Fig. 2

NEDD8 upregulation predicts a poor response to radiotherapy in oral cancer. A and B Dot plots for the correlation of NEDD8 mRNA levels with time to new tumor events (A) and overall survival time (B) in the radiation-treated patients derived from the TCGA HNSCC database and GSE42743 dataset, respectively. The Pearson correlation test was used to analyze the statistical significance. C The mRNA levels by RT‒PCR/Q-PCR and protein levels determined by Western blotting for NEDD8 detected in a panel of oral cancer cell lines HSC-2, HSC-3, HSC-4 and SAS. D Representative crystal violet staining for the colony formation of HSC-2, HSC-3, HSC-4 and SAS cells treated with the indicated irradiation dosages at the end of experiments (upper). The differences in colony formation post exposure to 4 Gy irradiation in the detected OSCC cells are shown in the histogram (lower). In C and D, the error bars denote the data from three independent experiments presented as the mean ± SEM, and the different letters indicate the statistical significance at p < 0.001 estimated by one-way ANOVA using Tukey’s post hoc tests