【作者】 郭长彬；

【导师】 郭宗儒；

【作者基本信息】 中国协和医科大学 ， 药物化学， 2004， 博士

【摘要】 环氧合酶-2（COX-2）选择性抑制剂是新一代抗炎镇痛药，由于比传统的非甾体抗炎药（NSAIDs）较小的胃肠道毒副作用，近十多年来，得到蓬勃发展。COX-2与COX-1在结构上存在的差异，是设计COX-2选择性抑制剂的基础，COX-2催化活性腔的体积比COX-1的大，并且COX-2活性腔有一个COX-1所没有的侧面口袋。在总结前人工作的基础上，根据已有构效关系，结合分子模拟技术和结构生物学知识，本论文设计合成了以下十一类目标化合物。第Ⅰ～Ⅲ类是对传统NSAIDs布洛芬和萘普生的结构改造，第Ⅰ类在布洛芬苯环3位引入一个取代的苯甲酰胺基，第Ⅱ和第Ⅲ类分别将布洛芬和萘普生的羧基改造为4位取代的噻唑基，以期引入一个结构片段占据COX-2侧面口袋；第Ⅳ和Ⅴ类是对COX-2选择性抑制剂尼美舒利的结构改造，分别将尼美舒利的氧醚键改造为酮羰基和肟基，以期利用构象变化提高对COX-2的选择性；第Ⅵ～Ⅺ类是对新型COX-2选择性抑制剂的me-too设计，以2-甲基-4-对甲磺酰基（或对氨磺酰基）苯基-噻唑为母核，根据生物电子等排原理，噻唑的5位分别设计为酰胺、氧醚、胺基、酮羰基和亚甲基侧链。本论文共合成化合物112个，其中目标化合物64个，新化合物97个。目标化合物都经过¹HNMR、MS和元素分析（或HRMS）确证结构，GCB0346B用X射线单晶衍射确定肟的构形为“Z”型。体外试验中，第Ⅲ、Ⅳ、Ⅴ、Ⅹ和Ⅺ类化合物对COX-2表现出较强的抑制作用，其中GCB0328、GCB0329、GCB0344和GCB0339B等IC₅₀达到10^-7～10^-8mol／L。部分化合物测定了COX-1抑制活性，GCB0339B对COX-2有选择性抑制作用。选择一些体外活性好的化合物进行了体内试验，结果表明：GCB0344对醋酸致小鼠扭体、角叉菜胶致大鼠足肿胀和巴豆油致小鼠耳肿胀有显著的抑制作用；GCB0328对醋酸致小鼠扭体、角叉菜胶致小鼠足肿胀和巴豆油致小鼠耳肿胀有显著的抑制作用，说明GCB0344和GCB0328有显著的抗炎镇痛作用，对其进一步结构优化可望获得高效低毒副作用和拥有自主知识产权的非甾体抗炎药。鉴于COX-2选择性抑制剂临床上已用于某些癌症的预防和治疗，对部分目标化合物进行了体外和体内抗肿瘤活性试验。结果表明：GCB0417和GCB0319等11个化合物在MTT改进法试验中对结肠癌、乳腺癌和胃癌等六种肿瘤细胞有不同程度的抑制作用；GCB0417等6个化合物对COX-2高表达的结肠癌细胞HT-29集落形成有较强抑制作用；GCB0417在200mg／kg剂量下对结肠癌HT-29模型裸鼠肿瘤有较弱的抑制作用。更多还原

【Abstract】 Cyclooxygenase-2 （COX-2） selective inhibitors belong to a new class of non-steroidal anti-inflammatory drugs （NSAIDs）. Owing to their reduced gastrointestinal side effects as compared to classic NSAIDs, COX-2 selective inhibitors have experienced tremendous development during the past 10 years. The differences between the active sites of COX-2 and COX-1 enzymes are the basis for design of COX-2 selective inhibitors. The volume of the active site of COX-2 is larger than that of COX-1; moreover, an additional pocket exists in the catalytic channel of COX-2, but not in COX-1.By taking advantage of the known structure-activity relationships （SAR） of selective COX-2 inhibitors, molecular modeling techniques and information provided by structural biology, eleven groups of target compounds with different structural scaffolds were designed and synthesized. The groups I , II and III involved the modification of NSAIDs ibuprofen and naproxen. A substituted benzamide group was introduced to the 3 position of the phenyl of ibuprofen in the I group. In groups II and III, the carboxyl groups of ibuprofen and naproxen were converted into thiazol-2-yl moiety. The purposes of these modifications were to introduce a structural segment to occupy the side pocket in COX-2. In groups IV and V, the oxygen ether linkage of nimesulide was replaced by a carbonyl or oxime, so as to take advantage of conformational alteration to enhance the selectivity for COX-2. In groups VI- XI, a series of thiazole derivatives were designed as me-too analogs of new structural selective COX-2 inhibitors based on the common skeleton 2-methyl-4- [4-mesyl （or 4-sulfamic）-phenyl]-thiazole. According to the principle of bioisosterism, the 5 position of the thiazole was substituted by amide, oxygen ether, amino, carbonyl and methylene moieties respectively.All together, 112 chemical substances were prepared, in which 64 compounds were target molecules, and 97 compounds were of novelty. All the target compounds were identified by the methods of ’HNMR, MS and elemental analysis （or high resolution MS）. The ’Z’ configuration of GCB0346B was identified by X-ray crystallography.The target compounds were biologically evaluated in vitro and some of them were tested in vivo and structure and activity relationships were analyzed to provide valuable clues to further study. The target compounds of group III IV V X XI exhibited inhibitory activity against COX-2 in vitro, among them the IC₅₀ values for COX-2 of GCB0328, GCB0329, GCB0344 and GCB0339B reached 10^-7～10^-8mol/L. Some of the target compounds were also screened in vitro against COX-1, which indicated that GCB0339B showed a selective inhibitory activity for COX-2. GCB0344 and GCB0328 were shown to significantly delay acetic acid induced mouse writhing and reduce croton oil induced mouse ear edema in vivo. GCB0344 was shown to inhibit carrageenan induced rat but not mouse paw edema; in contrast, GCB0328 was shown to inhibit carrageenan induced mouse but not rat paw edema. Such results suggested that GCB0328 and GCB0344 had remarkable analgesic and anti-inflammatory effects. It is possible that further structural optimization of these compounds will provide novel NSAIDs with high potency, low toxicity, and independent intellectual properties.Since the COX-2 selective inhibitors have been used clinically to prevent and treat some cancers, some target compounds were evaluated for their ability to inhibit cancers in vitro and in vivo. Results showed that eleven compounds such as GCB0417 and GCB0319 exhibited inhibitory effect to some extent against six cancer cell lines such as colon, mammary and gastric cancer cell lines in the improved MTT assay. Six compounds were shown inhibitory effect on colony forming of HT-29 colon cancer cells with high expression of COX-2. GCB0417 exhibited weak inhibitory activity against the growth of HT-29 colon cancer in nude mice at the dose of 200 mg/kg orally.更多还原