Figure 4. Regulation of Bcl-2 family proteins in CLL-stromal cell co-cultures and effect of ATO.

(A) 8–10 × 10⁶ CLL cells were cultured in suspension or with HS-27A stromal cells. After 2 h at 37°C, 2 μM ATO was added and cells further incubated for 24 h. Protein expression was analyzed by Western blotting. Vinculin was used as an internal control. The results from one representative sample and the quantitation of all samples analyzed, after normalizing control values to 1, are shown. (B) Ratios of relevant anti-apoptotic/pro-apoptotic partners of the Bcl-2 family. * CLL cells in suspension vs CLL cells on stroma; ^Δ ATO-treated cells vs their respective untreated controls. *or^Δ P ≤ 0.05; **or ^ΔΔ P ≤ 0.01; ***or ^ΔΔΔ P ≤ 0.001.