Fig. 3: Effects of bicyclic aminopyridinol compounds on CTSS activity, invasion, and viability of MDA-MB-231 cells.

a Chemical structure of three bicyclic aminopyridinol compounds, BJ-2302, BJ-2303, and BJ-2304. b, c Inhibitory effects of the three compounds on CTSS and CTSB activity. *P < 0.05 compared to vehicle-treated controls. d MDA-MB-231 cells were pretreated with the compounds, and a serum-induced invasion assay was performed. The photos are representative of three independent experiments, and the bar-diagram represents the mean ± S.E.M. *P < 0.05 compared to vehicle-treated cells. #P < 0.05 compared to serum-treated cells. e Measurement of the IC50 of serum-induced invasion of MDA-MB-231 cells treated with Z-FL-COCHO, batimastat, or BJ-2302. *P < 0.05 compared to serum-treated cells. f, g Effect of BJ-2302 or Z-FL-COCHO on the cell viability of MDA-MB-231 breast cancer cells (f) and MCF-10A normal breast cells (g). *P < 0.05 compared to vehicle-treated cells