探討具有保護作用細胞自噬減弱喜樹鹼抗肺癌細胞增生之機制

The role of autophagy in camptothecin-treated lung cancer cells

徐紹瑋(Shau-Wei Hsu)

指導教授 ： 許世賢

共同指導教授 ： 邱建智(Chien-Chih Chiu)

高雄醫學大學/醫學院/醫學研究所/基礎醫學組/碩士(2014年)

摘要

肺癌在世界各地的罹患率極高。除了罹患率高之外，也已名列在全世界的十大死因之一。儘管已經有許多抗癌藥的發明，但是對於肺癌之療效仍然是有其限制而導致預後不佳。造成高致死率的原因除了因為肺癌容易轉移外，主要還有肺癌對於抗癌藥所產生的抗藥性。喜樹鹼(camptothecin)是一種已經廣為人知的抗癌藥物，其效用可以藉由引發DNA損害(DNA damage) 導致細胞走向凋亡(apoptosis)。然而喜樹鹼對於抗肺癌增生的效用在較高的濃度下(1、2、5及10 μM)是很有限的。且喜樹鹼相關衍生物在臨床上也被報導有副作用的產生。根據我們的實驗結果顯示，喜樹鹼的處理也會伴隨細胞自噬(autophagy)作用的產生。經由細胞增生實驗，我們發現喜樹鹼所誘導的細胞自噬作用有助於細胞的存活。同樣地，從細胞凋亡(Annexin V染色)實驗也發現，喜樹鹼所誘導的細胞自噬確實會保護細胞，防止細胞走向細胞凋亡路徑。相反地，如果利用3-甲基腺嘌呤(3-Methyladenine)去抑制細胞自噬的發生，喜樹鹼在肺癌細胞上的抗增生能力將會增加。此外，除了增加喜樹鹼的抗增生能力外，也會增強喜樹鹼所造成的DNA損傷。根據以上的結果，我們推測發現喜樹鹼所誘導的細胞自噬在肺癌細胞中是扮演著一個保護的角色。因此，未來可以針對這些因抗癌藥物所引起的保護性細胞自噬，篩選專一性的細胞自噬抑制劑與抗癌藥物共同處理，希望能藉此方式達到更好的肺癌治療效果，發展對於治療肺癌具有潛力的策略。

關鍵字

喜樹鹼 ； DNA損傷 ； 細胞自噬 ； 抗藥性 ； 細胞凋亡

並列摘要

Lung cancer is a prevalent disease and one of leading death causes throughout world. Despite various anti-cancer drugs have developed, the cure rate of lung cancer is still low. Not only metastasis of lung cancer but drug resistance result in high mortality of lung cancer patients Camptothecin (CPT) is a well-known anti-cancer drug which causes cancer cell apoptosis through inducing DNA damage. However, the anti-proliferative effect of CPT on lung cancer cells easily reaches a plateau at relative high dose, therefore, causing side effects for further clinical applications. Our results showed that CPT also induced autophagy in lung cancer H1299 cells concomitantly. Furthermore, the proliferation assay showed the pro-survival effect of autophagy induced by CPT in H1299 cells. Likewise, the result of annexin v-staining showed that CPT-induced autophagy protects lung cancer cells from cell programmed death. On the contrary, the anti-proliferative effect of CPT is increased when autophagy is blocked by3-Methyladenine (3-MA) treatment. Besides, the inhibition of autophagy enhances the level of CPT-induced DNA damage in tested lung cancer cell lines. Accordingly, our recent work suggests the protective role of autophagy in CPT-induced lung cancer cells, and the combination of CPT and specific inhibitor of autophagy could be a promising strategy for lung cancer treatment in further applications.

並列關鍵字

CPT ； DNA damage ； autophagy ； drug resistance ； apoptosis

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