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 CAFs-derived exosomes involving in metastasis of PCa after ADT. Methods: PCa cells were co-cultured with exosomes derived from 10 nM dihydrotestosterone (DHT)-treated (simulating the high androgen level of prostate cancer microenvironment) or ethanol (ETOH) -treated (simulating the castration level of prostate cancer microenvironment after ADT) 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. Results: Compared with DHT-treated CAFs, exosomes derived from ETOH-treated CAFs dramatically increased 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. Conclusions: 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.

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. 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. 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. 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.

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 CAFs-derived exosomes involving in metastasis of PCa after ADT.Methods: PCa cells were co-cultured with exosomes derived from 10 nM dihydrotestosterone (DHT)-treated (simulating the high androgen level of prostate cancer microenvironment） or ethanol (ETOH) -treated (simulating the castration level of prostate cancer microenvironment after ADT) 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.Results: Compared with DHT-treated CAFs, exosomes derived from ETOH-treated CAFs dramatically increased 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.Conclusions: 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.

Purpose: To investigate the clinical implications of CD3+CD69+ T-cells and CD8+CD28+ T-cells in the peripheral blood of patients prior to radical prostatectomy. Materials and Methods: A total of 91 prostate cancer (PCa) patients and 50 benign prostatic hyperplasia (BPH) patients were enrolled from January 2016 to December 2017. The proportions of CD3+CD69+ T-cells and CD8+CD28+ T-cells in the peripheral blood of PCa and BPH patients were detected by flow cytometry, and the association of these T-cell populations with pathological Grade Group and pathological TNM classification was evaluated. Data analysis was performed with SAS version 9.4 software. Results: The proportions of CD3+CD69+ and CD8+CD28+ T-cells in peripheral blood were higher in PCa patients than those in BPH patients. Multivariate analysis identified a higher CD3+CD69+ T-cell proportion as a risk factor for PCa (odds ratio (OR) = 4.783, P = 0.0013), but the diagnostic efficacy of the CD3+CD69+ T-cell proportion (area under the curve (AUC)=0.6833, P = 0.0003) for PCa was still inferior to that of the tPSA level (AUC=0.7531, P < 0.0001). The AUCs for CD3+CD69+ T-cell and CD8+CD28+ T-cell proportions for PCa were 0.6959 (P = 0.0372) and 0.6935 (P = 0.0395), respectively, among men with tPSA levels of 4.0-10.0 ng/mL. A lower CD3+CD69+ T-cell proportion was associated with higher pathological Grade Group (P=0.0074). Conclusion: The proportions of CD3+CD69+ T-cells and CD8+CD28+ T-cells in peripheral blood are potential diagnostic indicators for PCa. The preoperative proportion of CD3+CD69+ T-cells in peripheral blood may have prognostic value in terms of the pathological Grade Group in PCa.