Evaluation of tumor microenvironmental immune regulation and prognostic in lung adenocarcinoma from the perspective of purinergic receptor P2Y13

Tumor-infiltrating immune cells (TICs) can serve as an important indicator to evaluate the prognosis and therapeutic response in lung adenocarcinoma (LUAD). The identification of mutated genes that can affect the abundance of TICs and prognosis has practical implications. In the presented study, tumor microenvironment (TME) scoring was performed by the ESTIMATE scoring system on 598 RNA transcripts selected from the TCGA database to determine the proportions of immune cells and stromal cells. The infiltration difference of TICs in LUAD samples was obtained by CIBERSORT. The ‘immuneeconv’ R software package, which integrates six latest algorithms, including TIMER, xCell, MCP-counter, CIBERSORT, EPIC and quanTIseq were used to verify the correlation between purinergic receptor P2Y13 (<i>P2RY13</i>) and immune cells. Based on RNA sequencing analysis of the Lewis lung cancer-bearing model in C57BL/6 mice and immunohistochemistry (IHC) of human LUAD tissues, the expression of <i>P2RY13</i> and associated pathways were verified. It was shown that differentially expressed genes (DEGs) obtained by interactive analysis based on Immunescore and Stromalscore were significantly enriched in immune-related pathways. The expression of <i>P2RY13</i> was significantly associated with prognosis and clinicopathological characteristics of LUAD patients. More importantly, this gene played an important role in maintaining the immune dominant environment and changing the regulation of TICs. <i>P2RY13</i> expression was positively correlated with the infiltration of dendritic cells (DCs) in various of tumor tissues as validated by the PanglaoDB scRNA-seq database. Therefore, <i>P2RY13</i> is expected to be a potential biomarker for predicting TME and the prognosis of LUAD after verification.

肿瘤浸润免疫细胞（Tumor-infiltrating immune cells, TICs）可作为评估肺腺癌（lung adenocarcinoma, LUAD）患者预后与治疗应答的重要指标。筛选可影响TIC丰度及患者预后的突变基因具有实际应用价值。本研究通过ESTIMATE评分系统，对从癌症基因组图谱（The Cancer Genome Atlas, TCGA）数据库中选取的598份RNA转录本进行肿瘤微环境（tumor microenvironment, TME）评分，以确定免疫细胞与基质细胞的占比；通过CIBERSORT算法分析LUAD样本中TIC的浸润差异。本研究使用整合了TIMER、xCell、MCP-counter、CIBERSORT、EPIC及quanTIseq六种最新算法的‘immuneeconv’ R软件包，验证嘌呤能受体P2Y13（purinergic receptor P2Y13, P2RY13）与免疫细胞的相关性。基于对C57BL/6小鼠路易斯肺癌荷瘤模型的RNA测序分析，以及对人LUAD组织的免疫组化（immunohistochemistry, IHC）检测，本研究验证了P2RY13的表达及其相关通路。研究结果显示，基于免疫评分与基质评分交互分析得到的差异表达基因（differentially expressed genes, DEGs）显著富集于免疫相关通路。P2RY13的表达与LUAD患者的预后及临床病理特征显著相关；更为重要的是，该基因在维持免疫主导的肿瘤微环境及调控TIC浸润中发挥关键作用。通过PanglaoDB单细胞RNA测序数据库验证发现，P2RY13的表达与多种肿瘤组织中树突状细胞（dendritic cells, DCs）的浸润水平呈正相关。综上，经验证后，P2RY13有望成为预测LUAD患者肿瘤微环境及预后的潜在生物标志物。