Fig. 5

Co-culture with THP-1 macrophages induces OPG secretion in breast cancer cells. a Diagram of the transwell co-culture experiment set-up. Breast cancer cells were co-cultured with THP-1 macrophages in the presence and absence of Interleukin-1 receptor antagonist (IL-1RA, 400 ng/mL). b After 8 h of co-culture, relative OPG mRNA was measured by qRT-PCR, (n ≥ 3). c Breast cancer cells were subsequently cultured alone in fresh media for an additional 16 h and OPG secreted protein was measured from this supernatant by ELISA, (n ≥ 3). OPG mRNA and secreted protein levels reveal that the co-culture mediated induction of OPG expression in breast cancer cells were partially repressed by IL-1RA. d Representative image for d CD68 immunohistochemistry and e OPG immunohistochemistry on primary/malignant tumor sections on a human breast cancer tissue microarray. Images are taken at 400× magnification. Data are represented by mean ± SD. Asterisks indicate statistical significance (p < 0.05)