| 摘要: | 本計畫主要內容是第一主題，至於第二題是分別配合台大醫學院黃德富教授與符文美教授的計畫，提供化合物的化學合成研究，遂將各主題的內容分述如下：第一主題：設計、合成及評估CHM-2133 類緣物在我們不斷尋找具有開發潛能的準新藥研究中，確認CHM-2133 是一種新穎的先導化合物，動物試驗結果顯示CHM-2133 以taxol resistant human hepatoma (HA-22T) xenograft model 試驗表現比Doxorubicin 更佳的抗腫瘤作用，而且毒性低微，最大耐藥劑量(MTD)大於200 mg/kg。CHM-2133 的作用機轉經深入探討結果得知CHM-2133 結合在tubulin 上，明顯的抑制其聚合，影響microtubule 功能，除了antimitotic action 外CHM-2133 經由非 caspase pathway 誘導apoptosis，而且CHM-2133 能抑制MMP-2 及MMP-9 而影響癌細胞metastasis。CHM-2133 又能抑制VEGF、bFGF-induced HUVEC proliferation，進而干擾血管新生(angiogenesis)。Kinase assay 結果顯示CHM-2133 會選擇的抑制EphB2 receptor tyrosine kinase。由上述先期研究結果我們確認CHM-2133 是多靶點的antimitotic agent。然而其溶解度低，前臨床及臨床試驗都有不便之處。於是在本計畫中我們將研究重點集中於下列各項： (1)合成CHM-2133 analogs 之親水性前藥。 (2)依循Prodrug Monotherapy (PMT)的策略，合成CHM-2133 analogs 之glucuronide-及sialidate-prodrugs。 (3) 合成CHM-2133 analogs 之polymer-conjugate 做為anticancer nanomedicines (4)利用分子模擬方法，尋找對EphB2 具有選擇性的強力拮抗劑。 (5)從事CHM-2133 analogs 之作用機轉，藥物動力學以及各種抗癌動物試驗等前臨床試驗。我們期待本計畫的執行能獲得一類新型的antimitotic agents 提供前臨床乃至臨床試驗。第二主題：Nstpbp 5185，5250 及130061 之優化本研究室於持續開發新型抗血小板凝集化合物過程中， 合成了 1-benzyl-2-(5-methyl-2-furyl)benzimidazole (nstpbp 5185)與pyrazole類化合物3-(5-methyl-2-furyl)-1,5-diphenylpyrazole (nstpbp 5250)，經測試其抗血小板活性。結果顯示化合物nstpbp 5185對於collagen所誘發之血小板凝集具有優越且專一之抑製作用，具發展成為治療栓塞新藥之潛力。化合物nstpbp 5250可廣效地抑制ADP, collagen和thrombin引發之血小板凝集，其主要作用來自Phosphodiesterase (PDE) 5之抑制，引起cGMP之提升所導致。另外發現 nstpbp 1300061則具有神經保護作用。於是本計畫擬以化合物nstpbp 5185、nstpbp 5250與nstpbp 1300061為先導化合物，合成下列各類新衍生物： (1) pyrido[2,3-d]imidazoles (2) pyrido[3,4-d]imidazoles (3) purines (4) 5- (or 6-) substituted benzimidazoles (5) pyrazoles (6) 6-fluoroquinazolines
Development of Potential Bioactive Compounds as New Drug Candidates There were two parts in this proposal.We have described in detail respectively. (I) Design, Synthesis and Evaluation of CHM-2133 Analogs As part of our continuing search for potential anticancer drug candidates, we have identified CHM-2133 as a novel lead compound of antimitotic agent. In murine preclinical model, antitumor activity of CHM-2133 against a taxol resistant human hepatoma (HA22T) xenograft was more potent than that of doxorubicin. Despite of this potency, CHM-2133 produces very low systemic toxicity with maximal tolerance dosage over 200 mg/kg in the nude mice. Detail mechanism studies demonstrated that CHM-2133 interacted with tubulin and markly inhibit polymerization, and drisrupted microtubule organization. Beside the antimitotic action, CHM-2133 induces apoptosis via caspase-independent pathway, CHM-2133 could significant affect the expression pattern of several metastasis relative molecules including down-regulated MMP-2 and MMP-9 in vitro. In addition, CHM-2133 also blocks VEGF and bFGF-induced HUVECs proliferation in vitro and neovasculation in vivo. Intriguingly, the kinase activity of EphB2, a receptor type tyrosine kinase is selectively inhibited by co-cultivated with CHM-2133 in the kinase assay, suggesting EphB2 might be the molecular target for CHM-2133. Above results suggest the CHM-2133 is a multiple targets anti-tumor agent, however, the poor solubility of CHM-2133 significant hindrances the further preclinical and clinical studies. In order to further develop this CHM-2133 analogs, we will focus on the followings: (1) synthesize the hydrophilic prodrugs of CHM-2133 analogs for lead optimization, (2) synthesize the glucuronide- and sialidate-base prodrugs of CHM-2133 for a prodrug monotherapy (tumor targeting) strategy, (3) synthesis of polymer-CHM-2133 analogs conjugates as anticancer nanomedicines, (4) search novel series of potent and selective EphB2 receptor antagonists using the techniques of computer-aided drug design, and (5) investigate the action mechanisms, pharmacokinetic properties and animal model suit for different cancer types for CHM-2133 analogs. Through this study, we wish we can build up a new class of anti-mitotic agent with potential therapeutic utilities for preclinical as well as clinical usage in the treatment of cancer. (II) Lead Optimization of Nstpbp 5185, 5250 and 130061 As a result of our continuing study aimed at the discovery and development of novel antiplatelet agents, the 1-benzyl-2-(5-methyl-2-furyl)benzimidazole (nstpbp 5185) and 3-(5-methyl-2-furyl)-1,5-diphenylpyrazole (nstpbp 5250) were synthesized and evaluated for its antiplatelet activity. The preliminary results showed that the nstpbp 5185 is specific for the inhibition of collagen-induced platelet aggregation, it can be developed as a new category of drug to treat thrombosis. And nstpbp 5250 inhibited platelets aggregation that stimulated by thrombin, and thromboxane A2 formation caused by collagen. It was demonstrated that nstpbp 5250 itself markedly increased cyclic GMP level by its phosphodiesterase 5 inhibition effect. On the other hand, nstpbp 1300061 was found to exhibit neuroprotective effect. Encourage by this results, compounds nstpbp 5185, nstpbp 5250 and nstpbp 1300061 were selected as a lead compound in this proposal. The following new derivatives will be synthesized: (1) pyrido[2,3-d]imidazoles (2) pyrido[3,4-d]imidazoles (3) purines (4) 5- (or 6-) substituted benzimidazoles (5) pyrazoles (6) 6-fluoroquinazolines |
