B lymphomas have high SFK activity as compared to normal B cells. (Panel A) The top row of blots is of mouse and the bottom row is of human B cells. SudHL-4 and 6, Ly3 and 10, and human primary lymphoma #1 are diffuse large B cell lymphomas while the murine primary lymphomas were from EμMyc transgenic mice. Human primary lymphomas #2 & 3 are small cell lymphomas. The cell lysates were first probed for phospho-SFK with p-Src (Y416) antibody, then stripped and re-probed for β-actin as a loading control. The ODs for the p-SFK bands were normalized to the corresponding β-actin bands. The ratios are provided under each lane and are depicted as a fold change over normal cells (i.e. murine lymphomas as a ratio to murine splenic B cells and human lymphomas as a ratio to PB B cells). (B) Cultures of murine (BKS-2) and human (SudHL-4) B lymphomas were treated with the SFK inhibitor PP2 (10 μM) or with the inactive control analog, PP3 (10 μM) for 48 hr and then the proliferation was measured by [3H]-thymidine uptake. Cultures of murine (C) and human (D) B lymphomas were treated with various doses of dasatinib (a dual BCR-ABL and SFK inhibitor) for 48 hr and then the proliferation was measured by [3H]-thymidine uptake. The proliferation assay was performed as described in the "Materials and Methods" section. Data points indicate percent control response ± S.E. of triplicate cultures from a representative experiment. The percent control response is defined as (cpm in the treated group/cpm in the untreated group) × 100. The levels of tritiated thymidine incorporation in the untreated groups were between 34,767 and 84,547 cpm.