我們過去發現檳榔子的萃取液（areca nut extract, ANE）可誘導細胞進行自體吞噬（autophagy）的死亡，並且得知此活性位於ANE 30-100 kDa 的部分，命名為ANE30-100K。我們已知在細胞培養模式中，幾種不同的癌細胞經過低濃度且不具細胞毒性濃度的ANE 或ANE30-100K 處理約三週，會透過自體吞噬活性的增強而對無血清，與順鉑（cisplatin, DDP）均有較高的耐受性。本研究擬進一步觀察經過類似處理的癌細胞是否亦會透過自體吞噬作用在裸鼠體內有較佳的生長情形。因此，我們選用可以在裸鼠體內生長的食道上皮癌細胞株CE81T/VGH，首先，細胞培養模式顯示在經過三週ANE 30-100K 的處裡後，CE81T/VGH 細胞對無血清與低氧環境均有較高的耐受性，並且在這兩種環境下，對DDP 也有較強的抗藥性；此外，自體吞噬抑制劑奎寧（chloroquine, CQ）與DDP，對這種經ANE 30-100K 處理過的CE81T/VGH細胞在抑制生長上有協同的效果。另一方面，經ANE 或ANE 30-100K 處理三週後的CE81T/VGH，在裸鼠體內也有顯著較佳的生長，單獨使用CQ 與單獨使用DDP 的抑癌效果類似，而合併使用此二者則可以達到協同抑制腫瘤生長的效果。這些結果顯示檳榔族中腫瘤細胞的生長有可能特別依賴自體吞噬，因此值得在未來治療上考慮使用諸如CQ 的自體吞噬抑制劑。本文最後亦附上我們試圖探討ANE 30-100K 作用機轉的實驗結果。 We found that the crude extract of areca nut (ANE) can induce autophagic cell death. This activity is located in the 30-100 kDa fraction of ANE, designated as ANE 30-100K. We also noticed that several different cancer cells showed higher resistance against serum starvation and cisplatin (DDP) after treatment of low concentrations of ANE or ANE 30-100K for about three weeks. This study was to verify whether similarly ANE or ANE 30-100K treatment for cancer cells results in better growth in nude mice. CE81T/VGH cells were chosen for its ability to grow in nude mice. Firstly, cell culturing model showed that CE81T/VGH cells exhibited stronger tolerance against serum deprivation and hypoxia conditions after 3-week ANE 30-100K treatment. Furthermore, the autophagy inhibitor, chloroquine (CQ), acted synergistically with DDP to inhibit ANE 30-100K-treated CE81T/VGH cells. On the other hand, CE81T/VGH cells also achieved better growth significantly in nude mice after 3-week ANE or ANE 30-100K treatment. Single reagent treatment with CQ or DDP received similar effects; however, combimed CQ and DDP application resulted in synergistic reduction in tumor sizes. These results suggest that the growth of tumors in AN users may particularly rely on autophagy, which highlights the possible values to include autophagy inhibitors like CQ in future treatment. Finally, the results of our attempt to explore the mechanism of ANE 30-100K were also given in the last section.
