Figure 3.

The role of Discoidin Domain Receptor 1 (DDR1) as a collagen type 1 (COL1) receptor in MCF-7 (a) and MDA-MB-231 (b) (scrambled, sc) cells upon integrin β₁-knockdown (kd) for the induction of COL1-mediated signaling via ERK1/2 (c,d). DDR1 is significantly increased in MDA-MB-231kd cells. Western blot data also indicate that DDR1 is activated by COL1 in both cell lines and DDR1 inhibition by 7rh attenuates pDDR1 and pERK1/2 in MCF-7kd cells. In contrast, DDR1-inhibition by 7rh increased pERK1/2 in MDA-MB-231 cells. GAPDH was used as loading control. Data represent means ± SEM of at least n = 3 biological samples, statistical analysis was performed using unpaired t-test (* p < 0.05; ** p < 0.01).