Molecular mechanism of suppressor of cytokine signaling 6/signal transducer and activator of transcription 6 pathway regulating proliferation in prostate epithelial cells under inflammatory condition.

Benign prostatic hyperplasia (BPH) is an increasingly prevalent pathology in adult men. We investigated the mechanism of suppressor of cytokine signaling 6 (SOCS6)/signal transducer and activator of transcription (STAT) 6 pathway regulating the proliferation of prostate epithelial cells under inflammation. In vitro cultured prostate epithelial cells (RWPE-1) were treated with 1 µg/mL lipopolysaccharide for 48 h to simulate an in vitro inflammatory environment and then treated with OE-SOCS6, si-SOCS6, si-STAT6 and their negative control, and a STAT6 inhibitor (AS1517499). SOCS6 expression and cell proliferation were assessed by RT-qPCR, Western blot, CCK-8 and EDU assays. The expression of proliferative proteins Ki-67, MCM7 and PCNA, along with cell cycle were determined by Western blot and flow cytometry. SOCS6 suppressed the proliferation of prostate epithelial cells under inflammation, while SOCS6 knockdown caused the opposite result. SOCS6 downregulation increased STAT6 phosphorylation level, stimulated STAT6 signaling pathway, and promoted progression of prostate epithelial cells under inflammation. Meanwhile, STAT6 knockdown decreased the STAT6 phosphorylation level, impeded the cell cycle progression of prostate epithelial cells under inflammation, and attenuated the cell viability, weakened the cell fluorescence intensity, and notably reduced the expression of proliferative proteins, indicating that STAT6 knockdown suppressed the prostate epithelial cell proliferation. Subsequently, STAT6 inactivation partially reversed the regulatory role of SOCS6 in cell cycle and prostate epithelial cell proliferation under inflammation. SOCS6 repressed prostate epithelial cell proliferation under inflammation, and knockdown of SOCS6 facilitated cell cycle progression by activating STAT6 signaling, thereby accelerating prostate epithelial cell proliferation.