ROLE OF TWIST1 IN EMT MAINTENANCE AND TUMOR DORMANCY

TIST1 在 EMT 维持和肿瘤休眠中的作用

• 批准号: 8706827
• 负责人: David D Tran
• 金额: $ 15.2万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8706827
• 关键词: Address; Biological Markers; Bone Marrow; Breast; Cancer Etiology; Cancer Patient; Cell Cycle Arrest; Cells; Clinical; Cytokine Network Pathway; Data; Diagnosis; Disease; Disease-Free Survival; Distant; Epithelial; Epithelial Cells; Genetic Models; Growth; Human; Interleukin-6; Link; Localized Malignant Neoplasm; MAPK14 gene; Maintenance; Malignant Neoplasms; Mammary Neoplasms; Mesenchymal; Modeling; Molecular; Mouse Mammary Tumor Virus; Mus; Neoplasm Metastasis; Patients; Play; Predictive Value; Primary Neoplasm; Proliferating; Recurrence; Relapse; Research; Residual Tumors; Resistance; Role; Scientist; Signal Pathway; Signal Transduction; Staging; Stem cells; System; TWIST1 gene; Testing; Time; Transcription Repressor/Corepressor; autocrine; base; cancer cell; chemotherapy; cytokine; genetic regulatory protein; in vivo; malignant breast neoplasm; mouse model; neoplastic cell; overexpression; paracrine; prevent; prognostic; programs; public health relevance; transcription factor; tumor; tumor progression

DESCRIPTION (provided by applicant): Cancer patients can develop metastatic disease years to decades after diagnosis. This pause can be explained by micrometastatic disseminated tumor cell (DTC) dormancy, a stage in cancer progression in which asymptomatic residual disease is present but clinically undetectable and resistant to conventional chemotherapy. The etiology of cancer dormancy and how to therapeutically address it have confounded scientists and clinicians. This is due in large part to the inherent difficulties in approaching this problem, including the rarity of DTCs and the surprising lack of genetic models of tumor dormancy. Although the Epithelial-Mesenchymal Transition (EMT) has been implicated in the initial stages of cancer metastasis, how it is maintained in late metastatic cells and whether it also regulates tumor dormancy remains unclear. We have recently detailed a mechanistic link between EMT and tumor dormancy in which Snail1 and Twist1, two key EMT-inducing transcription factors, cooperate with each other to initiate and maintain EMT, respectively, and in so doing Twist1 may contribute directly to tumor dormancy. Twist1 maintains EMT and perhaps tumor dormancy by inducing cell cycle arrest and a low ERK:p38 signaling ratio - two key features of tumor dormancy. The Snail1-Twist1 cooperation was observed in human breast cancer and the Twist1:Snail1 ratio in bone marrow DTCs was found to be highly predictive of distant relapses. Therefore, Twist1 represents a potential target to manipulate tumor dormancy for clinical benefits. To develop safe and effective Twist1-based applications, Twist1's role in EMT maintenance and tumor dormancy will need to be confirmed and characterized. To that end, we propose to develop a mouse genetic model of EMT maintenance and tumor dormancy and a cell-based system to determine the mechanism of Twist1-induced growth arrest: In specific aim 1, we take advantage of the MMTV-NeuNT mouse model of breast cancer which develops ErbB2- positive breast tumors de novo. We have shown that the Snail1-Twist1 temporal and spatial cooperation exists and dormant DTCs are present in this mouse model, establishing it as a bona fide genetic model of human breast cancer EMT and dormancy. To confirm that Twist1 is critical for maintaining tumor dormancy, we will determine the ability of Twist1- depleted tumor cells to maintain dormant DTCs, give rise to metastases, and confer treatment resistance as compared to control tumor cells. In specific aim 2, we have shown that the cytokine IL-6 is induced by Twist1 in late EMT and an important intermediary between Twist1 and p38. Using transient TGF¿1-treated epithelial cells and MMTV-NeuNT mice, we will determine how Twist1 induces IL-6, whether IL-6 is critical for Twist1-dependent EMT maintenance and tumor dormancy in vivo, and whether other cytokines or regulatory proteins are involved in Twist1-associated autocrine and paracrine cytokine network. In specific aim 3, we will collect additional paired primary human breast tumors and BM DTCs to determine the predictive and prognostic power of the Twist1:Snail1 ratio in BM DTCs as compared to other biomarkers. These 3 aims will allow us to critically address a role for Twist1 in EMT maintenance and tumor dormancy. The result will hopefully provide new targets to control tumor dormancy and stimulate research into this significant problem.

