Curcumin promotes cancer-associated fibroblasts apoptosis via ROS-mediated endoplasmic reticulum stress.

Cancer-associated fibroblasts (CAFs) play an important role in tumorigenesis, development, and migration. Eliminating CAFs or reducing their tumor-promoting activity is beneficial for tumor immunotherapy. Curcumin is a natural polyphenol derived from turmeric, which has been shown to inhibit the growth of many types of tumor. In this study, we explored the effect of curcumin on prostate-CAFs and its underlying molecular mechanism. The effect of curcumin on CAFs was measured using MTT assay and plate colony formation assay. Flow cytometry was used to detect cell apoptosis, ROS, Cell cycle, and mitochondrial membrane potential (ΔΨm) changes after curcumin treatment. Western Blot was used to detect changes in expression levels of related proteins in CAFs after curcumin stimulation. Colorimetry was used to detect the change of caspase 3 activity. The mRNA levels of Bims, Puma, ATF4 and CHOP were determined by qRT-PCR. We found that curcumin induced the apoptosis and cell cycle arrest of CAFs, which is mainly caused by the ROS-mediated endoplasmic reticulum stress pathway. For mechanism, the up-regulation of ROS caused by curcumin triggers endoplasmic reticulum stress of CAFs through the PERK-eIF2α-ATF4 axis. Our study suggests that curcumin selectively inhibits prostate-CAFs by inducing apoptosis and cell cycle arrest in G2-M phase, indicating a novel application of curcumin in tumor therapy.