大甲草（Euphorbia formasana）為台灣名間常用來治療之中草藥，是青草藥界傳頌的特殊藥用植物，野外族群漸漸消失，近年來也被拿來進行抗癌的相關研究，但其機轉並未被大家所了解。本研究主要探討大甲草的乙醇粗抽物（CEEF）對人類攝護腺癌細胞產生之細胞凋亡的相關機轉，並進一部探討能否對癌細胞轉移的抑制能力及其相關機轉。一開始先將大甲草乙醇粗抽物進行細胞毒性試驗，接者用流式細胞技術分析細胞週期的影響，並探討造成細胞凋亡的相關現象，如細胞內之活性氧化物、鈣離子濃度及粒線體膜電位，接著也發現到凋亡造成的電泳斷片，並進行單細胞電泳及細胞傷害試驗檢測細胞毒性，並進一步探討造成細胞凋亡的相關蛋白調控機轉，並使用real-time PCR來檢測相關基因表現，然後也發現到大甲草乙醇粗抽物能抑制癌細胞轉移，也利用細胞的侵入與增生試驗來檢測相關表現，並使用西方點墨法來檢測相關蛋白表現及利用real-time PCR來檢測相關基因表現。經研究結果發現大甲草乙醇粗抽物能對人類攝護腺癌細胞經由CASPASE路徑產生之細胞凋亡，並影響細胞週期調控，而且也能有效的抑制癌細胞的轉移。是作為開發抗癌藥的明日之星。
Prostate cancer is one of the popular cancers in the elder man through the world and harmful to the health of human beings. Euphorbia formosana radix has a long history in traditional Taiwanese medicine and has been used as a counter-poison to snake bite. In our preliminary studies, we found crude extract of Euphorbia formosana radix （CEEF） could induce apoptosis and cell cycle arrest in human prostate cancer cell line. In this study, we studied CEEF cytotoxicity in human prostate cancer cell line DU 145 and underlying mechanisms. We first investigated the effects of CEEF on viability and cell cycle in human prostate cancer cell line DU 145. The results indicated that CEEF induced cytotoxicity in DU 145 cells in a dose- and time- dependent manners. We also defined the IC50 （100 μg/ml） and use this concentration for the follering studies. Cell cycle analysis performed by flow cytometry showed that CEEF induced significant S phase arrest in DU 145 cells, and a significant damage to DNA integrity as revealed by Comet assay and DNA electrophoresis assay studies. Cytosolic reactive oxygen species (ROS) and calcium ion increased while mitochondria membrane potential (MMP, ΔΨm) was decreased after CEEF treatment. From Western blotting analysis, that CEEF can decrease pro-Caspase 3, pro-Caspase 9, Bcl-2 and increase Bax, Cytochrome C, Endo-G, Catalase, Glutathion transferase, SOD-2, Caspase-3 and Casepase-9 proteins. From these studies, we suggested that CEEF might activate mitochondria pathway resulting in DU 145 cells apoptosis. Based on the above findings Euphorbia species might be developed as a potential new drug candidate for cancer therapy in the future.
