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。在肿瘤中有一个亚群的细胞，称为 肿瘤启动细胞，可被分离并能够自我更新、分化并形成肿瘤的大部分。 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。了解监管机制 肿瘤的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 营养传感器O-GlcNAc转移酶(OGT)首次在体外调节启动癌症的细胞 在活体内。从基因或药物上减少OGT，在体外阻止乳房的形成 和减少的上皮间质标志物(EMT)，癌症干细胞标志物。重要的是 在多个乳腺癌细胞中过表达OGT会增加癌症干细胞标记物，包括 Nanog，在体外增加乳房形成，在体内增加肿瘤启动。在这 我们希望通过研究来揭示OGT调控肿瘤发生的分子机制。 了解OGT相互作用组和O-GlcNACome在乳腺癌肿瘤起始细胞中的作用。这 信息将使我们能够在治疗癌症和逆转耐药性方面找到新的治疗靶点。 根据我们的初步结果，这一应用的中心假设是营养传感器O- GlcNAc转移酶通过部分NANOG在乳腺癌起始细胞中发挥基础性作用 监管。这些实验的完成将有助于我们理解营养传感是如何 通路在分子水平上连接到自我更新的癌症干细胞(CSCs)，并提供 了解代谢途径中癌症改变如何调节核心自我更新的框架 控制CSC维护的信令。在目标1中，我们将确定OGT/O的分子基础- 主控CSC调节器NANOG的GlcNAc调节。这一目标将决定OGT的分子基础 NANOG在乳腺癌起始细胞中的调控。在目标2中，我们将鉴定OGT相互作用组/O- GlcNA介于癌细胞和癌症干细胞之间。这一目标将确定OGT交互 肿瘤起始细胞中的蛋白质和O-GlcNacylated蛋白识别新的途径和调节因子 启动肿瘤的能力。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靶向药物是否为潜在的乳腺抗肿瘤起始细胞治疗策略 肿瘤的体内生长和转移。这些研究将进一步加深我们对新陈代谢 癌细胞中的重新编程在分子水平上连接到肿瘤启动细胞，并将创造 从机制上理解营养感受器OGT如何与癌症启动途径和 建立OGT作为治疗耐药癌症的靶点。

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.