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Updated: Sep 14, 2025
MicroRNA Detection in Prostate Tumors by Quantitative Real-time PCR qPCR
Published on: May 16, 2012
Prostate cancer cell-derived exosomes inhibit macrophage phagocytosis through EIF3B-mediated exosomal sorting of
Yanyan Zhang1, Yinying Hu2, Hongyan Guo2
1Medical College of Nanchang University, Nanchang, China.
Abstract:
Exosomes play significant roles in the tumor microenvironment (TME). In particular, some exosomal microRNAs (miRNAs) have the ability to mediate macrophage polarization. However, the mechanism underlying the selective enrichment of miRNAs into exosomes remains largely unknown. Herein, we compared the expression of miR-100-5p in exosomes derived from normal prostate epithelial cells and PC-3 cells. Subsequently, macrophages were treated with the aforementioned exosomes separately. Our results demonstrate that prostate cancer (PC)-derived exosomes can transfer miRNA-100-5p to macrophages and significantly increase miR-100-5p expression. To explore the role and mechanisms of exosomal miR-100-5p in macrophages, we performed phagocytosis assay and reactive oxygen species (ROS) detection experiment. Knockdown of miR-100-5p markedly promoted ROS generation in macrophages induced with PC-3 exosomes through the NADPH oxidase 4 (NOX4) pathway, leading to the increased phagocytosis of macrophages. Importantly, our results confirmed that eukaryotic translation initiation factor 3 subunit B (EIF3B) was highly expressed in PC cells and specifically bound to miR-100-5p by pull-down assay, and EIF3B knockdown decreased the enrichment of miR-100-5p in PC-3 exosomes. Collectively, our data showed that EIF3B-mediated selective sorting of miR-100-5p into PC exosomes reduced the generation of ROS by targeting NOX4 in macrophages, thus inhibiting macrophage phagocytosis. These findings reveal a new role for EIF3B in regulating the sorting of miR-100-5p into PC-3-derived exosomes, and identify an important new mode of TME regulation.
Insights
Prostate cancer exosomes use EIF3B to package miR-100-5p, reducing macrophage ROS and phagocytosis via the NOX4 pathway. This reveals a novel mechanism of tumor microenvironment regulation.
Area of Science:
- Oncology
- Cell Biology
- Molecular Biology
Background:
- Exosomes mediate intercellular communication within the tumor microenvironment (TME).
- Exosomal microRNAs (miRNAs) influence macrophage polarization, but their selective sorting into exosomes is poorly understood.
- Prostate cancer (PC) progression involves complex interactions within the TME.
Purpose of the Study:
- To investigate the mechanism of selective enrichment of miR-100-5p into exosomes derived from prostate cancer cells.
- To elucidate the role of exosomal miR-100-5p in regulating macrophage function, specifically reactive oxygen species (ROS) generation and phagocytosis.
- To identify the protein responsible for the selective sorting of miR-100-5p into PC exosomes.
Main Methods:
- Comparative analysis of miR-100-5p expression in exosomes from normal and PC-3 cells.
- Treatment of macrophages with PC-derived exosomes and assessment of miR-100-5p levels.
- Phagocytosis assays and reactive oxygen species (ROS) detection experiments.
- Knockdown of miR-100-5p and NADPH oxidase 4 (NOX4) in macrophages.
- Pull-down assays to identify proteins binding to miR-100-5p.
- Knockdown of eukaryotic translation initiation factor 3 subunit B (EIF3B) in PC cells.
Main Results:
- PC-derived exosomes significantly increased miR-100-5p expression in macrophages.
- Knockdown of miR-100-5p in PC-exosome-treated macrophages promoted ROS generation via the NOX4 pathway, enhancing phagocytosis.
- Eukaryotic translation initiation factor 3 subunit B (EIF3B) was identified as a binding partner of miR-100-5p and mediated its selective enrichment into PC-3 exosomes.
- EIF3B knockdown reduced miR-100-5p packaging into exosomes.
Conclusions:
- Eukaryotic translation initiation factor 3 subunit B (EIF3B) mediates the selective sorting of miR-100-5p into prostate cancer exosomes.
- This process reduces ROS generation in macrophages by targeting NOX4, thereby inhibiting macrophage phagocytosis.
- These findings reveal a novel mechanism by which prostate cancer regulates the tumor microenvironment through exosomal miRNA sorting.
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