Robust assays to define telomere maintenance mechanisms as cancer biomarkers.

将端粒维持机制定义为癌症生物标志物的稳健测定。

• 批准号: 10693944
• 负责人: CHARLES Patrick REYNOLDS
• 金额: $ 35.83万
• 依托单位: TEXAS TECH UNIVERSITY HEALTH SCIS CENTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-16 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10693944
• 关键词: ATM activation; ATRX gene; Adult; Affect; Anticoagulants; Biological; Biological Assay; Biological Markers; Biology; Biopsy; Blood; Blood specimen; Bone Marrow; Bone Marrow Aspiration; CLIA certified; Catalytic Domain; Cells; Child; Chromosomes; Classification; Clinical; Clinical Trials; Code; Collection; DAXX gene; DNA; DNA Damage; Data; Detection; Drug Targeting; Enzymes; Fixatives; Genetic Recombination; Heparin; Human; Laboratories; Malignant Childhood Neoplasm; Malignant Neoplasms; Marrow; Messenger RNA; Modeling; Mutation; Neoplasm Metastasis; Neuroblastoma; Nucleic Acids; Nucleoproteins; Outcome; Patient risk; Patients; Pediatric Oncology Group; Phase III Clinical Trials; Phenotype; Plasma; Prevalence; Process; Prognosis; Prognostic Marker; Proliferating; Protocols documentation; Quality Control; Quantitative Reverse Transcriptase PCR; RNA; Research; Resistance; Reverse Transcriptase Polymerase Chain Reaction; Ribonucleoproteins; Sampling; Selection for Treatments; Sensitivity and Specificity; Solid Neoplasm; Source; TERC gene; TERT gene; TP53 gene; Telomerase; Telomere Maintenance; Temperature; Therapeutic Clinical Trial; Time; Tissues; Translating; Tube; Tumor Burden; Tumor Tissue; ataxia telangiectasia mutated protein; cancer biomarkers; cancer cell; cancer classification; cancer type; cell free DNA; chemotherapy; clinical application; clinical implementation; clinical risk; cohort; companion diagnostics; diagnostic assay; improved; inhibitor; mRNA Expression; molecular pathology; neoplastic cell; new therapeutic target; novel; novel strategies; novel therapeutics; participant enrollment; peripheral blood; prognostic; risk stratification; sample collection; success; targeted treatment; telomere; tumor; tumor DNA

Abstract Telomeres are nucleoproteins with TTAGGG DNA repeats at the ends of chromosomes that protect coding DNA from erosion and detection as DNA damage. Telomere maintenance is necessary for cancer cells to have unlimited proliferation capacity. Most cancers maintain their telomeres via activation of the ribonucleoprotein telomerase containing a catalytic subunit encoded by the TERT gene and an RNA template encoded by the TERC gene. Cancers with low or no telomerase activity often use another mechanism to extend their telomeres, the Alternative Lengthening of Telomeres (ALT) in which telomeres are maintained via homologous telomeric-DNA recombination, but the mechanism is still poorly understood. ALT tumors contain extra-chromosomal telomeric DNA C-circles, which (detected with a unique PCR assay) provides a specific and sensitive ALT biomarker. We have shown that quantifying TERT mRNA expression together with telomeric DNA C-circles enables classifying cancers into 3 groups based on telomere maintenance mechanism (TMM); telomerase- positive (high TERT), ALT-positive (C-circle+), and TMM-negative. Classifying the childhood cancer neuroblastoma by TMM provides prognostic information that overrides currently employed clinical and biological prognostic markers, and our preliminary data suggest this is possible for other cancer types. ALT cancers are consistently difficult to treat but have dysfunctional telomeres, creating unique vulnerabilities that can provide novel therapeutic targets. For example, we have recently demonstrated high ATM kinase activation at telomeres in ALT neuroblastoma leads to resistance to DNA damaging chemotherapy that can be reversed with a clinical-stage ATM inhibitor AZD0156. Biomarkers of TMM provide both prognostic information and the C-circle assay can potentially serve as a companion diagnostic assay to identify patients with tumors that are likely to be more responsive to novel ALT-targeted therapies. Thus, it is important to define parameters that impact accurate TMM assessment of cancers, i.e. accurate quantitation of TERT mRNA and DNA C-circles. We will define the impact of collection and storage conditions and the minimum amounts of tissue and amounts, and quality of nucleic acids needed for the assays. Identifying ALT patients from a blood sample would have clinical utility, and our preliminary data suggest that C-circles can be detected in plasma containing circulating tumor DNA. Thus, we also propose to develop and validate a plasma C-circle assay as a novel approach to identifying patients with ALT cancers. Finally, to ensure that these assays can be used for clinical risk stratification, and as companion diagnostics for selection of therapy, we propose to carry out studies necessary for CAP/CLIA certification of TERT mRNA qPCR and the telomeric DNA C- circle assay. To accomplish our aims, we are integrating sample collection from adult and pediatric cancers together with a team of experts in telomere biology and molecular pathology. This project will provide important information on analyzing cancer TMM phenotype that will be of value to both research and clinical labs and will enable completion of regulatory requirements necessary for clinical implementation of the assays.

