Next generation sequencing showing miRNA profiles of exosomes derived from DHT-treated CAFs and matched ETOH-treated CAFs

Background: Androgen deprivation therapy (ADT) is the backbone of therapy for advanced prostate cancer (PCa). Despite the good initial response, castration resistance and metastatic progression will inevitably occur. Cancer-associated fibroblasts (CAFs) may be implicated in promoting metastasis of PCa after ADT. Our aim is to investigate the role and mechanism of CAF-derived exosomes involving in metastasis of PCa after ADT. Methods: PCa cells were co-cultured with exosomes derived from DHT-treated or ETOH-treated CAFs, and their migration and invasion differences under castration condition were examined both in vitro and in vivo. The miRNA profiles of exosomes derived from DHT-treated CAFs and matched ETOH-treated CAFs were analysed via next generation sequencing. The transfer of exosomal miR-146a-5p from CAFs to PCa cells was identified by fluorescent microscopy. The function and direct target gene of exosomal miR-146a-5p in PCa cells were confirmed through Transwell assays, luciferase reporter, and western blot. Findings: Compared with DHT-treated CAFs, exosomes derived from ETOH-treated CAFs dramatically increase migration and invasion of PCa cells under castration condition. MiR-146a-5p level in exosomes from ETOH-treated CAFs was significantly reduced. The loss of miR-146a-5p may strengthen the epithelial-mesenchymal transition (EMT) to accelerate cancer cells metastasis by modulating epidermal growth factor receptor (EGFR)/ERK pathway. Interpretation: CAFs-derived exosomal miR-146a-5p confers metastasis in PCa cells under ADT through the EGFR/ERK pathway and it may present a new treatment for PCa. Examing 2 conditions, each with 3 replicates