Inhibition of Intracerebral Gliomas with DNAzymes

描述（由申请人提供）：实体瘤的血管生成是癌症治疗的重要靶点。已经充分认识到实体瘤的生长和转移需要持续的血管生成，并且血管生成的诱导是肿瘤表型的离散组分。血管内皮生长因子及其同源受体（VEGFR 1和2）是促进肿瘤血管生成的关键因子。 我们的实验室最近发现了一种催化寡脱氧核苷酸（DNAzyme），靶向VEGFR 2 mRNA转录。通过皮下植入的乳腺癌的肿瘤内注射，发现VEGFR 2 DNAzyme在体内显著抑制肿瘤生长。该建议的一个目的是将这种疗法扩展到临床相关模型C6胶质瘤。我们的实验室还合成了一种由组氨酸和赖氨酸组成的聚合物（HK聚合物），可显著增加转染和寡核苷酸递送。线性和支化HK聚合物提供了有效递送治疗性寡核苷酸（包括DNA酶）的潜力。我们的总体目标和长期目标是开发一种有效的抗血管生成寡核苷酸方法，以减少体内肿瘤生长。目的1为提高靶向VEGF 2受体mRNA的DNA酶的生物活性。 尽管我们实验室开发的靶向VEGFR 2的DNAzyme有效地减少了肿瘤生长，但通过添加硫代磷酸酯键来修饰退火臂有望增强DNAzyme的效力。因此，目前的VEGFR 2 DNA酶将被修饰以增强其对酶降解的抗性，从而增加其生物活性。为了更有效地将DNAzyme转运到肿瘤内皮细胞，目的2将确定更有效的DNAzyme的分支HK载体。将测试支化度和组氨酸/赖氨酸比率不同的几种HK聚合物增加DNAzyme功效的能力。然后用配体修饰最有效的HK载体，以进一步增加肿瘤内皮细胞对复合物的摄取。随着含HK复合物的改进设计，预期这种载体与VEGFR DNA酶复合将对原位植入的胶质瘤具有更好的抗肿瘤功效。

DESCRIPTION (provided by applicant): Angiogenesis of solid tumors is an important target of cancer therapy. It has been well recognized that growth and metastasis of solid tumors require persistent angiogenesis and that induction of angiogenesis is a discrete component of the tumor phenotype. Vascular endothelial growth factor and its cognate receptors (VEGFR1 and 2) are critical factors in promoting tumor angiogenesis. Our laboratory has recently identified a catalytic oligodeoxynucleotide (DNAzyme) that targets the VEGFR2 mRNA transcript. With intratumoral injections of subcutaneous implanted breast cancer, the VEGFR2 DNAzyme was found to inhibit tumor growth markedly in vivo. One objective of this proposal is to extend this therapy to a clinically relevant model, C6 gliomas. Our laboratory has also synthesized a polymer composed of histidine and lysine (HK polymer) that significantly increases transfection and oligonucleotide delivery. The linear and branched HK polymers offer the potential for effective delivery of therapeutic oligonucleotides including DNAzymes. Our overall aim and long term goal is to develop an effective antiangiogenic oligonucleotide approach to reduce tumor growth in vivo. Aim 1 is designed to improve the bioactivity efficiency of the DNAzyme targeting the mRNA of the VEGF 2 receptor. Although the DNAzyme targeting VEGFR2 developed by our laboratory effectively reduced tumor growth, modification of the annealing arms by the addition ofphosphorothioate linkages is expected to augment the potency of the DNAzyme. Therefore, the current VEGFR2 DNAzyme will be modified to augment its resistance to enzymatic degradation and thus increase its bioactivity. To transport the DNAzyme more effectively to tumor endothelial cells, Aim 2 will determine a more effective branched HK cartier of the DNAzyme. Several HK polymers that vary in the degree of branching and the histidine/lysine ratio will be tested for their ability to increase the efficacy of the DNAzyme. The most effective HK carrier will then be modified with a ligand to further augment the uptake of the complex into tumor endothelial cells. With improved design of HK-containing complexes, it is anticipated that this cartier in complex with the VEGFR DNAzyme will have more anfitumor efficacy toward an orthotopically implanted glioma.