Role of O-GlcNAcome on Breast Cancer Initiating Cells

项目摘要 人们普遍认为肿瘤是高度异质性的。肿瘤中有一个亚群的细胞， 被称为肿瘤启动细胞，可以被分离并能够自我更新、分化和形成大量的 肿瘤。许多癌症对传统的化疗或放射治疗没有反应，而那些最初 回应，往往故态复萌。传统疗法只攻击增殖细胞，留下一池耐药细胞。 能够再生整个肿瘤的干细胞样细胞。了解调节肿瘤的机制- 发起活动将导致设计和开发有效的治疗方法。我们的实验室已经证明了 营养感受器O-GlcNAc转移酶(OGT)首次在体外和体外调控启动癌症的细胞 活着。从基因或药物上减少OGT，在体外阻止乳房形成并减少 上皮间质标记物(EMT)，肿瘤干细胞标记物。重要的是，OGT，in 多个乳腺癌细胞，增加包括NANOG在内的癌症干细胞标记物，增加乳房 在体外形成并增加体内肿瘤的起始性。在这项提议中，我们希望发现分子 OGT通过部分了解OGT相互作用组和O-T调节肿瘤启动的机制 乳癌肿瘤起始细胞中的GlcNAcome。这一信息将使我们能够识别新的治疗方法 治疗癌症和逆转耐药性的靶点。根据我们的初步结果，中心假设 这种应用的一个特点是，营养感受器O-GlcNAc转移酶在乳腺癌中起着基础作用 部分通过NANOG调节启动细胞。这些实验的完成将有助于我们的 理解营养感知通路如何在分子水平上连接到自我更新的癌症干细胞 细胞(CSCs)，并为了解癌症在代谢途径中的变化提供了框架 规范控制CSC维护的核心自更新信令。在目标1中，我们将确定 OGT/O-GlcNAc调控CSC主调节子NANOG的分子基础。这一目标将决定 OGT调控乳腺癌肿瘤起始细胞NANOG的分子基础。在目标2中，我们将确定 OGT相互作用组/O-GlcNA介于癌细胞和肿瘤干细胞之间。这一目标将确定 OGT相互作用蛋白和O-GlcNacylated蛋白在肿瘤起始细胞中识别新的途径和 肿瘤启动能力的调节器。最终目的是评估OGT在调节肿瘤启动中的作用 活体内活动。重要的是，我们将在临床前癌症模型中测试新的OGT抑制剂，并测试 OGT靶向药物作为潜在的抗肿瘤起始细胞治疗策略抑制乳腺癌生长 和体内转移。这些研究将进一步加深我们对癌症中代谢重编程的理解 细胞在分子水平上连接到肿瘤启动细胞，并将建立机制的理解如何 营养传感器OGT可以偶联到癌症起始途径，并建立OGT作为治疗靶点 耐药癌症的治疗。

Project Summary It is widely accepted that tumors are highly heterogeneous. There is a subpopulation of cells in a tumor, called tumor-initiating cell, that can be isolated and are able to self-renew, differentiate and form the bulk of the tumor. Many cancers don't respond to traditional chemotherapy or radiotherapy, and those that initially respond, often relapse. Conventional therapy only attacks proliferating cells, leaving behind a pool of resistant stem-like cells that are able to regenerate the whole tumor. Understanding mechanisms that regulate tumor- initiating activity will lead to designing and developing effective therapeutics. Our lab has demonstrated for the first time that the nutrient sensor O-GlcNAc transferase (OGT) regulates cancer-initiating cells in vitro and in vivo. Reducing OGT, genetically or pharmacologically, blocks mammosphere formation in vitro and reduced epithelial-mesechymal markers (EMT), cancer stem cell markers. Importantly, overexpression of OGT, in multiple breast cancer cells, increases cancer stem cell markers including NANOG, increases mammosphere formation in vitro and increases tumor initiation in vivo. In this proposal, we hope to uncover molecular mechanism by which OGT regulates tumor initiation, by in part, understanding OGT interactome and O- GlcNAcome in breast cancer tumor initiating cells. This information will allow us to identify novel therapeutic targets in treating cancer and reverse drug resistance. Based on our preliminary results, the central hypothesis of this application is that the nutrient sensor O-GlcNAc transferase plays a fundamental role in breast cancer initiating cells via, in part, NANOG regulation. Completion of these experiments will contribute to our understanding of how nutrient-sensing pathways connects at the molecular level to self-renewing cancer stem cells (CSCs) and providing a framework for understanding how cancer alterations in metabolic pathways regulate core self-renewal signaling that controls CSC maintenance. In Aim #1, we will determine the molecular basis of OGT/O-GlcNAc regulation of the master CSC regulator NANOG. This aim will determine the molecular basis of OGT regulation of NANOG in breast cancer tumor initiating cells. In Aim #2, we will Identify OGT interactome/O-GlcNAcome between between cancer cells and cancer stem cells. This aim will identify OGT interacting proteins and O-GlcNAcylated protein in tumor initiating cells to identify novel pathways and regulators of tumor-initiating ability. The final aim will evaluate the role of OGT in regulating tumor-initiating activity in vivo. Importantly, we will test novel OGT inhibitors in preclinical cancer models and test whether OGT targeting drugs as potential anti-tumor initiation cell therapeutic strategy against breast cancer growth and metastasis in vivo. These studies will further our understanding of how metabolic reprogramming in cancer cells connects at the molecular level to tumor initiating cells and will create mechanistic understanding of how nutrient sensor OGT can couple to cancer initiation pathways and establish OGT as therapeutic target for treatment of resistant cancers.