Targeting Translation Control in Malignant Glioma

癌细胞表现出异常的性质，如不受抑制的生长/增殖，侵袭/转移周围组织，以及血液供应的分流，因为正常的基因表达程序阻止健康细胞发展为恶性肿瘤是去调节的。这种放松调控的一个重要部分是对癌细胞中信使RNA(MRNAs)合成蛋白质的异常控制。对具有重要生物学功能的特定mRNAs的翻译调控和基因表达的全球调控机制是理解肿瘤细胞生物学许多方面的关键。最重要的是，恶性细胞中蛋白质合成的异常调节可以用于癌症治疗。这一原理已经在基因工程病毒中得到证明，这种病毒可以在恶性胶质瘤细胞中特异性地表达病毒基因产物，而不能在正常脑细胞中翻译它们的基因组。我们的长期目标是解开癌细胞的翻译调控原理，以及它们与正常细胞的不同之处。更好地了解癌症中的翻译调控将有助于开发针对异常蛋白表达调控的新的治疗干预策略。这项提议旨在测试几个关于恶性胶质瘤翻译调控的假设，恶性胶质瘤是大脑中最常见和最具破坏性的癌症形式。我们将研究三个具体目标：1)DRBP76：NF45异源二聚体在初代外植体培养中翻译控制中的作用。我们将评估RNA结合蛋白复合体在调节患者来源的胶质瘤细胞蛋白质合成中的作用。2)DRBP76：NF45异源二聚体对神经胶质瘤细胞转录后基因的调控。我们将使用RNA结合蛋白：mRNA复合体和基因组阵列的免疫沉淀来鉴定胶质瘤和神经元细胞中受DRBP76：NF45异源二聚体调控的mRNAs。3)针对胶质瘤翻译控制的疱疹病毒重组体。我们将操纵疱疹病毒基因组，通过利用胶质瘤特异性翻译控制元件来选择性地驱动病毒基因在胶质瘤细胞中的表达。从我们的研究中获得的知识将被应用于针对恶性胶质瘤异常翻译调控的新的抗癌方法的实施。一种溶瘤脊髓灰质炎病毒的原型计划在明年进入临床研究，该病毒被设计成在翻译控制水平上选择性地针对恶性胶质瘤细胞。

Cancer cells exhibit abnormal properties, such as uninhibited growth/proliferation, invasion of surrounding tissues/metastasis and the diversion of blood supply, because normal gene expression programs preventing healthy cells from developing malignancy are deregulated. An important part of this deregulation is abnormal control of protein synthesis from messenger RNAs (mRNAs) in cancer cells. The mechanisms that provide global control of gene expression as well as translation regulation of specific mRNAs with important biological functions hold the key to understand many aspects of cancer cell biology. Most importantly, abnormal regulation of protein synthesis in malignant cells can be exploited for cancer therapy. This principle has been demonstrated with viruses genetically engineered to specifically express viral gene products in malignant glioma cells, while being unable to translate their genomes in normal brain cells. Our long-term goals are to unravel the principles of translation regulation in cancer cells and how they differ from normal cells. A better understanding of translation control in cancer will help to develop new strategies for therapeutic intervention targeting aberrant protein expression control. This proposal is designed to test several hypotheses regarding translation regulation in malignant glioma, the most common and devastating form of cancer in the brain. We will investigate three Specific Aims: 1) The role of the DRBP76:NF45 heterodimer in translation control in primary explant cultures. We will evaluate the role of an RNA-binding protein complex in the regulation of protein synthesis in patient-derived glioma cells. 2) Post-transcriptional gene regulation by the DRBP76:NF45 heterodimer in glioma vs. neuronal cells. We will employ immunoprecipitation of RNA-binding protein:mRNA complexes and genomic arrays to identify mRNAs in glioma and neuronal cells that are regulated by the DRBP76:NF45 heterodimer. 3) Herpesvirus recombinants targeting translation control in glioma. We will manipulate the herpesvirus genome to selectively drive viral gene expression in glioma cells by utilizing glioma-specific translation control elements. The knowledge obtained from our studies will be applied towards implementation of new anti-cancer approaches targeting abnormal translation regulation in malignant glioma. A prototype oncolytic poliovirus, engineered to selectively target malignant glioma cells at the level of translation control is scheduled to enter clinical investigation within the next year.