed immunologically with cyclin E antibodies for expression of cell cycle regulators.

Results

Flow cytometry revealed a dramatic reduction of percentage of cells in the S phase in response to vitamin E in two different cell lines (69% and 95%, respectively). This was accompanied by a 3-fold increase of the cell cycle regulator protein p27 .

Conclusion

The study demonstrates that at physiological concentrations vitamin E induces profound cell cycle arrest mediated by up-regulation of p27 . This observation provides a theoretical basis for the cancer prevention effect of vitamin E .

References

Venkateswaran V, Fleshner NE, Klotz LH. Modulation of cell proliferation and cell cycle regulators by vitamin E in human prostate carcinoma cell lines. The Journal of Urology 168 (4 Pt 1): 1576-1582, Oct 2002.