Research Project 1: Diffuse Midline Glioma

项目摘要 传统观点认为，放射疗法是一种物理靶向抗癌方式， 癌症靶点在遗传学和生物学上是一致的。然而，肿瘤的基质成分是复杂的 以及引起癌症靶的外在可变性的可变性。此外，最近的研究使用单细胞 基因组学甚至在肿瘤细胞本身内显示出内在的异质性。我们的广泛目标 哈佛/UCSF ROBIN计划是为了检验肿瘤内变异性是耐药的基础这一假设- 以及放疗后复发。为了实现这一目标，我们的中心选择专注于儿童癌症， 神经外胚层起源相对于常见的成人癌症，儿童肿瘤的突变负担较低， 因此，为“低氮/高含量”分子表征试验提供了更清洁的遗传环境， 罗宾RFA在此背景下，本项目的重点是弥漫性中线胶质瘤（DMG）的儿童。 大多数DMG最初对辐射有反应，但所有进展都没有治愈。初步 研究中，我们已经使用单细胞基因组学表明，DMG中的恶性细胞在发育过程中， 异质的我们的可验证假设是DMG瘤内异质性超越发育 标记包括共同DNA修复途径的差异表达/利用。这一假设使得 将通过绘制放疗前和放疗后肿瘤组织的配对样本来评估预测 来自前瞻性接受统一放疗方案治疗的儿童，并在我们的分子生物学研究中进行了分析。 表征试验（MCT）。我们有三个具体目标：目标1是测试肿瘤内 异质性反映在高于和超过肿瘤细胞特异性发育标志物的水平上， 初步研究;目的2是检验放疗降低DMG瘤内异质性的预测 通过选择有复制能力的、抗辐射的干细胞样癌细胞;目的3是检验预测， 肿瘤细胞内的不均匀放射反应是放射相关疾病中患者不均匀性的基础 毒性、神经认知效应和生活质量。 该研究计划结合了癌症基因组学、表观基因组学、染色质 生物学和DNA酶学。我们将利用临床人工智能和成像核心， 开发非侵入性方法来跟踪这些（具有手术挑战性的）儿科患者的肿瘤内异质性 肿瘤的凭借我们的分子数据科学和先进的剂量学核心，我们将开发计算 肿瘤细胞进化和治疗反应的建模，这对于理解肿瘤细胞的选择至关重要。 抗辐射亚克隆该项目的共同领导人具有互补的专业知识， 计划Daphne Haas-Kogan，医学博士是一名儿科放射肿瘤学家，治疗DMG患者， 在儿科临床试验的两个关键联盟（COG和PNOC）中担任领导职务。玛丽埃拉·菲尔宾， 医学博士/博士是一位儿科神经肿瘤学家，在单细胞基因组学和DMG生物学方面具有专长。

Project Summary Conventional wisdom holds that radiation therapy is a physically targeted anti-cancer modality and that its cancer targets are genetically and biologically uniform. However, the stromal composition of tumors is complex and variable giving rise to extrinsic variability of the cancer target. Moreover, recent studies using single cell genomics show intrinsic heterogeneity even within the tumor cells per se. The broad goal of our Harvard/UCSF ROBIN initiative is to test the hypothesis that intra-tumoral variability underlies resistance to - and relapse from – radiotherapy. Towards this goal, our Center has chosen to focus on pediatric cancers of neuro-ectodermal origin. Pediatric tumors have a low mutational burden relative to common adult cancers and thus a cleaner genetic surround for the “low N/high content” Molecular Characterization Trials specified by the ROBIN RFA. Against this backdrop, this project focuses upon diffuse midline glioma (DMG) of children. The majority of DMGs initially respond to radiation, but all progress, and none are cured. In preliminary studies, we have used single cell genomics to show that the malignant cells within DMG are developmentally heterogeneous. Our testable hypothesis is that DMG intratumoral heterogeneity transcends developmental markers to include differential expression/utilization of common DNA repair pathways. This hypothesis makes predictions that will be assessed by drawing upon paired samples of pre-and post-radiotherapy tumor tissue from children treated prospectively with a uniform radiotherapy regimen and profiled in our Molecular Characterization Trial (MCT). We have three specific aims: Aim 1 is to test the prediction that intratumoral heterogeneity is reflected at levels above and beyond tumor cell-specific developmental markers noted our preliminary studies; Aim 2 is to test the prediction that radiotherapy reduces DMG intratumoral heterogeneity via selection of replication-competent, radio-resistant stem-like cancer cells; Aim 3 is to test the prediction that heterogeneous radiation responses within tumor cells underlie patient heterogeneity in radiation-associated toxicities, neurocognitive effects and quality of life. The study plan incorporates contemporary methods in cancer genomics, epigenomics, chromatin biology and DNA enzymology. We will draw upon our Clinical Artificial Intelligence and Imaging Core to develop non-invasive methods to track intra-tumoral heterogeneity in these (surgically challenging) pediatric tumors. With our Molecular Data Science and Advanced Dosimetry Core, we will develop computational modeling of tumor cell evolution and treatment response that will be critical to understanding selection for radioresistant subclones. The co-leaders of this Project have complementary expertise to enable the study plan. Daphne Haas-Kogan, M.D. is a pediatric radiation oncologist who treats patients with DMG and holds leadership positions in two key consortia (COG and PNOC) for pediatric clinical trials. Mariella Filbin, M.D./Ph.D. is a pediatric neuro-oncologist with expertise in single cell genomics and DMG biology.