Molecular Imaging of Phospho-FADD and its role in resistance to therapy

描述（由申请人提供）：利用微阵列、定量2D凝胶电泳和数据挖掘，我们最近发现了一种新的预后生物标志物，fas相关死亡结构域（FADD），它在许多人类恶性肿瘤中过表达，如肺、头颈、脑和成年男性生殖细胞肿瘤。FADD在肺癌中的表达分析显示，FADD过表达与临床预后不良有显著相关性。基于免疫组织化学的组织微阵列分析显示，FADD磷酸化形式（p-FADD）的升高与ki67表达相关，且临床结果较差。p-FADD表达增加的肿瘤也显示NF-KB激活升高，并与cyclin B1和cyclin D1显著相关。综上所述，我们实验室和其他实验室发表的结果表明，FADD磷酸化和NF-KB活化之间存在因果关系，NF-KB活化是一种侵袭性治疗耐药癌症表型的标志。因此，我们假设切除肿瘤细胞中的p-FADD水平可能会使癌细胞对化疗药物敏感。为了帮助这一假设的实验，我们利用分子成像工具，开发了一种pan FADD激酶报告器（FKR），它可以无创地感知p-FADD水平并实时报告相同的水平。在本研究中，特异性目标1将确定FKR在分析p-FADD状态中的特异性和敏感性，特异性目标2将利用非侵入性分子成像技术的力量来解剖调节FADD磷酸化的表皮生长因子激活的信号级联反应。在具体目标3中，我们将探讨细胞中p-FADD状态与其对化疗药物的敏感性/耐药性之间的关系。在利用小鼠异种移植模型的具体目的4中，我们将研究p-FADD水平在肿瘤生长和治疗抵抗中的作用。这些研究将建立FADD激酶的非侵入性成像模式，了解最终导致FADD磷酸化的信号级联反应，以及磷酸化的FADD在肿瘤生长和治疗抵抗中的核心作用。

DESCRIPTION (provided by applicant): Using microarray, quantitative 2D gel electrophoresis and data mining we recently identified a new prognostic biomarker, Fas-associated death domain (FADD), which is overexpressed in a number of human malignancies such as lung, head and neck, brain and adult male germ cell tumors. Analysis of FADD expression in lung cancer revealed that overexpression of FADD is significantly associated with poor clinical outcome. Immunohistochemistry-based tissue microarray analysis showed elevation of the phosphorylated form of FADD (p-FADD) correlated with ki67 expression and with poor clinical outcome. Tumors with increased p-FADD expression also showed elevated NF-KB activation and significant co-relation with cyclin B1 and cyclin D1. Taken together, published results from our lab and others suggest a causal relationship between the phosphorylation of FADD and NF-KB activation, a hallmark of an aggressive therapy resistant cancer phenotype. Thereby we hypothesize that ablating p-FADD levels in tumor cells may sensitize cancer cells to chemotherapeutic agents. To aid in experimentation of this hypothesis we have resorted to molecular imaging tools and developed a pan FADD kinase reporter (FKR) which non-invasively senses p-FADD levels and reports the same in real time. In the present study specific aim 1 will determine the specificity and sensitivity of FKR in assaying p-FADD status, specific aim 2, will utilize the power of non-invasive molecular imaging technology to dissect the epidermal growth factor activated signaling cascades that modulates FADD phosphorylation. In specific aim 3 we will explore the relationship between p-FADD status in cells and their sensitivity/resistance to chemotherapeutic agents. In specific aim 4 utilizing mouse xenograft model, we will investigate the role of p-FADD levels in tumor growth and resistance to therapy. These studies will establish non-invasive imaging modality for FADD kinases, understanding of signaling cascade that culminate in FADD phosphorylation and the central role of phosphorylated FADD in tumor growth and resistance to therapy.