Targeting Glioma by Anti-MMPs-2 and -9 DNAzymes

描述(由申请人提供)：尽管诊断、手术技术和放射治疗方案不断改进，但对高度恶性胶质瘤的有效治疗方法仍然严重不足。大多数高级别胶质瘤患者的中位生存期在几个月左右。由于手术是目前唯一可以为这些患者提供一些好处的治疗方法，因此开发一种有效的手术佐剂确实可以使平衡朝着更好的结果倾斜。多形性胶质母细胞瘤是最常见和最恶性的脑肿瘤，以坏死、血管增生和侵袭周围正常脑组织为特征。尽管促进脑癌侵袭行为的具体机制尚不清楚，但肿瘤细胞的侵袭至少部分是通过肿瘤细胞和间质细胞产生的中性金属蛋白酶(MMPs)降解基底膜来实现的。有证据表明，基质金属蛋白酶-2和基质金属蛋白酶-9在中枢神经系统肿瘤细胞的侵袭和转移中起重要作用。最近，我们发现针对基质金属蛋白酶-2或基质金属蛋白酶-9基因的脱氧核酶在体外能够减少这些酶的表达，并且在体内动物模型中能够减少C6胶质瘤的大小。考虑到它们在全身给药和靶向方面的潜力，DNAzyme可能被证明是一种通过靶向MMPs来对抗胶质瘤侵袭的有效疗法。为了实现这一目标，1.在不对周围健康脑组织造成重大毒性的情况下完全根除肿瘤所需的最小有效DNAzyme剂量将通过DNAzyme在大鼠脑胶质瘤模型中的剂量递增和时程研究来确定。我们将同时评估DNAzyme在健康中枢组织中的安全性和生物利用度。2.在大鼠脑胶质瘤模型上观察DNAzyme对人脑胶质瘤的治疗效果。以及，3.将评估DNAzymes治疗对携带胶质瘤动物的预期寿命(存活率)的影响。因此，在这项建议中，我们正在采取一种创新的方法来治疗胶质瘤，通过研究抗基质金属蛋白酶-2和基质金属蛋白酶-9脱氧核酶治疗对发病率和死亡率的主要机制的影响。

DESCRIPTION (provided by applicant): Despite continued improvements in diagnosis, surgical techniques, and radiation protocols, the available treatments for high-grade malignant glioma are grossly inadequate. The median survival time for most patients with high-grade gliomas is on the order of months. Because surgery is the only therapy currently available that provides some benefit for these patients, the development of a potent adjuvant to surgery could indeed tip the balance towards a better outcome. The most common and malignant brain tumor, glioblastoma multiforme, is characterized by the presence of necrosis, vascular proliferation, and aggressive invasion into surrounding normal brain tissue. Although the specific mechanisms facilitating the invasive behaviors of brain cancer are unclear, tumor cell invasion are known to be mediated, at least in part, through degradation of basement membrane by neutral metalloproteinases (MMP) produced by tumor cells and stroma cells. Evidence suggests that MMP-2 and MMP-9 play a significant role in CNS tumor cell invasion and metastasis. Recently, we have shown that DNAzyme generated against either MMP-2 or MMP-9 mRNA was able to reduce the expression of the enzymes in vitro, as well as the size of the C6-glioma generated in the in vivo animal model. Given their potential for systemic administration and targeting, DNAzymes could prove useful as a therapy against Glioma invasion by targeting MMPs. Toward achievement of this goal, 1. the minimum effective dose of DNAzyme needed to completely eradicate the tumor without causing significant toxicity to the surrounding healthy tissue of the brain will be determined by a dose escalation and a time course study of DNAzyme in the rat intracranial glioma model. We will simultaneously evaluate the safety and bioavailability of DNAzymes in healthy CNS tissues. 2. the efficacy of DNAzyme in treating human glioma will be tested in rat xenograft intracranial glioma model. And, 3. the effect of DNAzymes treatment on life expectancy (survival rate) of the animals bearing glioma will be assessed. Thus, in this proposal we are taking an innovative approach to the treatment of glioma by studying the effect the anti MMP-2 and MMP-9 DNAzymes therapy on the major mechanism of morbidity and mortality.