OBJECTIVE: To investigate the expression of RNA binding protein ELAVL1 in prostate cancer (PCa), especially hormone-sensitive prostate cancer (HSPC), and its relationship with tumor proliferation. This study further aims to reveal the molecular mechanism by which ELAVL1 promotes HSPC proliferation by stabilizing SOX4 mRNA in an m6A-dependent manner. METHODS: The expression of ELAVL1 in PCa tissues and its relationship with prognosis were analyzed in the Cancer Genome Atlas (TCGA) database, and the differences in HSPC and hormone-resistant prostate cancer (HRPC) were compared. And its relationship with prognosis were analyzed in the Cancer Genome Atlas (TCGA) database, and the differences in HSPC and hormone-resistant prostate cancer (HRPC) were compared. Western blot was used to detect ELAVL1 protein expression in PCa cell lines. After ELAVL1 knockdown by siRNA, cell proliferation was evaluated using CCK-8 assays, and changes in downstream target genes were detected by RT-qPCR. Tumor xenograft experiments in nude mice were performed to further assess the impact of ELAVL1 on tumor growth. The interaction between ELAVL1 and SOX4 mRNA was verified by RIP-seq. And the mRNA and protein levels of SOX4 after knockdown of ELAVL1 were detected by RT-qPCR and Western blot, respectively. CCK-8 was used to evaluate the effect of SOX4 knockdown on cell proliferation. MeRIP-qPCR was used to detect the m6A modification level of SOX4 and the effect of knocking down METTL3. RNA pull-down experiments verified the interaction between SOX4 RNA fragments and ELAVL1 protein. RNA stability experiments evaluated the effect of ELAVL1 knockdown on SOX4 mRNA stability. RESULTS: The expression of ELAVL1 in PCa cells was higher than that in normal prostate epithelial cells. The prognosis of patients with high expression of ELAVL1 was significantly worse than that of patients with low expression. In the GSE32269 dataset, the expression level of ELAVL1 in HSPC was significantly higher than that in HRPC. After knocking down of ELAVL1 in LNCaP and VCaP cells, CCK-8 experiments showed that the cell proliferation ability was significantly affected after knocking down ELAVL1, and overexpressed ELAVL1 promoted the proliferation of HSPC cells. The results of in vivo studies showed that knockdown of ELAVL1 significantly inhibited the tumorigenic capacity of LNCaP cells and resulted in a marked reduction in xenograft tumor mass. The levels of SOX4 mRNA and protein in LNCaP and VCaP cells were significantly higher than those in normal prostate epithelial cells RWPE-1. RIP-qPCR confirmed the interaction between ELAVL1 protein and SOX4 mRNA. After knocking down of ELAVL1, the expression levels of SOX4 mRNA and protein were significantly decreased. After knocking down of SOX4, the proliferation ability of LNCaP and VCaP cells was significantly inhibited. CONCLUSION ELAVL1 is highly expressed in HSPC. High expression of ELAVL1 is associated with the proliferation of HSPC. SOX4 is a downstream molecule of ELAVL1 which promotes the proliferation of HSPC. ELAVL1 enhances the stability of SOX4 mRNA through an m6A-dependent mechanism.
Male ; Humans ; SOXC Transcription Factors/genetics* ; ELAV-Like Protein 1/metabolism* ; Cell Proliferation ; Prostatic Neoplasms/genetics* ; Animals ; Mice, Nude ; Cell Line, Tumor ; Mice ; Gene Expression Regulation, Neoplastic ; RNA, Messenger/metabolism* ; Prognosis

OBJECTIVE: To investigate whether circular RNA circRSF1 regulates radiation-induced inflammatory phenotype of hepatic stellate cells (HSCs) by binding to HuR protein and repressing its function. METHODS: Human HSC cell line LX2 with HuR overexpression or knockdown was exposed to 8 Gy X-ray irradiation, and the changes in the expression of inflammatory factors (IL-1β, IL-6 and TNF-α) were detected by qRT-PCR. The expressions of IκBα and phosphorylation of NF-κB were detected with Western blotting. The binding of circRSF1 to HuR was verified by RNA pull-down assay and RNA-binding protein immunoprecipitation (RIP). The expressions of inflammatory factors, IκBα and the phosphorylation of NF-κB were detected after modifying the interaction between circRSF1 and HuR. RESULTS: Knockdown of HuR significantly up- regulated the expressions of IL-1β, IL-6 and TNF-α, decreased IκBα expression and promoted NF-κB phosphorylation in irradiated LX2 cells, whereas overexpression of HuR produced the opposite changes (P < 0.05). Overexpression or knockdown of circRSF1 did not significantly affect the expression of HuR. RNA pull-down and RIP experiments confirmed the binding between circRSF1 and HuR. Overexpression of circRSF1 significantly reduced the binding of HuR to IκBα and down-regulated the expression of IκBα (P < 0.05). Overexpression of circRSF1 combined with HuR overexpression partially reversed the up-regulation of the inflammatory factors, down-regulated IκBα expression and increased phosphorylation of NFκB in LX2 cells, while the opposite effects were observed in cells with knockdown of both circRSF1 and HuR (P < 0.05). CONCLUSION circRSF1 reduces IκBα expression by binding to HuR to promote the activation of NF-κB pathway, thereby enhancing radiation- induced inflammatory phenotype of HSCs.
Humans ; Hepatic Stellate Cells/radiation effects* ; Interleukin-6 ; NF-kappa B ; NF-KappaB Inhibitor alpha ; Phenotype ; RNA ; RNA, Circular/metabolism* ; Tumor Necrosis Factor-alpha ; ELAV-Like Protein 1/metabolism*

OBJECTIVE: To investigate the role of miR-519 in regulating the cell activity of gastric cancer. 
 METHODS: The expression of miR-519 was measured by qPCR. The protein expression of HuR was detected by Western blot. MTT assay was used to detect the cell activity of gastric cancer cells.
 RESULTS: The protein level of HuR in the gastric cancer cells was higher than that in the control cells. Over-expression of HuR resulted in the increase in the cell activity of gastric cancer (P<0.001). Suppression of HuR decreased the cell activity of gastric cancer (P=0.001). The miR-519 level in the gastric cancer cells was lower than that in the control cells (P=0.001). Over-expression of miR-519 decreased the protein level of HuR and the activity of gastric cancer cells.
 CONCLUSION MiR-may inhibit the gastric cancer cell activity through suppression of HuR expression.
Cell Line, Tumor ; Cell Proliferation ; ELAV-Like Protein 1 ; genetics ; metabolism ; Gene Expression Regulation, Neoplastic ; Humans ; MicroRNAs ; genetics ; metabolism ; Stomach Neoplasms ; genetics ; metabolism