Figure 4From: Targeting early B-cell receptor signaling induces apoptosis in leukemic mantle cell lymphoma PP2 and dasatinib inhibit constitutive phosphorylation of LYN and induce apoptosis of primary MCL cells. (A) Constitutive phosphorylation profiles of LYN in MCL patients’ samples. Phospho-Tyr397 LYN was detected using a pan phospho-src family antibody. The blots were stripped and re-probed for total LYN. (B) Total proteins from HBL-2 cells were immunoprecipitated with an anti LYN antibody (Ig-LYN) or with an irrelevant IgG control and immunobloted (IB) with either an anti-phosphotyrosine antibody (P-Tyr) or an anti-LYN antibody. (C) Primary MCL cells (UPN3, UPN14) were treated with variable concentrations of PP2 (2 to 20 μM) or dasatinib (1 to 200nM) for 2 h. Phospho-Tyr397 LYN and LYN total were analyzed by western-blot. (D) Primary MCL cells were treated with various concentrations of PP2 (UPN3, top panel) or 10 μM of PP2 (UPN 1–3-7–8-9–14, middle panel) for 24 h and apoptosis was measured by flow cytometry after gating on CD19+ cells. All measurements were done in duplicate and the mean is provided. Results are also shown as median ± quartile (box) ± SE (bars) bottom panel). Differences between groups were determined using the paired Student t test. (E) Primary MCL cells were treated with dasatinib for 24 h with various concentrations (top panel) or with 100nM (middle panel). Apoptosis was measured as described above. Results are also shown as median ± quartile (box) ± SE (bars) bottom panel).Back to article page