To study the EMT contributions in tumor metastasis and chemoresistance by using lineage tracing models

利用谱系追踪模型研究 EMT 在肿瘤转移和化疗耐药中的贡献

• 批准号: 10436835
• 负责人: Dingcheng Gao
• 金额: $ 47.92万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-17 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10436835
• 关键词: Apoptosis; BT 474; Bar Codes; Blood; Blood Circulation; Breast Cancer Cell; Breast Cancer Model; Breast cancer metastasis; CCL7 gene; CRISPR/Cas technology; Cell Line; Cells; Chemoresistance; Clustered Regularly Interspaced Short Palindromic Repeats; Communities; Development; Disease; E-Cadherin; Embryonic Development; Epithelial; Event; Exhibits; Fluorescence; Genes; Genetic; Homing; Human; Individual; Knock-in; Lung; MDA MB 231; Mediating; Mesenchymal; Mesenchymal Cell Neoplasm; Metastatic Neoplasm to the Lung; Modeling; Mouse Mammary Tumor Virus; Mus; Nature; Neoplasm Metastasis; Phenotype; Primary Neoplasm; Process; Property; Recurrence; Reporter; Reporting; Resistance; Role; Site; Snails; Transgenic Mice; Transitional Cell; Transitional Cell Neoplasm; Transitional Epithelium; Tumor Cell Invasion; Vimentin; chemotherapy; epithelial to mesenchymal transition; improved; in vivo; migration; neoplastic cell; novel; programs; stemness; transcription factor; transdifferentiation; tumor; tumor progression

Epithelial to mesenchymal transition (EMT) has been enthusiastically proposed as an essential mechanism for tumor metastasis, since the EMT-associated features such as migration, invasion, resistance to apoptosis and stemness properties, adequately meet the requirements for metastasis. Taken the challenges of tracing the EMT process in vivo, we developed a strategy of using a mesenchymal-specific Cre-mediated switch of fluorescent markers in a multiple-transgenic mouse (MMTV-PyMT:Fsp1-Cre:Rosa26mT/mG, Tri-PyMT). Surprisingly, we found that lung metastases were predominantly composed of pre-EMT RFP+ tumor cells exhibiting epithelial phenotypes under normal conditions. Importantly, the post-EMT tumor cells did exhibit resistance to chemotherapy, significantly contributed to recurrent lung metastases after chemotherapy. These findings pointed to the complexity of EMT contributions in tumor progression and revived vigorous discussions in the community. Given the transient, reversible and dynamic natures of the EMT process, and concerns about the Tri-PyMT model, we proposed new lineage tracing models to study the roles of EMT in metastasis and chemoresistance. Aim 1. To explore the contributions of EMT mechanism in tumor metastasis and chemoresistance by using Snail-CreERT2 mediated EMT lineage tracing model. The Fsp1-Cre mediated Tri-PyMT model may not be sufficient to report all EMT events. Metastatic cells could undergo EMT by activating distinct EMT transcription factors (TFs) such as Snail. Therefore, we have established a Snail-CreERT2–mediated EMT lineage tracing model. In-depth analyses will be performed to clarify the roles of EMT in metastasis and chemoresistance with this model. Aim 2. To explore the dynamic changes of EMT statuses in human breast cancer metastasis and chemoresistance. EMT reporter cell lines (MDA-MB-231:Vim/RFP and BT-474:ECAD/GFP cells) carry knockin fluorescent tags within EMT marker genes (Vimentin and E-cadherin, respectively). Unlike the Cre-mediated models, the fluorescence expression in these cells is quantitative and reversible, which allows us to analyze the dynamic changes of EMT status with and without chemotherapy in human breast cancer models. Aim 3. To assess the evolutionary lineages of metastasis-initiating cells and the involvement of EMT mechanism via genetic barcoding models. In addition to using EMT markers, we will genetically barcode the Tri-PyMT cells using the homing-CRISPR technique. This model will allow us to depict the evolutionary trajectories from primary tumor cells to individual metastases, and determine the origins of the metastasis (pre- EMT vs. post-EMT cells). Further, we will develop genetic barcoding mice (MARC:CRISPR:PyMT) for lineage tracing of spontaneous metastatic cells and assessing the contributions of the EMT program to metastasis. Impact: Resolving the controversies in the field will not only improve our mechanistic understanding of tumor metastasis but also provide novel targets/opportunities in combatting the deadly disease.

上皮向间充质转化(EMT)已被认为是一种重要的机制。 肿瘤转移，因为EMT的相关特征，如迁移，侵袭，抗凋亡和 茎的特性，充分满足转移的要求。接受追踪EMT的挑战 在活体过程中，我们开发了一种策略，使用间充质特异性Cre介导的荧光开关 多重转基因小鼠(MMTV-PYMT：Fsp1-Cre：Rosa26mT/mg，Tri-PYMT)的标记。令人惊讶的是，我们 发现肺转移瘤主要由前EMT RFP+肿瘤细胞组成，表现为上皮性 正常情况下的表型。重要的是，EMT后的肿瘤细胞确实表现出对 化疗对化疗后复发的肺转移有显著影响。这些发现表明 对于EMT在肿瘤进展中的作用的复杂性，并在社区中重新引发了激烈的讨论。 鉴于EMT过程的瞬时性、可逆性和动态性，以及对Tri-PYMT的担忧 模型的基础上，我们提出了新的谱系追踪模型来研究EMT在转移和化疗耐药中的作用。 目的1.探讨EMT机制在肿瘤转移和化疗耐药中的作用。 采用Snail-CreERT2介导的EMT谱系追踪模型。Fsp1-Cre介导的Tri-PyMT模型可能不会 足以报告所有EMT事件。转移细胞可以通过激活不同的EMT转录来进行EMT 因子(TF)，如蜗牛。因此，我们建立了Snail-CreERT2介导的EMT谱系追踪 模特。将进行深入的分析，以阐明EMT在转移和化疗耐药中的作用 这个型号。 目的2.探讨乳腺癌转移和转移过程中EMT状态的动态变化。 化疗耐药。EMT报告细胞系(MDA-MB-231：VIM/RFP和BT-474：ECAD/GFP)携带敲门声 EMT标记基因(分别为Vimentin和E-cadherin)内的荧光标记。不同于CRE中介的 模型中，这些细胞的荧光表达是定量的和可逆的，这使得我们能够分析 乳腺癌模型中化疗前后EMT状态的动态变化。 目的3.评估肿瘤转移起始细胞的进化谱系和EMT的参与 通过遗传条形码模型的机制。除了使用EMT标记外，我们还将对 使用HOMING-CRISPR技术的Tri-PyMT细胞。这个模型将允许我们描绘进化的 从原发肿瘤细胞到单个转移的轨迹，并确定转移的来源(前- EMT与EMT后细胞相比)。此外，我们将开发遗传条形码小鼠(MARC：CRISPR：PYMT)以供谱系使用 追踪自发转移细胞并评估EMT计划对转移的贡献。 影响：解决该领域的争议不仅将提高我们对肿瘤的机制理解 但也为抗击这一致命疾病提供了新的靶点/机会。