Development of a novel anoikis-related prognostic signature and validation of CD36 as a potential target for reversing 5-FU resistance in gastric cancer

Gastric cancer (GC) remains a leading cause of cancer-related mortality, with chemoresistance and metastasis being primary hurdles to effective treatment. Anoikis resistance is a critical survival mechanism enabling tumor dissemination; however, the cellular heterogeneity of anoikis-related genes and their specific roles in remodeling the tumor microenvironment (TME) and mediating drug resistance remain ill-defined. This study aimed to construct a robust prognostic signature and elucidate the multi-dimensional mechanisms driving high-risk phenotypes in GC. By integrating bulk and single-cell transcriptomic data, we constructed a novel anoikis-related prognostic signature comprising eight genes. The signature demonstrated significant prognostic value for overall survival and served as an independent prognostic factor. Functional analysis revealed that high-risk patients exhibited an “immunosuppressed microenvironment” phenotype, characterized by suppressed T-cell infiltration and activation of stromal pathways. Single-cell RNA sequencing (scRNA-seq) further dissected the cellular origin of the signature, revealing a distinct cellular heterogeneity: stromal-remodeling genes (e.g., COL5A1) were enriched in fibroblasts, contributing to the immune-excluded barrier, while CD36 displayed a unique dual-distribution in both stromal and malignant cells. Experimental validation using 15 paired clinical tissues confirmed the significant upregulation of CD36 in GC. Functionally, in vitro assays demonstrated that CD36 acts as a key determinant of chemosensitivity: silencing CD36 significantly sensitized GC cells to 5-Fluorouracil (5-FU) and promoted growth inhibition, whereas CD36 overexpression conferred robust drug resistance. We established an anoikis-related signature and provided multi-omics evidence revealing how these genes orchestrate an immunosuppressive microenvironment and drive intrinsic chemotherapy resistance. Crucially, we identified CD36 as a metabolic vulnerability, suggesting that targeting CD36 represents a potential therapeutic strategy to overcome 5-FU resistance in gastric cancer.