Exploring the Altered Immune Microenvironment of Gastric Signet Ring Cell Carcinoma and Predicting Therapeutic Targets of Pseudobulbus Cremastrae Seu Pleiones using Single-Cell RNA Sequencing Combined with Network Pharmacology

Abstract

Background: Macrophages serve as crucial mediators in the progression of gastric signet ring cell carcinoma (GSRCC), while Pseudobulbus Cremastrae seu Pleiones (PCsP), a traditional Chinese medicine, demonstrates efficacy in promoting apoptotic processes in cancer cells. Our aim is to elucidate macrophage heterogeneity within GSRCC tissues and to delineate the therapeutic mechanisms of PCsP in regulating tumor microenvironment (TME).

Methods: Transcriptional profiling of GSRCC specimens was performed to elucidate the macrophage-associated gene expression patterns for intercellular communication and trajectory analyses. The TCMSP and Swiss Target Prediction databases were used to identify bioactive constituents of PCsP and their corresponding molecular targets. The Metascape platform facilitated GO and KEGG pathway analyses, while molecular docking simulations were conducted to evaluate component-gene binding affinities.

Results: Tumor-associated macrophages (TAMs) exhibited significant higher proliferation rates compared to normal tissue counterparts. Further stratification of TAMs identified 7 distinct subtypes. Temporal trajectory analysis revealed three distinct developmental states and four discrete gene expression modules within the macrophage population. A subsequent analysis of the intercellular communication network revealed enhanced signalling interactions between the TME and other cells. Eight bioactive constituents of PCsP and 489 GSRCC-associated target genes were identified based on the databases. PPI network analysis indicated 8 highest-centrality targets of PCsP. KEGG pathway analysis suggested predominant roles for lipid and atherosclerosis signaling pathways in GSRCC suppression. Molecular docking studies confirmed robust binding affinities between PCsP's primary constituents and central genetic targets.

Conclusions: This investigation identified alterations of TME in GSRCC, proposes a hypothesis for a potential mechanism of PCsP.