Extended Data Fig. 8: ER/PR/HER2 negatively regulate USP15 and PARP1 expression.
(a, b) Comparison of the changes in the PARP1 (a) and USP15 (b) protein levels in tumor tissues and the corresponding adjacent normal mammary tissues between the TNBC and non-TNBC groups. The analysis was based on Fig. 3. n = 16 for non-TNBC and n = 18 for TNBC. (c) Analysis of USP15 and PARP1 level in TNBC cell lines and non-TNBC cell lines. (d) Analysis of BER efficiency in TNBC cell lines and non-TNBC cell lines. n = 3 independent biological samples. (e, f) Comparison of the changes in the PARP1 expression and BER efficiency between cells of TNBC group and non-TNBC group, n = 4 cell lines. (g) Analysis of ER, PR and HER2 protein levels in MDA-MB-231 cells transfected with different groups of vectors. Cells were harvested for Western blot analysis at 24 h post transfection. (h) Analysis of USP15 and PARP1 protein levels in MDA-MB-231 and HCC70 cells overexpressing ER, PR and HER2. (i) Analysis of USP15 and PARP1 protein levels in MDA-MB-231 cells overexpressing ER, PR or HER2. (j) Analysis of PARP1 trapping on chromatin in ER, PR and HER2-overexpressing cells. (k, l) Analysis of xenograft growth in vivo. The HCC70 cells with a control vector or vectors expressing ER, PR and HER2 were engrafted into immunocompromised mice, and mice were treated with DMSO or olaparib. n = 6 mice for the group of pControl+olaparib, and n = 5 mice for other groups. Tumor volumes are shown in (k). Tumor weights at the experimental endpoint are shown in (l). (m) Analysis of USP15 and PARP1 protein levels in MDA-MB-436 cells overexpressing ER, PR and HER2. n = 3 independent biological samples. (n) Analysis of USP15 and PARP1 protein levels in HCC1954, MCF7 and T47D cells overexpressing ER, PR or HER2. Data are expressed as mean ± s.d. (d, m). Data are expressed as mean ± s.e.m. (a-b, e-f, k-l). P values are indicated (a-b, d-f, k-l). Statistical significance was determined by Student’s t test (a-b, d-f), or one-way ANOVA test followed by Tukey’s multiple comparison (l), or two-way ANOVA test followed by Tukey’s multiple comparison (k). Experiments were repeated three times independently with similar results; data of one representative experiment are shown (c-d, g-j, m-n).
