Silencing of HDAC11 gene expression by siRNA up-regulates OX40L in HL cell lines. (A) HL cell lines were transfected with HDAC11 or control siRNA (3 μg), and after 48 hours the cellular level of HDAC11 was determined by Western blot. Results represent 3 independent experiments showing the efficacy of HDAC11 siRNA in down-regulating HDAC11 expression. (B) HL cell lines were analyzed by FACS after 48 hours of HDAC11 siRNA transfection. Blocking HDAC11 increased OX40L expression. (C) Mean fluorescence intensity of 3 independent experiments (± SEM). *P < .05; **P < .005. (D) The Jeko-1 cell line was analyzed by FACS after 24 hours of HDAC11 siRNA transfection. Down-regulating HDAC11 did not have any effect on OX40L expression. (E) HDAC11 siRNA induced apoptosis in HL cell lines. (F) Representative experiment demonstrating the effect of down-regulating HDAC11 on induction of apoptosis in 3 HL cell lines as determined by propidium iodide and annexin V staining and FACS analysis. Results are shown after 48 hours of incubation. Each value is the mean of 3 independent experiments (± SEM). *P < .05; **P < .005. (G) Effect of HDAC11 siRNA on the caspase pathway. Down-regulation of HDAC11 decreased expression of caspase 9 and caspase 8 in HL cells, as determined after 24 hours of incubation.