Culturing CLL cells on MMP-9 modulates Bcl-2 family proteins in response to ATO, preventing downregulation of Mcl-1, Bcl-xL and Bcl-2.

(A,B) 10×106 primary CLL cells in RPMI/0.1% FBS were incubated on BSA- or 150 nM MMP-9-coated wells for 1 h prior to adding 3 µM ATO or vehicle. After 24 h, cell were lysed and the indicated proteins (A) and ratios (B) analyzed by Western blotting as explained. * or #P≤0.05; ** or ##P≤0.01; *** or ###P≤0.001. Symbols are: *, CLL cells on BSA vs CLL cells on MMP-9; #, ATO-treated cells compared to their respective untreated controls.