Department of Neurosurgery, Huashan Hospital, Shanghai Medical College, Fudan University, 200040, Shanghai, China.
School of Life Sciences, Fudan University, 200438, Shanghai, China.
Cell Death Dis. 2023 May 18;14(5):330. doi: 10.1038/s41419-023-05823-y.
This study aims to give a new perspective to the biomarkers in the lung adenocarcinoma (LUAD) brain metastasis, pathways involved and potential therapeutics. We performed a comprehensive single-cell level transcriptomic analysis on one LUAD patient with circulating tumor cells (CTCs), primary tumor tissue and metastatic tumor tissue using scRNA-seq approach to identify metastasis related biomarkers. Further scRNA-seq were performed on 7 patients to validate the cancer metastatic hallmark. with single cells collected from either metastatic or primary LUAD tissues. Pathological and functional studies were also performed to evidence the critical role of RAC1 in the LUAD metastasis. Hallmark gene was verified based on immunohistochemistry staining, cytological experiment, survival information from The Cancer Genome Atlas (TCGA), and staining results from Human Protein Atlas (HPA) databases. PCA analysis revealed that CTCs were in the intermediate place between the metastatic group and primary group. In the unsupervised clustering analysis CTCs were closer to one of the metastatic tumor cells, implying heterogeneity of the metastatic tumor and origin of the CTCs were from metastatic site. Transitional phase related gene analysis identified RAC1 was enriched in metastatic tumor tissue (MTT) preferred gene set functioning as regulated cell death and apoptosis as well as promoted macromolecule organization. Compared with normal tissue, expression levels of RAC1 increased significantly in LUAD tissue based on HPA database. High expression of RAC1 predicts worse prognosis and higher-risk. EMT analysis identified the propensity of mesenchymal state in primary cells while epithelial signals were higher in the metastatic site. Functional clustering and pathway analyses suggested genes in RAC1 highly expressed cells played critical roles in adhesion, ECM and VEGF signaling pathways. Inhibition of RAC1 attenuates the proliferation, invasiveness and migration ability of lung cancer cells. Besides, through MRI T2WI results, we proved that RAC1 can promote brain metastasis in the RAC1-overexpressed H1975 cell burden nude mouse model. RAC1 and its mechanisms might promote drug design against LUAD brain metastasis.
本研究旨在为肺腺癌（LUAD）脑转移的生物标志物、涉及的途径和潜在的治疗方法提供新的视角。我们使用 scRNA-seq 方法对一名患有循环肿瘤细胞（CTC）的 LUAD 患者的原发肿瘤组织和转移瘤组织进行了全面的单细胞水平转录组分析，以鉴定与转移相关的生物标志物。进一步对 7 名患者进行了 scRNA-seq 验证，以验证癌症转移的标志性特征。这些细胞是从转移或原发 LUAD 组织中收集的。还进行了病理学和功能研究，以证明 RAC1 在 LUAD 转移中的关键作用。标志性基因是基于免疫组织化学染色、细胞学实验、来自癌症基因组图谱（TCGA）的生存信息以及人类蛋白质图谱（HPA）数据库的染色结果进行验证的。PCA 分析表明 CTC 处于转移组和原发组之间的中间位置。在无监督聚类分析中，CTC 更接近其中一个转移瘤细胞，这表明转移瘤的异质性以及 CTC 的起源来自转移部位。过渡阶段相关基因分析表明，RAC1 在转移瘤组织（MTT）中富集，其作用是调节细胞死亡和凋亡，并促进大分子组织。与正常组织相比，根据 HPA 数据库，RAC1 在 LUAD 组织中的表达水平显著升高。RAC1 的高表达预示着预后更差和风险更高。EMT 分析表明，原代细胞中存在间充质状态的倾向，而转移部位上皮信号更高。功能聚类和途径分析表明，RAC1 高表达细胞中的基因在粘附、ECM 和 VEGF 信号通路中发挥关键作用。抑制 RAC1 可减弱肺癌细胞的增殖、侵袭和迁移能力。此外，通过 MRI T2WI 结果，我们证明 RAC1 可以促进 RAC1 过表达 H1975 细胞荷瘤裸鼠模型中的脑转移。RAC1 及其机制可能促进针对 LUAD 脑转移的药物设计。
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