Fig. 1.

HER2+ breast cancer cells are susceptible to CDK7 inhibition independent of hormone receptor status. a Dose-response curve of breast cancer cell viability after treatment with increasing concentrations of THZ1 for 72 h. Percent viability relative to that of DMSO-treated cells is shown. Data represent mean ± SD of replicates from two or three independent experiments. Red, ER/PR+; black, HER2+ and ER/PR+; blue, TNBC. b Crystal violet staining of cells and quantification of cell growth. Data represent mean ± SEM of three replicates. ***p < 0.001; ns, not significant (one-way ANOVA). c Cell cycle analysis of cells treated with vehicle control (DMSO) or THZ1 (100 nM) for 24 h. d Flow cytometric analysis of annexin V-positive cells. Each cell line was treated with THZ1 (100 nM) for 24 h and stained with FITC-conjugated annexin V. Data represent mean ± SEM from three independent experiments, *p < 0.05; ns, not significant (one-way ANOVA)