Translational Studies of Fn14 in Brain Tumors

描述(申请人提供)：多形性胶质母细胞瘤是最常见的原发恶性脑肿瘤，因其易局部侵袭邻近正常脑组织和罕见全身转移而具有独特的生物学特性。侵袭性胶质瘤细胞的潜在特异性治疗靶点尚待确定：然而，这些靶点的成功识别有望催化新疗法的发展。我们已经证明Fn14在正常脑组织中的表达微乎其微，但随着肿瘤分级的增加而增加。通过增加Fn14的重组TWEE或过表达来激活Fn14信号，提高了胶质瘤细胞的运动性和存活率。我们假设Fn14的活性增强了恶性胶质母细胞瘤细胞的存活和对正常脑实质的侵袭。干扰Fn14的功能可能会特异性地针对侵袭性胶质母细胞瘤细胞，并影响肿瘤的复发能力。这一假说将通过追求以下特定目标来验证：1.确定体外抑制Fn14信号是否使胶质瘤细胞对细胞毒治疗敏感。我们将通过siRNA、小抑制分子和显性负性结构来操纵Fn14信号级联反应，以评估临床细胞毒剂对多种胶质瘤细胞系和原代低传代细胞系诱导凋亡的影响。2.确定Fn14在脑胶质瘤侵袭中的作用。Fn14在胶质瘤侵袭中的作用将通过体外脑切片器官型底物和人胶质瘤细胞原位移植到免疫低下大鼠的大脑中来评估。此外，利用包含人脑肿瘤的组织微阵列的免疫组织化学方法，Fn14和信号蛋白的水平将与肿瘤的分级和侵袭模式相关。了解Fn14在胶质瘤迁移和细胞生存中的作用，将有助于更深入地了解胶质母细胞瘤的恶性进展和侵袭性表型的分子机制。这些研究的结果将描述FN 14作为治疗干预目标的适宜性和适用性。

DESCRIPTION (provided by applicant): Glioblastomas multiforme is the most common primary malignant brain tumor, biologically unique by virtue of their proclivity for local invasion into the adjacent normal brain tissue and the rarity of systemic metastasis. Potential specific therapeutic targets for invasive glioma cells have vet to be identified: however, the successful identification of these targets would be anticipated to catalyze development of novel therapies. We have demonstrated that Fn14 expression is minimal-to-absent in normal brain tissue but increases with increasing tumor grade. Activation of Fn14 signaling by addition of recombinant TWEAK or over-expression of Fn14 enhances glioma cell motility and survival. We HYPOTHESIZE that the activity of Fn14 enhances malignant glioblastoma cell survival and invasion into the normal brain parenchyma. Interfering with the function of Fn14 is likely to specifically target invasive glioblastoma cells and impact the ability of the tumor to recur. This hypothesis will be tested by pursuing the following specific aims: 1. Determine whether the in vitro inhibition of Fn14 signaling sensitizes glioma cells to cytotoxic therapy. Manipulation of the Fn14 signaling cascade by siRNA, small inhibitory molecules, and dominant negative constructs will be performed to assess the effects on apoptosis induction by clinical cytotoxic agents in multiple glioma cell lines and primary low passage cell strains. 2. Determine the function of Fn14 in glioma invasion in vivo. The role of Fn14 in glioma invasion will be assessed using an ex vivo brain slice organotypic substrate and xenografting of human glioma cells orthotopically into the cerebrum of immunocompromised rats. In addition, levels of Fn14 and signaling proteins will be correlated with tumor grade and patterns of invasion using immunohistochemistry on tissue microarrays containing human brain tumors. Understanding Fn14 in the context of glioma migration and cell survival will provide a more thorough insight into malignant progression of glioblastoma and the molecular mechanisms of the invasive phenotype. The results from these studies will profile the suitability and applicability of Fn 14 as a target for therapeutic intervention.