INPP4B specifically suppresses PC-3 invasion in vitro . (A) PC-3 Tet-On clones were cultured for 2 days ± 0.5 μg/ml Dox in full growth medium, followed by 24 hours without Dox as described in the methods section. Cells were seeded at 1.5×104 cells per well of an E-Plate 16 and cellular impedance (CI) as a measure of proliferation was monitored continuously for 24 hours. (B) Cells were cultured as indicated in (A), and proliferation was compared using MTT assay. The data are presented as percentage of control (means ± SEM) from three independent experiments. Invasion: (C-E) Cells were cultured as described in (A) and 5×104 cells were seeded onto Matrigel-coated CIM 16 plates and full serum was used as the chemoattractant. Cellular impedance (CI) as a measure of invasion, was monitored continuously for 24 hours for clone #14 (C), clone #4 (D) and negative control (E). Migration: (F-H) Cells were cultured as described in (A) and 5×104 cells seeded onto CIM 16 plates without Matrigel. CI, as a measure of migration was monitored continuously for 24 hours for clone #14 (F), clone #4 (G) and negative control (H). Blue lines denote untreated cells and red lines denote doxycycline-treated cells.