Fig. 6

USP7 is positively correlated with PLK1, and contributes to taxane resistance. a Expression levels and localizations of USP7 protein were detected by IHC in breast cancer tissues. b Summary of USP7 IHC positive signal and MP (Miller-Payne) score in primary breast tumor sections. USP7 expression levels were negatively correlated with MP score by statistical analysis using the Mann-Whitney test. c Paclitaxel-resistant CNE2-TR or docetaxel-resistant DU145-DR cells were generated, and USP7 and PLK1 proteins were assessed by western blot. d and e PLK1 or USP7 were depleted with siRNA in CNE2-TR and DU145-DR cells, and the cells were treated with DMSO, paclitaxel (100 ng/mL) or docetaxel (40 nM) for 48 h. The same number of cells were seeded for colony formation. Relative numbers of cell colonies were quantified. f USP7 was depleted with siRNA in CNE2-TR or DU145-DR cells, and cells were treated with paclitaxel or docetaxel for 24 h. The cells were stained with Annex-V/PI, and apoptotic cells were detected by flow cytometry. g CNE2-TR or DU145-DR cells were treated with or without P5091 (2 μM) together with paclitaxel or docetaxel at the doses shown for 24 h. Cell viability was tested by MTS assay. h CNE2-TR or DU145-DR cells were treated with or without P5091 (2 μM) together with paclitaxel or docetaxel at the doses shown for 24 h. The cells were stained with Annex-V/PI, and apoptotic cells were detected by flow cytometry