Targeting Ceramide Glycosylation in AML

项目总结 鞘磷脂(SL)神经酰胺是一种有效的肿瘤抑制因子，有助于促进细胞凋亡和 自噬。癌细胞中这些反应的管理依赖于 神经酰胺及其代谢物，其中一些可以促进细胞存活。维持较高的细胞内水平 神经酰胺是支持其独特的抗癌特性的重要因素。因此，从战略的角度来看，控制 神经酰胺的代谢为调节肿瘤生长提供了新的机会。这项工作的目标是评估 神经酰胺成为治疗急性髓系白血病有效抗癌剂的创新步骤 目的是研究成人最常见的白血病--急性髓系白血病(AML)，并评估SLS在化疗耐药性中的作用。 迫切需要开发更有效的治疗AML的方法，特别是在复发患者中。虽然 已经提出了许多假说来解释治疗复发，但没有一个能导致完全的 急性髓系白血病耐药的分子机制研究进展甚微 40年后。我们的前提是神经酰胺的糖基化是主要的代谢途径。 有助于癌细胞中神经酰胺的中和，它也与多药- 癌症中的耐药表型。该项目将专注于靶向神经酰胺糖基化，以增强和推动 神经酰胺导致的AML细胞死亡。将采用两种创新策略来增加细胞内神经酰胺 水平：1)使用纳米脂质体，细胞渗透性神经酰胺类似物，C6-神经酰胺(CNL，神经酰胺 纳米脂质体)，以及2)使用神经酰胺“产生剂”，如4-HPR(芬维甲酸)或PSC833 (Valspodar)，增加细胞内天然长链神经酰胺的水平。将对这些策略进行评估 单独、结合和在抑制神经酰胺糖基化的试剂存在的情况下。我们假设 采取措施从药物上提高和维持细胞内神经酰胺水平将提高整体 神经酰胺为中心的治疗的抗癌作用。此外，鉴于关于化疗选择压力的新发现 在AML中，我们假设SL代谢异常在耐药中起关键作用，靶向SL 新陈代谢可能会避开耐药性。将实现以下三个具体目标 达到我们在AML中使用神经酰胺和SL治疗的目标。 1.确定化疗选择压力对SL代谢及耐药性的影响 急性髓系白血病的表型。 2.测定神经酰胺糖基化抑制剂对细胞毒性的影响及作用机制 CNL和产生神经酰胺的药物。 3.在AML临床前模型中评估以神经酰胺为中心的治疗药物的抗癌活性。我们预测 使用佐剂阻断神经酰胺糖基化将增强神经酰胺中心(CNL神经酰胺 “发电机”)治疗急性髓系白血病。

PROJECT SUMMARY The sphingolipid (SL) ceramide is a potent tumor suppressor that contributes to the promotion of apoptosis and autophagy. Management of these responses in cancer cells is dependent on the dynamic balance between ceramide and its metabolites, some of which can promote cell survival. Maintaining elevated levels of intracellular ceramide is important for supporting its unique anticancer properties. Thus, from a strategic point, controlling the metabolism of ceramide offers new opportunities for regulating cancer growth. The goal of this work is to assess innovative steps to develop ceramide into an effective anticancer agent to treat acute myelogenous leukemia (AML), the most common type of leukemia in adults, and to evaluate the role of SLs in chemotherapy resistance. There is a critical need to develop more effective therapies for AML, especially in relapse patients. Although many hypotheses have been proposed to explain therapeutic relapse, none have led to a complete understanding of the molecular mechanisms of AML resistance, and there have been few treatment advances in 40 years. Our premise is that upregulated glycosylation of ceramide is the major metabolic avenue contributing to ceramide neutralization in cancer cells, and it is also strongly associated with the multidrug- resistant phenotype in cancer. This project will focus on targeting ceramide glycosylation to enhance and propel ceramide-driven AML cell death. Two innovative strategies will be employed to increase intracellular ceramide levels: 1) use of a nanoliposomal, cell-permeable ceramide analog, C6-ceramide (CNL, ceramide nanoliposome), and 2) employment of ceramide “generators”, drugs such as 4-HPR (fenretinide) or PSC833 (valspodar), that increase intracellular levels of natural long-chain ceramides. These strategies will be evaluated separately, in combination, and in the presence of agents that inhibit ceramide glycosylation. We hypothesize that taking steps to pharmacologically increase and maintain intracellular ceramide levels will enhance the overall anticancer impact of ceramide-centric therapy. Further, given new findings on chemotherapy selection pressure in AML, we hypothesize that aberrant SL metabolism plays a key role in drug resistance and that targeting SL metabolism will potentially circumvent drug resistance. The following three Specific Aims will be pursued to achieve our goal of employing ceramide and SL therapy in AML. 1. Determine the effects of chemotherapy selection pressure on SL metabolism and the drug resistant phenotype in AML. 2. Determine the effects of inhibitors of ceramide glycosylation on cytotoxicity and mechanism of action of CNL and ceramide-generating drugs. 3. Assess the anticancer activity of ceramide-centric therapeutics in AML preclinical models. We predict that using adjuvants to block ceramide glycosylation will enhance ceramide-centric (CNL + ceramide “generators”) therapy in AML.