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Figure 3 | BMC Cell Biology

Figure 3

From: A STAT3-decoy oligonucleotide induces cell death in a human colorectal carcinoma cell line by blocking nuclear transfer of STAT3 and STAT3-bound NF-κB

Figure 3

Inhibition of STAT3 nuclear localization by STAT3-decoy ODN. A: Nuclear localization of STAT3 (red) in non-treated SW 480 cells. Cells were fixed and labelled with anti-STAT3 antibody; B: cytoplasmic localization of STAT3 (red) in STAT3-decoy ODN- transfected (2 μg/ml) SW480 cells; FITC-labeled STAT3-decoy ODN was detected in the cytoplasm (green); C: nuclear localization of STAT3 (red) in mutated STAT3-ODN- transfected (2 μg/ml) SW480 cells; FITC-labeled mutated STAT3-ODN was detected in the cytoplasm (green); D: cytoplasmic localization of STAT3 in Stattic-treated cells (20 μM). Nuclei stained with DAPI. Scale: 10 nm. E: Cells transfected with STAT3-decoy ODN and STAT3 determined in cytoplasm and nucleus: no treatment (1 and 2), STAT3-decoy ODN 2 μg/ml (3 and 4), mutated STAT3-decoy ODN (mtODN) 2 μg/ml (5 and 6). OCT-1 antibody reprobing to check for cytoplasmic contamination. A typical result is shown. F: Cells were untreated (1 and 2), transfected with decoy NF-κB-ODN (2 μg/ml) (3 and 4), and STAT3 subcellular localization determined. G: Quantitative comparison. In control and mutated STAT3-decoy ODN (mtODN)- or decoy NF-κB-ODN-transfected cells, nuclear STAT3 (expressed as % of total STAT3, cytoplasmic + nuclear) was 50%; it was below 20% in STAT3-decoy ODN-transfected cells. Data from at least three independent experiments. A t test was used to calculate p values, n>3. H: Cells transfected with biotinylated STAT3-decoy ODN (1, 2 and 3) or its mutated equivalent (4) and complexes recovered and analyzed as in D; cells co-transfected with competitor: non-biotinylated STAT3-decoy ODN (2) or its mutated equivalent (3).

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