NF-κB inhibitor SC-514 potentiates rapamycin effect on BM-EC proliferation. (A) Semiconfluent BM-ECs were cultured for 12 hours in EBM2 and pretreated for 1 hour with rapamycin (10 ng/mL), SC514 (100 μM), or DMSO (vehicle control). Cells were then stimulated for 15 minutes with cytokine media/EGM2, lysed, and analyzed for activation of NF-κB pathway inhibitory protein IκB-α by Western blot. Data are representative of 4 BM-EC donors tested. (B) BM-ECs were cultured in cytokine media/EGM2 in the presence of rapamycin or SC514 (tested at indicated doses; left panel). Proliferation was measured using an MTS assay, and data are presented as proliferation index in percentage of control condition. At optimal inhibitory doses for both agents, combination of SC-514 (75 μM or 100 μM) and rapamycin (10 ng/mL) was tested (right panel; ^*significance level of P < .02 and P < .01, respectively). (C) Two constant ratio combinations of rapamycin and SC-514 were tested, with 2-fold (combination A) or 1.5-fold (combination B) dilutions from the highest dose combination (see rows marked with an asterisk in Table 1). Dose-effect analysis was performed using CalcuSyn software, with the combination index (CI) determined by the Chou-Talalay method. Data in panels B and C show a representative case from 4 independent experiments using BM-ECs from 3 to 6 donors. Error bars represent SEM.