利用单细胞 RNA 测序揭示人类胃癌器官特异性转移的转录异质性。

Revealing the transcriptional heterogeneity of organ-specific metastasis in human gastric cancer using single-cell RNA Sequencing.

机构信息

Department of Medical Oncology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.

Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.

出版信息

Clin Transl Med. 2022 Feb;12(2):e730. doi: 10.1002/ctm2.730.

DOI:10.1002/ctm2.730

PMID:35184420

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC8858624/

Abstract

BACKGROUND

Deciphering intra- and inter-tumoural heterogeneity is essential for understanding the biology of gastric cancer (GC) and its metastasis and identifying effective therapeutic targets. However, the characteristics of different organ-tropism metastases of GC are largely unknown.

METHODS

Ten fresh human tissue samples from six patients, including primary tumour and adjacent non-tumoural samples and six metastases from different organs or tissues (liver, peritoneum, ovary, lymph node) were evaluated using single-cell RNA sequencing. Validation experiments were performed using histological assays and bulk transcriptomic datasets.

RESULTS

Malignant epithelial subclusters associated with invasion features, intraperitoneal metastasis propensity, epithelial-mesenchymal transition-induced tumour stem cell phenotypes, or dormancy-like characteristics were discovered. High expression of the first three subcluster-associated genes displayed worse overall survival than those with low expression in a GC cohort containing 407 samples. Immune and stromal cells exhibited cellular heterogeneity and created a pro-tumoural and immunosuppressive microenvironment. Furthermore, a 20-gene signature of lymph node-derived exhausted CD8 T cells was acquired to forecast lymph node metastasis and validated in GC cohorts. Additionally, although anti-NKG2A (KLRC1) antibody have not been used to treat GC patients even in clinical trials, we uncovered not only malignant tumour cells but one endothelial subcluster, mucosal-associated invariant T cells, T cell-like B cells, plasmacytoid dendritic cells, macrophages, monocytes, and neutrophils may contribute to HLA-E-KLRC1/KLRC2 interaction with cytotoxic/exhausted CD8 T cells and/or natural killer (NK) cells, suggesting novel clinical therapeutic opportunities in GC. Additionally, our findings suggested that PD-1 expression in CD8 T cells might predict clinical responses to PD-1 blockade therapy in GC.

CONCLUSIONS

This study provided insights into heterogeneous microenvironment of GC primary tumours and organ-specific metastases and provide support for precise diagnosis and treatment.

摘要

背景

解析胃癌（GC）及其转移的肿瘤内和肿瘤间异质性对于理解其生物学特性以及鉴定有效的治疗靶点至关重要。然而，GC 不同器官倾向性转移的特征在很大程度上仍是未知的。

方法

对来自 6 名患者的 10 个人体新鲜组织样本（包括原发肿瘤和相邻非肿瘤样本）和来自不同器官或组织（肝脏、腹膜、卵巢、淋巴结）的 6 个转移灶进行单细胞 RNA 测序分析。使用组织学检测和批量转录组数据集进行了验证实验。

结果

发现了与侵袭特征、腹膜转移倾向、上皮-间充质转化诱导的肿瘤干细胞表型或休眠样特征相关的恶性上皮亚群。在包含 407 个样本的 GC 队列中，前三个亚群相关基因高表达的患者总生存期比低表达的患者差。免疫细胞和基质细胞表现出细胞异质性，并形成促肿瘤和免疫抑制的微环境。此外，获得了一个 20 基因的淋巴结来源耗竭 CD8 T 细胞的特征签名，用于预测淋巴结转移，并在 GC 队列中得到验证。此外，尽管抗 NKG2A（KLRC1）抗体甚至在临床试验中都未用于治疗 GC 患者，但我们不仅发现了恶性肿瘤细胞，还发现了一个内皮亚群、黏膜相关不变 T 细胞、T 细胞样 B 细胞、浆细胞样树突状细胞、巨噬细胞、单核细胞和中性粒细胞可能有助于 HLA-E-KLRC1/KLRC2 与细胞毒性/耗竭 CD8 T 细胞和/或自然杀伤（NK）细胞的相互作用，提示 GC 中有新的临床治疗机会。此外，我们的研究结果表明，CD8 T 细胞中的 PD-1 表达可能预测 GC 患者对 PD-1 阻断治疗的临床反应。