ADAM 17 and glioma-tumor progression and treatment

描述（由申请人提供）：没有治疗多形性胶质瘤的方法可以显著延长生命。无法有效治疗胶质瘤的原因尚不清楚。在本研究中，基于可靠的初步数据，我们提出了一个新的假设，即这种酶，一种崩解素和金属蛋白酶-17，也被称为肿瘤坏死因子转换酶（ADAM17， TACE）促进胶质瘤的侵袭、增殖和存活。因此，抑制ADAM17将有效降低肿瘤生长。我们提出了三个具体目标和相应的假设，旨在充分研究ADAM17作为促肿瘤因子和抑制ADAM17作为抗肿瘤治疗的潜力。目的1：表征ADAM17在体外胶质瘤侵袭、增殖、存活以及体内肿瘤进展中的功能。假设1a: ADAM17活性的增加在体外诱导胶质瘤细胞侵袭，促进细胞增殖和存活，在体内促进肿瘤进展。假设1b: ADAM17激活表皮生长因子（EGF）信号通路，通过刺激PI3K/Akt通路促进胶质瘤侵袭、细胞增殖和存活。目的2：探讨ADAM17在低氧应激下胶质瘤进展中的作用。假设2：缺氧诱导的细胞应激上调ADAM17的转录和蛋白水解活性，这种上调导致胶质瘤的增殖、侵袭性和存活率增强。目的3：探讨adam17靶向RNAi基因治疗U87和HF66人胶质瘤裸鼠模型的疗效。假设3：靶向ADAM17的RNAi基因治疗可降低胶质瘤细胞内ADAM17的表达和蛋白水解活性，从而减缓肿瘤进展，延长颅内胶质瘤裸鼠的生存期。胶质瘤的体外和体内模型均被用于拟议的研究。研究人员使用了siRNA、激光共聚焦显微镜和磁共振成像等方法来剖析ADAM17在肿瘤进展中的作用，并阐明肿瘤进展和有效治疗的分子基础。我们的长期目标是开发一种有效的治疗这种破坏性脑肿瘤的方法，并将我们的发现从实验系统转化为人类。公共卫生相关性：本项目旨在研究崩解素和金属蛋白酶17 （ADAM17/TACE）蛋白水解在胶质母细胞瘤多形性肿瘤进展中的功能。将阐明ADAM17在肿瘤细胞增殖和侵袭中的作用，特别关注由于低葡萄糖和低氧可用性导致的ADAM17诱导。我们将确定ADAM17活性的破坏或增强是否会导致肿瘤进展的变化，以及ADAM17沉默基因治疗是否在人类胶质瘤小鼠模型中提供治疗效果。

DESCRIPTION (provided by applicant): There are no treatments of glioma multiforme that substantially extend life. The reasons behind the inability to effectively treat glioma remain obscure. In this proposal, based on robust preliminary data, we develop a novel hypothesis, that the enzyme, a disintegrin and metalloproteinase-17, also known as, tumor necrosis factor converting enzyme (ADAM17, TACE) fosters glioma invasion, proliferation and survival. Thereby inhibition of ADAM17 will be effective in reducing tumor growth. We propose three specific aims and corresponding hypotheses, directed at fully investigating the potential of ADAM17 as a pro tumorgenic agent and inhibition of ADAM17 as an anti-tumor treatment. Aim 1: Characterize the function of ADAM17 in glioma invasion, proliferation and survival in vitro, and in tumor progression in vivo. Hypothesis 1a: Increased ADAM17 activity induces invasion and promotes cell proliferation and survival of glioma cells in vitro and promotes tumor progression in vivo. Hypothesis 1b: ADAM17 activation of the epidermal growth factor (EGF) signaling pathway promotes glioma invasion, cell proliferation and survival, by stimulating the PI3K/Akt pathway. Aim 2: Investigate the role of ADAM17 in glioma progression in the context of hypoxic stress. Hypothesis 2: ADAM17 transcription and proteolytic activity are up-regulated by hypoxia-induced cellular stress, and this increase leads to enhanced glioma proliferation, invasiveness and survival. Aim 3: Investigate the therapeutic effectiveness of ADAM17-targeting RNAi gene therapy to treat U87 and HF66 human glioma xenographs in nude mouse models. Hypothesis 3: ADAM17-targeting RNAi gene therapy decreases ADAM17 expression and proteolytic activity within glioma cells, and thus reduces tumor progression and prolongs survival of nude mice bearing intracranial glioma xenographs. Both in vitro and in vivo models of glioma are employed in the proposed studies. Methods used range from siRNA to laser capture confocal microscopy and magnetic resonance imaging in an effort to dissect the contribution of ADAM17 to tumor progression and to elucidate the molecular bases for tumor progression and effective treatment. Our long term goal is to develop an effective treatment for this devastating brain tumor and to translate our findings from the experimental system to the human. PUBLIC HEALTH RELEVANCE: This project is designed to investigate the function of a disintegrin and metalloprotease-17 (ADAM17/TACE) proteolysis in glioblastoma multiforme tumor progression. The contribution of ADAM17 to tumor cell proliferation and invasion will be elucidated, with a special focus upon ADAM17 induction due to low glucose and oxygen availability. We will determine whether disruption or augmentation of ADAM17 activity lead to changes in tumor progression, and whether ADAM17-silencing gene therapy provides a therapeutic effect in a mouse model of human glioma.