Cancer-associated fibroblasts promote cell growth by activating ERK5/PD-L1 signaling axis in colorectal cancer

Abstract Background Colorectal cancer (CRC) is one of the most common diseases, accounting for about 10% cancer-related deaths. Previous studies have found that caner-associated fibroblasts (CAFs) are closely related to the occurrence and metastasis of CRC, but the detailed mechanism is not precise. Methods Tumor cells and fibroblasts were co-cultured with a transwell system. Cell Counting Kit-8 and colony formation assays were performed to test the ability of cell proliferation. The flow cytometry was used to detect cell apoptosis. Western Blot was performed to assess protein expression levels. Quantitative real-time PCR was performed to detect mRNA expression levels. ERK5-IN-1 was used to inhibit the autophosphorylation of ERK5. Results CAFs promoted cell proliferation and inhibited cell apoptosis in CRC cells. CAFs promoted the phosphorylation of ERK5 and the expression of programmed death-ligand 1 (PD-L1). Activated ERK5 promotes cell proliferation and inhibited cell apoptosis in CRC cells. The expression levels of ERK5 correlated with the expression of PD-L1 in CRC cells. CAFs promote cell growth by activating the ERK5/PD-L1 signaling axis in colorectal cancer. Conclusions CAFs significantly promoted cell proliferation and inhibited cell apoptosis in CRC cells, which features are dependent on regulating the ERK5/PD-L1 signaling axis.