發展奈米金結合傳統化療藥物以抑制口腔鱗狀細胞癌之協同療法

Abstract

目前治療口腔鱗狀上皮細胞癌的標準化療藥物仍為氟尿嘧啶及甲氨蝶呤， 然而這些藥物常傷及正常細胞造成不可避免之副作用。近年來奈米金因具有生 物醫學的應用潛力而備受關注，其可藉由操控粒子之大小或與標靶結合之不同 區域以提高對腫瘤細胞選擇性之攻擊。本研究將觀察奈米金結合化療藥物是否 對癌細胞與正常細胞具有選擇毒殺性，我們計畫在各種條件下合成系列之氟尿 嘧啶-奈米金與甲氨蝶呤-奈米金複合物，運用紫外光吸收光譜、x 光能量螢光 光譜、遠紅外光光譜與穿透式電子顯微鏡鑑定物理特徵，並檢視藥物對不同細 胞之毒殺性。初步結果顯示，沉澱部分之氟尿嘧啶-奈米金藥物相較於原化療 藥物對口腔癌細胞具有較低之IC50 數值，且合成物呈圓形，大小均為20 nm 藥 效最佳。然而甲氨蝶呤-奈米金系列則無較好效果。有趣的是氟尿嘧啶-奈米金 對正常細胞幾乎不具毒殺性。於細胞機制層面，氟尿嘧啶-奈米金較原型藥物 不易誘發細胞自噬並表現較低之LC3 蛋白，顯示氟尿嘧啶原型藥物可能誘發細 胞自噬使癌細胞藉以逃脫凋亡，而氟尿嘧啶-奈米金則能避免癌細胞此自救行 為而提高毒殺效益。動物實驗確認氟尿嘧啶-奈米金誘發調低之肝腎細胞毒性， 且具有抑制癌細胞生成之效用。本研究合成之氟尿嘧啶-奈米金具有較高毒殺 效應、較低副作用且誘發較低之細胞自噬作用，我們期許此奈米金藥物於臨床 上治療口腔癌病患之未來應用。

Unavoidable side effects of chemotherapy drug, used in oral squamous cell carcinoma (OSCC), including 5-fluorouracil (5FU) and methotrexate (MTX), is still a burden issue clinically. Our present study has been demonstrated a simple and effective method for synthesizing 5FU-conjugated gold nanoparticles (5FU-AuNPs) to attenuate drug toxicity in normal cells, and directly target OSCC cells, in which to avoid off-target effect. On the basis of physical properties, Fourier transform infrared spectroscopy (FT-IR), UV-vis absorption spectroscopy (UV-vis), energy dispersive X-ray fluorescence spectrometry (EDX), and transmission electron microscopy (TEM) were utilized to characterize 5FU-AuNPs, and defined the optimal size approximately 20 nm and shaped in spherical structure. We thus comprehensively studied the effect of 5FU-AuNP in vitro. 5FU-AuNP showed identical effective IC50 value in cancer cell lines, but it showed no toxicity in normal fibroblast and epithelial cells compared to conventional 5FU drugs. Furthermore, 5FU-AuNP induced lower expression of LC3, the essential element of autophagosome in SAS cells than 5FU treatment group, which promoted autophagy to escape from OSCC cell death. In tumor-bearing mice model, 5FU-AuNP did not cause significant hepatotoxicity and kidney damage as evidenced by biochemical analysis, although the tumorigenicity was effectively reduced in both treatment, this study demonstrates that 5FU-AuNP iii could be a potential nanodrug to treat OSCC without off-target effects and unmanageable autophagy.