Abstract: Objective This study investigates the expression profile of sialic acid-binding immunoglobulin-like lectin 11 （SIGLEC11） in esophageal squamous cell carcinoma （ESCC） and elucidates its role in maintaining tumor stemness and promoting invasion and metastasis. We further evaluated whether SIGLEC11 acts as a key pro-tumorigenic molecule mediated by M2 macrophages, thereby providing theoretical support for understanding the regulatory mechanisms of the ESCC immune microenvironment and identifying potential therapeutic targets. Methods Proteomic analysis was performed to compare the secretome profiles of M0, M1, and M2 macrophages differentiated from THP-1 monocytes. The expression levels of SIGLEC11 in different macrophage subtypes were validated using qPCR, western blotting, and multiplex immunofluorescence, and its association with immune-cell infiltration was assessed via the TIMER2 database. Sphere formation assays and Transwell migration/invasion assays were conducted to evaluate the effects of exogenous recombinant SIGLEC11 protein on the stemness maintenance and motility of ESCC cell lines KYSE30, KYSE180, and KYSE510. Kaplan-Meier survival analysis and clinicopathological correlation analyses were performed based on publicly available datasets to determine the association between SIGLEC11 expression and patient prognosis. Results Proteomic screening and subsequent validation at both the protein and transcript levels demonstrated that SIGLEC11 was specifically and highly expressed in M2 macrophages and could be released via a secretory pathway. TIMER2 analysis indicated a positive correlation between SIGLEC11 expression and macrophage infiltration. Functional in vitro assays showed that exogenous SIGLEC11 significantly enhanced the self-renewal, migration, and invasion capacities of ESCC cells, suggesting its promotive effect on tumor stemness. Analysis of the TCGA database demonstrated that SIGLEC11 expression was closely associated with tumor aggressiveness, and survival analysis further indicated that high SIGLEC11 expression correlated with poor patient prognosis. Conclusion SIGLEC11 is specifically upregulated in M2-polarized macrophages, where it functions to enhance tumor stemness and to promote the migration and invasion of ESCC cells. Its expression is closely associated with tumor malignancy and with unfavorable clinical outcomes. These findings suggest that SIGLEC11 serves as a pivotal molecular hub linking the tumor immune microenvironment to the malignant phenotype of ESCC, highlighting its potential as a novel therapeutic target for diagnosis, prognostic assessment, and immunotherapy in ESCC.

Key words: ESCC, sialic scidbinding Ig-like lectin 11, macrophages

摘要： 目的 本研究探讨唾液酸结合免疫球蛋白样凝集素11（SIGLEC11）在食管鳞状细胞癌（ESCC）中的表达特征及其在肿瘤干性维持与侵袭转移过程中的作用,明确其是否作为由M2型巨噬细胞介导的关键促癌分子,为揭示ESCC免疫微环境调控机制及寻找潜在治疗靶点提供理论依据。方法 采用蛋白质谱分析由单核细胞THP-1诱导获得的M0、M1、M2型巨噬细胞的分泌蛋白组学差异;利用qPCR、Western blot和多重免疫荧光验证SIGLEC11在不同类型巨噬细胞中的表达水平,并结合TIMER2.0数据库分析其与免疫细胞浸润的关系。进一步采用成球实验以及Transwell迁移与侵袭实验,评估外源性重组SIGLEC11蛋白对KYSE30、KYSE180、KYSE510细胞干性维持及运动能力的影响。最后基于公开数据库进行Kaplan-Meier生存分析及临床病理参数相关性评估,探讨SIGLEC11表达与ESCC患者预后的关系。结果 蛋白质谱初筛及后续蛋白与转录水平验证均显示,SIGLEC11在M2型巨噬细胞中呈特异性高表达,并可经分泌途径释放。TIMER2数据库分析提示其表达水平与巨噬细胞浸润程度呈正相关。体外功能实验显示,外源性SIGLEC11可显著增强ESCC细胞的自我更新、迁移和侵袭能力,提示其具有增强肿瘤干性的生物学效应。TCGA数据库分析表明,SIGLEC11的表达与肿瘤的恶性程度密切相关。生存分析表明,SIGLEC11高表达与患者不良预后相关。结论 SIGLEC11在M2型巨噬细胞中呈特异性高表达,增强肿瘤干性促进ESCC细胞迁移和侵袭,并与患者肿瘤恶性程度及预后不良密切相关,提示其是连接肿瘤免疫微环境与ESCC恶性表型的重要调控分子,有望作为ESCC诊断、预后评估及免疫治疗的新型潜在靶点。

关键词: 食管鳞癌, SIGLEC11, 巨噬细胞