--- - |2- Our results showed that reticulon‐4 (RTN4) was downregulated and targeted by miR‐148a‐3p, and inhibited prostate cancer cell proliferation by inducing cell cycle arrest and senescence, suggesting that RTN4 may be an important molecular event linked to prostate cancer. Abstract Reticulon‐4 (RTN4), a reticulon family protein localized in the endoplasmic reticulum, is reported to be involved in multiple physiological processes like neuroendocrine secretion and membrane trafficking in neuroendocrine cells. Previous studies have presented a great potential of RTN4 for the treatment of autoimmune‐mediated demyelinating diseases and spinal cord injury regeneration. While interaction with Bcl‐2 and Bcl‐2‐like family in apoptosis modulation implicated its possible role in various human cancers. However, the investigation of this gene in prostate cancer is mainly ignored. Here in our current study, we focused on its role in prostate cancer and found that RTN4 DNA copy numbers were higher in prostate cancer than normal prostate gland while its RNA and protein expressions were relatively lower. Chromosomal neighbor gene EML6 had similar expression patterns with RTN4 in prostate cancer tissues and cell lines, and further research found that they could be both targeted by miR‐148a‐3p. Lentivirus‐mediated RTN4 overexpression potently inhibited DU145 and LNCaP cells proliferation. Cell cycle was blocked in G2/M phase and significant cell senescence was observed in RTN4 overexpressed prostate cancer cells. Finally, interaction networks in the normal prostate gland and cancer tissues further revealed that RTN4 maybe phosphorylated by MAPKAPK2 and FYN at tyrosine 591 and serine 107, respectively. All these results implied that RTN4 might somehow participate in prostate tumor progression, and this elicits possibility to develop or identify selective agents targeting RTN4 for prostate cancer therapy. - 'Journal of Cellular Physiology, EarlyView. '