Targeting Ceramide Glycosylation in AML

项目摘要 鞘脂（SL）神经酰胺是一种有效的肿瘤抑制剂，有助于促进细胞凋亡， 自噬癌细胞中这些反应的管理取决于以下因素之间的动态平衡： 神经酰胺及其代谢物，其中一些可以促进细胞存活。维持细胞内 神经酰胺对于支持其独特的抗癌性质是重要的。因此，从战略上讲， 神经酰胺的代谢为调节癌症生长提供了新的机会。这项工作的目的是评估 神经酰胺开发成为治疗急性髓细胞白血病的有效抗癌剂的创新步骤 (AML)是成人白血病中最常见的类型，并评估SL在化疗耐药中的作用。 迫切需要开发更有效的AML疗法，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 AML耐药的分子机制的理解，并且几乎没有治疗进展 在40年内。我们的前提是，上调的神经酰胺糖基化是主要的代谢途径 有助于癌细胞中的神经酰胺中和，它也与多药耐药密切相关。 癌症的耐药表型。该项目将重点关注靶向神经酰胺糖基化，以增强和推动 神经酰胺驱动的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、细胞可渗透的神经酰胺类似物，C6-神经酰胺（CNL，神经酰胺 纳米脂质体），和2）使用神经酰胺“发生剂”，药物如4-HPR（芬维A胺）或PSC 833 （valspodar），其增加天然长链神经酰胺的细胞内水平。将对这些战略进行评估 单独地、组合地以及在抑制神经酰胺糖基化的试剂存在下。我们假设 采取措施增加和维持细胞内神经酰胺水平将提高整体 以神经酰胺为中心的治疗的抗癌作用。此外，鉴于化疗选择压力的新发现， 在AML中，我们假设SL代谢异常在耐药性中起关键作用， 代谢将潜在地规避耐药性。将实现以下三个具体目标， 实现我们在AML中采用神经酰胺和SL治疗的目标。 1.确定化疗选择压力对SL代谢和耐药的影响 AML的表型。 2.确定神经酰胺糖基化抑制剂对细胞毒性的影响及其作用机制 CNL和神经酰胺生成药物。 3.评估以神经酰胺为中心的治疗药物在AML临床前模型中的抗癌活性。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。

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.