Differential expression of Bcl-2 in various myeloma cell lines.

Expression of Bcl-2 was determined in all cell lines used in this study, relative to ARP-1 cells. (A) Coomassie blue staining for loading control; (B) immunoblot for Bcl-2; and (C) quantitation of Bcl-2 bands by densitometry. Extraction of cellular protein, SDS-PAGE, immunoblotting, and quantitation of Bcl-2 bands were performed as described previously.9 Bcl-2 protein expression in ARP-1 cells and in the Bcl-2–transfected (ARP-1/Bcl-2) cells is shown in lanes 1 and 2, respectively. The expression of Bcl-2 protein in RPMI 8226 and in the Bcl-2–transfected (8226/Bcl-2) cells is depicted in lanes 3 and 4, respectively. The expression of Bcl-2 in ARH-77, HS-Sultan, IM9, and U266 cells is depicted in lanes 5, 6, 7, and 8, respectively. The level of Bcl-2 expression in ARP-1 cells was used throughout this study as a benchmark for low expression of Bcl-2. HS-Sultan and IM9 express relatively low levels of Bcl-2, whereas ARH-77, U266, and the Bcl-2–transfected ARP-1 and 8226 express relatively high levels of Bcl-2. For more details, see “Materials and methods.”