Enzyme Inhibitors as Potential Anticancer and Antiviral

A.蛋白激酶C项目：使用我们不断改进的固相合成方法生成DAG-内酯的新型化学文库，继续在具有潜在治疗重要性的各个领域产生重要的先导化合物。我们的第一个C1结构域选择性DAG-内酯的结果与RasGRP的独家选择性最近发表，以及我们的结果能够刺激α-分泌酶活性的DAG-内酯。今年发现的另一种DAG-内酯被发现在体内起着非常有效的放射性物质的作用，当与辐射结合使用时，可使前列腺特异性抗原（PSA）水平降至接近零。完成了一些DAG-内酯的大规模合成用于体内研究，目前正在进行研究与IL-12组合的干扰素产生的增加。与这些发现平行，我们继续研究这些DAG-内酯在分子水平上的作用，解剖两个化学上不同的羰基（sn-1和sn-2）与蛋白质或膜组分的相互作用。2005年底和2006年初发表了两份论述这些问题的论文全文。含芳基的DAG-内酯新家族的合成最近得到了扩展。B. Zebularine [2（1H）-嘧啶酮核苷]的临床进展在去年因恒河猴中的一种不可预见的毒性而结束，当血浆水平达到25微摩尔时，这种毒性是致命的。这与啮齿动物（大鼠和小鼠）完全没有毒性形成鲜明对比，即使在高剂量下也是如此。规避药物毒性和改善低剂量下zebularine活性的努力已经在两个方向上引导：（1）合成能够递送5 '-单磷酸酯（ZMP）并绕过代谢活化和降解的zebularine的亲脂性前药。这是一家德国公司（海德堡制药公司）和南加州大学的共同努力。为此，与这两个机构签署了合作协议，以制备和测试第一个候选物，以及（2）开发2 '-脱氧泽布拉林的前药，其旨在递送2-脱氧泽布拉林-5'-单磷酸（dZMP）。许多2 '-脱氧泽布拉林前药似乎起作用，但仅在添加胸苷的存在下起作用。最有可能的是，产生的dZMP抑制两种关键酶，脱氧胞苷脱氨酶和胸苷酸合成酶，两者都是维持正常胸苷水平所必需的。C.使用稳定的NAD类似物，β-亚甲基-天冬氨酸，在过去几年中在LMC合成，并用于单ADP核糖基化毒素（类似于白喉毒素）的高分辨率晶体结构，在去年发表在《自然》杂志上的一篇论文中得到了强调。

A.Protein kinase C project: The generation of novel chemical libraries of DAG-lactones using our constantly improved solid-phase method of synthesis continues to yield important lead compounds in various areas of potential therapeutic importance. The results on our first C1 domain-selective DAG-lactone with exclusive selectivity for RasGRP were published recently, as well as our results on DAG-lactones capable of stimulating alpha-secretase activity. Another DAG-lactone discovered this year was found to function as a very effective radiosentizer in vivo causing prostate-specific antigen (PSA) levels to drop to near zero when administered in conjunction with radiation. Large-scale syntheses of some of DAG-lactones were completed for in vivo studies, which are now in progress to investigate the increase in interferon production in combination with IL-12. In parallel to these findings, we continue to investigate the action of these DAG-lactones at the molecular level dissecting the interaction of the two chemically different carbonyl groups (sn-1 and sn-2) with the protein or membrane components. Two full papers addressing these issues were published late in 2005 and in early 2006. The syntheses of a new family or DAG-lactones containing aryl groups have been recently expanded. B.The progression toward the clinic for Zebularine [2(1H)-pyrimidinone riboside] was brought to an end last year by an unforeseen toxicity in rhesus monkeys, which was lethal when plasma levels reached 25 micromolar. This is in total contrast to the complete lack of toxicity in rodents (rats and mice), even at high doses. Efforts to circumvent the drug's toxicity and to improve the activity of zebularine at lower doses have been channeled in two directions: (1) Synthesis of a lipophilic prodrug of zebularine capable of delivering the 5'-monophosphate (ZMP), and bypassing metabolic activation and degradation. This is a joint effort with a German company (Heidelberg Pharma) and the University of Southern California. To that effect a Collaboration Agreement was signed with these two institutions to prepare and test the first candidate, and (2) The development of pro-drugs of 2'-deoxyzebularine, which are intended to deliver 2-deoxyzebularine-5'-monophosphate (dZMP). A number of 2'-deoxyzebularine prodrugs appear to work but only in the presence of added thymidine. Most likely, the dZMP generated inhibits two key enzymes, deoxycytidine deaminase and thymidylate synthase, and both are essential in maintaining normal thymidine levels.C.The use of stable NAD analogue, beta-methylene-TAD, synthesized at the LMC in years past and used for the high-resolution crystal structure of a mono-ADP -ribosylating toxin (similar to diphteria toxin) was highlighted in a paper published in Nature last year.