Targeting Translation Control in Malignant Glioma

癌细胞表现出异常性质，例如不受抑制的生长/增殖、周围组织的侵袭/转移和血液供应的转向，因为阻止健康细胞发展成恶性肿瘤的正常基因表达程序被解除调节。这种失调的一个重要部分是癌细胞中信使RNA（mRNA）蛋白质合成的异常控制。提供基因表达的全局控制以及具有重要生物学功能的特定mRNA的翻译调节的机制是理解癌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用于癌症治疗。这一原理已被证明与病毒基因工程，以特异性表达病毒基因产物在恶性胶质瘤细胞，而不能翻译其基因组在正常的脑细胞。我们的长期目标是揭示癌细胞中翻译调控的原理以及它们与正常细胞的区别。更好地理解癌症中的翻译控制将有助于开发针对异常蛋白表达控制的治疗干预的新策略。该提案旨在测试关于恶性胶质瘤（脑中最常见和最具破坏性的癌症形式）中翻译调控的几种假设。我们将研究三个特定的目的：1）DRBP 76：NF 45异二聚体在原代外植体培养中的翻译控制中的作用。我们将评估RNA结合蛋白复合物在患者源性神经胶质瘤细胞蛋白质合成调控中的作用。2)神经胶质瘤与神经元细胞中DRBP 76：NF 45异二聚体的转录后基因调控我们将采用免疫沉淀的RNA结合蛋白：mRNA复合物和基因组阵列，以确定在神经胶质瘤和神经元细胞的DRBP 76：NF 45异二聚体调控的mRNA。3)胶质瘤中靶向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选择性地驱动病毒基因在胶质瘤细胞中表达。从我们的研究中获得的知识将被应用于实施针对恶性胶质瘤中异常翻译调控的新的抗癌方法。一种原型溶瘤脊髓灰质炎病毒，经工程改造，在翻译控制水平上选择性地靶向恶性胶质瘤细胞，计划在明年内进入临床研究。

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.