Treatment of Malignant Gliomas with 2-5A-anti-hTR

2-5A-抗 hTR 治疗恶性胶质瘤

基本信息

批准号：
6917019
负责人：
SEIJI KONDO
金额：
$ 30.96万
依托单位：
UNIVERSITY OF TX MD ANDERSON CAN CTR
依托单位国家：
美国
项目类别：
财政年份：
2004
资助国家：
美国
起止时间：
2004-07-01 至 2009-04-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): Telomerase, a ribonucleoprotein enzyme, is detected in the vast majority of malignant gliomas, but not in normal brain tissues. In malignant gliomas, tumors with telomerase tend to have more malignant phenotype than those without telomerase. Therefore, our long-term goal is to explore a novel telomerase-targeting therapy for malignant gliomas. To inhibit telomerase function effectively, we have adopted the 2-5A (2', 5'-oligoadenylate) antisense system. 2-5A is a mediator of one pathway of interferon actions by activating RNase L, resulting in single-stranded RNA cleavage. By linking 2-5A to antisense, RNase L degrades the targeted RNA specifically and effectively. With the grant supported by NIH, we synthesized the antisense oligonucleotide against human telomerase RNA component (hTR) linked to 2-5A (2-5A-anti-hTR) and investigated its anti-tumor effect on malignant glioma cells. Treatment with 2-5A-anti-hTR for 4 days induced a massive apoptosis before a telomere length shortened critically. In contrast, normal cells such as astrocytes and fibroblasts lacking telomerase were insensitive to 2-5A-anti-hTR. Treatment of subcutaneous or intracerebral tumors in nude mice with intratumoral injections of 2-5A-anti-hTR was effective. Based on our previous results, we hypothesize that 2-5A-anti-hTR is a promising agent for the treatment of malignant gliomas expressing telomerase. However, the following questions remain to be answered. First, what molecular pathways play a key role in 2-5A-anti-hTR-induced apoptosis? Second, how can we enhance the effect of 2-5A-anti-hTR on intracerebral tumors? Third, which regimens based on 2-5A-anti-hTR show a significant combination effect on intracerebral tumors? The aim of this proposal is to address these issues. The specific aims are to: 1: Characterize the molecular pathways of 2-5A-anti-hTR-induced apoptosis. Using the microarray assay, we will identify which genes are involved in 2-5A-anti-hTR-induced cell death. We will also determine (i) the involvement of the mitochondria-associated cell death signaling pathways and (ii) the effect of 2-5A-anti-hTR on telomere 3' overhang or telomerase-positive astrocytes with or without tumorigenicity. 2: Define the effect of convection-enhanced drug delivery (CEDD) of 2-5A-anti-hTR on intracerebral tumors in nude mice. We will optimize CEDD and then compare the effect of CEDD and bolus injections of 2-5A-anti-hTR on intracerebral tumors. 3: Define the in vitro and in vivo effect of combination therapy based on 2-5A-anti-hTR. We will determine (i) the molecular pathways underlying the combination effect of 2-5A-anti-hTR and apoptosis-inducing agent (cisplatin, paclitaxel, or BCNU) and (ii) the effect of combination therapy on intracerebral tumors.

描述（由申请人提供）：端粒酶是一种核糖核蛋白酶，在绝大多数恶性神经胶质瘤中检测到，但在正常脑组织中未检测到。在恶性神经胶质瘤中，具有端粒酶的肿瘤往往比不具有端粒酶的肿瘤具有更多的恶性表型。因此，我们的长期目标是探索一种新型的端粒酶靶向治疗恶性胶质瘤的方法。为了有效抑制端粒酶功能，我们采用了2-5A（2',5'-寡腺苷酸）反义系统。 2-5A 是干扰素作用途径之一的介体，通过激活 RNase L 导致单链 RNA 裂解。通过将 2-5A 连接到反义链上，RNase L 特异性且有效地降解目标 RNA。在NIH的资助下，我们合成了与2-5A连接的针对人端粒酶RNA成分（hTR）的反义寡核苷酸（2-5A-抗hTR），并研究了其对恶性胶质瘤细胞的抗肿瘤作用。用 2-5A-抗 hTR 处理 4 天，在端粒长度严重缩短之前诱导大量细胞凋亡。相反，缺乏端粒酶的星形胶质细胞和成纤维细胞等正常细胞对2-5A-抗hTR不敏感。瘤内注射2-5A-抗hTR治疗裸鼠皮下或脑内肿瘤是有效的。根据我们之前的结果，我们假设 2-5A-抗 hTR 是治疗表达端粒酶的恶性神经胶质瘤的有前途的药物。然而，以下问题仍有待回答。首先，哪些分子途径在2-5A-抗hTR诱导的细胞凋亡中起关键作用？第二，如何增强2-5A-抗hTR对脑内肿瘤的作用？第三，哪些基于2-5A-抗hTR的方案对脑内肿瘤显示出显着的联合作用？本提案的目的是解决这些问题。具体目标是： 1：表征2-5A-抗hTR诱导细胞凋亡的分子途径。使用微阵列测定，我们将鉴定哪些基因参与 2-5A-抗 hTR 诱导的细胞死亡。我们还将确定 (i) 线粒体相关细胞死亡信号通路的参与和 (ii) 2-5A-抗 hTR 对端粒 3' 突出或端粒酶阳性星形胶质细胞（有或没有致瘤性）的影响。图2：定义2-5A-抗hTR的对流增强药物递送（CEDD）对裸鼠脑内肿瘤的作用。我们将优化CEDD，然后比较CEDD和推注2-5A-抗hTR对脑内肿瘤的效果。图3：定义基于2-5A-抗hTR的联合疗法的体外和体内效果。我们将确定 (i) 2-5A-抗 hTR 和细胞凋亡诱导剂（顺铂、紫杉醇或 BCNU）联合作用的分子途径，以及 (ii) 联合治疗对脑内肿瘤的作用。