MFAP5+ Cancer-associated fibroblasts promote EMT in gastric cancer via lactylation modification leading to CT-detected extramural venous invasion

Abstract Background Computed tomography (CT)-detected extramural venous invasion (EMVI) has been identified as independent risk factors for distant metastasis in patients with advanced gastric cancer (GC). Cancer-associated fibroblasts (CAFs) are crucial for remodeling the tumor microenvironment in GC. This study aimed to explore the relationship between CAFs and EMVI imaging characteristics to provide a new entry point for the diagnosis and treatment of GC. Methods We collected postoperative pathological specimens from 13 patients with advanced GC associated with EMVI. Next generation sequencing and radiogenomics correlation analysis was used to identify the relationship between the EMVI score and the degree of CAFs infiltration in GC. Based on single-cell sequencing data, we completed pathway activity and functional enrichment analyses for specific CAF subtypes in GC. CAFs were extracted using the collagenase method and were cocultured with GC cell line in vitro. After lentivirus-mediated regulation of MFAP5 and LDHA expression, we detected changes in the degree of EMT and the invasion ability in GC cell. A nude mouse orthotopic EMVI model was constructed, and MRI and Immunohistochemistry were performed to verify that MFAP5 affected EMVI in GC by regulating LDHA. Results The correlation analysis results showed that the EMVI score of GC patients was directly proportional to the degree of CAFs infiltration, and the degree of CAFs infiltration in GC was closely related to EMT pathway Single-cell data analysis suggested that the Fibro-MFAP5+ subtypes were enriched in tumor lactylation modification and EMT. Immunohistochemistry revealed that the expression of MFAP5, L-lactyl and EMT markers in GC tissues was proportional to the EMVI score. After knocking down MFAP5 in CAFs, the levels of L-lactyl and histone lactylation modifications were significantly reduced, and the sphere-forming ability and blood vessel formation ability of CAFs were significantly inhibited. Cell functional experiments demonstrated that MFAP5+ CAFs could affect EMT and the metastasis and invasion capabilities of GC cells. The results obtained with the nude mouse EMVI model suggested that MFAP5+ CAFs may promote the acquisition of EMVI features in GC by regulating lactylation modification. Conclusions This study explores the relationship between radiographic features of GC and the tumor microenvironment, and preliminarily elucidates its potential mechanisms. This innovative work may provide important new insights into the diagnosis and treatment of GC.