2020-08-012024-05-17https://scholars.lib.ntu.edu.tw/handle/123456789/689988肺癌是全世界高死亡率的癌症之一，其中有高達85%肺癌是屬於非小細胞肺癌。化學治療為肺癌治療的處理方式之一，通常第一線的化療藥物以鉑類的化合物為主，再共同處理第二及第三線的毒殺細胞化學藥物。愛寧達(pemetrexed; Alimta)是新一代葉酸拮抗劑，可作為單一或第二線藥物治療非小細胞肺癌病患。一般而言，接受化療的肺癌病人可增加平均一年的存活率，但效果十分有限，這與化學治療產生抗藥性有關。硝酸甘油具有血管擴張作用，可緩解心血管狹窄收縮，使心肌獲得適當血流與氧氣來改善急性胸痛與胸悶。臨床研究研究指出硝酸甘油可以增加化療藥物的敏感性，但分子機制仍不清楚。胸腺嘧啶合成酶(thymidylate synthase; TS)為參與嘧啶生成之回收路徑 (pyrimidine salvage pathway)的重要代謝酵素，研究指出胸腺嘧啶合成酶的高度表現與接受順鉑及愛寧達化學治療的預後效果較差有關。我們研究首次發表硝酸甘油可以抑制肺癌細胞內胸腺嘧啶合成酶的表現，以及降低細胞存活訊號分子AKT激脢的活化，進而協力增加化療藥物順鉑所誘導細胞毒性與生長抑制，然而詳盡分子機轉仍有待釐清。因此，本計畫將分析硝酸甘油如何負向調控AKT訊號，及如何降低調節胸腺嘧啶合成酶表現來增加化療藥物順鉑與愛寧達的敏感性。觀察硝酸甘油是否單獨能抑制肺腫瘤生長，及並用是否能增愛寧達化療藥物抑制肺腫瘤生長的效果。希望計畫研究成果在未來非小細胞肺癌的治療上能提供更好的方法與研究方向，並可作為評估硝酸甘油是否能用治療高度胸腺嘧啶合成酶表現所產生順鉑或愛寧達抗藥性之體外及臨床上研究依據，以延長病人的存活時間。Lung cancer is one of the leading causes of cancer-related deaths in Taiwan and worldwide, of which more than 85% are non-small cell lung cancer (NSCLC), mainly because of the lack of effective systemic treatment and rapid development of resistance to chemotherapy. The current first-line therapeutic option for patients with advanced NSCLC includes chemotherapy with a platinum-containing compound such as cisplatin or carboplatin in combination with a second- or third-generation cytotoxic agent. The multitargeted antifolate pemetrexed (Alimta) is approved as a single agent in second-line treatment of patients with locally advanced or metastatic NSCLC after earlier chemotherapy. Nitroglycerin (NTG), nitric oxide-donating drug, may decrease hypoxia and increase tumor blood flow and consequently drug delivery. Thymidylate synthase (TS) is an essential enzyme for the de novo synthesis of dTMP; studies show that cisplatin or pemetrexed-resistant carcinomas exhibit high levels of TS expression. Our study illustrates for the first time that nitroglycerin down-regulated TS expression and AKT activation in NSCLC cells. Compared to a single agent alone, nitroglycerin combined with cisplatin resulted in cytotoxicity and cell growth inhibition synergistically in NSCLC cells. In this study, we will plan to explore how nitroglycerin to down-regulate the AKT activation and TS expression in chemotherapeutic drug (cisplatin and pemetrexed)-exposed NSCLC cells. Moreover, we have established pemetrexed-resistant A549 lung cancer sublines. All three pemetrexed-resistant A549 sublines expressed more TS than the parental cells. Therefore, we will use these pemetrexed-resistant A549 sublines to understand the physiological effect of nitroglycerin -mediated TS down-regulation to enhance pemetrexed sensitivity. Examine the role of TS in nitroglycerin and pemetrexed-mediated anti-tumor activity in animal model. The final goal of this project is to understand the how the nitroglycerin to modulate TS expression, and its role in synergistic cytotoxic effects in chemotherapeutic drug (cisplatin and pemetrexed)-treated NSCLC cell lines. We elucidate that these observations may provide strong evidence for an experimental rationale to use nitroglycerin as part of combined therapy with chemotherapeutic agents in a variety of clinical settings for NSCLC, including reducing the dosage of chemotherapeutic agents and side effects in NSCLC cancer patients.