Cancer-Related Glycolytic Gene:Regulation and Targeting

描述（由申请人提供）：该申请专注于编码II型己糖激酶的基因的调控和靶向，II型己糖激酶是许多癌症生长和发病的主要参与者。这种酶对于维持癌症最常见的生化特征至关重要，即它们以高速率代谢葡萄糖的能力。表达这种表型的癌症通常是最恶性的，生长迅速，经常转移。这种细胞中II型己糖激酶的过度表达促进了它们在缺氧条件下的快速生长和存活。值得注意的是，在过去的进展期间，我们提供的证据表明，表观遗传因素，即去甲基化和甲基化可能分别对II型己糖激酶基因的开启和关闭很重要；低氧条件+葡萄糖提供最大的激活；启动子的大部分强度存在于转录起始位点周围的区域；反义己糖激酶RNA能显著抑制肿瘤细胞的生长。最后，利用肝癌动物模型，我们在一项试验研究中表明，烷基化剂3-溴丙酮酸可以通过直接靶向（通过动脉注射）II型己糖激酶和线粒体ATP合成来阻止肿瘤生长。这项工作为该项目的未来具体目标提供了坚实的基础，具体目标有三个方面：1。阐明转化相关表观遗传事件的分子基础，这些事件使转录起始位点周围的CpG岛完全去甲基化，并“开启”II型己糖激酶基因。2. 鉴定II型己糖激酶基因CpG岛中的缺氧敏感元件，并评估缺氧胁迫对II型己糖激酶甲基化模式和表达的影响。3. 评估针对II型己糖激酶的RNA和化学药物在肝癌/肺转移兔模型中的相对治疗效果。考虑到FDG-PET目前在世界范围内广泛用于检测癌症和监测其治疗，主要基于己糖激酶表达水平的升高，似乎人类患者的许多癌症可能被这种酶显著促进。从这个角度来看，这里提出的基础工作重点是确定沉默和促进II型己糖激酶的潜在机制，以及确定抑制它的新型药物，可能有助于扭转我们对癌症的失败战争。

DESCRIPTION (provided by applicant): This application focuses on the regulation and targeting of the gene that encodes Type II hexokinase, a major player in the growth and pathogenesis of many cancers. This enzyme is essential for maintaining the most common biochemical signature of cancers, i.e., their capacity to metabolize glucose at high rates. Cancers expressing this phenotype are usually the most malignant, growing rapidly and frequently becoming metastatic. The overexpressed Type II hexokinase in such cells promotes their rapid growth and survival even under hypoxic conditions. Significantly, during the past progress period we provided evidence that epigenetic factors, i.e., demethylation and methylation may be important for respectively turning the Type II hexokinase gene on and off; that hypoxic conditions + glucose provide maximal activation; that much of the strength of the promoter lies in the region encompassing the transcription start site; and that antisense hexokinase RNA can inhibit markedly tumor cell growth in culture. Finally, using an animal model for liver cancer, we showed in a test study that the alkylating agent 3-bromopyruvic acid can arrest tumor growth by targeting directly (via intraarterial injection) both Type II hexokinase and mitochondrial ATP synthesis. This work has provided a strong foundation for the future Specific Aims of this project that are threefold: 1. Elucidate the molecular basis of those transformation-related epigenetic events that completely demethylate the CpG island encompassing the transcription start site and "switch on" the Type II hexokinase gene. 2. Identify the hypoxia sensitive element(s) within the CpG island of the Type II hexokinase gene and evaluate the effect of hypoxic stress both on the methylation pattern and on the expression of Type II hexokinase. 3. Assess the relative therapeutic efficacies of RNA and chemical based agents targeted to Type II hexokinase in a liver cancer/lung metastasis rabbit model. Considering that FDG-PET, now commonly used worldwide to detect cancer and monitor its treatment, is based largely on elevated expression levels of hexokinase, it would seem that numerous cancers in human patients may be markedly promoted by this enzyme. In this light, the basic work proposed here that focuses both on identifying the underlying mechanisms that silence and promote Type II hexokinase and in identifying novel agents that inhibit it, may help turn the tide on our losing war on cancer.