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Fig. 6 | Journal of Experimental & Clinical Cancer Research

Fig. 6

From: Targeting selenoprotein H in the nucleolus suppresses tumors and metastases by Isovalerylspiramycin I

Fig. 6

ISP I induces a nucleolar stress response. A Immunofluorescence staining assay shows a loss of SELH and nucleolar labelling of Fibrillarin, NPM1 and POLI, in ISP I-treated cells. LN229 cells were treated with ISP I at 10 μM for 8 h. B Western blots show NPM1 and p53 expression in LN229 cells treated with ISP I for 24 h. GAPDH expression was used as an internal control. C and D Transcriptomic profiling reveals that ISP I activates p53 pathway. C Heatmap of statistically significant differential gene expression as determined by RNA-seq between saline-treated and ISP I-treated cells. LN229 cells were treated with ISP I at 10 μM or saline for 6 h. N = 4. P < 0.05. D GSEA demonstrates that ISP I-treated cells are highly enriched in genes associated with p53 activation. NES = 1.71. P < 0.001. E Real-time RT-PCR analysis shows pre-rRNA transcription in LN229 cells treated with ISP I for 8 h. GAPDH expression was used as an internal control. F Western blots show phosphorylated JNK2, POLI, and TIF-IA expression in LN229 cells treated with ISP I for 24 h. GAPDH expression was used as an internal control. G Immunoprecipitation by anti-TIF-IA antibody showing POLI interacts with TIF-IA in LN229 cells. The POLI and TIF-IA interaction is interrupted in ISP I-treated (10 μM, 24 h) and SELH-deficient LN229 cells. H Quantitative CHIP evaluations showing that ISP I treatment (10 μM, 24 h) or deficiency of SELH reduces the occupancy of POLI on the promoter and the coding region (5’ETS, 5.8S and 28S) of rDNA. All data are shown as mean ± SEM. P value: *p < 0.05; **p < 0.01; ***p < 0.001

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