RNA-based Immunotherapy Targeting Antigens Unique to Brain Tumor Stem Cells

基于 RNA 的免疫疗法靶向脑肿瘤干细胞特有的抗原

• 批准号: 8106189
• 负责人: JOHN H. SAMPSON
• 金额: $ 45.88万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2013-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8106189
• 关键词: Accounting; Adult; Affinity; Anaplastic astrocytoma; Antigen Targeting; Antigens; Autoimmune Process; Autoimmunity; Brain; Brain Neoplasms; CD8B1 gene; Cause of Death; Cell surface; Cells; Cessation of life; Child; Clinical; Clinical Trials; Complementary DNA; DNA; Data; Dendritic Cells; Epidermal Growth Factor; Epitopes; Figs - dietary; Genes; Glioblastoma; Health; Heterogeneity; Human; Immune response; Immunocompetent; Immunologics; Immunotherapeutic agent; Immunotherapy; Inbreeding; Lead; Length; Libraries; Malignant - descriptor; Medical; Mesenchymal Stem Cells; Messenger RNA; Minority; Modeling; Molecular; Molecular Target; Mus; MutS DNA mismatch-binding protein; Mutation; Natural regeneration; Normal Cell; Oncogenic; Pathway interactions; Patients; Peptide Vaccines; Phase I Clinical Trials; Phase II Clinical Trials; Phase III Clinical Trials; Physiologic pulse; Predisposition; Preparation; Primary Brain Neoplasms; Property; Proteins; Protocols documentation; Quality-Adjusted Life Years; RNA; RNA library; Radiation; Recurrence; Resistance; Reverse Transcriptase Polymerase Chain Reaction; Risk; Safety; Sorting - Cell Movement; Source; Techniques; Testing; Therapeutic; Toxic effect; Transgenic Organisms; Translating; Translations; Transplantation; Tumor Antigens; Tumor Stem Cells; United States; Vaccination; Vaccines; base; chemotherapy; conventional therapy; epidermal growth factor receptor VIII; immunogenicity; innovation; melanoma; neoplastic cell; nerve stem cell; novel; phase 1 study; relating to nervous system; response; self-renewal; tumor; vaccination strategy

DESCRIPTION (provided by applicant): A subset of cells in glioblastoma multiforme (GBM) has been identified that enjoy a unique capacity to regenerate tumors. These brain tumor stem cells (BTSC) can be segregated by the neural stem cell marker, CD133, and are widely believed to be the cells responsible for resistance to conventional therapies. An effective means of specifically eliminating these cells may reduce the need for intensive and non-specific conventional therapy and lower the risk of tumor recurrence. EGFRvIII is a tumor-specific mutation found on BTSC. We have successfully targeted EGFRvIII using a peptide vaccine that allowed rapid translation to an ongoing Phase III trial. EGFRvIII expression is heterogeneous, however, and the recurrence of EGFRvIII-negative tumors suggests that BTSC can rely on other oncogenic pathways. While our data suggests that targeting tumor-specific mutations in BTSC may be important, few highly-conserved tumor-specific mutations like EGFRvIII will be identified and antigen defined vaccine approaches will ultimately be limited. Dendritic cells (DCs) loaded with amplified total tumor RNA is an innovative strategy to induce cellular and humoral antitumor immune responses. Although CD133(+) BTSC are a minority subpopulation of GBM that cannot be reliably isolated or propagated in sufficient quantities to serve as an antigen source for human vaccination protocols, we have been able to reproducibly amplify the RNA content from as few as 500 sorted CD133(+) tumor cells to generate RNA libraries sufficient for clinical scale DC-based vaccination. In order to focus the immunologic response on antigens preferentially or uniquely expressed within BTSC and limit the potential for autoimmune reactivity against shared antigens expressed in normal cells, we will evaluate approaches to enrich for antigens preferentially or uniquely expressed in BTSC by using full length cDNA affinity based substractive hybridization or an innovative strategy that leverages the ability of the DNA mismatch binding protein, MutS, to isolate cDNAs that contain tumor-specific mutations. These various preparations will be evaluated for differential toxicity and efficacy in an inbred transgenic murine malignant astrocytoma model, in which a subpopulation of CD133(+) tumor cells with BTSC qualities have been identified and CD8(+) and CD4(+) epitopes have been found. If efficacy is seen, the least toxic strategy will be translated into a Phase I study within the context of our existing clinical trial platform. PUBLIC HEALTH RELEVANCE: Treatment for malignant primary brain tumors, which are the most common cause of death among children and account for more deaths in adults than melanoma, currently represents the most expensive medical therapy per quality-adjusted life-year saved currently provided in the United States. A subset of malignant primary brain tumor cells (BTSCs), called brain tumor stem cells, enjoy a unique capacity to regenerate tumors and to resist conventional therapies. In this proposal we will see if targeting antigens preferentially or uniquely expressed by BTSCs will enhance the efficacy and reduce toxicity of immunotherapy.

描述（由申请人提供）：已鉴定出多形性胶质母细胞瘤（GBM）中的一个细胞亚群，它们具有独特的肿瘤再生能力。这些脑肿瘤干细胞（BTSC）可以通过神经干细胞标记物CD133分离，并且被广泛认为是负责对常规疗法产生抗性的细胞。特异性消除这些细胞的有效方法可以减少对密集和非特异性常规治疗的需求，并降低肿瘤复发的风险。EGFRvIII是在BTSC上发现的肿瘤特异性突变。我们使用肽疫苗成功靶向EGFRvIII，可以快速转化为正在进行的III期试验。然而，EGFRvIII表达是异质性的，EGFRvIII阴性肿瘤的复发表明BTSC可以依赖于其他致癌途径。虽然我们的数据表明，靶向BTSC中的肿瘤特异性突变可能很重要，但很少有高度保守的肿瘤特异性突变（如EGFRvIII）将被鉴定，抗原定义的疫苗方法最终将受到限制。树突状细胞（DC）负载扩增的肿瘤总RNA是一种创新的策略，以诱导细胞和体液抗肿瘤免疫反应。尽管CD133（+）BTSC是GBM的少数亚群，其不能可靠地分离或以足够的量繁殖以用作人类疫苗接种方案的抗原来源，但我们已经能够从少至500个分选的CD133（+）肿瘤细胞中可重复地扩增RNA内容物以产生足以用于临床规模的基于DC的疫苗接种的RNA文库。为了将免疫应答集中在BTSC内优先或独特表达的抗原上，并限制针对正常细胞中表达的共有抗原的自身免疫反应性的可能性，我们将评估通过使用基于全长cDNA亲和力的消减杂交或利用DNA错配结合蛋白MutS的能力的创新策略来富集BTSC中优先或独特表达的抗原的方法，分离出含有肿瘤特异性突变的cDNA将在近交系转基因鼠恶性星形细胞瘤模型中评价这些不同制剂的不同毒性和功效，其中已经鉴定了具有BTSC品质的CD 133（+）肿瘤细胞亚群，并且已经发现了CD 8（+）和CD 4（+）表位。毒性最小的策略将在我们现有的临床试验平台范围内转化为I期研究。公共卫生关系：恶性原发性脑肿瘤是儿童死亡的最常见原因，在成人中的死亡人数比黑色素瘤多，目前在美国提供的每质量调整生命年节省的医疗费用最高。恶性原发性脑肿瘤细胞（BTSC）的一个子集，称为脑肿瘤干细胞，具有再生肿瘤和抵抗常规治疗的独特能力。在本提案中，我们将看看靶向BTSC优先或独特表达的抗原是否会增强免疫治疗的功效并降低毒性。