AR regulation of amphiregulin mediates baseline proliferation and migration of TNBC. A, quantitative real-time PCR (qRT-PCR) for amphiregulin (AREG) in SUM159PT cells and HCC1806 cells treated with enzalutamide (ENZ) in full serum. B, ELISA for extracellular AREG in SUM159PT and HCC1806 cell lines treated with vehicle (Veh) or dihydrotestosterone (DHT) for 48 and 72 hours, respectively. C, Western blotting of HCC1806 shNEG and shAR15 cells treated for 30 minutes with exogenous human recombinant AREG. D, proliferation assay of HCC1806 shNEG and shAR15 cells in the absence or presence of exogenous AREG. E, migration (left) and proliferation (right) assays of HCC1806 cells treated with or without exogenous AREG in identical, serum-starved conditions. F, AREG protein expression by IHC in SUM159PT xenografts. P = 0.04 using a 1-tailed t test. Photomicrographs depict representative AREG staining (400×). *, P < 0.05; ***, P < 0.001 by the t test.