MiR-199~214 cluster at the crossroads of plasticity and malignancy in breastcancer

癌症的恶性进展与肿瘤细胞对现有肿瘤细胞的耐药性增加有关 治疗，并对美国每年40,000例与乳腺癌有关的死亡事件负责 独自一人。更好地了解乳腺癌细胞(BCC)的恶性特征及其如何成为 转移将导致更有效的治疗方法的发展，以挽救患者的生命。 我们先前的研究已经证实，乳腺肿瘤的微环境一定是丰富的。 被称为间充质干细胞(MSCs)的前体细胞，在其他方面有助于维持和 损伤和炎症过程中结缔组织的再生。重要的是，我们证明了 肿瘤相关的MSCs发挥着强大的促癌功能，甚至会导致转移性乳腺癌。 细胞(Bcc)扩散到远处的组织。这些发现将MSCs的一个新角色归因于重要 乳腺癌发病机制的决定因素，并为癌症转移提供了新的见解。 为了阐明骨髓间充质干细胞与基底细胞癌在转移过程中的异型相互作用，我们 对MSC刺激的BCC进行了详细的分子分析，确定miR-199a~214是最多的 骨髓基质细胞中MSC刺激的microRNA。我们提出了miR-199A~214促进肿瘤干细胞的证据 (CSC)样属性的癌细胞，其作用涉及下调FOXP2，叉头 转录因子与言语和语言发育密切相关。我们证明了FOXP2 BCCs表型miR-199a~214表达下调，足以促进CSC 繁殖、肿瘤启动和转移。重要的是，我们发现miR-199a的升高和抑制 Foxp2的表达水平代表了恶性临床乳腺癌的显著特征， 在三阴性(TN)和HER2富集型乳腺癌中显著。 在这项建议中，我们将阐明新发现的miR-199a-foxp2轴与乳腺的关系。 癌症发病机制。使用体外、体内和临床方法，我们将：(1)确定miR- 199a作为晚期临床疾病的生物标志物，并证明其在临床前转移中的重要性 模型，以确定其作为乳腺癌治疗靶点的相关性；(2)阐明转移- MiR-199a~214的体内外相关活性；(3)破译调控分子网络 在BCC中诱导miR-199a的潜在原因，阐明了这种网络如何汇聚到FOXP2上并调节FOXP2 沉默，并确定FOXP2如何发挥其下游功能。 总的来说，我们提议的研究将确定和定义新的和重要的分子决定因素 调控乳腺CSC的发生、维持和转移。这些洞察力将揭示其内在 乳腺癌最恶性细胞的工作原理，并将提供潜在有用的新工具 恶性疾病的预后和治疗。

Malignant progression of cancer is associated with increased resistance of neoplastic cells to existing therapies, and is responsible for the majority of the >40,000 breast-cancer-related yearly fatalities in the US alone. A better understanding of the malignant features of breast cancer cells (BCCs) and how they become metastatic will lead to the development of more effective therapies that save patients' lives. Our prior studies have identified that the microenvironment of breast tumors is enriched for certain progenitor cells called mesenchymal stem cells (MSCs), cells that otherwise contribute to the maintenance and regeneration of connective tissues during wounding and inflammation. Importantly, we demonstrated that tumor-associated MSCs exerted potent pro-malignant functions, causing even poorly metastatic breast cancer cells (BCCs) to spread to distant tissues. These findings ascribed a novel role for MSCs as important determinants of breast cancer pathogenesis and provided new insights into cancer metastasis. To elucidate the heterotypic interactions that MSCs establish with BCCs in the context of metastasis, we conducted detailed molecular analyses of MSC-stimulated BCCs, and identified miR-199a~214 as the most MSC-stimulated microRNA in BCCs. We present evidence that miR-199a~214 promotes cancer stem cell (CSC) -like properties in cancer cells, and that its actions involve the downregulation of FOXP2, a forkhead transcription factor tightly associated with speech and language development. We show that FOXP2 knockdown in BCCs phenocopies miR-199a~214 expression, and that it is sufficient in promoting CSC propagation, tumor-initiation, and metastasis. Importantly, we show that elevated miR-199a and depressed FOXP2 expression levels represent prominent features of malignant clinical breast cancer, associating significantly with triple-negative (TN) and HER2-enriched breast cancers. In this proposal, we will elucidate the involvement of the newly discovered miR-199a-FOXP2 axis in breast cancer pathogenesis. Using in vitro, in vivo, and clinical approaches, we will: (1) determine the role of miR- 199a as a biomarker of advanced clinical disease, and demonstrate its essentiality for metastasis in pre-clinical models so as to establish its relevance as a target in breast cancer therapy; (2) elucidate the metastasis- associated activities of miR-199a~214 in vitro and in vivo; and (3) decipher the regulatory molecular networks underlying the induction of miR-199a in BCCs, elucidate how such networks converge on and regulate FOXP2 silencing, and determine how FOXP2 exerts its downstream functions. Collectively, our proposed studies will identify and define novel and important molecular determinants that regulate breast CSC genesis, maintenance, and metastasis. These insights would shed light on the inner workings of breast cancer's most malignant cells, and will serve to provide novel tools of potential utility in the prognosis and therapy of malignant disease.