SMAD4 does not significantly affect PDAC cell viability or proliferation, but increase PDAC cell motility in vitro. (A) SMAD4 does not significantly affect growth of PDAC cells in vitro. Cells were seeded (5X103 cells per well) in 96-well plates and cell proliferation rates were determined by MTT assay at indicated time points. (B) SMAD4 does not affect PDAC tumor growth in SCID mice. Xenograft tumors were established using SMAD4 proficient or deficient AsPC-1 and PANC-1 cells implanted by s.c injection (1 × 106 cells) and analyzed after 8 weeks. Tumor weights were measured at autopsy. Mean + SE (n = 6). (C) Wound healing assays indicated that SMAD4 restoration reduces PDAC cells migration in vitro. The closure rates of cell free gap were recorded by phase contrast microscope after overnight incubation. Similar results were reproduced in three independent experiments. (magnification x40). (D) SMAD4 promotes the invasive ability of PDAC cells in vitro. Invaded cells were fixed and stained with crystal violet, and quantitative results were normalized against vector controls. Mean + SEM (n > 3). *p < 0.05.