描述（由申请人提供）：癌症患者在诊断后数年至数十年可能会出现转移性疾病。这种暂停可以用微转移播散性肿瘤细胞（DTC）休眠来解释，这是癌症进展的一个阶段，其中存在无症状残留疾病，但临床上无法检测到并且对常规化疗具有抵抗力。癌症休眠的病因以及如何治疗解决这一问题让科学家和临床医生感到困惑。这在很大程度上是由于解决这个问题的固有困难， 包括 DTC 的稀有性和肿瘤休眠遗传模型的令人惊讶的缺乏。尽管上皮-间质转化（EMT）与癌症转移的初始阶段有关，但它如何在晚期转移细胞中维持以及它是否也调节肿瘤休眠仍不清楚。我们最近详细介绍了 EMT 和肿瘤休眠之间的机制联系，其中 Snail1 和 Twist1 这两个关键的 EMT 诱导转录因子相互合作，分别启动和维持 EMT，因此 Twist1 可能直接促进肿瘤休眠。 Twist1 通过诱导细胞周期停滞和低 ERK:p38 信号比（肿瘤休眠的两个关键特征）来维持 EMT，或许还维持肿瘤休眠。在人类乳腺癌中观察到了 Snail1-Twist1 的协同作用，并且发现骨髓 DTC 中的 Twist1:Snail1 比率可以高度预测远处复发。因此，Twist1 代表了操纵肿瘤休眠以获得临床益处的潜在靶点。 为了开发安全有效的基于 Twist1 的应用，需要确认和表征 Twist1 在 EMT 维持和肿瘤休眠中的作用。为此，我们建议开发一种 EMT 维持和肿瘤休眠的小鼠遗传模型，以及一个基于细胞的系统来确定 Twist1 诱导的生长停滞的机制：在具体目标 1 中，我们利用 MMTV-NeuNT 乳腺癌小鼠模型，该模型从头形成 ErbB2 阳性乳腺肿瘤。我们已经证明，在该小鼠模型中存在 Snail1-Twist1 时空协作，并且存在休眠 DTC，将其建立为人类乳腺癌 EMT 和休眠的真正遗传模型。为了确认 Twist1 对于维持肿瘤休眠至关重要，我们将确定 Twist1 耗尽的肿瘤的能力 与对照肿瘤细胞相比，这些细胞维持休眠 DTC、引起转移并赋予治疗抗性。在具体目标 2 中，我们发现细胞因子 IL-6 在 EMT 晚期由 Twist1 诱导，并且是 Twist1 和 p38 之间的重要中介。使用瞬时TGF¿1处理的上皮细胞和MMTV-NeuNT小鼠，我们将确定Twist1如何诱导IL-6，IL-6是否对于Twist1依赖性EMT维持和体内肿瘤休眠至关重要，以及其他细胞因子或调节蛋白是否参与Twist1相关的自分泌和旁分泌细胞因子网络。在具体目标 3 中，我们将收集额外配对的原发性人类乳腺肿瘤和 BM DTC，以确定 BM DTC 中 Twist1:Snail1 比率与其他生物标志物相比的预测和预后能力。 这 3 个目标将使我们能够批判性地探讨 Twist1 在 EMT 维持和肿瘤休眠中的作用。该结果有望提供控制肿瘤休眠的新靶标，并刺激对这一重大问题的研究。