STAT5 inhibits NF-κB signaling and proliferation in HL cells. (A) Percentage of IkBSR-IRES-ΔNGFR (□) or control ΔNGFR (■) retrovirally transduced CA-STAT5b+ tonsil B cells over time (n = 3). (B) Purity of the nuclear protein fraction of L591 and 2 CD40L-independent CA-STAT5b tonsil B-cell lines was tested by PKC expression. (C) p65 ELISA was performed on the nuclear fractions using equal protein loading. The values obtained from the nuclear lysate from L591 were set as one (n = 2). Negative control is not incubated with protein lysate. (D) L1236 cells were electroporated with control luciferase vector (pBasic) or a luciferase vector with a NF-κB–responsive element in combination with a pSuper vector that knocks down STAT5 using siRNA or an empty control. (n = 3). At 72 hours, firefly luciferase activity was measured, normalized to the cotransfected Renilla luciferase activity. L428 gave similar results. (E) L428 was retrovirally transduced with a GFP-marked vector expressing siRNAs targeting either STAT5 (●) or Renilla (■) as a control. The absolute numbers of GFP-purified cells over time are depicted. Data represent means (± SD) of 3 independent experiments. Similar results were obtained using another HL cell line L1236. (F) Percentage of double-transduced CA-STAT5bER-IRES-ΔNGFR plus CA-IKK2-IRES-GFP cells (□ ■) or CA-STAT5bER-IRES-ΔNGFR plus control GFP cells (○ ●) in time, cultured in the absence of CD40L and in the presence (● ■) or absence (○ □) of tamoxifen. (G) Cumulative expansion of double-transduced CA-STAT5bER/CA-IKK2 cells cultured in the presence (●) or absence (■) of tamoxifen. For panels F and G, 1 representative of 2 experiments is shown.
