柚皮素增敏人類口腔癌SAS細胞促進TRAIL引起的細胞凋亡機轉之研究

The Study of Naringenin Sensitizes Human Oral Cancer SAS Cells to TRAIL-induced Apoptosis

林安安(An-An Lin)

指導教授 ： 陳信銘

國立臺灣大學/牙醫專業學院/口腔生物科學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.10884

摘要

口腔癌發生率與死亡率的排名居高不下，且口腔癌為癌症個案數增加之前5名。目前口腔癌的治療仍以手術為第一線，放射線治療、化學治療和免疫療法佐以輔助手術治療。在化學治療方面，其使用藥物經常會影響生長快速的細胞，因此，患者可能會產生抵抗力降低、失去食慾、噁心、嘔吐或口腔潰瘍等副作用出現。
如何找到毒性低的化學治療藥物，具有良好的抗癌效用並不會對正常細胞造成影響，以改善目前的癌症治療方法，成為目前癌症研究的主要趨勢之一。
柚皮素(Naringenin)屬於黃烷酮類，是類黃酮的一種。已有不少研究指出，柚皮素具有降血脂、抗發炎、抗氧化、抗腫瘤增生及轉移等作用。而TRAIL[Tumor necrosis factor (TNF) related apoptosis-inducing ligand]在近年來被視為良好的抗癌藥劑，可以有效地在癌症細胞而不在正常細胞引發細胞凋亡，但許多種人類的癌症細胞對於TRAIL有阻抗性的現象產生，導致不少病患對TRAIL的治療沒有反應。因此本實驗來探討柚皮素與TRAIL合併使用後，其對於人類口腔癌細胞株SAS的影響，並了解其可能的作用機制。
結果顯示，不論以柚皮素或TRAIL處理細胞，皆不會造成顯著細胞存活率變化，但以柚皮素與TRAIL合併使用後，可以顯著地降低細胞存活率。以各種螢光染色分析及流式細胞儀分析發現柚皮素與TRAIL兩者合併使用後，皆比個別分別使用時，可以顯著地增加細胞凋亡的比例。
之後以西方墨點法分析顯示柚皮素與TRAIL協同造成的細胞凋亡主要是經由外生性細胞凋亡路徑的活化。進一步研究發現，隨著柚皮素濃度與時間的增加，不論是在蛋白質或mRNA方面，會使DR5表現上升及XIAP表現量下降，也因此造成外生性細胞凋亡路徑的活化，進而誘發細胞凋亡。
總結來說，柚皮素可以藉由增加DR5的表現及降低XIAP、cIAP-1的表現，促進外生性細胞凋亡路徑，因此加上低濃度TRAIL時，便會加乘性地造成細胞凋亡。

關鍵字

口腔癌 ； 柚皮素 ； TRAIL ； DR5 ； XIAP ； 細胞凋亡

並列摘要

Oral cancer incidence and mortality rank high, and the increased number of oral cancer cases are within the top 5 in Taiwan. Currently the frontline therapy of oral cancer is still surgery. Radiation therapy, chemotherapy and immunotherapy are combined as an adjunctive therapy. The drugs used in chemotherapy often affect the fast-growing cells, so patients may cause low immunity, loss of appetite, nausea, vomiting, mouth ulcers and other side effects. How to find chemotherapeutic agents with low toxicity that does not affect normal cells is one of the main trends in cancer research.
Naringenin is a flavonoid that is believed to have a bioactive effect on human health. Several previous studies had demonstrated that naringenin exhibits aorta dilatory, antioxidant, antiestrogenic, anti-proliferative and antimetastatic effects.
TRAIL[Tumor necrosis factor (TNF) related apoptosis-inducing ligand] has attracted even more attention because TRAIL can induce apoptosis in most cancer cells and not affect normal cells. The emergence of resistance to TRAIL is a major problem that limits its utility as a therapeutic. In this study, we investigated the effect and the possible mechanism of naringenin plus TRAIL in human oral cancer SAS cells.
Our results revealed that naringenin and TRAIL could not change cell viability individually. When naringenin combined with TRAIL, cellular activity was significantly decreased and the proportion of apoptosis was increased by a variety of fluorescent staining and flow cytometry.
Then we found out that the apoptosis caused by naringenin plus TRAIL is mainly through the activation of extrinsic pathway. Further studies showed that naringenin dose -and time-dependently up-regulates DR5 expression and down-regulates XIAP expression in protein and mRNA level. Thus, the activated extrinsic pathway caused apoptosis.
Summary, our results showed that naringenin may enhance the apoptotic extrinsic pathway by up-regulating DR5 expression and down-regulating XIAP、cIAP-1 expression. Furthermore, co-treatment with naringenin and TRAIL resulted in apoptosis synergistically.

並列關鍵字

Oral cancer ； naringenin ； TRAIL ； DR5 ； XIAP ； apoptosis

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