| 摘要: | 在棕櫚油及米糠油中含量豐富的生育三烯醇被證明具有抗癌、降血壓及降低膽固醇等的功效。本研究目的為：(1)檢測α-生育醇與α-,γ-,δ-生育三烯醇作用於3T3-L1脂肪細胞後之細胞存活率；(2)分析γ-生育三烯醇作用於3T3-L1脂肪細胞後細胞週期(cell cycle)變化、活性氧自由基(ROS)生成量、粒線體膜電位（ΔΨm）之變化及DNA斷裂情形；(3)探討γ-生育三烯醇對細胞凋亡及脂肪細胞分化相關分子機制之影響。結果顯示γ-T3其半數致死劑量(IC50)為13.91 ± 0.25 μΜ，為抑制細胞增生之最佳藥物。γ-T3能有效的誘導細胞凋亡、促進細胞活性氧自由基的生成，造成細胞粒線體膜電位下降及細胞週期停滯在S期。在20 μM處理下，γ-T3能顯著的造成DNA斷裂片段出現。西方墨點法分析結果發現γ-T3會活化p53, CD95（APO-1/CD95）及Bax之表現，造成粒線體中的cytochrome c釋放到細胞質，而使caspase-3活化，促使PARP分裂，這些表現情形均呈劑量及時間效應。另外，細胞經γ- T3處理後，並不影響JNK, p-JNK, p38, p-p38和AMPK等蛋白質的表現，但卻會調降Akt, p-Akt, ERK, p-ERK, PPAR-γ等蛋白質及升調p-AMPK的表現。這些結果顯示，γ-T3對於3T3-L1脂肪細胞具有抗細胞增生，其造成細胞凋亡係透過(CD95APO-1/CD95)系統及粒線體訊息傳遞路徑。
Tocotrienols of palm oil and rice bran oil have been shown to possess potent anticancer, lower blood pressure and cholesterol-lowering activities. In this study, our aims were (i) to evaluate the antiproliferative activities of α-, γ- and δ-tocotrienols (α-T3, γ-T3, and δ-T3), and α-tocopherol (αT) in 3T3-L1 adipocytes, (ii) to study the effects of γT3 on the cell cycle distribution, ROS production and mitochondrial membrane potential, and (iii) to examine the apoptotic and the adipogenesis molecular mechanism (s) of action in 3T3-L1 cells. The results showed that γ-T3 was the most effective, with an IC50 value of 13.91 ± 0.25 μM. It effectiveness induced the 3T3-L1 cells apoptosis, caused ROS formation, collapse of the mitochondrial membrane potential and cell cycle perturbation (S-phase arrest). At 20 μM, γ-T3 significantly increased the accumulation of the DNA fragmentation. Western blot data revealed that γ-T3 treatment increased the expression of active p53, CD95 (APO-1/CD95), and led to up-regulation of Bax and release cytochrome c from mitochondria to cytosol, as well as causing the caspase-3 activation, and PARP cleavage in a dose- and time-dependent pattern. Furthermore, γ-T3 did not affect the expression of JNK, p-JNK, p38, p-p38 and AMPK proteins, however it down-regulated the Akt, p-Akt, ERK, p-ERK, and PPAR-γ levels and up-regulated the expression of p-AMPK. These results suggest that γ-T3 has contributed to the potent antiproliferative activity and apoptosis in 3T3-L1 adipocytes through the CD95 (APO-1/CD95) system and the mitochondrial signaling transduction pathway. |
