Cellular phenotypic heterogeneity and resistance to radiotherapy in pancreatic adenocarcinoma

项目摘要/摘要 特定癌症类型中的单个细胞能够表达导致的表型状态的多样性 来自遗传、表观遗传、转录和分子特征的潜在异质性。这是怎么回事 多样性进化和影响治疗反应是癌症生物学中的一个基本问题。一个新出现的 形成这种异质性的机制是肿瘤内微环境生态位的进化 支持癌症干细胞(CSC)状态。CSC由其功能能力定义，例如长期自我 更新，产生一系列分化细胞类型的能力，并增强肿瘤形成能力。 据信，它们还会导致对放射治疗等抗肿瘤疗法的抵抗力。胰管 腺癌(PDAC)预后很差，5年总存活率为10%，迫切需要新的治疗方法。 治疗策略。放射治疗是PDAC治疗中不可或缺的一部分，然而，并不是所有的癌细胞都有反应。 明确放射抵抗的机制将改变PDAC的临床治疗。使用胰腺 肿瘤模型，我们的初步结果表明，由一个癌细胞亚群产生的分泌的Wnt配体 在另一个癌细胞亚群中驱动Lgr5+干细胞状态，本质上形成一个支持性利基，促进 胰腺肿瘤内的茎。在这个提案中，我将测试WNT驱动的细胞 表型的异质性和干性促进了胰腺癌的放射抵抗。这就做 检查胰腺肿瘤细胞亚群在辐射抵抗中的作用，包括Lgr5+细胞(AIM 1)和WNT生产生态位(目标2)。在目标1下，我将描述癌症干细胞的特性 胰腺癌中的Lgr5+细胞、它们对放射治疗的相对抵抗力及其在肿瘤中的作用 重新繁衍。这些结果将决定Lgr5+细胞是否是CSCs和辐射抵抗的驱动因素 已建立的肿瘤并告知它们的分子特征，这可能提供额外的手段来靶向这些 细胞。在目标2下，我将调查结合辐射对产生WNT的利基的靶向。 具体地说，我将结合辐射使用Wnt途径的遗传或药物干扰 并检测肿瘤反应和动物存活率。这些努力将考验Wnt抑制剂的治疗潜力 作为PDAC中的放射增敏剂。总而言之，这项工作将促进对两个细胞 异质性和辐射抗性，最终目标是将这些发现转化为 改进了对PDAC患者的治疗策略。

PROJECT SUMMARY/ABSTRACT Individual cells within a given cancer type are capable of expressing a diversity of phenotypic states resulting from an underlying heterogeneity of genetic, epigenetic, transcriptomic, and molecular features. How this diversity evolves and influences therapeutic response is an essential question in cancer biology. One emerging mechanism of developing such heterogeneity is the evolution of microenvironmental niches within tumors that support a cancer stem cell (CSC) state. CSCs are defined by their functional capabilities such as long-term self- renewal, the capacity to give rise to a range of differentiated cell types, and enhanced tumor-forming ability. They are also believed to drive resistance to anti-tumor therapies, such as radiation therapy. Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis, with a 5-year overall survival of <10% and a dire need for novel therapeutic strategies. Radiation is an integral part of PDAC therapy, however not all cancer cells respond. Identifying mechanisms of radioresistance would transform the clinical management of PDAC. Using pancreatic tumor models, our preliminary results suggest that secreted Wnt ligands produced by one cancer cell subset drive a Lgr5+ stem-like state in another cancer cell subset, in essence forming a supportive niche that promotes stemness within pancreatic tumors. In this proposal, I will test the central hypothesis that Wnt-driven cellular phenotypic heterogeneity and stemness promote radiotherapy resistance in pancreatic adenocarcinoma. I will examine the role of pancreatic tumor cell subpopulations in radiation resistance, including the Lgr5+ cells (Aim 1) and the Wnt producing niche (Aim 2). Under Aim 1, I will characterize the cancer stem cell properties of Lgr5+ cells in pancreatic cancer, their relative resistance to radiation therapy, and their role in tumor repopulation. These results will determine whether Lgr5+ cells are CSCs and drivers of radioresistance in established tumors and inform their molecular characteristics, which may provide added means to target these cells. Under Aim 2, I will investigate the targeting of the Wnt-producing niche in combination with radiation. Specifically, I will use genetic or pharmacologic perturbation of the Wnt pathway in combination with radiation and assay tumor response and animal survival. These efforts will test the therapeutic potential of Wnt inhibitors as radiosensitizers in PDAC. Collectively, this work will facilitate basic mechanistic insights into both cellular heterogeneity and radioresistance, with the ultimate goal of translating these discoveries and developing improved treatment strategies for PDAC patients.