Supplementary Figure 3: Additional data for Fig. 3.

(a) Levels of selected proteasome subunits are lowered on TP53 expression silencing in the 5 TNBC cell lines. Below—a bar graphs demonstrating protein levels of proteasome subunits measured by densitometry in 5 TNBC cell lines with mutant p53 (averages of two western-blots per each result are used; two alternative siRNAs—TP53 siRNA I and II; normalized control silencing level shown as the dashed line); (b) Overexpressed mutant p53 variants rescue proteasome genes transcription in the stably silenced endogenous mutant TP53 background of MDA-MB-231 cells. Lower panel: western blot demonstrating stable silencing of mutant TP53 and expression of the mutant p53 variants (representative of 2 repeats); (c) trypsin-like proteasome activity is decreased in mutant p53 TNBC cell lines versus WT p53 cell lines (MCF10A and MCF7) on silencing of mutant TP53 or PSMA2 or proteasome inhibitor treatment (24 h; Carfilzomib, Bortezomib).; (d) IHC staining of p53 (brown) in representative samples from Fig. 3b with indicated numbers corresponding to the Supplementary Table 15; Scale bars are 100 μM; (e) trypsin-like proteasome activity in MCF10A cell lines treated with 20 μM Nutlin for 24 h, stably transfected with vector encoding shRNA targeting TP53 and indicated mutant p53 cds shRNA-resistant HA-tagged variants (+p53 changed residue); (f) Transcript levels of proteasome subunits in MCF10A cell lines treated with 20 μM Nutlin for 24 h, stably transfected with vector encoding shRNA targeting TP53 and indicated mutant p53 cds shRNA-resistant HA-tagged variants (+p53 changed residue); (g) Basal chymotrypsin-like and trypsin-like proteasome activities are elevated in the TNBC cell lines (mutant p53), as compared to the MCF10A cell line (WT p53).; (h) Transcript levels of proteasome subunits are decreased in the indicated non-breast cancer cell lines on mutant TP53 expression silencing. Control level is marked with the dashed line. (b, c, e–h) Means of n = 3 biologically independent samples with s.d. are shown, ANOVA test with Bonferroni correction: *P < 0.05, **P < 0.01, ***P < 0.001; Unprocessed original scans of blots are shown in Supplementary Fig. 9. Statistics source data for (a–c, e–h) provided in Supplementary Table 10.