Role of O-GlcNAc-ylation on tumor progression

摘要 O-连接-N-乙酰氨基葡萄糖(O-GlcNAc)是一种附着在丝氨酸或 蛋白质上的苏氨酸残基。O-GlcN酰化控制关键信号和生物过程，如信号 转导、转录、细胞周期进程和新陈代谢。O-GlcNAc动态平衡中的扰动 与糖尿病、癌症和神经退行性疾病有关。血糖水平升高通道流量 通过己糖胺生物合成途径(HBP)，最终导致O-GlcNAc水平增加。 在几种癌症类型中，HBP的活性以及由此导致的细胞O-GlcNAc甲基化水平升高，包括 乳腺癌。我们最近报道，抑制HBP活性显著降低了侵袭性表型 乳腺肿瘤细胞。我们推测，丰富的葡萄糖，一种易代谢的碳水化合物，将推动 通过HBP的通量，导致通过O-GlcNAc修饰的蛋白质组合的丰富。vbl.使用 无偏蛋白质组学分析，我们发现高糖培养条件富含O-GlcNAc- 修饰的GLI蛋白，Hedgehog(HH)途径的转录因子。重要的是，我们在 高糖条件下，O-GlcNAc修饰GLI加剧HH/GLI活性；并抑制HBP 减轻了这一影响。我们假设HBP引导的O-GlcNAc基化从根本上编程侵袭性和 通过激活HH/GLI信号使肿瘤细胞具有化疗耐药特性。 在目标1中，我们将确定HBP指导的GLI的O-GlcNAc基化的分子基础。我们会 确定GLiO-GlcNAc甲基化的原因和后果。我们将首先确定HBP的参与度 GLI蛋白的O-GlcNAc修饰。接下来，我们将进行调查，以确定 HBP信号如何参与O-GlcNAc修饰的GLI来编程侵袭性和 肿瘤细胞的化疗耐药属性。 在目标2中，我们将评估升高的O-GlcNAc景观对细胞的分子和细胞属性的影响 两个不同互补的同源基因与乳腺肿瘤及其相关免疫小气候 小鼠乳腺癌模型。为了丰富相关性，我们还将评估人类TNBC和PDX模型 系统。我们将测试在O-GlcNAc升高的情况下，抑制GLI活性是否解偶联O- 乳腺肿瘤细胞侵袭和耐药属性的GlcNAc甲基化。 相关性：我们建议的研究旨在系统地研究O-GlcNAc如何驱动代谢 癌细胞中的重编程在分子水平上连接，以异常激活HH/GLI信号。这个 累积的结果将建立对O-GlcNAc甲基化如何规划肿瘤侵袭的机械性理解， 抗肿瘤药物的进展和反应。

Abstract O-linked ß-N-acetylglucosamine (O-GlcNAc) is a sugar attachment to the side chain hydroxyl of a serine or threonine residue on proteins. O-GlcNAcylation controls key signaling and biological processes such as signal transduction, transcription, cell cycle progression, and metabolism. Perturbations in O-GlcNAc homeostasis have been linked with diabetes, cancer, and neurodegenerative diseases. Increased glucose levels channel flux through the Hexoseamine Biosynthetic Pathway (HBP), culminating in increased O-GlcNAc levels. The activity of HBP and consequently cellular O-GlcNAc-ylation are elevated in several cancer types, including breast cancer. We recently reported that inhibiting HBP activity significantly decreased the invasive phenotype of breast tumor cells. We surmised that abundance of glucose, a readily-metabolizable carbohydrate, will drive flux through HBP, resulting in enrichment of a portfolio of proteins that are modified by O-GlcNAc-ylation. Using unbiased proteomics analysis, we identified that elevated glucose culture conditions enrich for O-GlcNAc- modified GLI proteins, transcription factors of the Hedgehog (Hh) pathway. Importantly, we identified that in elevated glucose conditions, O-GlcNAc-modification of GLI exacerbates Hh/GLI activity; and inhibiting HBP mitigated this effect. We hypothesize that HBP-directed O-GlcNAc-ylation fundamentally programs invasive and chemoresistant attributes in tumor cells through activating Hh/GLI signaling. In Aim 1 we will determine the molecular underpinnings of HBP-directed O-GlcNAc-ylation of GLI. We will determine the causes and consequences of GLI O-GlcNAc-ylation. We will first identify engagement of the HBP in O-GlcNAc-modification of GLI proteins. Next, we will undertake investigations to identify establish the mechanistic basis of how HBP signaling engages O-GlcNAc-modified GLI to program invasive and chemoresistant attributes in tumor cells. In Aim 2 we will evaluate the impact of an elevated O-GlcNAc landscape on molecular and cellular attributes of the mammary tumor and the associated immune microclimate using two distinct and complementary syngeneic mouse models of mammary cancer. To enrich the relevance, we will also evaluate human TNBC and PDX model systems. We will test if inhibiting GLI activity, in the context of elevated O-GlcNAc, uncouples the influence of O- GlcNAc-ylation on invasive and chemoresistant attributes of mammary tumor cells. Relevance: Our proposed studies are structured to systematically investigate how O-GlcNAc-driven metabolic reprogramming in cancer cells connects at the molecular level to aberrantly activate Hh/GLI signaling. The cumulative outcomes will create mechanistic understanding of how O-GlcNAc-ylation programs tumor invasion, progression and response to anti-neoplastics.