PRMT2 regulates the response of breast cancer cells to tamoxifen (TAM). (A) Knockdown of PRMT2 reduces TAM sensitivity in MCF-7 cells. MCF-7-NC and MCF-7-shPRMT2 cells were treated with or without 7.5 µM TAM for 36 h, and then cells were collected, washed, fixed and stained with Annexin V-PE/7-AAD to detect the cell death with flow cytometry. (B) PRMT2 overexpression reverses TAM resistance in MDA-MB-231 cells. MDA-MB-231-NC and MDA-MB-231-PRMT2 cells were treated with or without 7.5 µM TAM for 36 h, and then cells were collected, washed, fixed and stained with Annexin V-FITC/PI to detect the cell death with flow cytometry. Upper panel, representative graphs of 3 independent experiments; lower panel, statistical charts. Columns, mean; error bars, SD. Student's t-test; *P<0.05, **P<0.01, ***P<0.0001. (C) PRMT2 overexpression induces G1 arrest in MDA-MB-231 cells. MDA-MB-231-NC and MDA-MB-231-PRMT2 cells were treated with or without 5 µM TAM for 36 h; and then cells were collected, washed, stained with propidium iodide (PI) and analyzed using flow cytometry. PRMT2, protein arginine N-methyltransferase 2.