Inhibition of Intracerebral Gliomas with DNAzymes

描述（申请人提供）：实体瘤血管生成是肿瘤治疗的重要靶点。众所周知，实体瘤的生长和转移需要持续的血管生成，而血管生成的诱导是肿瘤表型的一个离散组成部分。血管内皮生长因子及其同源受体（VEGFR1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靶向VEGFR2 mRNA转录物的催化寡脱氧核苷酸（DNAzyme）。通过皮下植入乳腺癌的瘤内注射，发现VEGFR2 DNAzyme在体内显著抑制肿瘤生长。该建议的一个目标是将该疗法扩展到临床相关模型C6胶质瘤。我们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），显著增加转染和寡核苷酸传递。线性和支链HK聚合物提供了有效递送治疗性寡核苷酸的潜力，包括DNAzymes。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来减少肿瘤在体内的生长。Aim 1旨在提高DNAzyme靶向VEGF 2受体mRNA的生物活性效率。虽然我们实验室开发的靶向VEGFR2的DNAzyme有效地降低了肿瘤生长，但通过添加硫代磷酸酯键对退火臂进行修饰有望增强DNAzyme的效力。因此，目前的VEGFR2 DNAzyme将被修饰，以增强其对酶降解的抵抗力，从而提高其生物活性。为了更有效地将DNAzyme运输到肿瘤内皮细胞，Aim 2将确定一个更有效的DNAzyme分支HK载体。几种不同分支程度和组氨酸/赖氨酸比例的HK聚合物将被测试其提高DNAzyme功效的能力。然后用配体修饰最有效的HK载体，以进一步增强复合物进入肿瘤内皮细胞的摄取。随着含hk复合物设计的改进，预计该载体与VEGFR DNAzyme复合物将对原位植入的胶质瘤具有更强的抗肿瘤功效。

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.