Figure 4
Sorafenib induces a downmodulation of the prosurvival molecule Mcl-1 in CLL cells cultured alone or in the presence of CXCL12, NLCs and MSCs. CLL B cells purified from freeze-thawed PBMCs were either cultured alone (A), in the presence of 30 nmol/L CXCL12 (B), or in the presence of NLCs or MSCs (C) and exposed to 10 µmol/L sorafenib or DMSO for 24 h. CLL cell lysates were analyzed for the expression of Mcl-1, Bcl-XL, Bcl-2, Bim and β-actin. Mcl-1 downregulation was observed in five of six CLL samples and Bim downregulation in four of six CLL samples, and unchanged levels of Bcl-2 and Bcl-xL were observed in six of six CLL samples. Data from one representative of six CLL samples is shown in (A), and one representative CLL sample out of three is shown in (B) and (C). (D) CLL cells purified from freeze-thawed PBMCs were incubated in MSC-conditioned media in the presence of sorafenib (10 µmol/L) or DMSO for 24 h, at which point the cells were harvested, lysed and analyzed by Western blot for the expression of Mcl-1 and GAPDH as loading and transfer control. Data from one representative CLL samples out of seven is shown on the left and densitometry analysis quantifying the modulation of Mcl-1 expression after sorafenib exposure is shown on the right for all seven patients. Mcl-1 protein expression levels are shown normalized to GAPDH.