For protein expression assay, BEAS-2B and BEAS-2B-catalase-stably expressing (Cat stable) cells (1 × 106) were treated with or without Cr(VI) for 3 weeks. Cytosolic and nuclear proteins were extracted and separated on 10% SDS-polyacrylamide gel to determine E-cadherin (E-cad) and vimentin expression (A). Blots are representative of three separate experiments with similar results, arrows indicate specific band. For invasion assay (B-D), BEAS-2B and BEAS-2B-catalase-stably expressing (Cat stable) cells were treated with or without Cr(VI) 0.5 μM for 6 weeks and seeded in matrigel chamber as described in Fig 4. For colony formation assay, BEAS-2B and BEAS-2B-catalase-stably expressing (Cat stable) cells (2.5 × 103) (E-G) treated with or without Cr(VI) for 8 weeks, and plated in 0.35% soft agar in duplicate in 10% FBS DMEM media for additional 4-12 weeks to allow colony formation. Colony numbers from 12 weeks group was determined in each well and compared with controls (F). Data are mean±SEM from three separate experiments, *P<0.01 when compared with controls.