Figure 3

MIF secretion from breast cancer cells is upregulated by exogenous MIF. (a) Comparison of MIF secretion levels in unstimulated non-invasive MDA-MB-468, invasive MDA-MB-231 tumour cells, and MCF-12A control cells. Supernatants of 100,000 cells were subjected to human MIF ELISA at the indicated time intervals. Of note, MDA-MB-468 cells secreted MIF levels of up to 35 ng/ml. Asterisks indicate statistical significance compared to MCF-12A. (b) Exogenous rMIF dramatically upregulates the secretion of MIF from breast cancer cells. As in (a), but stimulation of cells with 150 ng/ml rMIF for the indicated time periods. Asterisks indicate statistical significance compared to MCF-12A. (c) Invasive MDA-MB-231 breast cancer cells exhibit the highest relative increase in MIF secretion. Relative increase of MIF secretion calculated from (b). To account for the addition of the 150 ng/ml exogenously added rMIF, this value was subtracted for all incubations. Data represent means ± SD of three determinations and two (b) or three (a and c) independent experiments.