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。在肿瘤中有一个细胞亚群， 称为肿瘤起始细胞，可以分离并能够自我更新，分化并形成大部分肿瘤细胞。 肿瘤许多癌症对传统的化疗或放疗没有反应，而那些最初 反应，经常复发。传统疗法只攻击增殖细胞，留下一个耐药细胞池。 能够再生整个肿瘤的干细胞样细胞。了解调节肿瘤的机制- 启动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 营养传感器O-GlcNAc转移酶（OGT）首次在体外和体内调节癌症起始细胞， vivo.减少OGT，遗传或非遗传，在体外阻断乳腺球形成， 上皮细胞-间质细胞标志物（EMT）、癌症干细胞标志物。重要的是，OGT的过表达， 多种乳腺癌细胞，增加癌症干细胞标记物，包括NANOG，增加乳腺球 在体外形成并在体内增加肿瘤起始。在这个提议中，我们希望揭示分子 OGT调节肿瘤发生的机制，部分是通过理解OGT相互作用组和O- GlcNAcome在乳腺癌肿瘤起始细胞中的表达这些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 该应用的一个重要方面是营养传感器O-GlcNAc转移酶在乳腺癌中起着重要作用 启动细胞，部分通过NANOG调节。这些实验的完成将有助于我们 了解营养感应途径如何在分子水平上与自我更新的癌症干细胞连接 细胞（CSC），并为理解癌症如何改变代谢途径提供了框架 调节控制CSC维护的核心自我更新信令。在目标#1中，我们将确定 主CSC调节剂NANOG的OGT/O-GlcNAc调节的分子基础。这一目标将决定 乳腺癌肿瘤起始细胞中NANOG的OGT调节的分子基础。在目标#2中，我们将识别 OGT interactome/O-GlcNA介于癌细胞和癌干细胞之间。这一目标将确定 在肿瘤起始细胞中OGT相互作用蛋白和O-GlcNAc酰化蛋白以鉴定新的途径和 肿瘤引发能力的调节剂。最终的目的是评价OGT在调节肿瘤启动过程中的作用。 体内活性。重要的是，我们将在临床前癌症模型中测试新型OGT抑制剂，并测试其是否 OGT靶向药物作为抗乳腺癌生长的潜在抗肿瘤起始细胞治疗策略 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 细胞在分子水平上与肿瘤起始细胞连接， 营养素传感器OGT可以与癌症起始途径偶联，并建立OGT作为治疗靶点， 治疗耐药癌症。

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.