Therapeutic Potential Of Tocotrienols On Breast Cancer

Author

Kalanithi Nesaretnam, Malaysian Palm Oil Board, Persiaran Insitusi Bandar Baru Bangi, 43000 Kajang, Malaysia

Proceeding

1st International Conference & Exhibition on Women's Health & Asian Traditional (WHAT) Medicine

Date

23/8/2005

Keyword

tocotrienols , nutritional supplements, antioxidant, cholesterol levels, atherosclerosis, breast cancer , clinical studies, antiproliferative effects

Abstract

Tocotrienols are emerging as one of the new nutritional supplements that appear to play a beneficial role in reducing the risk of certain diseases. Scientific evidence has shown that in addition to being powerful biological antioxidants, these compounds may reduce cholesterol levels in people with hypercholesterolemia, may slow down the progression of atherosclerosis, and inhibit the proliferation and growth of human breast cancer cells. Tocotrienols are fat soluble vitamins related to the family of tocopherols. The only difference between tocopherols and tocotrienols is the presence of three double bonds in the carbon side chain of the tocotrienol molecule. Commercial quantities are extracted from the distillates of palm oil and rice bran oil. Tocotrienols have been the focus of increasing research interest in the last 5-10 years. Given the marginal breakthrough of therapeutic solutions, the development of more effective biological therapies for breast cancer is under intense investigation. Naturally occurring agents such as fat soluble vitamins (A, D, E and K) have been investigated for anticancer properties and found to possess antiproliferative effects. In this paper evidence is presented that palm oil tocotrienols, have potential in the prevention of breast cancer. Evidence is provided by both in vivo, in vitro and clinical studies. In the animal experiment where a chemical carcinogen, dimethyl benzanthracene (DMBA), was used to initiate cancer, rats fed palm oil stripped of its vitamin E showed increased tumour incidence and numbers compared to rats fed palm oil with its vitamin E intact. When further tested on human breast cancer cell lines, tocotrienols were able to inhibit the proliferation of both oestrogen receptor negative and positive cell lines at very low concentrations. In comparison, a-tocopherol, the vitamin E available commercially, had no similar effect on both the in vivo and in vitro systems studied. Further in vivo findings on athymic nude mice showed the role of natural killer cells in inhibiting tumourigenesis and metastasis. Therapy for breast cancer comes in the form of drugs such as tamoxifen which are oestrogen antagonists. However, tamoxifen in some instances works as an oestrogen agonist and after sometime breast cancer cells develop resistance to tamoxifen therapy. Tamoxifen also works best on women who have oestrogen receptor positive tumours which represents only 30% of breast cancer tumours. In our experiments, tocotrienols worked on both oestrogen receptor positive and negative cells. This has led to a clinical trial on primary breast cancer patients. The current status in this actively developing field will be presented.