摘要 端粒是在染色体末端具有TTAGGG DNA重复序列的核蛋白，其保护编码DNA不受染色体的损伤。 腐蚀和检测作为DNA损伤。端粒的维持是癌细胞无限增殖所必需的 容量大多数癌症通过激活含有催化剂的核糖核蛋白端粒酶来维持其端粒。 在一个实施方案中，所述方法包括将由TERT基因编码的RNA亚基和由TERC基因编码的RNA模板结合。低端粒酶或无端粒酶的癌症 活动通常使用另一种机制来延长其端粒，端粒替代延长（ALT），其中 端粒通过同源端粒-DNA重组来维持，但其机制仍然知之甚少。 ALT肿瘤含有染色体外端粒DNA C环，其（用独特的PCR测定法检测）提供了一种新的检测方法。 特异性和敏感性ALT生物标志物。我们已经证明，定量TERTmRNA表达与端粒长度相关。 DNA C环可以根据端粒维持机制（TMM）将癌症分为3组;端粒酶- 阳性（高TERT）、ALT阳性（C-circle+）和TM阴性。儿童癌症神经母细胞瘤的分类 TMM提供了超越目前采用的临床和生物学预后标志物的预后信息， 我们的初步数据表明，这对其他癌症类型也是可能的。ALT癌症一直难以治疗，但 功能失调的端粒，创造独特的脆弱性，可以提供新的治疗目标。比如我们有 最近证实，ALT神经母细胞瘤中端粒的ATM激酶高活化导致对DNA损伤的抵抗 临床阶段的ATM抑制剂AZD 0156可以逆转化疗。TMM的生物标志物提供了 预后信息和C-环测定可潜在地用作伴随诊断测定，以鉴定患有以下疾病的患者： 这些肿瘤可能对新的ALT靶向治疗更敏感。因此，定义参数非常重要 这影响了癌症的准确TMM评估，即精确定量TERTmRNA和DNA C环。我们将 定义收集和储存条件的影响以及组织的最小量和数量，以及 分析所需的核酸。从血液样本中识别ALT患者将具有临床实用性，并且我们的 初步数据表明，在含有循环肿瘤DNA的血浆中可以检测到C环。因此，我们还建议 开发和验证血浆C环测定作为识别ALT癌症患者的新方法。最后为 确保这些检测可用于临床风险分层，并作为选择治疗的伴随诊断， 我们建议开展对TERTmRNA qPCR和端粒DNA C- 圆检定为了实现我们的目标，我们正在整合成人和儿童癌症的样本收集， 端粒生物学和分子病理学的专家团队。该项目将提供重要的信息分析 癌症TMM表型，这将对研究和临床实验室都有价值，并将使完成监管 试验临床实施所需的要求。