Fig. 4

Knockdown STAT3 induced apoptosis in ECA109 cells. A Induction of DNA fragmentation in ECA109 cells transfected with pSi-STAT3 and pSi-Scramble. Extracted the DNA of ECA109 cells in the pSi-STAT3, pSi-Scramble and untreated groups, then analyzed with gel electrophoresis. DNA markers and sizes in base pair (bp) are indicated. B Detection of apoptosis in pSi-STAT3 transfected ECA109 cells was performed by TUNEL assay. The TUNEL-positive cells are indicted by a red fluorescence signal and the nuclei of normal cells are stained with DAPI in blue (original magnification, ×200). C Quantification of STAT3 knockdown induced apoptosis of ECA109 cells by flow cytometry. (a) ECA109 cells were transfected with pSi-Scramble or pSi-STAT3, respectively, and apoptosis rates were evaluated by flow cytometry using annexin-V and PI staining 24 and 48 h after transfection. (b) The percentage of apoptotic cells was presented as the mean ± SE.*P < 0.05, pSi-STAT3 group vs. pSi-Scramble group