Figure 1

STAT3 activation is required for SW 480 colon carcinoma cell survival. A: Western blotting of STAT3 in cells not transfected with siRNA (lane 1) or transfected with either STAT3 siRNA (lane 2) or control siRNA (lane 3). B: Detection by cytometry of annexin V and propidium iodide (PI)-positive cells in the absence of transfection (NT), or after transfection with STAT3 siRNA (siRNA) or control siRNA (ctRNA). A typical experiment is shown. C: Western blotting of phospho-STAT3 and STAT3 in cytoplasmic (C) and nuclear (N) fractions of non-treated SW 480 cells. OCT-1 was used as nuclear marker control. D: Pull-down with biotinylated STAT3-decoy ODN using cytoplasmic (lanes 1 and 3) and nuclear (lanes 2 and 4) extracts from untreated (lanes 1 and 2) or IL-6-treated (50 ng/ml, 1 h) cells (lanes 3 and 4). E: Western blotting of phospho-STAT3 and STAT3 in cytoplasmic (C) and nuclear (N) fractions of non-treated SW 480 cells (1, 2) or Stattic-treated cells (20 μM). OCT-1 was used as nuclear marker control. F: Measurement of cell death using trypan blue-staining and counting with a V-cell automatic apparatus. Cells were either not treated or treated with Stattic (20 μM, 48 h).