Fig. 5: M2-type macrophages promote gastric cancer progression by secreting VEGF to induce angiogenesis.

A–D Fra-1 was overexpressed or knocked down in gastric cancer cells HGC27/AGS. After 48 h, the cell culture supernatant was collected to prepare conditioned medium. Following the induction of M0 macrophages to M2 polarization using IL4 and IL13, the conditioned medium was co-cultured with the M2 macrophages for an additional 48 h. The ELISA detection kit was used to measure the secretion of vascular endothelial growth factor (VEGF) by M2-type macrophages. The p-value was calculated through unpaired t-test correction. E, F Fra-1 was overexpressed in gastric cancer cells HGC27/AGS, with or without HMGA2 knockdown. After 48 h, the cell culture supernatant was collected to prepare conditioned medium. The M0 macrophages were induced to polarize towards M2 using IL4 and IL13, and then co-cultured with the conditioned medium for 48 h. The secretion of VEGF from M2 macrophages was detected using an ELISA kit. Multiple comparisons were analyzed using ANOVA, and two groups were compared by Wilcoxon rank sum test. G, H Fra-1 was overexpressed or knocked down in gastric cancer cells HGC27/AGS. The cell culture supernatant was collected after 48 h to prepare conditioned medium. After inducing M0 macrophages to polarize to M2 using IL4 and IL13, the conditioned medium was co-cultured with M2 macrophages. The cell culture supernatant was collected after an additional 48 h to prepare macrophage-conditioned medium. This was further co-cultured with vascular endothelial cells for 48 h, and the tubule formation ability of the vascular endothelial cells was assessed using a tubule formation assay. The p-value was calculated through unpaired t-test correction. I, J Fra-1 was overexpressed in gastric cancer cells HGC27/AGS, with or without concomitant HMGA2 knockdown. Macrophage-conditioned medium was prepared and further co-cultured with vascular endothelial cells. After 48 h, the tubule formation ability of the vascular endothelial cells was detected using a tubule formation assay. The p-value was calculated through unpaired t-test correction. K, L M0 macrophages were induced or not induced to polarize towards M2 using IL4 and IL13. After 48 h, the cell culture supernatants were collected, and macrophage-conditioned medium was prepared. This was further co-cultured with gastric cancer cells, and the effect of M2 macrophages on the proliferative ability of gastric cancer cells was detected using EdU incorporation combined with flow cytometry. The p-value was calculated through unpaired t-test correction. All experiments were performed with three or more independent replications, and the data shown are from representative individual experiments. “ns” indicates no significant difference; “*” indicates p < 0.05; “**“ indicates p < 0.01; “***” indicates p < 0.001; “****” indicates p < 0.0001.