The Prognostic Significance and Mechanistic Determination of Chromatin Remodeling Biomarkers in Non-Functional Pancreatic Neuroendocrine Tumor

项目摘要/摘要 摘要无功能性胰腺神经内分泌肿瘤是一组异质性肿瘤，其发病率呈上升趋势。 发病率和定义不清的病理生物学。虽然许多NF-PanNET是惰性的，并保持多年的稳定，但显著的 子集可能表现为侵袭性，并广泛转移。因此，NF-PanNETs的检测越来越频繁 出现了一种治疗困境。当前的预测参数和系统容易受到解释误差、抽样 问题，并且不能准确地反映这些肿瘤的临床行为。因此，需要更多的生物标志物来 改善NF-PanNETs患者的预后分层。以前，我们和其他人报告了复发性 ATRX和DAXX的基因组改变与NF-PanNETs的转移进展有关。这些基因的突变 基因会导致它们各自的蛋白质丢失，并与端粒交替延长(ALT)相一致 端粒酶不依赖的维持机制。我们还表明ATRX/DAXX的丢失和ALT与 转移的发生，是较短无病生存期的预后生物标志物，并且独立于其他 影响预后的临床病理参数。因此，ATRX/DAXX和ALT是很有前景的生物标志物。然而，他们 没有进行前瞻性评估，也没有在术前样本中进行评估，在这些样本中，预后分层对患者很重要 管理层。此外，只有50%的转移性NF-PanNETs存在ATRX/DAXX失活和 Alt.为了确定更多的生物标志物，我们最近对ATRX/DAXX野生型转移性NF-PanNETs进行了分析，并报道了 SETD2/H3K36me3和ARID1A与ATRX和DAXX类似，是染色质调节基因。 因此，我们假设NF-PanNETs的转移进展是以染色质的变化为特征的 调节和确定关键的基因组和表观基因组特征不仅将改善预后分层 这不仅有助于我们对这种日益流行的疾病的发病机制的理解。 目的1是发展和临床验证核因子-泛神经营养不良的术前预后生物标记物分析方法。通过这两个 回顾和前瞻性研究，我们将确定ATRX，DAXX， ALT、H3K36me3和ARID1A。对于目标2，我们计划定义不同表观遗传状态下的染色质模式 NF-PanNETs的转移进展。考虑到ATRX、DAXX、SETD2和ARID1A是染色质调节剂，我们将 评价不同核因子-PANet状态下染色质的纳米结构及其影响的分子途径 PathSTORM和Cut&Run/RNA-Seq检测。最后，Aim 3将研究ATRX/DAXX的适应性响应 失活和ALT启动。我们发现组蛋白伴侣蛋白Hira可以重建端粒染色质 和ATRX/DAXX缺乏型ALT癌细胞的功能。在这一目标范围内，我们将描述Hira在监管方面的作用 端粒完整性、染色质和转录。总体而言，这项建议将导致开发一种临床可用的 用于患者管理的检测，洞察致病性染色质结构的变化并确定新的 不仅是NF-PanNETs的驱动/通路，而且可能是其他ALT相关肿瘤的驱动/通路。

Project Summary/Abstract Non-functional pancreatic neuroendocrine tumors (NF-PanNETs) are a heterogeneous group of neoplasms with increasing incidence and ill-defined pathobiology. While many NF-PanNETs are indolent and remain stable for years, a significant subset may behave aggressively and metastasize widely. Thus, the increasing and frequent detection of NF-PanNETs presents a treatment dilemma. Current prognostic parameters and systems are susceptible to interpretation errors, sampling issues, and do not accurately reflect the clinical behavior of these neoplasms. Hence, additional biomarkers are needed to improve the prognostic stratification of patients with NF-PanNETs. Previously, we and others have reported recurrent genomic alterations in ATRX and DAXX are associated with metastatic progression of NF-PanNETs. Mutations in these genes result in loss of their respective proteins and coincide with the alternative lengthening of telomeres (ALT), a telomerase-independent maintenance mechanism. We have also shown that loss of ATRX/DAXX and ALT correlate with the development of metastases, are prognostic biomarkers for shorter disease-free survival and are independent of other prognostic clinicopathologic parameters. Thus, ATRX/DAXX and ALT represent promising biomarkers. However, they have not been evaluated prospectively nor in preoperative specimens, where prognostic stratification is important for patient management. In addition, only 50% of metastatic NF-PanNETs harbor inactivation of ATRX/DAXX and the presence of ALT. To identify additional biomarkers, we recently profiled ATRX/DAXX wild type metastatic NF-PanNETs and reported recurrent alterations in SETD2/H3K36me3 and ARID1A, which similar to ATRX and DAXX are chromatin regulating genes. We therefore hypothesize that the metastatic progression of NF-PanNETs is characterized by changes in chromatin regulation and determining the key genomic and epigenomic hallmarks will not only improve the prognostic stratification of patients with NF-PanNETs, but advance our understanding of the pathogenesis of this increasingly prevalent disease. Aim 1 will be to develop and clinically validate preoperative prognostic biomarker assays for NF-PanNETs. Through both retrospective and prospective studies, we will determine the prognostic performance and significance of ATRX, DAXX, ALT, H3K36me3 and ARID1A. For Aim 2, we plan to define the chromatin patterns at different epigenetic states in the metastatic progression of NF-PanNETs. Considering ATRX, DAXX, SETD2 and ARID1A are chromatin regulators, we will evaluate the nanoscale chromatin structure and affected molecular pathways of various NF-PanNET states using PathSTORM and CUT&RUN/RNA-seq assays. Finally, Aim 3 will investigate the adaptive response of ATRX/DAXX inactivation and ALT initiation. We have discovered that the histone chaperone, HIRA, can reconstitute telomeric chromatin and function of ATRX/DAXX deficiency ALT cancer cells. Within this aim, we will delineate the role of HIRA in regulating telomeric integrity, chromatin and transcription. Overall, this proposal will lead to the development of a clinically available assay for patient management, insight in the pathognomonic chromatin structural changes and identify novel drivers/pathways for not only NF-PanNETs, but likely other ALT-associated neoplasms.