探討resveratrol和osajin對鼻咽癌之抗腫瘤作用及機制

The anti-tumor effects and mechanisms of resveratrol and osajin in human nasopharyngeal carcinoma

黃宗騰(Tsung-Teng Huang)

指導教授 ： 劉阜果

國立中央大學/理學院/生命科學系/博士(2011年)

摘要

白藜蘆醇 (resveratrol) 為一天然多酚類化合物。先前研究指出白藜蘆醇具有誘導癌症細胞走向細胞凋亡之抗腫瘤的特性。然而尚未有研究指出白藜蘆醇對人類鼻咽癌細胞是否具相同之抗腫瘤特性，所以本研究則探討白藜蘆醇對人類鼻咽癌細胞之抗腫瘤作用及機制。實驗結果顯示，白藜蘆醇能有效的抑制人類鼻咽癌細胞的細胞存活率，且此細胞存活率的降低是由於細胞凋亡所引起。進一步探討白藜蘆醇造成鼻咽癌細胞凋亡的分子機制，發現白藜蘆醇會導致粒線體膜電位的破壞、細胞色素c (cytochrome c) 的釋放、Fas配位體 (FasL) 的增強表現及抑制葡萄糖調節蛋白78kDa (GRP78)的表現，並且伴隨著硫胱氨酸蛋白酶 (caspases) -3、-4、-8和 -9的活化，最後導致DNA的片段化及細胞死亡。除此之外，白藜蘆醇也能增強促細胞凋亡蛋白 (Bax) 的表現及抑制抗細胞凋亡蛋白 (Bcl-2) 的表現。因此，白藜蘆醇能透過粒線體、死亡受體及內質網受迫力 (ER stress) 等調控路徑誘導人類鼻咽癌細胞走向細胞凋亡。白藜蘆醇可作為鼻咽癌治療之有效化合物。
Osajin為一黃酮類化合物。先前研究同樣發現osajin具有抗腫瘤的特性，然而osajin造成腫瘤細胞死亡的機制尚未完全清楚。本研究同樣探討osajin對人類鼻咽癌細胞之抗腫瘤作用及機制。實驗結果顯示，osajin能有效的抑制人類鼻咽癌細胞的細胞存活率，且此細胞存活率的降低是由於細胞凋亡所引起。進一步探討osajin造成鼻咽癌細胞凋亡的分子機制，發現osajin會導致粒線體膜電位的破壞、細胞色素c (cytochrome c) 的釋放、Fas配位體 (FasL) 的增強表現及抑制葡萄糖調節蛋白78kDa (GRP78)的表現，並且伴隨著硫胱氨酸蛋白酶 (caspases) -3、-4、-8和 -9的活化，最後導致DNA的片段化及細胞死亡。除此之外，osajin同樣也能增強促細胞凋亡蛋白 (Bax) 的表現及抑制抗細胞凋亡蛋白 (Bcl-2) 的表現。因此，osajin也能透過粒線體、死亡受體及內質網受迫力 (ER stress) 等調控路徑誘導人類鼻咽癌細胞走向細胞凋亡。Osajin也可作為鼻咽癌治療之有效化合物。

關鍵字

細胞凋亡 ； 鼻咽癌

並列摘要

Resveratrol, a naturally occurring dietary compound with chemopreventive properties has been reported to trigger a variety of cancer cell types to apoptosis. Whether resveratrol shows any activity on human nasopharyngeal carcinoma (NPC) cells remained to be determined. The aim of this study was to investigate the effect and mechanism of resveratrol on human NPC cells. Treatment of resveratrol resulted in significant decrease in cell viability of NPC cell lines in a dose- and time-dependent manner. A dose-dependent apoptotic cell death was also measured by flow cytometery analysis. Molecular mechanistic studies of apoptosis unraveled resveratrol treatment resulted in a significant loss of mitochondrial transmembrane potential, release of cytochrome c, enhanced expression of Fas ligand (FasL), and suppression of glucose-regulated protein 78 kDa (GRP78). These were followed by activation of caspases-3, -4, -8 and -9, subsequently leading to DNA fragmentation and cell apoptosis. Furthermore, up-regulation of proapoptotic Bax and down-regulation of antiapoptotic Bcl-2 protein were also observed. Taken together, resveratrol induces apoptosis in human NPC cells through regulation of multiple apoptotic pathways, including death receptor, mitochondria and endoplasmic reticulum (ER) stress. Resveratrol can be developed as an effective compound for human NPC treatment.
Osajin is a prenylated isoflavone showing antitumor activity in different tumor cell lines. The underlying mechanism of osajin-induced cancer cell death is not clearly understood. In the present study, the mechanisms of osajin-induced cell death of human nasopharyngeal carcinoma (NPC) cells were explored. Osajin was found to significantly induce apoptosis of NPC cells in a dose- and time-dependent manner. Multiple molecular effects were observed during osajin treatment including a significant loss of mitochondrial transmembrane potential, release of cytochrome c into the cytosol, enhanced expression of Fas ligand (FasL), suppression of glucose-regulated protein 78 kDa (GRP78), and activation of caspases-3, -4, -8 and -9. In addition, up-regulation of proapoptotic Bax protein and down-regulation of antiapoptotic Bcl-2 protein were also observed. Taken together, osajin induces apoptosis in human NPC cells through multiple apoptotic pathways, including the extrinsic death receptor pathway, and intrinsic pathways relying on mitochondria and endoplasmic reticulum stress. Thus, osajin could be developed as a new effective and chemopreventive compound for human NPC.

並列關鍵字

nasopharyngeal carcinoma ； apoptosis

參考文獻

radiotherapy in advanced nasopharyngeal carcinoma. J

Endoplasmic reticulum stress-induced caspase-4

Huang DC, O''Reilly LA, Strasser A, Cory S. (1997) The anti-

Yu MC, Huang TB, Henderson BE. (1989a) Diet and

Yu MC, Nichols PW, Zou XN, Estes J, Henderson BE. (1989b)