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Title: | 靈芝酸T對肺癌細胞株之抗癌活性研究 Studies on the Anticancer Activity of Ganoderic Acid T in Lung Cancer Cells |
Authors: | Hsiao-Hsuan Lai 賴曉萱 |
Advisor: | 林淑萍(Shwu-Bin Lin) |
Keyword: | 肺癌,靈芝三萜,類,靈芝酸T,細胞自噬,上皮間葉細胞轉化,抗癌藥, Lung cancer,Ganoderma triterpenoid,Ganoderic acid T,Autophagy,Epithelial-mesenchymal transition,Anti-cancer agent, |
Publication Year : | 2010 |
Degree: | 碩士 |
Abstract: | 肺癌為全世界當前發生頻率最高且預後差的癌症,其高致死率使它近年來竄升為癌症死亡原因的首位。儘管目前醫學對於肺癌已經有早期診斷以及標準的治療流程,多數肺癌患者經診斷後,其癌症病程可能已至第三期或第四期,且伴隨遠端轉移以及較差的預後,因此如何有效的治療肺癌上為當前熱門的研究領域。靈芝是一種在亞洲國家被廣泛使用的傳統中藥,而其中的活性成分三萜類為已有許多研究接證實靈芝中其具有抗癌的功效。由於在肺癌中,肺腺癌所佔的比例為大多數,因此本研究欲探討由靈芝中所純化出之三帖類靈芝酸T (Ganoderic acid T, GAT)作用在肺腺癌細胞上的抗癌效果。以GAT處理多種肺腺癌細胞株後,我們觀察到將癌細胞維持在含有低血清濃度的培養液時,GAT能夠抑制多種肺癌細胞株生長且在高濃度具有毒殺的效果,而同樣濃度的GAT處理並不影響人類單核球細胞的存活。進一步挑選了其中生長能力最旺盛的A549肺癌細胞株探討其中機制。實驗發現,GAT能夠誘導A549細胞發生不可逆的細胞自噬現象進而造成細胞死亡。此外,由於肺癌是一具有高度的轉移能力的癌症,因此我們也探討了GAT是否具有抑制癌細胞轉移的能力。上皮間葉轉化(Epithelial-mesenchymal transition, EMT)是指細胞從上皮細胞型態轉變成間葉細胞型態,當細胞發生EMT的轉變時,癌細胞的性質改變、細胞爬行能力增加,使其能侵入微血管壁並且進入血流中,進而能夠轉移至其他的器官。我們以TGF-β誘使A549肺癌細胞發生EMT,並且同時給予GAT處理。結果顯示,GAT確實能抑制TGF-β所誘發之A549細胞的EMT探討其中的分子機制,我們發現GAT能夠防止TGF-β所誘導的細胞內ROS上升,抑制其下游ERK蛋白的活化,進而抑制EMT活化分子Slug的表現,使得EMT相關的基因調控受到限制來達到抑制EMT的效果,包括能夠使經TGF-β誘導的A549細胞不發生型態上的改變,阻止與上皮細胞特性相關蛋白基因(E-cadherin)表現下降、抑制與間葉細胞特性相關蛋白基因(N-cadherin, CXCR4)表現上升以及抑制細胞爬行能力增加。此外我們也利用動物實驗來探討GAT在體內抑制腫瘤生長以及轉移的效果。將A549肺癌細胞株接種於小鼠皮下後再給予GAT治療,結果顯示腫瘤內注射GAT能有效抑制腫瘤的生長與轉移並且不影響的小鼠體重與活動力。而以口服的方式給予小鼠GAT亦能有效抑制A549肺腺癌腫瘤的生長且不影響小鼠的存活。綜合以上結果,本研究從體外細胞實驗與體內動物實驗皆證實了GAT抗肺腺癌的活性,顯示靈芝酸T具有成為抗癌藥物或癌症輔助治療藥物的潛力,也從中證實了靈芝三萜類的抗癌效能。 Lung cancer is one of the most common malignant diseases with a dismal prognosis; the high mortality rate has made it one of the leading causes of cancer-related death over the past years. Despite of advances in early detection and cancer therapy, most patients with lung cancer present with advanced disease and their long-term prognosis remains poor. Therefore, providing an effective treatment for lung cancer is important. Lingzhi has long been reputed as anticancer medicinal mushroom in folk medicine. The bioactive component triterpenoids have been known as anticancer ingredients of the medicinal mushroom. As adenocarcinoma is the most prevalent subtype of lung cancer, we are interested in investigating the anti-cancer efficacy of a ganoderma triterpenoid, ganoderic acid T (GAT), in lung adenocarcinoma cells. Our data revealed that GAT displayed growth inhibitory and cytotoxicity effects on various lung adenocarcinoma cell lines whereas it exerted no effect on the survival of normal human peripheral blood mononuclear cells. The mechanism of GAT-induced cytotoxicity was studied further and GAT was found to induce irreversible autophagic response thus resulted in autophagic cell death in highly proliferative A549 cells. Besides, as lung cancer is considered to be highly metastatic and a great majority of patients are found with distant metastases, we also accessed the anti-metastatic potential of GAT. Epithelial-mesenchymal transition (EMT) is a biological process which allows stationary epithelial cells to become motile. By using a TGF-β-induced-EMT cell model, GAT was found to act as a protective role in TGF-β-induced-EMT through blocking ROS generation, pERK activation and the EMT-activator Slug expression thus prevent further cell morphological change, transcriptional regulation (including E-cadherin loss as well as N-cadherin and CXCR4 up regulation) and further cell migration. Finally, the anti-cancer efficacy of GAT in vivo was confirmed in SCID mouse xenograft model. The results of animal experiments indicated that intra-tumor GAT injection can restrain the growth of A549 tumors subcutaneously implanted in the mice and prevent further hepatic metastasis. Besides, oral treatment of GAT can successfully restrain the growth of A549 tumors and exerts no toxicity to SCID mice. Taken together, the anticancer activity of triterpenoids from Lingzhi is confirmed in this study. Thus, GAT is a potential anti-cancer agent or therapeutic drug adjuvant for cancer treatment. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/10752 |
Fulltext Rights: | 同意授權(全球公開) |
Appears in Collections: | 醫學檢驗暨生物技術學系 |
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