Transduction of Tumor Suppressor Proteins into Gliomas

描述：（由申请人提供）脑肿瘤、神经胶质瘤和星形细胞瘤， 是毁灭性的恶性肿瘤，占美国所有癌症的2.3%， 是儿童中第二常见的实体瘤。恶性 脑肿瘤对目前的治疗反应不佳，平均存活率为 尽管治疗了不到一年，由于神经胶质瘤的侵袭性， 特别是多形性胶质母细胞瘤（GBM），局部抗癌策略， 例如手术切除，也不能充分阻止疾病。胶质瘤 选择多个肿瘤抑制基因的遗传失活，包括 p53（> 60%）、PTEN（> 75%）、p16/pI4ARF（50%）、pRB（30 百分比），以及p27 Cdk抑制剂的表观遗传下调。 抗癌疗法的一个中心假设认为， 抑制基因在恶性细胞中的功能将导致特异性死亡， 癌细胞的凋亡，同时保留周围的正常组织。 事实上，肿瘤细胞正在经历持续的DNA损伤，因此， 腺病毒在胶质瘤中表达野生型p53的特异性结果 对胶质瘤细胞凋亡的影响。我们建议通过以下方式来检验这一假设： 产生可转导的肿瘤抑制蛋白。 我的实验室进一步发展了蛋白质转导的方法。 含有N'末端的重组细菌表达的融合蛋白 HIV达特的蛋白转导结构域迅速转化为100%的 细胞使用这种方法，我们已经产生和转导了60多个 15-120 kDa的TAT融合蛋白。最近，我们证明了 的TAT-B-gal蛋白，以进入大多数，如果不是全部，细胞和组织， 小鼠体内模型，包括穿过血脑屏障。因此在 原则和实践，所有哺乳动物细胞类型都对蛋白质敏感， 转导 我们建议测试抗癌的有效性和特异性杀死 通过可转导的肿瘤抑制蛋白，即 TAT-ARF和TAT-p53，以及可转导的促凋亡病毒蛋白， TAT-Apoptin将在体外分析和优化TAT融合蛋白， 然后在裸鼠和小鼠体内进行抗异种移植颅内神经胶质瘤的试验， B8转基因ras ~ 2+小鼠中的新生星形细胞瘤。此外，要 量化小鼠模型中的蛋白转导潜力，我们打算分析 TAT-报告融合蛋白的转导和重折叠速率，包括 TAT-B-gal和TAT-TK。TAT-TK活性也将通过以下方法在体内监测： 使用18F-荧光更昔洛韦作为正电子发射体的microPET成像。

DESCRIPTION: (provided by applicant) Brain tumors, gliomas and astrocytomas, are devastating malignancies that account for 2.3 percent of all US cancer deaths and represent the second most common solid tumor of children. Malignant brain tumors respond poorly to current therapies with a mean survival rate of less than one year despite treatment, Due to the invasive nature of gliomas, particularly glioblastoma multiformes (GBM), localized anti-cancer strategies, such as surgical removal, also fail to adequately halt the disease. Gliomas select for genetic inactivation of multiple tumor suppressor genes, including p53 (>60 percent), PTEN (>75 percent), p16/p I4ARF (50 percent), pRB (30 percent), and epigenetic down-regulation of the p27 Cdk inhibitor. A central hypothesis of anti-cancer therapies holds that replacement of tumor suppressor gene functions in malignant cells will result in specific death or apoptosis of the cancer cell while sparing the surrounding normal tissue. Indeed, tumor cells are undergoing continuous DNA damage and therefore, adenovirus expression of wild type p53 in gliomas by results in specific apoptosis to the glioma tumor cells. We propose to test this hypothesis by generating transducible tumor suppressor proteins. My laboratory has further developed the methodology of protein transduction. Recombinant, bacterially expressed fusion proteins containing an N' terminal protein transduction domain from HIV TAT rapidly transduce into 100 percent of cells. Using this methodology, we have generated and transduced over 60 TAT-fusion proteins from 15-120 kDa. Recently, we have demonstrated the ability of TAT-B-gal protein to transduce into most, if not all, cells and tissues of mouse models in vivo, including across the blood-brain barrier. Thus, in principle and practice, all mammalian cell types are susceptible to protein transduction. We propose to test the anti-cancer effectiveness and specificity of killing glioma tumors in mouse models by transducible tumor suppressor proteins, namely TAT-ARF and TAT-p53, and by a transducible pro-apoptotic viral protein, TAT-Apoptin. TAT-fusion proteins will be analyzed and optimized in vitro and then tested against xenograft intracranial glioma tumors in nude mice and in de novo derived astrocytomas in B8 transgenic ras about2" mice. In addition, to quantify protein transduction potential in mouse models, we intend to analyze the transduction and refolding rates of TAT-reporter fusion proteins, including TAT-B-gal and TAT-TK. TAT-TK activity will also be monitored in vivo by microPET imaging using '8F-fluoroganciclovir as a positron emitter.