CS-6 inhibited NF-κB and p300 translocation and their binging to COX-2 promoter. (A-C) Human A549 cells were treated with CS-6 at the indicated doses. (A) At 12 h after treatment, the subcellular localization of p50, p65, and p300 and the colocalization of p65 with p50 or p300 were examined by confocal microscopy analysis with a confocal microscope. More than 100 cells were inspected per experiment, and cells with typical morphology were presented. (B) At 12 and 48 h after treatment, the binding of p300, p65 and p50 to COX-2 promoter probe was analyzed by a streptavidin-agarose pulldown assay. (C) At 48 h after treatment, chromatin in the treated cells was immunoprecipitated with antibodies to p50, p65, and p300, and the COX-2 promoter region in the precipitated chromatin was amplified by PCR.