Elucidating IL-6/STAT3-mediated Phenotypic Changes in Head and Neck Cancer Stem Cells

摘要 头颈部鳞状细胞癌(HNSCC)是一种常见的致命性恶性肿瘤。尽管意义重大 HNSCC的病理生物学研究进展以及与HNSCC相关的大量患者发病率 治疗和肿瘤复发/转移的高频率导致患者存活率低得令人无法接受 以及糟糕的生活质量。癌症干细胞(CSC)假说试图解释观察到的异质性 肿瘤内的癌细胞，癌细胞的许多恶性特征源于向干细胞的转移- 就像功能一样。在HNSCC中，CSCs作为肿瘤启动、治疗逃避和复发的驱动力发挥作用。 基于铂的药物，如顺铂，已被证明可以提高CSC分数和自我更新，如 由BMI-1表达决定。头部和颈部CSCs依赖于血管周围缝隙内的细胞串扰， 尤其是内皮细胞分泌的IL-6。我们的初步数据显示，抑制IL-6/STAT3可以防止 顺铂诱导CSC自我更新。但抑制IL-6信号的机制可以断言这一点 其功能及其对治疗耐药和肿瘤复发的影响尚不清楚。长期的 本项目的目的是研究在获得和维持的分子机制 干细胞样癌细胞表型。这项工作的总体假设是，对IL-1的治疗性阻断 6/STAT3通路抑制BMI-1介导的CSC自我更新，抑制HNSCC复发。至 为了验证这一假说，我们提出了以下具体目标：1)阐明IL-6/STAT3- 2)用来描述IL-6/STAT3的实时效应 抑制和顺铂治疗对CSC增殖模式的影响；3)确定抑制CSC的效果 HNSCC对常规顺铂治疗的耐药性和复发的自我更新。要实现这些目标 目的：在体外和体内的CSC检测中，将使用遗传学和药理学方法来测试 假设CSC表型受BMI-1通过IL-6/STAT3信号调节。我们将调查真正的- 使用CRISPR/Cas9报告系统验证假设的CSC人群中的时间表型变化 IL-6/STAT3抑制通过减少CSC的自我更新而促进CSC的不对称分裂。顺铂- 耐药细胞系和患者来源的异种移植小鼠模型将被用来检验抑制 IL-6/STAT3信号通路将克服顺铂的逃逸耐药，防止肿瘤复发。澄清 决定头颈部癌症干细胞命运的关键机制将提供基于机制的信息 有可能提高头颈癌患者的生存和生活质量的治疗方法。

ABSTRACT Head and neck squamous cell carcinoma (HNSCC) is a frequent and deadly malignancy. Despite significant advances in the understanding of the pathobiology of HNSCC, the substantial patient morbidity associated with treatment and the high frequency of tumor recurrence/metastasis result in an unacceptably low patient survival and poor quality of life. The cancer stem cell (CSC) hypothesis attempts to explain the observed heterogeneity of cancer cells within a tumor, with many malignant features of a cancer cell deriving from a shift towards stem- like features. CSCs function as drivers of tumor initiation, therapeutic evasion, and recurrence in HNSCC. Platinum-based agents such as Cisplatin have been shown to enhance the CSC fraction and self-renewal, as determined by Bmi-1 expression. Head and neck CSCs rely on cellular crosstalk within the perivascular niche, particularly on endothelial cell-secreted IL-6. Our preliminary data showed that IL-6/STAT3 inhibition prevents Cisplatin-induced CSC self-renewal. But the mechanism through which inhibition of IL-6 signaling asserts this function and its implications on therapeutic resistance and tumor recurrence remain unclear. The long-term objective of this project is to study molecular mechanisms underlying the acquisition and maintenance of the stem-like cancer cell phenotype. The overall hypothesis of this work is that therapeutic blockade of the IL- 6/STAT3 pathway suppresses the Bmi-1-mediated CSC self-renewal and inhibits HNSCC recurrence. To test this hypothesis, we propose the following specific aims: 1) to elucidate mechanisms underlying IL-6/STAT3- mediated phenotypic changes in the cancer cell population, 2) to describe the real-time effect of IL-6/STAT3 inhibition and Cisplatin therapy on CSC proliferation patterns, and 3) to determine the effect of inhibiting CSC self-renewal on resistance to conventional Cisplatin therapy and recurrence in HNSCC. To accomplish these aims, both genetic and pharmacologic approaches will be used in CSC assays in vitro and in vivo to test the hypothesis that the CSC phenotype is regulated by Bmi-1 via IL-6/STAT3 signaling. We will investigate the real- time phenotypic changes within the CSC population using a CRISPR/Cas9 reporter system to test the hypothesis that IL-6/STAT3 inhibition promotes asymmetric cell division of CSC by decreasing their self-renewal. Cisplatin- resistant cell lines and patient-derived xenograft mouse models will be used to test the hypothesis that inhibiting IL-6/STAT3 signaling will overcome evasive resistance to Cisplatin and prevent tumor recurrence. Elucidating crucial mechanisms that define the fate of head and neck cancer stem cells will inform mechanism-based therapies that have the potential to enhance the survival and quality of life of patients with head and neck cancer.