Vitamin E in Combination with Selenium Shown to Induce Self-Destruction of Human Prostate Cancer Cells

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Abstracted by Susan Sweeny Johnson, PhD, Biochem. Posted December 4, 2008.

Prostate cancer is the most common form of cancer in men, with an expected 186,320 new cases and 28,660 deaths in 2008 in the United States alone (1). About 16% of all men will be diagnosed with prostate cancer as they age; about 8% between 50 to 70 years of age. (2). Ninety-one percent are diagnosed at early stage before metastasis (2). Prostate cancer typically goes through a long progression beginning with a non-malignant hormone sensitive phase and then moving on to a metastatic, hormone insensitive phase. Nutritional mediation could slow the progression of the disease.

In a recent study, the researchers wanted to see if they could induce cell death in both early and late prostate cancer cells without harming normal prostate cells. They chose to examine the effects of vitamin E (+-α-tocopherol succinate) and selenium (methylselenic acid) on the viability of four different prostate cell lines: one representing early stage androgen-sensitive cancer, two representing later stage androgen-insensitive cancer, and one normal prostate cell line. The forms of vitamin E and selenium were chosen based on previous studies of bioactivity (3,4). Cell lines were incubated for 48 hours and then assessed for the action of vitamin E alone (5 micromolar (μM)) and selenium alone (2 μM), as well as together. 

Results showed that cell viability (% alive after incubation) dropped by about 20% with vitamin E alone and 10 – 25 % with selenium alone, while the normal prostate cells were not affected. When both vitamin E and selenium were used together, a 40-70% decrease in cell viability was observed for all three cancer cell lines, but there was no effect on the normal prostate cells. Cancer cell growth was significantly decreased (~30%) by a combination of vitamin E and selenium, but very little by each nutrient alone. Again, very little effect was seen with normal prostate cells. 

 The researchers additionally wanted to find a mechanism that would explain the action of vitamin E and selenium on cell death, so they looked at their effect on the production of certain known cell-death proteins. Once again, the combination of vitamin E and selenium increased the ratio of cell-death to cell-rescue protein synergistically, as compared to either nutrient alone.

These results provide support for further trials on the efficacy of supplementation with vitamin E and selenium together to slow the progression of prostate cancers in vivo.

Costs for traditional prostate cancer treatment vary by type of treatment. In the first six months, costs ranged from only $2,568 for watchful waiting to $24,204 for external beam radiation. Subsequent annual cost was found to average $7,740 and ranged from $5,843 for watchful waiting to $12,590 for androgen deprivation therapy (5).

Abstracted from “Combination of Vitamin E and Selenium Causes an Induction of Apoptosis of Human Prostate Cancer Cells by Enhancing Bax/Bcl-2 Ratio”, The Prostate 68:1624 ^1634 (2008).

References:

  1. Jemal A, Siegel R, Ward E, Hao Y, Xu J, Murray T, Thun MJ. Cancer Statistics, 2008. CA Cancer J Clin 2008;58:71–96.
  2. National Cancer Institute.
  3. Prasad KN, Kumar B, Yan XD, Hanson AJ, Cole WC. {alpha}- tocopheryl succinate, the most effective form of Vitamin E for adjuvant cancer treatment: A review. J Am Coll Nutr 2003;22:108–117.
  4. Ip C, Thompson HJ, Zhu Z, Ganther HE. In vitro and in vivo studies of methylseleninic acid: Evidence that a monomethylated selenium metabolite is critical for cancer chemoprevention. Cancer Res 2000;60:2882–2886.
  5. Medical News Today.

Men's Health-Prostate Health, Minerals-Selenium, Vitamin E