Positive Health Online

Abstract

ZU and IP, Department of Cancer Chemoprevention, Roswell Park Cancer Institute, Buffalo, New York 14263, USA, have researched the synergistic effects of vitamin E and selenium in the prevention of prostate cancer.

Background

The ongoing Selenium and Vitamin E Chemoprevention trial is designed to evaluate the efficacy of these two agents, singly and in combination, in protecting against prostate cancer. Little is known however about possible synergistic effects of the two chemicals.

Methodology

In vitro study using human prostate cancer cells in culture.

Results

The most growth-inhibitory form of vitamin E was alpha-tocopheryl succinate. Combining this with methylselenic acid, a selenium metabolite, produced a synergistic effect on cell growth suppression. The synergy was accounted for by an increased apoptotic response, ie, an increase in programmed cell death. It was shown that specific caspases were activated by either of the two agents or both.

Conclusion

The authors propose that the mitochondrial pathway for apoptosis and the endoplasmic reticulum stress / cytokine signalling pathway might be involved in apoptosis induction by vitamin E and selenium, respectively. These two pathways may act in a cooperative manner to switch on the full apoptotic response when cancer cells are treated with both agents.

References

Zu K, Ip C. Synergy between selenium and vitamin E in apoptosis induction is associated with activation of distinctive initiator caspases in human prostate cancer cells. Cancer Research 63 (20): 6988-6995, Oct 2003.