Depletion of MTCBP-1 promotes the invasive properties of pancreatic cancer cells. (A and B) Loss of MTCBP-1 increases invasive migration of PDAC cells. BxPC3 cells (A) or Panc-1 cells (B) were transfected with control or siRNA against MTCBP-1 for 2 d and then seeded in a transwell invasion assay for 6 h (BxPC3) or 24 h (Panc-1). The percentage of cells that invaded across the filter was counted by DAPI staining after fixation. The knockdowns were confirmed by Western blot. Graphs represent normalized averages ± SEM from three independent experiments. *, P < 0.05. Bars, 50 µm. (C–E) MTCBP-1 depletion promotes ECM degradation by PDAC cells. DanG cells (C), BxPC3 cells (D), and Panc-1 cells (E) were treated with control or siRNA targeting MTCBP-1 for 2 d and then seeded onto green fluorescent gelatin-coated coverslips. Gelatin degradation was quantified after 8 h (DanG), 6 h (BxPC3), or 24 h (Panc-1). Bars: 20 µm (C); 20 µm (D); 10 µm (E). Reduction of MTCBP-1 results in a 2–19-fold increase in the percentage of cells degrading the gelatin substrate in BxPC3 and Panc-1 cells (≥100 cells per condition) and a 3–5 fold increase in the area degraded per cell in BxPC3, DanG, and Panc-1 cells (≥10 cells per condition). The results represent the mean ± SEM of three independent experiments. *, P < 0.05; **P < 0.005; ***, P < 0.0005. The knockdown efficiency was confirmed by Western blot. All blot measurements in kD.