Qian Yiting, Sun Bo, Lai Linying, Xu Fengying, Liu Ruilin, Yang Wenzhuo
Department of Gastroenterology and Hepatology, Digestive Disease Institute, Tongji Hospital, Tongji University School of Medicine, Shanghai, China.
Animal Experiment Center of Tongji Hospital, Tongji University School of Medicine, Shanghai, China.
Int J Genomics. 2025 Jun 13;2025:6629479. doi: 10.1155/ijog/6629479. eCollection 2025.
CD8 T cells play pivotal roles in antitumor immunity, where infiltration levels often correlate with favorable prognosis. However, the functional heterogeneity of CD8 T cell subsets within the gastric cancer (GC) tumor microenvironment (TME)-particularly their divergent impacts on tumor progression, immunotherapy response, and clinical outcomes-remains poorly characterized. We integrated single-cell RNA sequencing (scRNA-seq) data from 23 GC tissues (GEO: GSE150290) with bulk transcriptomic profiles from TCGA-STAD to dissect CD8 T cell heterogeneity. Analytical pipelines included unsupervised clustering, pseudotime trajectory analysis, and protein-protein interaction (PPI) network construction to identify survival-associated hub genes. Differential gene expression, functional enrichment, and experimental validation were performed to confirm clinical relevance. scRNA-seq resolved CD8 T cells into five functionally distinct subsets: naïve/memory, exhausted, and three cytotoxic subpopulations. Among these, cytotoxic CD8 T1 cells exhibited the strongest prognostic relevance, with high infiltration correlating to improved survival and enrichment in G2-grade tumors. Pseudotime analysis revealed differentiation trajectories from naïve to exhausted subsets, accompanied by metabolic and immune checkpoint pathway alterations. PPI network analysis identified SELL, CD79B, and RAMP2 as hub genes, all significantly linked to survival and differentially expressed across tumor grades/stages. Experimental validation confirmed that SELL, CD79B, and RAMP2 knockdown suppressed GC cell proliferation, underscoring their functional roles. Our study unveils the landscape of CD8 T cell heterogeneity in GC and proposes a three-gene signature (SELL/CD79B/RAMP2) with dual prognostic and therapeutic potential. These findings provide actionable insights for stratifying patients, tailoring immunotherapy regimens, and developing novel targets to enhance antitumor immunity in GC.
CD8 T细胞在抗肿瘤免疫中发挥着关键作用，其浸润水平通常与良好的预后相关。然而，胃癌（GC）肿瘤微环境（TME）中CD8 T细胞亚群的功能异质性——尤其是它们对肿瘤进展、免疫治疗反应和临床结果的不同影响——仍未得到充分表征。我们将来自23个GC组织的单细胞RNA测序（scRNA-seq）数据（GEO：GSE150290）与来自TCGA-STAD的批量转录组图谱整合起来，以剖析CD8 T细胞的异质性。分析流程包括无监督聚类、伪时间轨迹分析和蛋白质-蛋白质相互作用（PPI）网络构建，以识别与生存相关的枢纽基因。进行了差异基因表达、功能富集和实验验证，以确认临床相关性。scRNA-seq将CD8 T细胞解析为五个功能不同的亚群：幼稚/记忆、耗竭和三个细胞毒性亚群。其中，细胞毒性CD8 T1细胞表现出最强的预后相关性，高浸润与生存率提高和G2级肿瘤中的富集相关。伪时间分析揭示了从幼稚亚群到耗竭亚群的分化轨迹，同时伴随着代谢和免疫检查点途径的改变。PPI网络分析确定SELL、CD79B和RAMP2为枢纽基因，它们均与生存显著相关，且在不同肿瘤分级/阶段存在差异表达。实验验证证实，SELL、CD79B和RAMP2基因敲低可抑制GC细胞增殖，突出了它们的功能作用。我们的研究揭示了GC中CD8 T细胞异质性的全貌，并提出了一个具有双重预后和治疗潜力的三基因特征（SELL/CD79B/RAMP2）。这些发现为GC患者分层、定制免疫治疗方案以及开发新靶点以增强抗肿瘤免疫提供了可行的见解。
