Fig. 4

HuR positively regulates BCAT1 expression by stabilizing BCAT1 mRNA in CRPC cells. A The expression of BCAT1 in CRPC tissues compared with LPC tissues in the GSE74367 database. B The correlation between the expression levels of HuR and BCAT1 in the TCGA database was analysed with Spearman correlation (T3bN0, n = 26). C Representative immunostaining (scale bar: 50 μm) of BCAT1 in human HSPC tissues and CRPC tissues. The dashed square outlines the higher magnification image. The right panel shows the percentages of BCAT1-positive areas (brown) in each type of tissue (n = 5). D Representative western blots showing BCAT1 expression in the different cell lines. The lower show the expression intensity normalized to that of β-tubulin. E Representative western blots showing BCAT1 and HuR expression in HuR KO clones of PC3 and DU145 cells. The lower show the expression intensity normalized to that of β-tubulin. F Representative images (scale bar: 50 μm) of BCAT1 expression in tumour xenografts generated from sgControl or HuR KO PC3 cells. The dashed square outlines the higher magnification image. The right panel shows the percentages of BCAT1-positive areas (brown) in each group of xenografts (n = 5). G Treatment with 5 μg/mL actinomycin D reduced the half-life of BCAT1 mRNA in HuR KO clones of PC3 and DU145 cells. H RIP qRT-PCR analysis showed that the binding of HuR to BCAT1 mRNA was affected by HuR knockout in PC3 and DU145 cells. Isotype IgG was used as a negative control for the HuR antibody. p values are shown for each comparison (^**p < 0.01, ^#p < 0.05, ^##p < 0.01)