第一部份：設計與合成抗生素添加物以抑制金黃色葡萄球菌素之生成。第二部份：合成Latifolicinin A之衍生物以抑制三重陰性乳癌

第一部份、摘要金黃色葡萄球菌 (Staphylococcus aureus, SA) 與抗藥性金黃色葡萄球菌 (methicillin-resistant S. aureus, MRSA)之金黃色色素staphyloxanthin (STX, 11)是經由前驅物dehydrosqualene (7)所合成，且STX 具有抗氧化的功能，並且帶有毒性。Gotz 確定了金黃色葡萄球菌合成STX 時，必須經過酵素CrtM (dehydrosqualene synthase)。2005 年， Nizet 證實，藉著干擾STX 的生成能夠弱化細菌足以被宿主的免疫系統清除。CrtM 的共結晶結構在2008 年被發表，提供了在抑制劑的設計上所需的資訊。在CrtM 抑制劑的研究中，大部份是以模擬天然受質farnesyl diphosphate (FPP, 5)為策略，進而達到抑制細菌的目的。本篇論文主要以苯甲酸之衍生物，來模擬以CrtM 催化兩分子的FPP 所合成之中間體presqualene diphosphate (PSPP, 6)，藉以發展新型抑制劑。我們合成並測試了一系列具有潛力的CrtM 抑制劑的生物活性(IC50 and MIC) 希望能藉此降低STX 的生成。在此研究中我們發現，當此系列抑制劑並與抗生素(如安比西林)共同針對MRSA 投藥時，能夠降低投藥劑量並有效抑制MRSA 的生長，是相當有趣的發現。第二部份、摘要全世界每年約有130 萬名女性罹患乳癌，其中約有42 萬人因此死亡。在台灣，女性罹患乳癌人數高居癌症的排行榜第四名，每年約有1800 位乳癌病患因此而死。在醫療水準較高的地區，如歐美、日本、台灣等地，乳癌只要能夠在初期被驗出，施以手術，或以藥物治療都有相當好的效果，治癒率非常高。乳癌的檢驗經常利用癌細胞過度表示之受體ER、PgR、HER2 等，然而其中一型的乳癌細胞完全不表現ER、PgR、HER2，因此被稱為三重陰性乳癌(triple-negative breast cancer，TNBC)。由於不易檢測，腫瘤發現的晚，治癒率也隨之下降，另一方面，荷爾蒙及標靶治療上也需要依賴受體，因此三重陰性乳癌不易治療，其罹癌五年死亡率比其他型的乳癌更高，需要更有效的治療方式。本實驗室與中央研究院合作，發現大豆發酵濃縮液「田中寶」之萃取物中的成份latifolicinin A 能夠抑制三重陰性乳癌。我們因此合成及測試一系列latifolicinin A 之酯類與醯胺類衍生物，成功發現數個半數抑制濃度(IC50)小於10 μM 之有效化合物，較latifolicinin A 的抑制性高100 倍以上，除對正常細胞之細胞毒性表現仍待改善外，確實有成為藥品的潛力。

關鍵字

金黃色葡萄球菌；抗生素；乳癌；抑制劑

並列摘要

Abstract Part I Staphyloxanthin (STX, 11) is the yellow pigment produced biogenetically from dehydrosqualene (7) in Staphylococcus aureus (SA), including the methicillin-resistant strain (MRSA). STX is a toxin and functions as an antioxidant of SA. Dehydrosqualene synthase(CrtM) is an essential enzyme in the biosynthetic pathway of STX. In 2005, Nizet and coworkers have shown that interference of the STX biosynthesis will weaken bacteria for facile eradication by host immune system. The cocrystal structure of CrtM was published in 2008 to provide useful information for design of the enzyme inhibitors. To construct the inhibitors by mimicking native substrate is a widely applied strategy for development of antibacterial. In another approach, we aimed to design and synthesize a series of benzoic acid derivatives to mimic the transition state in formation of presqualene diphosphate (PSPP, 6) by the CrtM-catalyzed coupling reaction between two farnesyl diphosphonate (FPP, 5) molecules. We also evaluated the bioactivity (IC50 and MIC) of these potential CrtM inhibitors which blocked the STX production. It is interesting to observe that the combined use of the CrtM inhibitor with antibiotics, e.g. ampicillin, has shown synergstic effect to suppress the growth of MRSA. Abstract Part II Every year, about 1.3 million women suffer from breast cancer, and which about 420 thousands patients will die in the whole world. In Taiwan, the number of women suffering from breast cancer ranks fourth highest, and about 1800 patients die each year. As long as breast cancer can be detected at early stage, the cure rate in Europe, America, Japan, and Taiwan is excellent by imposing surgery or drug therapy. Diagnoses of breast cancer are commonly related to the overexpressed receptors, such as, estrogen receptor (ER), progesterone (PgR), and human epidermal growth factor 2 (HER2). However, one subtype of breast cancer cell namely triple-negative breast cancer (TNBC) does not express such receptors. Due to difficulty in detection the cure rate of TNBC decreases is also problematic due to lacking the receptor for hormonal and targeted therapy. Treatment of triple-negative breast cancer, the five-year mortality of TNBC is higher than other subtypes of breast cancer. Effective therapy of TNBC is urgently needed. This research, in cooperation with the Academia Sinica, focus on using latifolicinin A extracted from the fermentation broth of soybean product (FSP), for inhibition of triple-negative breast cancer. We synthesized and tested a series of ester and amide derivatives of latifolicinin A. Some of these compounds were good TNBC inhibitor with IC50 values lower than 10 μM, about 100-fold more potent than latifolicinin A. However, more structural modification is needed to reduce the cytotoxicity to normal cell.