Bcl-2 overexpression blocks TPA-induced differentiation of U937 cells.

(A) Adhesion of parental (black bar) and Bcl-2–transfected (gray bar) U937 cells exposed for 72 hours to 20 nM TPA (mean ± SD of 3 experiments in duplicate). (B) Flow cytometry analysis of CD11b expression on the plasma membrane of cells left untreated (white curves) or exposed for 72 hours to 20 nM TPA (gray curves). 1 representative of 3 experiments is shown.