#A149 Gamma-Tocopherol is Superior to alpha-Tocopherol at Growth Arrest of Human Colon Cancer Cell Lines, HCT-116 and SW480. Sharon Campbell, Sarah Whaley, Devin Sherman, William Stone, Koyamangalath Krishnan, East Tennessee State Univ., Johnson City, TN. Background: gamma-tocopherol is a major component of tocopherols in the US diet and the second most common tocopherol in the human serum. Until recently, most of the antioxidant and protective effects of tocopherols have been focused only on alpha-tocopherol. alpha-Tocopherol is the main form of vitamin E in supplements. gamma-Tocopherol is present in rich amounts in plant seeds (corn, soybean, sesame), vegetable oils and nuts (walnuts, pecans and peanuts. Epidemiological and experimental data show that delta-tocopherol is more efficient at prostate cancer prevention than the alpha-form. gamma-Tocopherol (vitamin E) may be more efficient than alpha-tocopherol in arresting cancer progression. Methodology: The effects of the vitamin E isoforms at different concentrations (25, 50, 100, 150, 200 ìm) on cell viability were monitored in SW 480 (APC truncated, COX-2 negative) and HCT 116 (APC wild type, COX-2 inducible) colon cancer cell lines. The Live/Dead Viability/Cytotoxicity Assay Kit (Molecular Probes, Eugene, OR) was employed along side the standard trypan blue stain and cell counting at 100 ìM. In addition, apoptosis studies were employed at 100 ìM tocopherols at 2.5, 5.0 and 24 hours of treatment. Results: In both HCT 116 and SW 480 cell lines, maximal cell death occurred at a concentration of 100 ìm for both alpha-tocopherol and gamma-tocopherol. In HCT 116 cell lines, gamma-tocopherol was able to kill 71% and 100% of the cells at days 2 and 5; alpha-tocopherol was able to kill only 42% and 41%. In SW 480 cell lines, alpha-tocopherol was able to kill 43% and 74% of the cells at day 2 and day 5 compared to 18% by delta-tocopherol. Caspase-3 activity was observed to increase above the blank in both cell lines at 24 hours indicating induction of caspase-3-mediated apoptosis. gamma-Tocopherol resulted in higher caspase-3 activation than alpha-tocopherol. Conclusions: Our work adds to the growing body of evidence that supports the idea that gamma-tocopherol may be the more relevant form of vitamin E in cancer prevention. We show a differential effect of gamma-tocopherol and alpha-tocopherol in their ability to induce cell death in two human colon cancer cell lines with different molecular characteristics. In both cell lines at the time and concentration tested, gamma-tocopherol is more efficient in inducing cell death. The molecular basis of these differences are being explored. gamma-Tocopherol needs to be given more attention in colon cancer prevention strategies and in human nutrition models. Ann's NOTE: This is so interesting given that it is only in the last few years that the 'lay' public at least, has even heard that vitamin E is not JUST alpha-tocopherol. Now there are studies indicating that just using the alpha-tocopherol may drain the other elements of vitamin E. Consider adding delta, (is there a beta?) gamma tocopherol, etc and tocotrienols. Frontiers in Cancer Prevention Research, 2003 AACR Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.