CAFs-derived HSPA1A promotes gastric cancer growth and affects chemotherapy by interacting with SEMG1 and regulating glycolysis

Gastric cancer (GC) progression and drug resistance are strongly influenced by the tumor microenvironment, especially cancer-associated fibroblasts (CAFs). This study aimed to clarify the role of CAF-derived HSPA1A in GC growth and chemosensitivity and to explore the underlying mechanism. HSPA1A expression and clinical relevance were evaluated using the GEO dataset (GSE163558) and immunohistochemistry (IHC) on 168 cases of GC tissue microarray. Immunofluorescence (IF) with the CAF marker FAP were used to identify the cellular source of HSPA1A. Functional effects of HSPA1A were examined in CAF–GC cell co-culture systems, tumor sphere assays, patient-derived organoids, and a subcutaneous xenograft model. RNA-sequencing (RNA-seq), co-immunoprecipitation (co-IP), Western blotting, and Seahorse glycolysis assays were used to identify HSPA1A-interacting proteins and to assess glycolytic activity. Through the above experiments, we found that HSPA1A was upregulated in GC tissues and associated with advanced T stage and poor prognosis, and was predominantly expressed in CAFs. Silencing HSPA1A in CAFs reduced GC cell proliferation, migration, and sphere formation, inhibited organoid growth, and enhanced sensitivity to 5-fluorouracil(5-FU), with similar effect on paclitaxel (PTX). In vivo, HSPA1A blockade suppressed xenograft growth and potentiated chemotherapy. Mechanistically, SEMG1 was identified as a binding partner of HSPA1A. So we concluded that targeting the HSPA1A–SEMG1 axis decreased expression of glycolysis-related enzymes, reduced glycolytic flux, and synergistically impaired GC cell growth. CAFs-derived HSPA1A promotes GC progression and 5-FU resistance by interacting with SEMG1 and enhancing glycolysis in tumor cells. The HSPA1A–SEMG1 axis represents a potential therapeutic target to inhibit GC growth and improve chemosensitivity.