Telomerase Specific Caspase Transfer for Gliomas

端粒酶特异性半胱天冬酶转移用于神经胶质瘤

基本信息

批准号：
6679715
负责人：
SEIJI KONDO
金额：
$ 19.41万
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：
2001
资助国家：
美国
起止时间：
2001-07-01 至 2005-06-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): Our efforts to treat malignant gliomas are focused on methods to transfer the caspase genes to tumors. Because the apoptotic pathway may be disrupted in tumors and caspases are the mainstay of apoptosis programs, this approach is one of the most promising strategies for cancer gene therapy. However, if caspases were transduced to normal brain cells, they will undergo apoptosis. To restrict induction of apoptosis to tumor cells, we need to establish a tumor specific expression system of caspases. Telomerase is a particularly attractive target for the tumor-targeting system. It is because a vast majority of malignant gliomas have telomerase activity, while most normal brain cells do not. Activation of telomerase is tightly regulated at the transcriptional level of the telomerase catalytic subunit (hTERT). Therefore, we hypothesize that by using the hTERT promoter-driven vector system, the expression of caspases can be restricted to telomerase-positive malignant gliomas. In preliminary studies, we constructed the caspase-8 (initiator caspase) or rev-caspase-6 (executioner caspase) expression vector with the hTERT promoter (hTERT/caspase-8 or rev-caspase-6) and demonstrated that each construct induced apoptosis in telomerase-positive malignant glioma cells, but not in cultured astrocytes lacking telomerase. Furthermore, the growth of subcutaneous tumors in nude mice was significantly suppressed by the treatment with the hTERT/rev-caspase-6. Additionally, the antitumor effect of hTERT/caspase-8 or rev-caspase-6 was enhanced by the combination with anticancer drug, cisplatin. The goal of this proposal is to investigate whether treatment with the hTERT/caspase-8 or rev-caspase-6 construct is an effective approach for telomerase-positive malignant gliomas using an experimental model of human malignant gliomas. The specific aims are: 1) to select tumor model systems for the in vivo treatment with hTERT/caspase-8 or rev-caspase-6 construct, 2) to investigate the antitumor effect of the hTERT/caspase-8 or rev-caspase-6 construct on intracranial tumors, 3) to investigate their in vitro and in vivo antitumor efficacy combined with conventional therapy (cisplatin, temozolomide, or gamma-irradiation), and 4) to investigate the molecular mechanisms underlying the effect of the hTERT/caspase-8 or rev-caspase-6. A unique focus of this work is the emphasis on the telomerase-specific gene transfer of caspases. We anticipate that the studies described in the current proposal will lead to a novel and promising targeting approach for malignant gliomas expressing telomerase activity.

描述（由申请人提供）：我们治疗恶性神经胶质瘤的努力是重点研究将 caspase 基因转移到肿瘤的方法。因为肿瘤中细胞凋亡途径可能被破坏，而半胱天冬酶是其中的支柱细胞凋亡程序，这种方法是最有前途的策略之一癌症基因治疗。然而，如果半胱天冬酶被转导到正常大脑中细胞，就会发生凋亡。限制肿瘤细胞凋亡的诱导细胞中，我们需要建立肿瘤特异性的caspases表达系统。端粒酶是肿瘤靶向系统特别有吸引力的靶标。这是因为绝大多数恶性胶质瘤都具有端粒酶活性，而大多数正常脑细胞则不然。端粒酶的激活紧密在端粒酶催化亚基的转录水平上进行调节 (hTERT)。因此，我们假设通过使用 hTERT 启动子驱动载体系统，半胱天冬酶的表达可以限制为端粒酶阳性恶性神经胶质瘤。在初步研究中，我们构建了 caspase-8（启动 caspase）或 rev-caspase-6（执行 caspase）带有 hTERT 启动子的表达载体（hTERT/caspase-8 或 rev-caspase-6）并证明每种构建体都能诱导端粒酶阳性细胞凋亡恶性胶质瘤细胞，但不存在于缺乏端粒酶的培养星形胶质细胞中。此外，裸鼠皮下肿瘤生长显着 hTERT/rev-caspase-6 治疗可抑制。此外， hTERT/caspase-8 或 rev-caspase-6 的抗肿瘤作用通过与抗癌药物顺铂联合使用。该提案的目标是研究是否使用 hTERT/caspase-8 或 rev-caspase-6 进行治疗构建体是端粒酶阳性恶性胶质瘤的有效方法使用人类恶性神经胶质瘤的实验模型。具体目标是： 1) 选择hTERT/caspase-8体内治疗的肿瘤模型系统或 rev-caspase-6 构建体，2) 研究其抗肿瘤作用颅内肿瘤上的 hTERT/caspase-8 或 rev-caspase-6 构建体，3) 研究它们的体外和体内抗肿瘤功效常规治疗（顺铂、替莫唑胺或伽玛射线照射），以及 4) 研究影响的分子机制 hTERT/caspase-8 或 rev-caspase-6。这项工作的一个独特的重点是强调半胱天冬酶的端粒酶特异性基因转移。我们预计当前提案中描述的研究将带来一种新颖且有前途的研究表达端粒酶活性的恶性神经胶质瘤的靶向方法。