FIGURE 5.

Smad7 sensitizes MCF7 cells into TRAIL-mediated apoptosis. A, representative images of mock or TRAIL-treated cells. MCF7 control or Smad7-overexpressing cells were treated with 100 ng/ml TRAIL for 24 h. B, cell viability was measured using the MTT assay. After treatment with TRAIL at indicated doses for 24 h, cells were incubated with MTT for 4 h and solubilized overnight. The intensity of color was measured with an ELISA reader and displayed as percentage of nontreated cells. C, MCF7 cells were treated with 100 ng/ml TRAIL for 24 h and harvested as described under “Experimental Procedures.” The isolated genomic DNA was separated by agarose gel electrophoresis, and the fragmented DNA was shown by staining with EtBr. D, PARP and cleaved PARP were detected by Western blotting after treatment with TRAIL. The expression of Smad7 was confirmed with anti-FLAG antibody.