Knockdown of STAT3 significantly promotes apoptosis and suppresses cell migration and STAT3 downstream target genes in T24 cells. (A) The effects of knockdown of STAT3 on migration in T24 were analyzed using wound healing assays with a 24 h recovery period. (B) Apoptosis was determined by fluorescence-activated cell sorting. Cells in early apoptosis are in the bottom right quadrant, while cells in late apoptosis are in the top right quadrant. (C) Western blot analysis was used to detect the expression of STAT3 downstream target proteins. All data are presented as the mean ± standard deviation of the mean. *P<0.05 and **P<0.01. shRNA, short hairpin RNA; STAT3, signal transducer and activator of transcription; PI, propidium iodide; FITC, fluorescein isothiocyanate; VEGFR, vascular endothelial growth factor receptor; Bcl-2, B-cell lymphoma 2; Bcl-xl, B-cell lymphoma-extra large; Mcl-1, MCL1, Bcl2 family apoptosis regulator; cMyc, MYC proto-oncogene, BHLH transcription factor.