Fig. 1.

Expression of APP and its proteolytic product in breast cancer cell lines. (A) Immunoblot analysis using an antibody against APP N-terminal (clone 22C11) showing differential expression of APP on breast cancer cell lines BT-549, MDA-MB231, MCF7, MDA-MB468, SK-BR-3 and ZR-75-1. α-tubulin was used as a control. Densitometric analysis of APP expression from triplicate experiments was shown at the lower panel. (mean ± SD; n = 3). (B) Conditioned medium from cell line culture was examined using antibodies specific for sAPPα and sAPPβ, in addition to clone 22C11. Secretion of sAPPα, but not sAPPβ into cell culture supernatant can be detected. All experiments were performed at least three times.