Downregulation of p63 expression inhibits the MIF-induced VLA-4 expression. CLL cells were incubated in the presence or absence of siRNA for p63 and for a control gene, lacz, for 6 h. A, Following an additional 18 h, RNA was purified, and levels of p63, α4, and actin mRNA were analyzed by PCR. The graph summarizes the results of three separate experiments. B, After 24 h, cells were stained with anti–VLA-4 (gray) or a control Ab (black) and analyzed by FACS. The results presented are representative of five CLL patients. The graph summarizes the results of five separate experiments. C and D, The cells were then stimulated with MIF, and RNA was purified after an additional 18 h. C, VLA-4 and actin mRNA were analyzed. The results presented are representative of two CLL patients. D, Quantitative RT-PCR: results are expressed as a fold-change in α4 expression in stimulated cells compared with nonstimulated cells, which was defined as 1. Results shown represent a summary of two separate experiments.