Mechanisms of tumor cell clustering in breast cancer metastasis

肿瘤细胞聚集在乳腺癌转移中的机制

基本信息

批准号：
10744976
负责人：
Chonghui Cheng
金额：
$ 46.29万
依托单位：
BAYLOR COLLEGE OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-07-28 至 2028-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10744976
关键词：
Adherens Junction Adhesions Adhesives Anoikis Basic Science Binding Biological Assay Blood Blood Circulation Blood specimen Breast Cancer Cell Breast Cancer Patient Breast cancer metastasis Cell Communication Cell Survival Cell model Cell-Cell Adhesion Cells ChIP-seq Characteristics Chromatin Chromatin Loop Clinical Data Data Data Analyses Data Set Deposition Development Disease Progression Distant E-Cadherin Electron Microscopy Enzymes Epigenetic Process Exhibits Extracellular Matrix Future Genetic Transcription Goals Hi-C Histone-Lysine N-Methyltransferase Homeobox Hyaluronic Acid In Vitro Incidence Intercellular Junctions Licensing Mammary Neoplasms Mediating Mediator Metastatic breast cancer Morbidity - disease rate Multiomic Data Neoplasm Circulating Cells Neoplasm Metastasis Organ Patients Physiological Polysaccharides Primary Neoplasm Production Prognosis Proteins Regulation Research Role Shapes Signal Transduction Stress Testing Therapeutic Transmission Electron Microscopy Travel Tumor Promotion Work cancer cell cancer subtypes clinically relevant epigenetic regulation experimental study gain of function improved in vivo in vivo Model innovation insight loss of function malignant breast neoplasm mortality mouse model neoplastic cell novel novel therapeutic intervention novel therapeutics pre-clinical prevent promoter receptor shear stress transcription factor transcriptome sequencing triple-negative invasive breast carcinoma tumor tumor diagnosis

项目摘要

Metastasis is the primary cause of breast cancer-related morbidity and mortality. During metastasis, cells from primary tumors shed into the bloodstream as circulating tumor cells (CTCs). CTCs travel to distant organs to establish secondary tumors. CTCs that form clusters exhibit a drastic increase in metastatic potential compared to single CTCs. While previous studies have described E-cadherin as a key mediator of adhesion in CTC clusters and metastasis, many breast tumors, including tumors of the highly metastatic triple negative breast cancer (TNBC), express little to no E-cadherin. Thus, an alternative, E-cadherin-independent mechanism must exist to mediate clustering between CTCs, thereby promoting metastasis and disease progression. To investigate CTC clustering mechanisms, we developed an in vitro tumor cell clustering assay that incorporates physiological shear force and mimics in vivo conditions. Using this assay, we found that E-cadherin-negative metastatic breast cancer cells can form cellular interactions with characteristics similar to cell adherens junctions. Speculating that extracellular matrix (ECM) components from tumor cells may contribute to CTC clustering, we analyzed ECM components by breast cancer subtypes. We found that hyaluronic acid synthase 2 (HAS2), which is the primary enzyme responsible for hyaluronic acid (HA) production in breast cancer cells, is significantly upregulated in TNBC. We further observed that HA mediates clustering between TNBC tumor cells and confers them with the ability to overcome insults present in the bloodstream, including shear forces. Importantly, we detected HA enrichment at the cell-cell junction of interacting CTCs in TNBC patient blood specimens. Mechanistically, our preliminary results suggest that metastatic TNBC cells upregulate HAS2 expression in a chromatin looping mechanism mediated by PRDM6, a transcriptional regulator and putative histone lysine methyltransferase. Collectively, these preliminary findings lead us to hypothesize that in aggressive TNBC, high levels of HA augment CTC clustering via HA-dependent adhesive interactions between neighboring cells. We further hypothesize that the PRDM6 upregulates HA levels through epigenetic modulation of HAS2 expression, including chromatin looping interactions. We propose to study our hypotheses through two specific aims: 1) determine the role of HA in TNBC tumor cell clustering and metastasis and 2) elucidate the epigenetic regulation of HAS2 that impacts breast tumor cell clustering. To investigate our hypotheses, we will utilize novel in vitro clustering assays and in vivo mouse models along with electron microscopy to reveal the structural characteristics of CTC clusters. In addition, we will utilize integrative multi-omics data analysis to elucidate the co-regulatory network governing HAS2 expression during CTC clustering. Importantly, our results will be extensively validated in blood specimens from metastatic TNBC patients. Consequently, successful completion of our proposed work will not only identify a novel mechanism that mediates strong cell-cell interactions, but also pave the mechanistic groundwork for identifying novel therapeutic options to suppress CTC clustering.

转移是乳腺癌相关发病率和死亡率的主要原因。在转移过程中，细胞从原发性肿瘤以循环肿瘤细胞（CTC）的形式流入血液。 CTC 前往远处的器官建立继发性肿瘤。相比之下，形成簇的 CTC 的转移潜力显着增加到单个 CTC。虽然之前的研究已将 E-钙粘蛋白描述为 CTC 簇中粘附的关键介质和转移，许多乳腺肿瘤，包括高度转移性三阴性乳腺癌的肿瘤 (TNBC)，表达很少或不表达 E-钙粘蛋白。因此，必须存在一种独立于 E-钙粘蛋白的替代机制介导 CTC 之间的聚集，从而促进转移和疾病进展。调查CTC 聚类机制，我们开发了一种体外肿瘤细胞聚类分析，其中结合了生理学剪切力并模拟体内条件。使用该测定，我们发现 E-钙粘蛋白阴性转移性乳腺癌细胞可以形成具有类似于细胞粘附连接特征的细胞相互作用。推测肿瘤细胞的细胞外基质 (ECM) 成分可能有助于 CTC 聚类，我们分析了 ECM 乳腺癌亚型的组成部分。我们发现透明质酸合酶 2 (HAS2)，它是主要的负责乳腺癌细胞中透明质酸 (HA) 产生的酶，在 TNBC。我们进一步观察到 HA 介导 TNBC 肿瘤细胞之间的聚集，并赋予它们克服血液中存在的损伤的能力，包括剪切力。重要的是，我们检测到了HA TNBC 患者血液样本中相互作用的 CTC 在细胞与细胞连接处富集。从机制上讲，我们的初步结果表明，转移性 TNBC 细胞上调染色质环中的 HAS2 表达该机制由转录调节因子 PRDM6 和假定的组蛋白赖氨酸甲基转移酶介导。总的来说，这些初步发现使我们推测，在侵袭性 TNBC 中，高水平的 HA 通过相邻细胞之间依赖 HA 的粘附相互作用增强 CTC 聚类。我们进一步假设 PRDM6 通过 HAS2 表达的表观遗传调节上调 HA 水平，包括染色质环相互作用。我们建议通过两个具体目标来研究我们的假设：1）确定 HA 在 TNBC 肿瘤细胞聚集和转移中的作用，2) 阐明表观遗传调控 HAS2 影响乳腺肿瘤细胞聚集。为了研究我们的假设，我们将利用新颖的体外聚类分析和体内小鼠模型以及电子显微镜揭示结构 CTC簇的特征。此外，我们将利用综合多组学数据分析来阐明 CTC 聚类过程中控制 HAS2 表达的共同调控网络。重要的是，我们的结果将是在转移性 TNBC 患者的血液样本中得到广泛验证。结果顺利完成我们提出的工作不仅将确定一种介导强细胞间相互作用的新机制，而且为确定抑制 CTC 聚集的新治疗方案奠定机制基础。