Introduction: The Hedgehog (Hh) signaling pathway is aberrantly activated in various types of cancer and plays a critical regulatory role. However, its biological significance in gastric cancer remains unclear. In this study, the mechanism underlying the role of Hh in gastric cancer progression and prognosis was investigated through bioinformatics analysis as well as in vitro and in vivo experiments.Methods: In this study, a systematic analysis of scRNA-seq datasets and bulk RNA-seq datasets from gastric cancer patients derived from the GEO database and TCGA database was performed by us, which revealed the activation characteristics of Hh in different cell types within the gastric cancer tumor microenvironment (TME). Furthermore, through conducting multiplex immunofluorescence staining experiments on clinical gastric cancer samples, we clarified the association mechanism between fibroblasts with highly activated Hh and the gastric cancer tumor immunosuppressive microenvironment. Finally, by means of in vitro and in vivo experiments, we elucidated the key molecular mechanism by which fibroblasts with highly activated Hh remodel the gastric cancer tumor immunosuppressive microenvironment.Results: We identified a distinct subpopulation of fibroblasts, designated MMP1 + FIB, in the gastric cancer tumor microenvironment. Studies revealed that this subpopulation can significantly activate Hh, suggesting it may play a crucial role in the regulation of the TME. Subsequent mechanistic investigations further confirmed that MMP1 + FIB exhibits a significant correlation with the immunosuppressive state of the TME (R = 0.29,p= 2.5 × 10−0.8). In terms of the specific functions, the complement system in this fibroblast subpopulation is significantly activated (p< 0.05); further studies demonstrated that MMP1 + FIB can induce the polarization of macrophages toward the M2 subtype (an immunosuppressive phenotype) by specifically secreting complement C3 protein. Collectively, these processes contribute to the establishment of an immunosuppressive TME and ultimately promote the proliferation and metastasis of gastric cancer cells.Discussion: Aberrant activation of the Hh signaling pathway promotes gastric cancer progression via the MMP1 + FIB–C3–macrophage axis, providing a potential therapeutic strategy for targeting the tumor microenvironment.
引言：Hedgehog（Hh）信号通路在多种癌症中异常激活并发挥关键调控作用，但其在胃癌中的生物学意义尚不明确。本研究通过生物信息学分析及体内外实验，探究了Hh在胃癌进展及预后中的作用机制。 方法：本研究通过对GEO数据库和TCGA数据库中胃癌患者的单细胞RNA测序数据集及批量RNA测序数据集进行系统分析，揭示了Hh在胃癌肿瘤微环境（TME）中不同细胞类型的激活特征。进一步通过对临床胃癌样本进行多重免疫荧光染色实验，阐明了Hh高活化成纤维细胞与胃癌肿瘤免疫抑制微环境的关联机制。最后通过体内外实验，解析了Hh高活化成纤维细胞重塑胃癌肿瘤免疫抑制微环境的关键分子机制。 结果：我们在胃癌肿瘤微环境中鉴定出一类特殊的成纤维细胞亚群，命名为MMP1+FIB。研究发现该亚群能够显著激活Hh，提示其可能在TME调控中发挥关键作用。后续机制研究进一步证实，MMP1+FIB与TME的免疫抑制状态呈显著正相关（R=0.29，p=2.5×10⁻⁸）。在具体功能方面，该成纤维细胞亚群中的补体系统被显著激活（p<0.05）；进一步研究表明，MMP1+FIB能够通过特异性分泌补体C3蛋白，诱导巨噬细胞向M2亚型（免疫抑制表型）极化。这些过程共同促进了免疫抑制性TME的形成，最终推动胃癌细胞的增殖与转移。 讨论：Hh信号通路的异常激活通过MMP1+FIB–C3–巨噬细胞轴促进胃癌进展，为靶向肿瘤微环境提供了潜在治疗策略。
肿瘤(癌症)患者之家