Contextual Glioblastoma Screening For Efficacious Radiation Sensitizers

有效放射增敏剂的胶质母细胞瘤筛查

• 批准号: 8769836
• 负责人: Mary Helen Barcellos-Hoff
• 金额: $ 25.43万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8769836
• 关键词: Accounting; Acute; Address; Adjuvant Radiotherapy; Biological; Biological Assay; Brain; Brain Neoplasms; Cell Communication; Cell Culture Techniques; Cell Survival; Cells; Clinical Trials; DNA Double Strand Break; Diagnosis; Disease; Dose; Excision; Glioblastoma; Heterogeneity; Human; In Situ; In Vitro; Knowledge; Lead; Link; Malignant Neoplasms; Measures; Mediating; Mesenchymal; Modeling; Molecular; Molecular Profiling; Newly Diagnosed; Operative Surgical Procedures; Patients; Pharmaceutical Preparations; Preclinical Drug Evaluation; Prevalence; Primary Brain Neoplasms; Property; Radiation; Radiation Tolerance; Radiation therapy; Radiation-Sensitizing Agents; Radiobiology; Radioresistance; Radiosensitization; Regulation; Relative (related person); Research; Research Personnel; Resistance; Series; Signal Transduction; Specimen; Stem cells; Testing; Tissues; Work; Xenograft procedure; base; cancer stem cell; cancer therapy; chemotherapy; drug efficacy; drug testing; in vivo; inhibitor/antagonist; neoplastic cell; neutralizing antibody; novel; novel strategies; outcome forecast; preclinical study; prevent; public health relevance; radiation effect; radiation resistance; relating to nervous system; repaired; research study; response; screening; small molecule; standard of care; stem cell biology; temozolomide; tumor; tumor initiation; tumor microenvironment

DESCRIPTION (provided by applicant): The prognosis for patients with glioblastoma multiforme (GBM) remains extremely poor despite decades of research. The current standard of care for newly diagnosed glioblastoma is surgical resection to the extent feasible, followed by adjuvant radiotherapy and temozolomide chemotherapy. GBM tumor cells in situ are considered to be radioresistant, which is classically thought to be a cell-intrinsic property. However, recent studies point to the contribution of two non-classical mechanisms that contribute to radiation resistance in GBM: glioblastoma stem cells (GSCs) and the tumor microenvironment (TME). While GSCs employ defined molecular mechanisms that lead to radioresistance, these mechanisms are dramatically potentiated in vivo, suggesting a strong TME influence. Given that non-classical radioresistance in GBM is modulated by the TME, it follows that testing of radiosensitizing agents cannot be performed in cell culture. Instead, novel testing platforms are required that both provide appropriate biological context that takes into account the TME, as well as allow for rapid drug testing. Such testing is further complicated by intertumoral heterogeneity in GBM. The identification of four major molecular GBM subtypes that have different prognoses motivates concerns that such heterogeneity may confound drug testing if specific radiosensitizing agents are efficacious in one subtype but not others. Here we propose to implement a novel approach to screen contextual GBM response to radiosensitizers using organotypic culture of human GBM operative specimens to evaluate the molecular and cellular response to radiation in situ. Based on our preclinical studies and the knowledge of current GBM clinical trials, we propose to evaluate TGF¿ inhibition as a means to increase GBM radiosensitivity to validate this testing platform. The proposed experiments are based on the hypothesis that response to radiation is enhanced by inhibition of TGF¿ in the form of decreased recognition and repair of radiation-induced double-stranded DNA breaks (DSBs). We predict that inhibition of TGF¿ signaling will prevent the observed radiation-induced increase in the prevalence of GSCs in organotypic cultures, as measured by functional clonogenic assays and tumor initiation potential. Importantly, we will evaluate the relative efficacy of TGF¿ inhibitors as radiosensitizers in human GBM specimens representing all molecular subtypes previously described. We posit that this approach, which preserves TME and GSC contributions to GBM radiobiology in an ex vivo setting, will allow for efficient drug screening by incorporating both cellular and functional readouts for drug efficacy, as well as by examining drug effects in distinct molecular subtypes of GBM. Importantly, we envision this approach becoming a paradigm for discovery of radiosensitizing agents that can be applied to other brain tumors.

描述（由申请人提供）：尽管经过数十年的研究，多形性胶质母细胞瘤（GBM）患者的预后仍然极差。目前新诊断的胶质母细胞瘤的护理标准是在可行的范围内进行手术切除，然后进行辅助放疗和替莫唑胺化疗。原位 GBM 肿瘤细胞被认为具有抗辐射性，这通常被认为是细胞固有的特性。然而，最近 研究指出两种非经典机制有助于 GBM 的辐射抵抗：胶质母细胞瘤干细胞 (GSC) 和肿瘤微环境 (TME)。虽然 GSC 采用明确的分子机制导致放射抗性，但这些机制在体内显着增强，表明 TME 具有很强的影响力。鉴于 GBM 中的非经典放射抗性是由 TME 调节的，因此放射增敏剂的测试不能在细胞培养物中进行。相反，需要新颖的测试平台，既能提供考虑 TME 的适当生物学背景，又能进行快速药物测试。 GBM 中肿瘤间的异质性使此类测试变得更加复杂。具有不同预后的四种主要分子 GBM 亚型的鉴定引发了人们的担忧，即如果特定的放射增敏剂对一种亚型有效但对其他亚型无效，那么这种异质性可能会混淆药物测试。在这里，我们建议实施一种新方法，利用人类 GBM 手术标本的器官培养来筛选 GBM 对放射增敏剂的背景反应，以评估原位辐射的分子和细胞反应。根据我们的临床前研究和当前 GBM 临床试验的知识，我们建议评估 TGF¿ 抑制作为增加 GBM 放射敏感性的一种手段，以验证该测试平台。所提出的实验基于这样的假设：抑制 TGF 会增强对辐射的反应，其形式是减少对辐射引起的双链 DNA 断裂 (DSB) 的识别和修复。我们预测，抑制 TGF¿ 信号传导将阻止观察到的辐射诱导的器官型培养物中 GSC 患病率的增加，这是通过功能性克隆形成测定和肿瘤起始潜力来测量的。重要的是，我们将评估 TGF 抑制剂作为代表先前描述的所有分子亚型的人类 GBM 样本中放射增敏剂的相对功效。 我们认为这种方法在离体环境中保留了 TME 和 GSC 对 GBM 放射生物学的贡献，将允许通过以下方式进行有效的药物筛选： 结合细胞和功能读数来了解药物功效，以及检查药物在 GBM 不同分子亚型中的作用。重要的是，我们设想这种方法成为发现可应用于其他脑肿瘤的放射增敏剂的范例。