Beta 2-Microglobulin signaling and targeting in bone metastasis

描述（由申请人提供）：在这个修改后的申请中，我们采纳了审稿人的建议，特别关注于开发抗b2-微球蛋白（b2-M）抗体作为治疗人类前列腺癌骨转移的治疗剂。此外，我们还提供了关于假定的b2-M受体的新信息，利用b2-M受体介导的细胞信号传导机制的新策略，以及抗b2-M单克隆抗体（mAb）与放疗之间实现协同作用的组合方法，作为前列腺癌骨转移的有希望的治疗方案。该建议的假设是，抗b2- m单抗干扰HFE（遗传性血色素沉病相关基因）-TFRC（转铁蛋白受体）-TF（转铁蛋白）复合物和铁转运，从而引发下游氧化还原信号变化，microRNAs （miRNAs）作为一系列细胞应激反应蛋白和DNA修复酶的调节因子，最终引发癌症细胞死亡，而不是正常细胞死亡。修订后的申请中提出了两个具体目标。特异性目的1：利用实验性人前列腺癌异种移植和转基因小鼠模型，开发抗b2- m单抗作为前列腺癌骨转移治疗的治疗性抗体，评估抗体对小鼠的毒性，确定抗b2- m单抗与电离辐射对前列腺癌细胞和肿瘤生长的协同作用。这一目标是基于我们发现b2-M是一种主要的生长因子和多效性信号分子，赋予人类前列腺癌细胞的生长、存活和上皮到间充质转化（EMT）。这一目标的成功实现将加速靶向b2-M的翻译，使其成为治疗人类前列腺癌骨转移的新方法。特异性目的2：评估和验证一种假定的b2-M受体，一种非经典主要组织相容性复合体（MHC）样分子，遗传性血色素沉着病相关基因，HFE。将评估HFE的功能作用及其与TFRC-TF复合物、铁摄取、活性氧（ROS）产生、DNA损伤和细胞死亡的关系。在这个目的中，我们将研究抗b2- m单抗对TFRC-TF复合物的功能，该复合物可以通过内体铁循环促进铁摄取，产生ROS和高活性羟基自由基，这些自由基可能导致癌症细胞而不是正常细胞的DNA损伤。mirna，氧化还原信号的潜在下游靶点，对细胞应激反应蛋白和DNA修复酶的调节将被特别强调。总之，本修订后的应用程序严格遵循审稿人的建议，开发针对人类前列腺癌中b2- m介导的下游生长和信号通路的新方法，这在治疗前列腺癌骨转移的临床转化方面具有令人兴奋的潜力。公共卫生相关性：前列腺癌骨转移与前列腺癌患者的死亡率和发病率有关。我们已经开发了一种新的治疗方法，即使用一种新的抗b2微球蛋白抗体加辐射，已被证明可以完全消除小鼠体内人类肿瘤的生长。该项目的重点是确定这种协同作用的分子机制，并进行适当的临床前研究，将这些发现从实验室转移到床边。

DESCRIPTION (provided by applicant): In this revised application, we have taken the recommendations from the reviewers by focusing specifically on the development of anti-b2-Microglobulin (b2-M) antibody as a therapeutic agent for the treatment of human prostate cancer bone metastasis. In addition, we also provided new information on a putative b2-M receptor, a novel strategy exploiting b2-M-receptor mediated cell signaling mechanisms and combinatorial approach achieving synergism between anti-b2-M monoclonal antibody (mAb) plus radiation as a promising therapeutic regimen for prostate cancer bone metastases. The hypothesis of this proposal is that anti-b2-M mAb interferes with HFE (a hereditary hemochromatosis associated gene)-TFRC (Transferrin Receptor)-TF (Transferrin) complex and iron transport, thus provokes downstream redox signaling changes with microRNAs (miRNAs) serving as regulators for a series of cell stress response proteins and DNA repair enzymes that ultimately trigger cell death in cancer but not normal cells. Two Specific Aims are proposed in this revised application. Specific Aim 1: to develop anti-b2-M mAb as a therapeutic antibody for prostate cancer bone metastasis therapy using experimental human prostate cancer xenograft and transgenic mouse models, evaluate antibody toxicity in mice, and determine the synergistic interaction between anti-b2-M mAb plus ionizing radiation on the growth of prostate cancer cells and tumors. This Aim is based on our discovery that b2-M is a major growth factor and pleiotropic signaling molecule that confers the growth, survival, and epithelial to mesenchymal transition (EMT) of human prostate cancer cells. Successful accomplishment of this Aim will allow accelerated translation of targeting b2-M as a novel therapeutic approach for human prostate cancer bone metastasis. Specific Aim 2: to evaluate and validate a putative b2-M receptor, a non-classical major histocompatibility complex (MHC)-like molecule, the hereditary hemochromatosis associated gene, HFE. The functional role of HFE and its relationship to TFRC-TF complex, iron uptake, reactive oxygen species (ROS) production, DNA damages, and cell death will be assessed. In this aim, we will investigate the function of anti-b2-M mAb on TFRC-TF complex that could promote iron uptake via endosomal iron recycling, production of ROS and highly reactive hydroxy radicals that could cause DNA damages in cancer but not normal cells. Regulation of miRNAs, potential downstream targets of redox signaling, on cell stress response proteins and DNA repair enzymes will be specially emphasized. In summary, this revised application carefully follows the recommendations of the reviewers to develop novel approaches for targeting b2-M-mediated downstream growth and signaling pathways in human prostate cancer, which has exciting potential for clinical translation to manage prostate cancer bone metastasis. PUBLIC HEALTH RELEVANCE: Prostate cancer bone metastasis contributes to mortality and morbidity of prostate cancer patients. We have developed a new therapeutic approach by using a novel anti-b2-Microglobulin antibody plus radiation, which has been shown to completely abolish the growth of human tumors in mice. This project focuses on defining the molecular mechanism of this synergism and the appropriate preclinical studies to move these discoveries from bench to the bedside.