REDUCTIVE AND PHOTOSENSITIZED ACTIVATION OF TUMOR-TARGETED QUINONES

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 醌类化合物是重要的抗肿瘤药物和治疗人类疾病的药物。这些化合物的共同特征是它们易于在生物介质中被化学、光化学或酶促还原以产生活性中间体和产物。这些化合物还原后，超氧化物和亚硝酰基的生产率提高的方式取决于醌单电子氧化还原电位。此外，在低氧条件下还原时，烷基化醌也被活化以共价结合DMA。在我们过去的几年中，我们发现氮丙啶醌可以通过光敏化，缺氧，然后通过DNA共价结合来还原。我们还发现，在存在的牺牲电子供体，如次黄嘌呤，醌还原和共价加合物的DNA的增加被检测到。由于给电子体可以改变单重态的光敏化产生， 由于超氧化物和过氧化氢都可以在组织内比单线态氧更远的地方旅行以产生损伤，我们将在这里研究染料和电子供体的疏水性/亲水性如何在单线态氧和超氧化物的相对产生中发挥相互作用。由于许多肿瘤过表达叶酸受体（FR），降低醌对正常组织的毒性并增加对肿瘤的毒性损伤的一种方法是选择性地将醌递送至FR过表达的肿瘤。目前的研究建议也旨在探索新的潜在途径，醌增强毒性发起的醌还原使用FR-靶向醌。FR靶向 将合成醌类化合物，并测定它们催化活性氧物质的产生以及DNA和蛋白质烷基化的能力。 具体目标： 1.确定脂质/缓冲体系中染料和牺牲电子供体的疏水性/疏水性对超氧化物和单线态氧相对产率的影响。 2.合成FR靶向醌类化合物和FR靶向依托泊苷醌衍生物。 3.表征FR靶向醌类的酶促和光敏还原后的半醌类和活性氧（ROS）产生速率。 4.使用红色吸收染料确定光敏FR靶向氮丙啶醌-DNA共价结合是否发生。 5.确定FR靶向依托泊苷醌衍生物是否与蛋白质巯基和DNA碱基结合。 6.为了确定FR-靶向半醌和活性氧的生产在HeLa和非FR过度表达细胞，使用EPR光谱，以及这些物种的生产是否与FR结合。 7.确定FR靶向醌衍生物在HeLa和非FR过表达细胞中的细胞毒活性。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Quinones are important compounds used in antitumor therapy and to treat other human illnesses. The common feature of these compounds is that these are prone to be reduced chemically, photochemically or enzymatically in biological media to produce reactive intermediates and products. Upon reduction of these compounds, superoxide and nitrosyl production rates are enhanced in a way which depends on the quinone one-electron redox potential. In addition, alkylating quinones are also activated to covalently bind DMA upon reduction under hypoxic conditions. In our previous years we found that aziridinylquinones can be reduced by photosensitization, under anoxia, followed by DNA covalent binding. We also found that in the presence of a sacrificial electron donor such as hypoxanthine, an increase in both quinone reduction and covalent adducts to DNA were detected. Since electron donors could shift the photosensitized production of singlet oxygen to superoxide and since both superoxide and hydrogen peroxide can travel within tissues farther away than singlet oxygen to produce damage, we will deal here with a study on how the hydrophobicity/hydrophilicity of dyes and electron donors play interacting roles in the relative production of singlet oxygen and superoxide. Since many tumors overexpress folate receptors (FR), one way to reduce quinone toxicity to normal tissues, and increase toxic damage to tumor, is to deliver selectively quinones to FR-overexpressing tumors. The present research proposal is also aimed at exploring new potential pathways in quinone-enhanced toxicity initiated by quinone reduction using FR-targeted quinones. FRtargeted quinones will be synthesized and their abilities to catalyze the production of reactive oxygen species and DNA and protein alkylation will be determined. Specific Aims: 1. To determine the effects of dyes and sacrificial electron donors hydrophobicities/hydrophilicities in lipid/buffer systems on the relative yields of superoxide and singlet oxygen. 2. To synthesize FR-targeted quinones and an FR-targeted etoposide quinone derivative. 3. To characterize the semiquinones and the rate of reactive oxygen species (ROS) production upon enzymatic and photosensitized reduction of FR-targeted quinones. 4. To determine if photosensitized FR-targeted aziridinylquinone-DNA covalent binding occurs, using red-absorbing dyes. 5. To determine if the FR-targeted etoposide quinone derivative binds to protein thiols and DNA bases. 6. To determine FR-targeted semiquinone and ROS production in HeLa and non-FRoverexpressing cells, using EPR spectroscopy, and whether or not the production of these species is related to FR binding. 7. To determine FR-targeted quinone derivative cytotoxic activity in HeLa and non-FR overexpressing cells.