Abstract | OBJECTIVE:
gamma-Tocotrienol is a major component of the tocotrienol-rich fraction of palm oil, but there is limited evidence that it has antitumor activity. In particular, the effects of gamma-tocotrienol on human colon carcinoma cells have not been reported. To investigate the chemopreventive effects of gamma-tocotrienol on colon cancer, we examined its capacity to inhibit proliferation and induce apoptosis in HT-29 cells and explored the mechanism underlying these effects. METHODS: RESULTS:
gamma-Tocotrienol inhibited cell growth and arrested HT-29 cells in G(0)/G(1) phase. The 50% inhibitory concentration was 31.7 micromol/L (48 h). gamma-Tocotrienol-induced apoptosis in HT-29 cells was accompanied by downregulation of Bcl-2, upregulation of Bax, and activation of caspase-3. Furthermore, we found that gamma-tocotrienol reduced the expression level of total nuclear factor-kappaB p65 protein and inhibited its nuclear translocation. CONCLUSION: The results indicated that gamma-tocotrienol inhibits cell proliferation and induces apoptosis in HT-29 cells in a time- and dose-dependent manner, and that this process is accompanied by cell-cycle arrest at G(0)/G(1), an increased Bax/Bcl-2 ratio, and activation of caspase-3. Our data also indicated that nuclear factor-kappaB p65 protein may be involved in these effects.
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Authors | Wei-Li Xu, Jia-Ren Liu, Hui-Kun Liu, Gui-Yun Qi, Xiang-Rong Sun, Wen-Guang Sun, Bing-Qing Chen |
Journal | Nutrition (Burbank, Los Angeles County, Calif.)
(Nutrition)
Vol. 25
Issue 5
Pg. 555-66
(May 2009)
ISSN: 1873-1244 [Electronic] United States |
PMID | 19121919
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Anticarcinogenic Agents
- BAX protein, human
- Chromans
- Proto-Oncogene Proteins c-bcl-2
- Transcription Factor RelA
- bcl-2-Associated X Protein
- Vitamin E
- plastochromanol 8
- Caspase 3
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Topics |
- Anticarcinogenic Agents
(pharmacology, therapeutic use)
- Apoptosis
(drug effects)
- Blotting, Western
- Caspase 3
(metabolism)
- Cell Proliferation
(drug effects)
- Chromans
(pharmacology, therapeutic use)
- Colonic Neoplasms
(prevention & control)
- DNA Fragmentation
- Dose-Response Relationship, Drug
- Enzyme Activation
- G1 Phase
(drug effects)
- HT29 Cells
- Humans
- Inhibitory Concentration 50
- Mitotic Index
- Proto-Oncogene Proteins c-bcl-2
(metabolism)
- Resting Phase, Cell Cycle
(drug effects)
- Transcription Factor RelA
(drug effects, metabolism)
- Vitamin E
(analogs & derivatives, pharmacology, therapeutic use)
- bcl-2-Associated X Protein
(metabolism)
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