Fig. 1

Cancer-associated fibroblast (CAF)-induced resistance to 5-fluorouracil (5-FU) in gastric cancer cells. a MKN-45 and MKN-1 gastric cancer cells treated with 5-FU were treated with fibroblast culture-conditioned media, and the half maximal inhibitory concentration (IC₅₀) was measured. The results are presented as the mean (± SEM). *P < 0.05, based on Kruskal-Wallis test followed by a Dunn’s multiple comparison. b Schematic figure detailing the transwell co-culture system with fibroblasts isolated from paired normal gastric tissues (normal-associated fibroblasts or NAFs) and gastric cancer tissues (CAFs). Western blot analysis results show changes in the expression of apoptotic markers such as cleaved PARP and caspase-3 72 h after 5-FU treatment with and without co-culture with NAFs and CAFs. c Representative micrographs demonstrating morphological changes in MKN-45 and MKN-1 cells after 5-FU treatment for 72 h with and without co-culture with fibroblasts. Scale bar = 100 μm. d A line graph comparing tumor growth among the in vivo xenograft tumors derived from MKN-1 cells alone (n = 6), MKN-1 cells combined with NAFs (n = 5), or MNK-1 cells combined with CAFs (n = 5) after 5-FU treatments. The bar graph compares the harvested tumor weight among the three groups. Graphs show the mean (± SEM) tumor weights of the mice. ^*P < 0.05, based on one-way ANOVA analysis, followed by a post hoc test with Tukey’s method. The photographs show the harvested tumors. Scale bar = 1 cm. e. Representative micrographs showing H&E staining, Masson’s trichrome staining for stromal collagen fibers, and immunohistochemical staining for α-smooth muscle actin (a-SMA), cytokeratin, and cleaved caspase-3 in harvested xenograft tumors derived from only MKN-1 cells and those derived from MKN-1 cells mixed with CAFs after treatment with 5-FU. Scale bar = 100 μm