CDKN2A couples lipid metabolism to ferroptosis in glioblastoma

摘要 胶质母细胞瘤(GBM)是成人最常见和最致命的原发脑肿瘤； 患有GBM的患者仍然有14-16个月的痛苦，没有超过标准的护理，因为 15年前的介绍。因此，寻找治疗基底膜的新策略是一个亟待解决的问题。 需要。重要的证据表明，与其他癌症一样，GBM已经重新编程为 支持助长恶性生长和生存的必要需求。值得注意的是，我们小组和其他人的工作 已经证明了GBM中特定的基因改变(例如，EGFR)和重新连接的新陈代谢之间的联系， 从而揭示了利用GBM代谢进行治疗干预的节点。然而，全面的 分子图谱显示，在GBM患者中存在相当大的分子异质性，并且 关于GBM中的这种分子多样性如何塑造代谢组的公正调查尚未进行。 在初步研究中，我们已经将整合的下一代测序(RNA和Exome Seq)结合使用 从50多名GBM患者和患者来源的样本中进行大规模的“猎枪”脂质组学研究，以确定 分子的异质性影响基底膜的脂质体。使用这种尖端的系统级方法，我们 已经确定了一种独特的脂质信号，该信号通过缺失肿瘤抑制因子CDKN2A在GBM肿瘤中丰富： GBM中最常发生变化的驱动基因。重要的是，作为这种特殊脂质的明显后果 CDKN2A缺失的GBM表现出对铁下垂的选择性易感性-一种最近描述的形式的 依赖脂质过氧化的细胞死亡。这些令人振奋的初步结果导致了以下目标： 确定这些观察的潜在机制基础，并评估其治疗潜力 诱导CDKN2A基因缺失的GBM小鼠模型发生铁下垂。在目标1中，稳定同位素标记的代谢示踪 并将进行代谢流量分析，以评估CDKN2A的丢失如何引起脂肪酸的转变 相对于CDKN2AWT GBM的组成。目的2研究增强的分子途径 CDNK2A缺失的GBM对铁性下垂的敏感性。最后，目标3将评估是否利用铁性下垂 可以选择性地抑制CDKN2A缺失患者来源的原位GBM异种移植的生长。总而言之，建议的 研究将提供对常见基因改变之间以前未被认识到的联系的机械性洞察 对GBM(CDKN2A缺失)和GBM脂质体的组成进行研究，并评价其治疗潜力 铁下垂在控制这种遗传定义的基底膜肿瘤亚群的生长中的作用。

ABSTRACT Glioblastoma (GBM) is the most frequent and deadly primary brain tumor in adults; the median survival of patients with GBM remains a dismal 14-16 months with no improvement over standard of care since its introduction 15 years ago. Thus, identifying new therapeutic strategies for GBM is an urgent unmet medical need. Significant evidence indicates that, similar to other cancers, GBM have reprogrammed metabolism to support the requisite demands to fuel malignant growth and survival. Notably, work from our group and others has demonstrated a link between specific genetic alterations (e.g., EGFR) in GBM and rewired metabolism, consequently revealing nodes of therapeutic intervention to exploit GBM metabolism. However, comprehensive molecular profiling has shown that there is considerable molecular heterogeneity among GBM patients, and an unbiased investigation into how this molecular diversity in GBM shapes the metabolome has yet to be conducted. In preliminary studies, we have used integrated next-generation sequencing (RNA and Exome Seq) together with large-scale “shotgun” lipidomics from over 50 GBM patient and patient-derived samples to determine if molecular heterogeneity influences the lipidome of GBM. Using this cutting edge, systems-level approach we have identified a unique lipid signature enriched in GBM tumors with deletion of the tumor suppressor, CDKN2A: the most frequently altered driver gene in GBM. Importantly, as an apparent consequence of this specific lipid enrichment, CDKN2A null GBM demonstrate selective susceptibility to ferroptosis – a recently described form of lipid-peroxidation dependent cell death. These exciting preliminary results have led to the following aims both to determine the underlying mechanistic basis for these observations and to evaluate the therapeutic potential of inducing ferroptosis in CDKN2A-deleted GBM mouse models. In Aim 1, stable isotope-labeled metabolic tracing and metabolic flux analysis will be conducted to evaluate how the loss of CDKN2A elicits a shift in fatty acid composition relative to CDKN2A WT GBM. Aim 2 investigates the molecular pathways underlying enhanced sensitivity to ferroptosis in CDNK2A null GBM. Finally, Aim 3 will assess whether the exploitation of ferroptosis can selectively inhibit growth of CDKN2A null patient-derived orthotopic GBM xenografts. Together, the proposed studies will provide mechanistic insight into a previously unappreciated link between a common genetic alteration in GBM (CDKN2A deletion) and composition of the GBM lipidome, and evaluate the therapeutic potential of ferroptosis in controlling growth of this genetically-defined subset of GBM tumors.