| Abstract: | 根據衛生福利部國民健康署資料統計顯示，惡性腫瘤(癌症)已蟬連多年冠軍，死亡率第一位的仍是肺癌。肺癌是一種生長於支氣管或肺泡的惡性腫瘤，有許多的危險因素都會提高肺癌的發生機率(包括吸菸、氡氣、石綿、空氣汙染、放射線物質、體質或遺傳以及其他因素)。而肺癌的症狀多為非特異性的，所以病患常常誤以為是其他原因早成的身體不適，而錯失治療的黃金時刻，造成肺癌的死亡率一直居高不下。多數腫瘤治療失敗的原因是因為轉移，轉移過程的結果取決於轉移癌細胞多重和複雜的相互作用，其中腫瘤細胞的侵襲是癌症轉移的第一步驟，而上皮間質轉化(eithelial-mesenchymal transition，EMT)是癌症轉移前一個很重要的機制。EMT的過程涉及細胞與細胞間連接的分解，肌動蛋白細胞骨架重組和增加細胞運動與侵襲，其特徵在於E-鈣黏蛋白(epithelial cadherin，E-cadherin)的表現量下降以及間質分子標誌物如波形蛋白(vimentin)、纖連蛋白(fibronectin)和N-鈣黏蛋白(neural cadherin，N-cadherin)的增加。茶是世界三分之二人口中最受歡迎的飲料。茶多酚是茶葉多酚類物質的總稱，包括黃烷醇類、黃酮類、黃酮醇類、花色苷類和酚酸類等。其中以黃烷醇類物質(兒茶素)最為重要，含量約占茶多酚總量的70%左右。綠茶含有許多眾所皆知的兒茶素，包括表兒茶素(epicatechin;EC)、表沒食子兒茶素(epigallocatechin;EGC)、表兒茶素沒食子酸酯(epicatechin-3-gallate;ECG)和表沒食子兒茶素沒食子酸酯(epigallocatechin gallate;EGCG)。許多的研究報導，EGCG具有抑制癌細胞的生長、調節細胞週期，誘導細胞凋亡，而同樣為兒茶素的ECG，似乎也有相同的功效，然而，ECG對人類肺癌EMT的影響仍然未知。因此本篇研究是以人類肺癌細胞株A549為實驗對象，進行裸鼠異種移植的體內試驗來檢測ECG的抗腫瘤效果。結果證實該化合物的皮下接種也抑制A549細胞在體內的腫瘤生長。因此，ECG有潛力可作用於人肺癌細胞的輔助治療和轉移控制的抗癌治劑。According to the statistics of the Health Promotion Administration of the Ministry of Health and Welfare, malignant tumors (cancer) have ranked first among the leading causes of death for years. In particular, lung cancer has exhibited the highest mortality rate. Lung cancer involves a type of malignant tumor growing in the bronchi or alveoli, and its incidence is affected by various risk factors (including, smoking, gaseous radon, asbestos, air pollution, radioactive materials, and physical or genetic factors).「Most symptoms of lung cancer are nonspecific, often causing patients to misjudge it as physical discomforts induced by other diseases and thereby miss the optimal treatment time.」 Consequently, the mortality rate of lung cancer remains high. Failures in tumor treatment are mostly caused by metastasis, which is related to the complex interactions between cancer cells. The invasion of tumor cells is the first step of metastasis, in which the epithelial-mesenchymal transition (EMT) is a crucial mechanism prior to this step. Specifically, this transition loosens cell–cell adhesion, enables the cytoskeleton recombination of actin cells, and thereby promotes cell movement and invasion. During the EMT, the epithelial cadherin is down-regulated, whereas mesenchymal molecular tags such as vimentin, fibronectin, and neural cadherin are up-regulated. Tea is a popular drink among two-thirds of the global population, and contains tea polyphenols such as flavanols, flavonoids, flavonols, anthocyanins, and phenolic acids. In particular, flavanols are highly crucial and accounted for approximately 70% of total tea polyphenols. Green tea contains various types of flavanol, including epicatechin (EC), epigallocatechin (EGC),epicatechin-3-gallate (ECG), and epigallocatechin gallate (EGCG). Studies have reported that EGCG can inhibit the growth of cancer cells, regulate cell cycles, and induce cell apoptosis. ECG seems to exhibit similar functions, but its effect on the EMT of lung cancer remains to be confirmed. Therefore, this study adopted the human alveolar basal epithelial cells A549 to conduct xenotransplantation in nude mice and examine the antitumor effect of ECG in situ. The results showed that the subcutaneous inoculation of ECG inhibited the tumor growth induced by A549 cells, verifying the potential of ECG as an anticancer drug for treating and controlling lung cancer. |
