Fig. 3.

SETDB1 knockdown sensitizes therapy resistant cells to endocrine treatment. A SETDB1 expression in MCF7 and tamoxifen-resistant (TamR) or fulvestrant -resistant (FR) cells were examined by Western blotting. B, C Effect of tamoxifen or fulvestrant on the cell viability of MCF7-TamR (B) or MCF7-FR (C) that stably express control-sh and SETDB1-sh was determined using MTT assays. D SETDB1 expression was knocked down in MCF7-TamR and MCF7-FR cells and the status of Akt activation was measured using Western blotting. Cells were serum-starved for 24 h and stimulated with 10% serum for 15 min before being harvested and subjected to western blotting. E Confirmation of SETDB1-KD in MCF7-PELP1cyto cells. F Effect of SETDB1-KD on the colony formation of MCF7-PELP1cyto cells. G Effect of tamoxifen on the viability of PELP1cyto control-sh or SETDB1-sh cells was determined using MTT assays. H MCF7-PELP1cyto cells with/without SETDB1 KD were serum-starved for 24 h, stimulated with serum and total lysates were analyzed for Akt activation using Western blotting. I Cells were treated with indicated dose of Mithramycin A for 3 days, and the status of SETDB1 was determined using Western blotting. J, K Effect of Mithramycin A alone (J) or in combination with tamoxifen (K) on the cell survival was measured using colony formation assays. L, M Effect of Mithramycin A on the cell viability of MCF7-TamR (L) and MCF7-FR (M) cells was determined using MTT assays. Data was represented as mean ± SEM. *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001