Modulation of DDR1 levels in bladder cancer cells. (A, B) A human bladder cancer cell line, RT4, was transfected with either a DDR1 overexpressing plasmid (DDR1), or a small short hairpin interfering RNA for DDR1 (shDDR1). The RT4 cells were transfected with a scrambled sequence as a control (scr). The levels of DDR1 were determined by RT-qPCR (A), and by Western blot (B). *P<0.05. N=5.