RNAi-mediated STAT3 knockdown in ABC-DLBCL cells also triggered cell-cycle arrest and apoptosis. (A) STAT3 siRNA (STAT3i, +) and control (−) oligos were transiently transfected into Ly3 and Ly10 cells. At the indicated time points after transfection, total STAT3 and PY-STAT3 expression was examined by Western blot analysis. (B) Proliferation of STAT3i-transfected Ly3 and Ly10 cells was measured by 3H-thymdine incorporation assays. The amount of radioactivity recovered from STAT3i-transfected cells was normalized to that from the control cells defined as 100%. Represented in the graph are the mean plus or minus standard derivation of 3 independent STAT3 siRNA experiments. (C) Western blot showing increased PARP cleavage (▷) and, thus, activation of caspase 3/7 in STAT3i-transfected cells. (D) Western blot analysis demonstrating alterations in selected cell cycle and survival regulators following STAT3 knockdown. Vertical lines have been inserted to indicate a repositioned gel lane.
