本論文之目的為探討癌症幹細胞在口腔鱗狀細胞癌中對鉑類化療藥cisplatin化療抗藥性的產生扮演何種角色，期能釐清癌症幹細胞對產生cisplatin的抗藥性是否具有關連性。
研究方法：首先以無血清選擇性培養液促使癌細胞形成球體的現象分離出口腔癌幹細胞，再以MTT [3- (4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay確認其對cisplatin是否具有化療藥抗藥性。口腔癌幹細胞中excision repair cross-complementation group 1(ERCC1)的表達與否也以RT-PCR及西方墨點法做確認。另外我們於口腔癌細胞株中逐量加入cisplatin以篩選出具cisplatin抗藥性的口腔癌細胞，將之與原細胞株相較，看其是否具有較多的癌症幹細胞特性。我們同時以免疫組織化學染色法分析具cisplatin化療抗藥性的患者檢體中其癌症幹細胞生物標記的表達是否增加。
結果:與原細胞株相較，口腔癌幹細胞對cisplatin較具化療藥抗藥性, 而其化療抗藥性可能源自於ERCC1的上升。而具cisplatin抗藥性的口腔癌細胞相較於原細胞株有較佳的球體細胞形成能力及自我更新能力。該細胞中也高度的表現了幹細胞表面標記 (Nanog, Oct4, Bmi1, CD117, CD133 及 ABCG2)。臨床上產生化療抗藥性的口腔癌患者檢體中也發現有較多的 Oct4 及 Nanog表達(**p<0.01) 。
The purpose of this study is to investigate the role of cancer stem cells (CSCs) in resistance to cisplatin chemotherapy of human oral squamous cell carcinoma (OSCC). We expected to clarify the correlation between cisplatin chemoresistance and CSCs in OSCC. Materials and methods: Oral cancer stem-like cells (OC-SLCs) were isolated through sphere formation by cultivating OC2 within defined serum-free medium. Chemoresistance to cisplatin was checked by MTT assay. Expression of ERCC1 in OC-SLCs was also examined by RT-PCR and western blotting. We also established the cisplatin-resistant oral cancer cells by treating the OC2 cells with cisplatin. The CSCs characteristics were then identified. Expression of stemness markers in chemo-resistant OSCC patients was also detected by immunohistochemistry staining. Results: Enhanced chemoresistance to cisplatin was noted in OC-SLCs. Chemoresistance to cisplatin might be correlative with ERCC1 up-regulation. On the other hand, sphere-forming/self-renewal capability was increased in cisplatin-resistant cells. Cisplatin-resistant cells also highly expressed the stemness markers (Nanog, Oct4, Bmi1, CD117, CD133 and ABCG2). Furthermore, up-regulation of Oct4 and Nanog expression was significantly observed in cisplatin-resistant OSCC patients (**p<0.01).
