EFFECTS OF SHORT-AND LONG-TERM FLEX-HET THERAPY ON MITOCHONDRIAL ELECTRON

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 中心，不一定是研究者的机构。 我们最近发表了我们的观察的快速影响的铅Flex-Het化合物，SHetA 2，线粒体密度，膜完整性，细胞色素C的释放和ROS的产生，所有的内在凋亡途径的指示。最近，我们观察到Flex-Hets是线粒体电子传递链复合物I的有效的非竞争性抑制剂，也是复合物II的抑制剂。由于目前已知复合物I和II的抑制剂很少，因此在本提案的第一部分中，我们将进一步研究Flex-Het药物对琥珀酸脱氢酶和完全泛醌依赖性琥珀酸：泛醌氧化还原酶活性的影响。然而，线粒体靶向药物可能是一把双刃剑，ROS本身对细胞具有高度毒性，线粒体可以逐渐消除氧化损伤，导致线粒体崩溃和细胞死亡。在本提案的第二部分，我们建议评估长期Flex-Het治疗后心脏和肝脏细胞线粒体损伤的可能性。将在两种细胞、线粒体和亚线粒体颗粒中测量线粒体功能受损的标志物，如细胞ATP降低、线粒体谷胱甘肽降低和复合物I活性降低，所述线粒体和亚线粒体颗粒分离自在正在进行的长期结肠癌化学预防项目中评价ShetA 2的尸检后处死的动物的速冻心脏和肝脏组织。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We have recently published our observation of the rapid effects of the lead Flex-Het compound, SHetA2, on mitochondrial density, membrane integrity, Cytochrome C release and ROS generation, all indicative of the intrinsic apoptosis pathway. More recently, we have observed that Flex-Hets are potent, uncompetitive inhibitors of mitochondrial electron transport chain complex I and also inhibitors of complex II. Since few inhibitors of both complex I and II are know at present, in the first part of this proposal we will further examine the effect of Flex-Het drugs on succinate dehydrogenase and full ubiquinone dependent succinate:ubiquinone oxidoreductase activity. However mitochondria targeting drugs may be a two-edged sword, ROS themselves are highly toxic to cells and mitochondria can gradually accumUlate oxidative damage leading to mitochondrial collapse and cell death. In the second part of this proposal we propose to assess the possibility of mitochondrial injury in heart and liver cells following long-term Flex-Het treatment. Markers of impaired mitochondrial function such as decreased cellular ATP, decreased mitochondrial glutathione and decreased complex I activity will be measured in both cells, mitochondria and submitochondrial particles isolated from snap-frozen heart and liver tissue obtained from animals sacrificed following necropsy in an ongoing long-term colon cancer chemoprevention project evaluating ShetA2.