Fig.3. P2Y₂R-mediated LOX release induced collagen crosslinking.

CTRL siRNA-transfected MDA-MB-231 cells (A) or P2Y₂R siRNA-transfected MDA-MB-231 cells (B) were pretreated with βAPN (300 μM), a LOX inhibitor, for 1 h and then stimulated with ATP (10 μM) or UTP (10 μM) for 8 h. CM from the cells were concentrated 20-fold, and 100 μl of CM was mixed with collagen type I solution (4 mg/ml, 100 μl) as described in the Methods. After a 16-h incubation in a 37°C cell culture incubator, the amount of crosslinked collagen was determined using a fluorescence microscope. Data represent mean values ± SEM of three independent experiments in triplicate (compared with the control, **P < 0.01; compared with ATP or UTP treatment, ^††P < 0.01).