MODELING MALIGNANT PROGRESSION IN GLIOMA

总结 神经胶质瘤是人类最常见和最致命的原发性脑肿瘤。高度恶性的神经胶质瘤通常会 低级别胶质瘤的症状尽管低级别胶质瘤（LGG）患者可能存活10年， 多年来，他们的肿瘤几乎不可避免地进展为高级别胶质瘤（HGG），之后死亡发生在他们的大脑中。 十二到十五个月。恶性进展的过程知之甚少。我们发表的研究（由 临床科学家指导计划[K 08]）表明，抗凋亡信号在促进 LGG向HGG的发展。我们还发现，抑制细胞凋亡会引起严重的 肿瘤微环境中的免疫抑制。此外，我们还证明，使用几个 免疫治疗策略，逆转瘤内免疫抑制可以减轻恶性肿瘤 在胶质瘤的鼠模型中的进展。我们现在假设抗凋亡信号促进恶性肿瘤的发生， 通过诱导免疫抑制肿瘤微环境在胶质瘤中的进展。的主要障碍 研究恶性进展一直缺乏LGG和HGG的匹配患者样本， 他们进步了。然而，我们已经确定了超过250名患者，他们在2011年接受了LGG和后来的HGG治疗。 MD安德森癌症中心。对这些患者的匹配肿瘤样本的分析代表了一种独特的 研究恶性进展的机会。在拟议的工作中，我们将利用下一个- 世代测序（NGS）来研究LGG退化为HGG的机制。在Aim中 1，我们将使用NGS来鉴定相对于LGG在HGG中过表达的抗凋亡基因。一 这些基因在神经胶质瘤的免疫活性鼠模型中的功能分析将确定它们的 免疫抑制和恶性转化促进作用。在目标2中，我们将研究两种抗凋亡的药物， 基因（MCL-1和BIRC 3）已成为免疫抑制的主要促进者，从分析 TCGA LGG和HGG表达数据以及我们自己的内部患者队列。我们将模拟这些 基因，以确定其对恶性进展的影响。在目标3中，我们将分析我们的标本， 识别激活已知引起肿瘤内关键内流的趋化因子的转录因子， 免疫抑制细胞这些转录因子将在体内建模，以确定它们对细胞的影响。 恶性进展确定导致恶性进展的因素可能使我们能够 以减轻疾病进展的原因。因此，肿瘤可以维持在更惰性的低级别状态 而不是发展成HGG，从而显著延长生存期。最终，我们的结果也可能适用于 其他肿瘤类型，表现出从低到高级别病变的进展。这项工作是在 与基因表达谱、计算生物学、生物统计学和 脑肿瘤免疫学我们还将利用MD安德森的测序和微阵列设施。

SUMMARY Glioma is the most common and deadliest primary brain tumor in humans. Highly malignant gliomas often arise from more indolent lower grade gliomas. Although patients with low-grade gliomas (LGG) may survive for many years, their tumors almost inevitably progress to high-grade gliomas (HGG), after which death occurs in 12 to 15 months. The process of malignant progression is poorly understood. Our published studies (funded by a Mentored Clinical Scientist Program [K08]) showed that anti-apoptotic signaling plays a key role in facilitating the progression of LGG to HGG. We also showed that suppression of apoptosis caused profound immunosuppression in the tumor microenvironment. Furthermore, we have shown, using several immunotherapeutic strategies, that reversing intratumoral immunosuppression can mitigate malignant progression in a murine model of glioma. We now hypothesize that antiapoptotic signaling promotes malignant progression in glioma by inducing an immunosuppressive tumor microenvironment. A major obstacle to studying malignant progression has been the lack of matched patient samples of LGGs and the HGGs to which they progress. However, we have identified over 250 patients who were treated for both LGG and later HGG at MD Anderson Cancer Center. The analysis of matched tumor samples from these patients represents a unique opportunity for the study of malignant progression. In the proposed work, we will take advantage of next- generation sequencing (NGS) to investigate the mechanisms through which LGG degenerates to HGG. In Aim 1, we will use NGS to identify anti-apoptotic genes that are overexpressed in HGGs relative to LGGs. A functional analysis of these genes in an immune competent murine model of glioma will determine their immunosuppression- and malignant transformation–promoting effects. In Aim 2, we will study two antiapoptotic genes (MCL-1 and BIRC3) that have emerged as lead facilitators of immunosuppression from analysis of TCGA LGG and HGG expression data as well as our own internal cohort of patients. We will model these genes in vivo to determine their impact on malignant progression. In Aim 3, we will profile our specimens to identify transcription factors that activate chemokines known to cause the intratumoral influx of key immunosuppressive cells. These transcription factors will be modeled in vivo to determine their effect on malignant progression. Identifying the factors that contribute to malignant progression will potentially enable us to mitigate the causes of progression. Thus, tumors may be maintained in the more indolent low-grade state rather than progressing to HGG, significantly prolonging survival. Ultimately, our results may also be applicable to other tumor types that demonstrate progression from a low- to high-grade lesion. This work is being done in collaboration with recognized experts in gene expression profiling, computational biology, biostatistics, and brain tumor immunology. We will also leverage MD Anderson’s Sequencing and Microarray Facility.