Figure 10: ShRNA silencing of CD24 restores tumour-suppressor activity of cancer-associated p53 mutants.

(a) DU145 cells whose endogenous TP53 was silenced were transduced with cDNAs of cancer-associated p53 mutants used in Fig. 8e,f and then cultured in six-well plates in the presence of neomycin for 2 weeks before the colonies were photographed and counted. Representative image of each transfectant is shown. (b) ShRNA silencing of CD24 reactivates the tumour-suppressor activity of p53^R273H as assessed by the number of DU145 colonies visualized by crystal violet. Data shown are means and s.d. of triplicate samples and have been normalized against the vector control (artificially defined as 100%) from DU145 cells transduced with either Scr or CD24 ShRNA. The data have been reproduced twice. (c) In silico analysis revealed an association between CD24 levels and TP53 status. The expression and mutational status data were obtained from the TCGA database as detailed in the Methods section. Glioblastoma, low-grade brain glioma and prostate cancer samples were divided into CD24^hi (above the mean) and CD24^lo (below the mean) groups based on RNA-seq data. The frequencies of the samples with somatic Tp53 mutations were compared using either Pearson’s χ² tests with correction for low counts of mutant samples in the prostate cancer cohort. CFU, colony-forming unit.