Fig. 6: PADI4-mediated HIF-1αR698 citrullination promotes HCC tumorigenesis.
From: Citrullination modulation stabilizes HIF-1α to promote tumour progression
a, b The cell lines described in Fig. 3g were injected subcutaneously into male BALB/c nude mice (n = 6 per group). Tumour volume was measured starting on Day 10 and determined based on calliper measurements every 3 days (a). Photographs show xenografts at the end of the experiment (Day 25) (b). c Representative results of the IHC analysis of HIF-1α, HIF-1αR698Cit and PADI4 in normal liver tissues (Non-tumour, n = 40) and HCC specimens (Tumour, n = 41) with low or high HIF-1α expression. Scale bars, 50 μm. d Statistical analysis of the IHC results shown in Fig. 6c. HIF-1α, HIF-1αR698Cit and PADI4 protein levels in high HIF-1α expression samples were quantified using HALO software (Non-tumour, n = 27; Tumour, n = 28). e HIF-1αR698Cit protein levels are positively correlated with PADI4 protein levels in clinical HCC lesions (n = 41). Pearson correlation analyses were performed. f Representative multiplex IHC (mIHC) image of HIF-1αR698Cit and PADI4 in HCC samples. Scale bars, 50 µm (upper panel), 20 µm (left layer panel) and 10 µm (right layer panel). The intensity profiles of each line were quantified with ImageJ software and drawn with GraphPad Prism 7.0. Experiments were performed in four HCC tumour specimens. The results are shown as the means of the colocalization coefficient of HIF-1αR698Cit and PADI4. Error bars denote the mean ± SEM (a) and mean ± SD (d). Statistical analyses were performed by ordinary two-way ANOVA with Turkey’s multiple comparisons test (a), two-tailed paired Student’s t-test (d), or Pearson correlation analyses (e). Source data are provided as a Source Data file.
