Cancer-associated fibroblast-secreted exosomes promote prostate cancer cell migration and invasion by the FGL1/SOX5 axis.

Exosomes secreted by cancer-associated fibroblasts (CAFs) play a critical role in cancer progression. This study aimed to explore the effects of CAF exosomes on prostate cancer (PC) cell metastasis. PC cells were treated with these exosomes, and their processes were evaluated using cell-counting kit-8 and Transwell assays. Exosome-regulated mRNAs were explored using quantitative real-time PCR. The relationship between FGL1 and SOX5 was analyzed using co-immunoprecipitation and fluorescence in situ hybridization (FISH) assays. The results of this study showed that exosomes derived from CAFs promoted PC cell viability, migration, and invasion. CAFs promoted PC cell viability and metastasis by releasing exosomes. Exosome treatment increased the levels of FGL1, which interacted with SOX5 and negatively regulated its expression. Rescue experiments demonstrated that CAF exosomes promoted the biological behaviors of PC cells by upregulating FGL1 and downregulating SOX5. Moreover, exosomes accelerated tumor growth by regulating the FGL1 level. In conclusion, CAF-derived exosomes promoted PC cell viability, migration, and invasion by elevating the FGL1/SOX5 axis, suggesting a novel strategy for the treatment of metastatic PC.