Implications of Metabolic Regulation of BCL-2 Dependence for Myeloma Therapy

项目摘要 多发性骨髓瘤（MM）是浆细胞恶性肿瘤，占所有血液恶性肿瘤的13%， 在美国，每年有11，000人死亡，其中大多数死于疾病， 阻力细胞凋亡的逃避是肿瘤发展和抵抗的核心。的一个关键组成部分， 大多数癌症的耐药性发展在于BCL-2家族的无效参与， 凋亡调节因子。内源性凋亡途径的诱导由促凋亡蛋白的释放决定。 来自抗凋亡BCL-2家族成员（BCL-2，BCL-xL， MCL-1、BCL-w和A1），其又激活BAX和巴克，导致线粒体膜透化 和细胞色素C的释放。BH 3激活蛋白的释放是通过减少抗- 它们所结合的凋亡BCL-2蛋白，或者如果是敏化剂（如NOXA、BAD或BH 3模拟物）， 释放BH 3激活蛋白结合抗凋亡蛋白。当一个细胞的抗肿瘤药物 通过促凋亡剂的结合（使其更接近凋亡阈值），它是“死亡的准备”。耐药MM， 发现急性髓细胞性和淋巴细胞性白血病以及各种实体瘤的死亡率较低 这有助于抵抗。从而找到有效地重新接合BCL-2蛋白的替代策略， 增加启动状态可以潜在地规避阻力。葡萄糖和谷氨酰胺是关键营养素 促进增殖，重要的是，通过BCL-2蛋白的离散调节来逃避凋亡 如BIA、BIM、NOXA、BAX、BAD和MCL-1。我们已经确定营养缺乏会导致 BCL-2家族改变有效降低凋亡阈值，即增加“致敏状态”。 比较代谢组学使得能够鉴定在调节中具有潜在作用的代谢物的子集。 BCL-2蛋白表达和相互作用。抑制这一代谢途径的子集， MM细胞系和复发/难治性患者样品的遗传多样性组与BH 3模拟物类 小分子。此外，MM患者的基因表达谱检查显示， 参与产生这些特定代谢物的酶，并分离出具有较低代谢物的患者。 总体生存率。我们将研究的一个中心问题是，这些酶的表达水平升高是如何影响这些酶的活性的？ 与实际代谢通量相关，以告知我们可操作的目标。这些观察结果构成了 我们的基本原理是，描述非冗余限速代谢酶调节BCL-2依赖性， 揭示了有效的代谢驱动的合成致死性的策略，对于肿瘤细胞具有选择性， 正常细胞的BCL-2依赖性因此，我们的长期目标是1）了解特定的代谢是如何 酶调节BCL-2蛋白家族，2）证明了 靶向MM中的代谢途径以规避耐药性。

PROJECT SUMMARY Multiple myeloma (MM) is a plasma cell malignancy accounting for 13% of all hematological malignancies and 11,000 deaths annually in the US, with the majority succumbing to disease due to the development of resistance. Evasion of apoptosis is central to tumor development and resistance. A key component to the development of resistance across most cancers lies in the ineffective engagement of the BCL-2 family of apoptosis regulators. Induction of the intrinsic pathway of apoptosis is dictated by the release of pro-apoptotic BH3-only activator proteins (BIM, PUMA, BID) from anti-apoptotic BCL-2 family members (BCL-2, BCL-xL, MCL-1, BCL-w and A1) that in turn activate BAX and BAK leading to mitochondrial membrane permeabilization and release of cytochrome C. BH3 activator proteins are released either by reduction in expression of an anti- apoptotic BCL-2 protein to which they are bound or if a sensitizer (such as NOXA, BAD or a BH3 mimetic) releases the BH3 activator protein from binding the anti-apoptotic. When a cell has its anti-apoptotics largely bound by pro-apoptotics (bringing it closer to the apoptotic threshold) it is “primed for death”. Resistant MM, acute myelogenous and lymphocytic leukemia and various solid tumors are found to be less primed for death that contributes to resistance. Thus finding alternative strategies to effectively re-engage BCL-2 proteins to increase the primed state can potentially circumvent resistance. Glucose and glutamine are key nutrients promoting proliferation and importantly, evasion of apoptosis through discrete regulation of BCL-2 proteins such as PUMA, BIM, NOXA, BAX, BAD and MCL-1. We have determined that nutrient deprivation leads to BCL-2 family alterations that effectively lower the apoptotic threshold i.e. increase the “primed state”. Comparative metabolomics enabled identification of a subset of metabolites with potential roles in regulating BCL-2 protein expression and interactions. Inhibition of this subset of metabolic pathways sensitized a genetically diverse panel of MM cell lines and relapse/refractory patient samples to the BH3 mimetic class of small molecules. Furthermore, examination of gene expression profiles of MM patient's revealed upregulation of the enzymes involved in generation of these specific metabolites and segregated out patients with lower overall survival. One of the central questions we will investigate is how elevated expression of these enzymes correlates with actual metabolic flux to inform us of actionable targets. These observations form the basis of our rationale that delineating non-redundant rate-limiting metabolic enzymes regulating BCL-2 dependence will reveal strategies of potent metabolically-driven synthetic lethality with selectivity for tumor cells given the lower BCL-2 dependence of normal cells. Therefore, our long-term goals are to 1) understand how specific metabolic enzymes regulate the BCL-2 family of proteins and 2) demonstrate the feasibility and therapeutic promise of targeting metabolic pathways in MM to circumvent resistance.