Mitochondrial DNA in Mutations in Prostate Cancer

描述（由申请人提供）：线粒体DNA（mtDNA）突变在多种人类肿瘤中发生频率很高，但此类突变的功能后果尚不清楚。我们计划的总体目标是了解mtDNA突变如何影响癌细胞的恶性潜能。我们假设mtDNA突变增强了肿瘤细胞的存活和增殖，同时减少了那些碰巧获得它们的肿瘤细胞的凋亡。我们进一步提出，线粒体DNA突变增加了活性氧（ROS）的线粒体生产，这种增加的ROS生产是促有丝分裂，增强增殖和减少凋亡。我们实验室的初步数据显示，一个这样的mtDNA突变确实能够促进人类前列腺癌异种移植物的生长。为了检验这一假设，提出了3个具体目标。首先，我们将生成测试假设所需的实验结构。具体来说，我们将创建细胞质杂交体（cybrids），其将充分表征的前列腺癌细胞系的细胞核与含有突变型或野生型mtDNA的细胞质（因此线粒体）结合。其次，我们将确定特定的突变是否影响恶性表型，测量细胞增殖，凋亡，细胞周期进展和肿瘤发生。最后，我们将确定ROS在观察到的表型改变中的作用，确定ROS是否是mtDNA突变和增强肿瘤生长之间的功能性中间体。这些目标的实现将使我们能够确定mtDNA突变是否会增强恶性表型，以及这种改变是否是由于ROS增加。此外，我们将产生细胞，肿瘤和动物模型，这将使其他研究人员能够在未来研究mtDNA在癌症中的作用，并有助于针对携带mtDNA突变的肿瘤的潜在抗肿瘤药物的临床前筛选。

DESCRIPTION (provided by applicant): Mitochondrial DNA (mtDNA) mutations occur with high frequency in a variety of human tumors but the functional consequences of such mutations are unknown. The overall goal of our proposal is to understand how mtDNA mutations affect the malignant potential of cancer cells. We hypothesize that mtDNA mutations enhance the survival and proliferation while decreasing apoptosis of those tumors cells that happen to acquire them. We further propose that mtDNA mutations increase the mitochondrial production of reactive oxygen species (ROS) and that this increased ROS production is mitogenic, enhancing proliferation and decreasing apoptosis. Preliminary data from our lab shows that one such mtDNA mutation is indeed capable of enhancing the growth of human prostate cancer xenografts. In order to test this hypothesis 3 specific aims are proposed. First we will generate the laboratory constructs required to test the hypothesis. Specifically, we will create cytoplasmic hybrids (cybrids) that combine the nucleus of well-characterized prostate cancer cell lines with cytoplasm (and therefore mitochondria) containing either mutant or wild type mtDNA. Second, we will determine whether specific mutations affect the malignant phenotype, measuring cellular proliferation, apoptosis, cell cycle progression and tumorigenesis. Finally, we will determine the role of ROS in the observed phenotypic alterations, establishing whether ROS are a functional intermediate between mtDNA mutation and enhanced tumor growth. The accomplishment of these aims will allow us to determine whether mtDNA mutations enhance the malignant phenotype and whether such an alteration is due to increased ROS. In addition, we will generate cells, tumors and animal models that will allow the future study of the role of mtDNA in cancer by other investigators and aid in the pre-clinical screening of potential anti-neoplastics directed at tumors that harbor mtDNA mutations.