Additional File 2 A B C 200 150 - + - + Dox MMP9 MMP2 % MMP2 Level #14 % MMP9 Level Neg 150 100 100 50 0 0 Neg D Neg #14 Neg #14 F #14 - + Dox 150 kDa 90 kDa G 120 100 #14 60 40 20 120 100 80 60 40 20 0 Neg % uPA Activity Neg 80 0 H 120 100 80 60 40 20 0 % 90 kDa Level + % 150 kDa level - % Cath. B Activity #14 E Neg 50 #14 120 100 80 60 40 20 0 Neg WT14 #14 Additional Figure 2. INPP4B expression does not suppress basal levels of secreted and cellular proteases. (A-C) PC-3 Tet-On clone #14 and negative for INPP4B clone were cultured for 2 days 0.5 µg/ml doxycycline in serum-containing media, followed by incubation for 24 hours without doxycycline in serum-free media as described in Materials and Methods. Conditioned media were collected, concentrated by centrifugation, and analyzed by gelatin zymography (A). Enzyme levels were determined by gelatin digestion in 0.1% gelatin 10% PAGE. Levels of MMP-9 (B) and MMP-2 (C) expression were quantified by densitometry of corresponding bands and normalized to no-doxycycline control for each clone. Bars are means ± SEM determined from 3 independent experiments. (D) Cells were cultured as described in (A) and casein zymography was performed for analysis of caseincleaving proteases. Expression levels of the ~150-kDa band (E) and ~90-kDa band (F) were quantified by densitometry analysis of the corresponding bands and normalized to nodoxycycline control for each clone. (G) Cathepsin B activity was assayed as described in Materials and Methods, from 10 µg of cell lysate prepared from cells cultured as described in (A). Data from 6 independent experiments were averaged and normalized to untreated cells for each clone (100%). (H) uPA activity was assayed from concentrated media harvested from cells cultured as described in (A) and Materials and Methods. Data from 4 independent experiments were averaged and normalized to untreated cells for each clone (100%). For all graphs, open bars denote untreated cells and closed bars denote doxycycline treated cells.