Fig. 5: Pharmacological USP2 inhibition sensitizes ErbB2-positive breast cancer cells to HSP90 inhibition.

a Colony formation assays carried out with SKBR3 and HCC1954 cells under the treatment of vehicle, ML364 (10 μM), 17-AAG (100 nM), and the combination of ML364 (10 μM) and 17-AAG (100 nM). b Quantification data from a showing the relative amounts of colonies formed in each group. c SKBR3 and HCC1954 cells were treated as in a for 24 h and then processed for cell cycle analysis. Representative histograms are shown to illustrate cell cycle distributions. Column charts on the right demonstrate quantification data of cells within each stage as indicated. d AU565 and AU565-USP2del cells were treated with 80 nM of 17-AAG for indicated times. Cell lysates were subjected to immunoblotting analysis using indicated antibodies. Degradation curves show the relative quantification of ErbB2 levels at corresponding time points. e Colony formation assays performed using AU565, AU565-USP2del, and AU565-USP2del-CCND1 cells. Column chart shows the relative amounts of colonies formed in each cell line. f AU565 and AU565-USP2del-CCND1 cells were treated with 100 μg/ml of cycloheximide for indicated times and lysed. Samples were analyzed by immunoblotting using indicated antibodies. Actin was probed to confirm equal loading. The turnover curve on the right shows the quantification of relative ErbB2 abundance from immunoblotting assays. Error bars represent standard error of the mean (n = 3), with *p < 0.05 and **p < 0.01.