Reducing C/EBPδ expression increases HC11 cell migration and invasion. (A) HC11 nontransfected cells, HC11 stably transfected vector (pSilencer ™ 2.1 neo) control ("vector") cells and HC11 C/EBPδ siRNA treated cells were grown to confluence in CGM. A 200 μl pipet tip was used to produce an open area or "scratch" in the confluent monolayers and migration into the open area assessed at 0 h, 24 h and 48 h by crystal violet staining. (B) HC11 cell lines were grown to confluence in CGM and then switched to growth arrest media (GAM, 0.1% FBS) for 24 hours prior to the creation of the open area in the cell monolayers. Migration into the open area in the GAM cultured cells was assessed as described in "A" above. (C) HC11 vector control and C/EBPδ siRNA treated cells (1 × 106) were suspended in serum-free media and cultured on the inner (top) chamber of the insert; serum containing media was placed in the outer (lower) chamber of the insert (Chemicon Cell Invasion Assay Kit). Plates were incubated for up to 6 days at 37°C. Migration of cells to the lower surface of the membrane was assessed by staining with crystal violet and photographed. Results presented are representative of 3 independent experiments with duplicates.