BACKGROUND: Preliminary clinical trials have found that vitamin E supplements can reduce the risk of prostate cancer. Vitamin E may be protective because it is an antioxidant and capable of preventing cell mutations. However, it may reduce the risk of prostate cancer through other mechanisms as well.
RESEARCH: Researchers grew two different types of human prostate cancer cells with and without vitamin E succinate, a common form of the vitamin. They studied the details of cell growth, particularly the gene regulation of p27, a key protein that controls cell growth.
RESULTS: Vitamin E reduced the growth of the two types of prostate cancer cells by 95 and 69 percent. Vitamin E also increased gene production of protective p27 three-fold, and it appeared that the increase in p27 was responsible for the cessation of cell growth and replication.
IMPLICATIONS: The significant increase in the protective p27 protein following exposure to vitamin E is consistent with clinical observations, which show that high p27 is associated with better survival of prostate cancer patients and that low p27 levels are linked to poor survival. The researchers wrote that p27 "has a role in normal prostate cell cycle regulation and, restoration of normal p27 protein expression is a route by which prostate cancer may be manipulated therapeutically." Although normal cells were not used for comparison, other studies have found that vitamin E succinate had no adverse effect on normal cells. Caution must be used in relating the results of cell culture studies to humans. Orally ingested vitamin E succinate is known to be cleaved during the digestive process.
Venkateswaran V, Fleshner NE, Klotz LH. "Modulation of cell proliferation and cell cycle regulators by vitamin E in human prostate carcinoma cell lines," Journal of Urology, 2002;168:1578-1582.
For the original abstract, visit: http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12352461&dopt=Abstract