CAF-derived exosomal miR-196b-5p after androgen deprivation therapy promotes epithelial-mesenchymal transition in prostate cancer cells through HOXC8/NF-κB signaling pathway.

BACKGROUND: Cancer-associated fibroblasts (CAFs) have been reported to play a significant role in the development and metastasis of various tumors; however, research on their role in promoting prostate cancer (PCa) metastasis under castration conditions remains unclear. METHODS: In this study, we utilized quantitative reverse transcription polymerase chain reaction (qRT-PCR) to detect the expression differences of microRNA-196b-5p (miR-196b-5p) in the exosomes secreted by CAFs before and after castration. We further characterized the transcriptional regulatory landscape through RNA sequencing combined with bioinformatics databases. In vitro and in vivo experiments were conducted to determine the role of miR-196b-5p in promoting tumor migration and metastasis. The dual-luciferase reporter assay, RT-PCR analysis, and Western blot analysis confirmed that miR-196b-5p targets HOXC8 in prostate cancer. Additionally, transwell assays and Western blot analysis were performed to elucidate the role and specific mechanisms of HOXC8 in tumor metastasis. RESULTS: By analyzing the expression differences of miRNAs in the exosomes secreted by CAFs before and after castration, along with relevant data from databases, we found that miR-196b-5p is highly secreted by CAFs after castration. miR-196b-5p promotes the migration and metastasis of prostate cancer cells. Subsequently, through RNA sequencing analysis and experimental validation, we determined that miR-196b-5p targets HOXC8. This interaction activates the NF-κB pathway, leading to the upregulation of epithelial-mesenchymal transition (EMT)-related protein expression, thereby driving the metastasis of prostate cancer. CONCLUSIONS: Our study elucidates a specific mechanism by which CAF-derived exosomes promote prostate cancer metastasis via miR-196b-5p regulation, contributing to the identification of therapeutic targets for managing tumor metastasis following castration.