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. 2015 Jun 23;6(24):19990–20001. doi: 10.18632/oncotarget.4598

Figure 2. IRE1α expression is regulated by p53.

Figure 2

A. Western blot analysis of the expression of endogenous IRE1α in 23 human cancer cell lines. Cell lines were grouped according to expression of wild-type or mutant p53 as indicated. (A well between wt-p53 and mutant-p53 cell lines was cut, from the gel as indicated by a black line, due to the controversial p53 status of the cell line). Right panel: The intensities of the IRE1α bands (left panel) are expressed relative to those of β-actin. Values shown are the mean ± standard deviation (s.d.). The P value was calculated using two-way ANOVA. B. Downregulation of p53 expression induces increased expression of IRE1α. HCT116 p53+/+ and U2OS cells were transfected with shLuc, shp53 (753), or shp53 (814), and selected using puromycin. Whole cell lysates of a pool of transfectants were analyzed using western blotting with the indicated antibodies. C. Overexpression of wild-type p53 inhibits IRE1α expression in mutant-p53 cell lines. Cell lysates, prepared 48 h after transfection with wild-type p53, were analyzed for the expression of indicated proteins. D. Mutant p53 proteins do not inhibit IRE1α expression. Cell lysates were prepared from cells transfected with p53-G245S, p53-R248W, p53-249S, and p53-R273H expression vectors or from cells that constitutively expressed wild-type p53 and were analyzed for the expression of the indicated proteins.