Multi-Target, Mechanism-Based Drug Design for the Treatment of Breast Cancer: Syn

描述（由申请人提供）：许多研究表明鞘脂代谢途径与癌症发病机制以及耐药性之间存在相关性。鞘脂代谢的中心分子神经酰胺已知参与许多人类癌症，特别是乳腺癌中的细胞凋亡、衰老和生长停滞的诱导。然而，其代谢产物鞘氨醇-1-磷酸和葡萄糖神经酰胺导致细胞转化、增殖和耐药性。因此，神经酰胺水平的升高和神经酰胺代谢的抑制被认为是乳腺癌治疗的新的治疗靶点。神经酰胺类似物可被设计成作为神经酰胺激活的效应物的激动剂或神经酰胺代谢酶的抑制剂。此外，由于这是一个多靶点系统，神经酰胺类似物自然具有多种可能的作用机制。因此，我们假设使用多样性导向的合成和筛选、多靶点机制研究以及围绕神经酰胺类似物的系统性结构-活性关系研究可以产生用于治疗乳腺癌的多作用药剂。 为了实现本项目的总体目标，我们提出了三个具体目标：1.合成新型神经酰胺类似物，用于乳腺癌细胞系抗癌药物的筛选;确定发现有效的神经酰胺类似物的作用机制;以及3.研究神经酰胺类似物在乳腺癌中的构效关系，建立药效团模型。 我们计划合成三个系列的神经酰胺类似物，其中在神经酰胺主链和/或1-羟基官能团上进行修饰。所有新合成的神经酰胺类似物将在敏感和耐药乳腺癌细胞系中筛选活力抑制和耐药逆转。将进一步测试细胞活力抑制剂的促凋亡活性以及神经酰胺酶和鞘氨醇激酶抑制活性。将在葡糖神经酰胺合酶活性测定中进一步研究引起抗性逆转的化合物。将研究具有凋亡活性的类似物以确定促凋亡是否如神经酰胺的情况那样经由线粒体途径发生。通过上述研究，将确定神经酰胺类似物的作用机制，并产生大量的活性数据。将使用计算化学对每种作用机制进行定量构效关系（QSAR）分析。此外，还将建立神经酰胺相关分子的系统药效团模型。 公共卫生相关性：乳腺癌是美国女性癌症死亡的第二大原因，对当前化疗药物的耐药性是治疗失败的主要原因。本课题旨在开发一组具有逆转耐药能力的新型化疗药物。这些基于神经酰胺结构设计的双作用化疗药物，有可能在乳腺癌的治疗中发挥重要作用。

DESCRIPTION (provided by applicant): Many studies have shown a correlation between the sphingolipid metabolism pathway and cancer pathogenesis as well as drug-resistance. The central molecule in sphingolipid metabolism, ceramide, is known to be involved in the induction of apoptosis, senescence and growth arrest in many human cancers, especially in breast cancer. However, its metabolites, sphingosine-1-phosphate and glucosylceramide lead to cellular transformation, proliferation and drug-resistance. Thus, elevation of ceramide levels and inhibition of ceramide metabolism are considered to be novel therapeutic targets for breast cancer treatment. Ceramide analogs can be designed to act as agonists of ceramide-activated effectors or inhibitors of ceramide-metabolizing enzymes. Also since this is a multi-target system, ceramide analogs naturally possess multiple possible mechanisms of actions. Therefore, we hypothesize that the use of diversity- oriented synthesis and screening, multi-target mechanism investigation, and systematic structure-activity relationship studies around ceramide analogs can generate multi-action agents for the treatment of breast cancer. To achieve the overall goal of this project, we propose three specific aims: 1. To synthesize novel ceramide analogs for screening as anti-cancer agents in breast cancer cell lines; 2. To determine the mechanisms of actions of the ceramide analogs found to be effective; and 3. To perform mechanism-based structure-activity relationship studies of ceramide analogs in breast cancer and build a pharmacophore model. We plan to synthesize three series of ceramide analogs in which modifications are made on the ceramide backbone and/or 1-hydroxy functional group. All of the newly synthesized ceramide analogs will be screened for viability inhibition and resistance-reversal in sensitive- and resistant- breast cancer cell lines. The inhibitors of cell viability will be further tested for pro-apoptotic activity as well as ceramidase and sphingosine kinase inhibition activities. Compounds causing resistance-reversal will be further studied in glucosylceramide synthase activity assays. Analogs with apoptotic activity will be studied to determine whether pro-apoptosis occurs via the mitochondrial pathway as in the case of ceramide. Through the above investigations, the mechanisms of actions of ceramide analogs will be identified and a large amount of activity data will be generated. Quantitative structure-activity relationship (QSAR) analysis will be carried out for each mechanism of action using computational chemistry. Furthermore a systematic pharmacophore model for ceramide-related molecules will be established. PUBLIC HEALTH RELEVANCE: Breast cancer is the second leading cause of death from cancer in American women, and resistance to current chemotherapeutics is the major cause of treatment failure. The purpose of this project is to develop a group of novel chemotherapeutic agents, which possess the capability of reversing drug-resistance. These dual-action chemotherapeutics designed based on the structure of ceramide, have the potential to play an important role in the treatment of breast cancer.