利用奈米鑽石作為運送紫杉醇之藥物奈米載體以阻斷乳癌和大腸癌的有絲分裂及腫瘤形成

Abstract

奈米鑽石是一種相當有潛力的碳奈米材料，近幾年被開發於生物醫學的應用。在本論文中，我們利用奈米鑽石作為一個新穎的藥物奈米載體，研究其在治療乳癌及大腸癌之藥物運送。我們利用化學合成方式，將紫杉醇此種有絲分裂抑制劑的臨床癌症用藥連接上奈米鑽石。以奈米鑽石-紫杉醇處理人類乳癌細胞株(MDA-MB-231、MCF-7及BT474)及大腸癌細胞株(RKO)後，會誘發細胞毒性及凋亡，然而，單獨處理奈米鑽石並不會造成細胞的死亡。以共軛焦螢光顯微鏡觀察分析，發現奈米鑽石-紫杉醇會運送進入癌細胞中，並位於細胞質及微小管。進一步發現奈米鑽石-紫杉醇處理後，會顯著地增加有絲分裂之磷酸化組蛋白 H3的表現量、阻止有絲分裂進行、造成不正常的染色體分離，最後導致有絲分裂崩毀。更重要地，奈米鑽石-紫杉醇能有效抑制在先天免疫缺失的裸鼠中，異體移植人類乳癌及大腸癌的腫瘤形成，並且在奈米鑽石-紫杉醇處理的腫瘤中，磷酸化組蛋白 H3的表現量會顯著增加。利用非侵入式活體分子影像系統進行不同時間的觀察，發現處理奈米鑽石-紫杉醇，會隨時間顯著地降低異體移植乳癌腫瘤的體積及螢光強度。綜合以上結果，顯示奈米鑽石是一種有潛力可作為抗癌藥物的奈米載體，應用在未來乳癌和大腸癌的治療。

Nanodiamond (ND), a promising carbon nanomaterial, has been developed for biomedical applications in recent years. Here, we develop ND as a novel drug nanocarrier for drug delivery in the breast and colon cancer therapy. Paclitaxel, a mitotic inhibitor used in clinical cancer therapy, was conjugated to ND by chemical synthesis. Treatment with ND-paclitaxel induced cytotoxicity and apoptosis in breast cancer cell lines (MDA-MB-231, MCF-7, and BT474) and colon cancer cell line (RKO); however, ND alone did not induce the cell death. ND-paclitaxel delivered into cancer cells and located in microtubules and cytoplasm by confocal microscopy analysis. Furthermore, ND-paclitaxel markedly increased mitotic phospho-histone H3 proteins, blocked mitotic progression, caused abnormal chromosome separation, and finally induced mitotic catastrophe. More importantly, ND-paclitaxel inhibited the tumor formation of the xenografted human breast and colon tumors in nude mice. The phospho-histone H3 proteins were elevated in the xenograft tumors after treatment with ND-paclitaxel. Using in vivo imaging system (IVIS) for time-lapse observation, the xenografted breast tumor sizes and fluorescence intensities were markedly reduced following ND-paclitaxel in a time-dependent manner. These findings provide that ND is a potential anticancer drug nanocarrier for breast and colon cancer therapy in the future.