Mechanistic Comparison of Cisplatin with Synthetic DNA Repair-Shielding Anticance

描述（由申请人提供）：拟议工作的目标是将我们最近关于顺铂抗肿瘤反应机制的实验结果转化为治疗顺铂耐药肿瘤的新型化合物的开发。该基金的早期工作发现了顺铂的三种新的潜在毒性机制：（1）其DNA加合物吸引蛋白质，其中一些在癌细胞中表达，阻断DNA修复;（2）其DNA加合物“劫持”特定的HMG结构域转录因子远离其启动子，导致某些基因的表达减少;和（3）错配修复蛋白结合顺铂加合物并使细胞对药物敏感。基于上述发现，在当前的资助期内，我们已经开发了几种具有潜在新作用机制的新型抗癌候选药物-顺铂激发的机制。这些化合物中的主要候选者E27 a被设计为通过可能与顺铂耐药卵巢癌治疗相关的机制起作用。E27 a是一种双功能DNA损伤剂，可以在DNA中产生对雌激素受体具有高亲和力的损伤位点。通过我们对顺铂的研究发现的纳入E27 a设计的原理包括顺铂DNA加合物结合和螯合对肿瘤生长和存活重要的蛋白质的能力。这项建议有两个平行的目标。一个是进一步描绘负责我们的新代理，E27 a的细胞毒性和抗肿瘤作用的分子机制。第二是将其对卵巢癌的疗效与临床使用或临床候选的顺铂和相关化合物进行比较。拟开展的研究的具体目标是：（1）合成铂和E27 a的分子变体和放射性标记类似物，作为结构-活性研究的工具;（2）在敏感和耐药卵巢癌细胞中对顺铂和顺铂同系物进行比较细胞毒性研究;（3）探讨卵巢癌雌激素受体表达与E27 a敏感性及顺铂耐药的关系;（4）比较E27 a和顺铂在人卵巢癌动物模型中的疗效。使用卵巢癌的常规和遗传动物模型以及相关细胞系，我们计划确定我们最近制造的分子在多大程度上发挥了我们预期的机制，并确定它们与癌症治疗的相关性。将使用传统（免疫化学，遗传学）和最新（RNAi，加速器质谱法）方法的组合。

DESCRIPTION (provided by applicant): The goal of the proposed work is to translate our recent experimental findings on the mechanisms of antitumor responses to cisplatin into the development of novel compounds to treat cisplatin-resistant tumors. Earlier work on this grant discovered three novel prospective mechanisms of toxicity for cisplatin: (1) its DNA adducts attract proteins, some of which are expressed in cancer cells, that block DNA repair; (2) its DNA adducts "hijack" specific HMG-domain transcription factors away from their promoters, resulting in diminished expression of certain genes; and (3) mismatch repair proteins bind cisplatin adducts and sensitize cells to the drug. Based on the aforementioned discoveries, in the current grant period, we have developed several novel anticancer candidates with potentially novel mechanisms of action - mechanisms inspired by cisplatin. The lead candidate among these compounds, E27a, was designed to act by mechanisms that may be relevant for the treatment of cisplatin-resistant ovarian cancers. E27a is a bifunctional DNA damaging agent that can create damaged sites in DNA that have high affinity for the estrogen receptor. Principles incorporated into the design of E27a that were uncovered by our investigations of cisplatin include the ability of cisplatin DNA adducts to bind and sequester proteins important to tumor growth and survival. This proposal has two parallel objectives. One is to delineate further the molecular mechanisms responsible for the cytotoxic and antitumor effects of our new agent, E27a. The second is to compare its efficacy against ovarian cancers with that of cisplatin and related compounds that are in clinical use or are clinical candidates. The specific objectives of the proposed research are: (1) to synthesize molecular variants and radiolabeled analogs of platinum and E27a that are tools for structure-activity studies; (2) to perform comparative cytotoxicity studies against cisplatin and cisplatin homologues in sensitive and resistant ovarian cancer cells; (3) to determine the relationship between estrogen receptor expression and sensitivity of ovarian cancers to E27a and the resistance of those cancer cells to cisplatin; and (4) to compare the efficacy of E27a to that of cisplatin in animal models of human ovarian cancer. Using conventional and genetic animal models for ovarian cancer, and relevant cell lines, we plan to determine to what extent the molecules we have recently made work the mechanisms that we intended and to determine their relevance to cancer treatment. A combination of traditional (immunochemical, genetic) and recent (RNAi, accelerator mass spectrometry) methods will be used.