Tumor-necrosis factor receptor (TNFR)1 and TNFR2 levels in MCF-7
cell lines. (a) Protein levels of TNFR1, TNFR2, and GAPDH in MCF-7CC, MCF-7TXT8, MCF-7TXT9, MCF-7TXT10, and MCF-7TXT12 cells. (b) TNFR1 and S28 transcript levels in MCF-7CC and MCF-7TXT10 cells determined with reverse transcription quantitative PCR (RTqPCR). (c) The mean concentration (± standard error; n = 4) of secreted TNFR1 protein was examined in the cell lines by using an ELISA. (d) The ability of MCF-7CC cells to form colonies in a clonogenic assay at various concentrations of docetaxel in the absence (broken line) or presence (solid line) of 5 μg/ml of a TNFR1 neutralizing antibody (R&D Systems). Error bars represent standard error of the mean. Significance of differences was assessed by using a Student t test; P values of < 0.05, < 0.01, and < 0.001 are represented by *, **, and *** symbols, respectively.