Fig. 4

OSM-induced LOXL2 is glycosylated, enzymatically active, and secreted from breast cancer cells. a MCF7 and b MDA-MB-468 cells were treated with OSM for 24 h to induce the expression of LOXL2. PNGase F, an N-linked glycosylase, is then added to cleave N-linked glycosylation sites. The immunoblot results confirm LOXL2 glycosylation as the LOXL2 protein band size goes from ~ 105 to ~ 87 kDa with PNGase F treatment. c Lysyl oxidase activity assay performed on MCF7 cell conditioned media (CM) is analyzed by using an Amplex red-based fluorometric assay. Immunoblot analysis is utilized to confirm siLOXL2 knockdown of LOXL2 expression. Results show that 24-h OSM treatment led to significantly increased lysyl oxidase activity, this is repressed with exposure to siLOXL2. d ELISA is used to quantify LOXL2 protein secreted into CM from MCF7 cells after 36 h with OSM treatment. The results confirm that OSM signaling induces the expression, and promotes the secretion, of LOXL2 protein. (All experiments n = 3+; *p < 0.05, **p < 0.01, ***p < 0.001; Students t test)