| Abstract: | 癌症幹細胞（CSCs）是一種具有正常幹細胞特性的癌症細胞，能分化產成不同類型型態細胞。癌症幹細胞能透過幹細胞自我更新和分化的能力，維持自體細胞之健全功能，並分化為多種細胞型態。為了維持癌症的高度惡性特質，癌症幹細胞相較於其他癌細胞，往往具有更強的致瘤性、化學療法阻抗性／放射療法阻抗性，以及轉移性。因此，發展能夠標靶癌症幹細胞的新穎治療方法，將能顯著地改善臨床醫學上對於癌症治療的結果。中草藥在醫學上使用已有多年歷史，其中存在於植物黃連（Huanglian）中的黃連素（Berberine），也是一項廣為人知的成分，過去的研究顯示，黃連素對於癌症細胞具有細胞毒殺作用，且不傷害正常的細胞或組織。本研究的目的，是想調查黃連素在體外和體內實驗中，對於口腔癌症幹細胞的化學治療效果。利用細胞存活率分析實驗（MTT assay）發現黃連素可抑制一般的癌症細胞（parental）及會形成球體（sphere）的癌症幹細胞之增殖能力，在人類口腔鱗狀細胞癌細胞株（SAS），和人類口腔上皮細胞癌細胞株（OECM1）這兩株細胞中，均發現隨著黃連素劑量上升，口腔癌症細胞及癌症幹細胞之增殖能力下降。黃連素對人類正常口腔牙齦角化細胞（SG）而言，並沒有顯著的細胞毒性產生。我們的研究顯示，黃連素能顯著降低口腔癌症幹細胞標記－乙醛脫氫酶（ALDH1）的表現量，黃連素投予之濃度越高，則ALDH1之表現量越低。多項研究證據已證明，隨著黃連素劑量上升，其抑制口腔癌症幹細胞之遷移、侵襲和群落形成的能力更佳。口腔癌症幹細胞與一般口腔癌症細胞相比，具有更強的化療藥物阻抗性。更重要的是，細胞存活率實驗（Cell viability assay）分析結果顯示，黃連素能降低口腔癌症幹細胞對於化療藥物－氟尿嘧啶（5-FU）的抗藥性。此外，餵食黃連素後，顯示黃連素可使腫瘤之重量及體積減少，由體重監測發現，並無任何明顯徵兆顯示黃連素對於實驗動物具有毒性影響。基於上述研究證實，黃連素在體外和體內實驗中，均能有效地抑制口腔癌症幹細胞之自我更新，腫瘤起始，化療耐藥性能力。
Cancer stem cells (CSCs) are cancer cells that possess characteristics associated with normal stem cells, specifically the ability to give rise to all cell types found in a particular cancer sample. CSCs may generate tumors through the stem cell processes of self-renewal and differentiation into multiple cell types. Relative to remaining the tumor bulk, CSCs are often more tumorigenic, chemo-resistant/radio-resistant, and metastatic. Therefore, development of novel therapeutics targeting CSCs could significantly improve clinical outcome of cancer treatment. As Berberine, a well-known component of the Chinese herbal medicine Huanglian, can exert cytotoxic effects on cancer cells without harming normal tissues. The aim of this study was to investigate the chemo-therapeutic effect of Berberine on oral CSCs in vitro and in vivo. By using MTT assay (3-(4,5-Dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide assay), Berberine could suppress cell proliferation of parental and oral sphere-forming CSCs (Squamous cell carcinoma cell line and Oral human epithelial carcinoma M1 cell line) in a dose-dependent manner. The effect of Berberine on normal human oral epithelial cells (SG) revealed that this compound did not have any significant cytotoxicity on these cells. Our data suggested Berberine treatment significantly decrease ALDH1, a marker of oral CSCs, activity in a concentration-dependent manner. Substantial evidence has demonstrated that Berberine dose-dependently inhibited migration, invasion, and colony-forming abilities in oral CSCs. Oral CSCs were more chemo-resistant compared with the parental oral cancer cells. Importantly, cell viability assays showed that Berberine ameliorated the drug resistance of oral CSCs to fluorouracil (5-FU) treatment. Moreover, Berberine feeding dose-dependently induced a reduction in tumor weight and tumor volume and without apparent signs of toxicity as evidenced by body weight monitoring. Conclusively, the present reports showed that the Berberine effectively suppressed self-renewal, tumor-initiating, and chemo-resistant properties of oral CSCs in vitro and in vivo. |
