Maximal potentiation effect of Bcl-2-ASO with DEX.

Bcl-2-ASO potentiates DEX-induced apoptosis (A) and down-regulation of Bcl-2 (B) in ARH-77 and U266 cells. U266 and ARH-77 cells were cultured with or without 5 μg/mL Bcl-2-ASO for 3 days. Cultures were further incubated with no DEX, with low DEX (1 μM), or with high DEX (2 μM) for additional 2 days. Apoptosis was determined by annexin V in cells treated with Bcl-2-ASO alone, DEX alone, or with Bcl-2-ASO (3 days) followed by 1 day or 2 days of DEX. Bcl-2-ASO was replenished every other day. Apoptosis (A) and Western immunoblotting (B) were performed as described in the legend to Figure 1. In panel B, lane 1 indicates nontreated, control cells; lane 2, cells treated for 4 (left panel) or 5 days (right panel) with Bcl-2-ASO alone; lane 3, cells treated with 2 μM DEX alone (1 day, left panel; 2 days, right panel); lane 4, cells treated with Bcl-2-ASO plus DEX for 1 day (left panel) or 2 days (right panel). Note that cells treated with Bcl-2-ASO and DEX exhibited additivity in apoptosis and in down-regulation of Bcl-2. Bars in panel A are ± SD of at least 3 experiments. One of 3 representative immunoblotting experiments is shown in panel B.