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Targeting the epithelial to mesenchymal transition-mediated chemoresistance in breast cancer

靶向乳腺癌中上皮间质转化介导的化疗耐药性

基本信息

批准号：
9891022
负责人：
Dingcheng Gao
金额：
$ 34.54万
依托单位：
WEILL MEDICAL COLL OF CORNELL UNIV
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-04-28 至 2021-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9891022
关键词：
Ablation Address Animal Model Apoptosis Apoptotic Blood Circulation Breast Breast Cancer Treatment Breast Cancer therapy CRISPR library CRISPR screen Cell Proliferation Clinical Clinical Trials Clustered Regularly Interspaced Short Palindromic Repeats Combined Modality Therapy Development Distant Drug resistance E-Cadherin Epithelial Epithelium Event Family Fluorescence Future Genes Genetic Genetic Recombination Guide RNA Human IL6 gene Impairment Libraries Mammary Neoplasms Mediating Mesenchymal Metastatic Neoplasm to the Lung Metastatic breast cancer Modeling Molecular Mouse Mammary Tumor Virus Neoplasm Metastasis Organ Paracrine Communication Pathway interactions Patient-derived xenograft models of breast cancer Pharmacology Phenotype Pre-Clinical Model Primary Neoplasm Process Regimen Resistance Resistance development Series Snails System Therapeutic Transcription Repressor Transgenic Model Transitional Cell Transitional Cell Neoplasm Tumor Cell Invasion autocrine base cadherin 8 cancer therapy chemotherapy design differential expression drug development drug metabolism epithelial to mesenchymal transition improved in vivo malignant breast neoplasm neoplastic cell new therapeutic target novel overexpression paracrine pre-clinical programs public health relevance screening slug stemness transcription factor transcriptome transdifferentiation tumor progression

项目摘要

DESCRIPTION (provided by applicant) Despite significant advances in the treatment, development of resistance to conventional chemotherapy remains an unresolved problem. Consequently an in-depth understanding of the mechanisms underlying the development of chemoresistance is of utmost importance for improving the therapeutic regimens. Recent evidence indicates that epithelial to mesenchymal transition (EMT), the transdifferentiation program involved in tumor invasion and metastasis, may also contribute to chemoresistance. However, the importance of EMT in vivo is fiercely debated due to the inability of tracking EMT events during tumor progression. To solve this critical issue, we have established a novel EMT lineage tracing system in breast cancer by combining multiple transgenic models (MMTV-PyMT/Fsp1-Cre/Rosa26-GRFP). In this model, mesenchymal- specific Cre-mediated recombination initiates a permanent switch of fluorescent markers in tumor cells undergoing EMT, which enable us to track the EMT tumor cells throughout the breast tumor progression. The initial studies with this model found that within a predominantly epithelial primary tumor, a small portion (approx. 2%) of tumor cells underwent EMT. Strikingly, these EMT cells did not give rise to metastasis as the metastases were mainly comprised of non-EMT tumor cells (no fluorescence switch). Importantly, we discovered that EMT tumor cells significantly contributed to lung metastasis after chemotherapy. The EMT tumor cells survived chemotherapy due to reduced proliferation, apoptotic tolerance, and elevated expression of chemoresistance- related genes. Inhibiting EMT by overexpressing miR-200 family abrogated this resistance. These results provide direct evidence of EMT in chemoresistance and open the window to investigate EMT-targeting strategies as a means to overcome chemoresistance in breast cancer. In this proposal, we will take advantage of the EMT lineage tracing model, to further investigate a series of rationally guided anti-EMT approaches such as targeting EMT-induced autocrine/paracrine signals (Aim 1) and EMT-promoting transcription factors (Aim 2). We will use both genetic and pharmacological approaches to evaluate their importance in EMT-mediated chemoresistance. Moreover, based on our preliminary transcriptome analysis we will generate a CRISPR gRNA library targeting the differentially expressed genes in EMT tumor cells. The EMT lineage tracing model will provides a unique platform for the CRISPR screen to identify novel therapeutic targets for the EMT-mediated chemoresistance (Aim 3). At the end, we will validate our findings in human breast cancer and evaluate efficacy of combination therapies in a series of metastatic breast cancer patient-derived xenograft (PDX) models (Aim 4). We envision that this mechanism-based targeting of EMT- mediated chemoresistance will constitute feasible strategies for breast cancer therapy.

描述（由申请人提供）尽管治疗取得了重大进展，但对常规化疗产生耐药性仍然是一个未解决的问题。因此，深入了解化疗耐药性发展的机制对于改善治疗方案至关重要。最近的证据表明，上皮间质转化（EMT），即参与肿瘤侵袭和转移的转分化程序，也可能导致化疗耐药。然而，由于无法追踪肿瘤进展过程中的 EMT 事件，EMT 在体内的重要性受到激烈争论。为了解决这个关键问题，我们通过结合多种转基因模型（MMTV-PyMT/Fsp1-Cre/Rosa26-GRFP）建立了一种新型乳腺癌EMT谱系追踪系统。在该模型中，间充质特异性 Cre 介导的重组启动了正在进行 EMT 的肿瘤细胞中荧光标记的永久转换，这使我们能够在整个乳腺肿瘤进展过程中追踪 EMT 肿瘤细胞。对该模型的初步研究发现，在以上皮为主的原发肿瘤中，一小部分（约 2%）肿瘤细胞经历了 EMT。引人注目的是，这些 EMT 细胞并未引起转移，因为转移主要由非 EMT 肿瘤细胞组成（无荧光开关）。重要的是，我们发现 EMT 肿瘤细胞在化疗后显着促进肺转移。 EMT 肿瘤细胞由于增殖减少、凋亡耐受性和化疗耐药相关基因表达升高而在化疗中幸存下来。通过过表达 miR-200 家族抑制 EMT 消除了这种耐药性。这些结果提供了 EMT 在化疗耐药性中的直接证据，并为研究 EMT 靶向策略作为克服乳腺癌化疗耐药性的手段打开了窗口。在本提案中，我们将利用EMT谱系追踪模型，进一步研究一系列合理引导的抗EMT方法，例如针对EMT诱导的自分泌/旁分泌信号（目标1）和促进EMT的转录因子（目标2）。我们将使用遗传和药理学方法来评估它们在 EMT 介导的化疗耐药性中的重要性。此外，根据我们的初步转录组分析，我们将生成针对 EMT 肿瘤细胞中差异表达基因的 CRISPR gRNA 文库。 EMT 谱系追踪模型将为 CRISPR 筛选提供一个独特的平台，以确定 EMT 介导的化学耐药性的新治疗靶点（目标 3）。最后，我们将验证我们在人类乳腺癌中的发现，并评估联合疗法在一系列转移性乳腺癌患者来源的异种移植 (PDX) 模型中的疗效（目标 4）。我们设想，这种基于 EMT 介导的化疗耐药机制的靶向将成为乳腺癌治疗的可行策略。