Mg132 solution

A 100 mg tamoxifen was dissolved in 2 ml ethanol and then suspended in 8 ml corn oil. 4-OH tamoxifen (Sigma) was dissolved in ethanol at a concentration of 0.5 mM to prepare stock solution. Cyclophosphamide (Sigma) and bafilomycin A1 (Sigma) were dissolved in DMSO at a concentration of 100 mg ml⁻¹ and 100 μM, respectively, to prepare stock solution. CBP-CREB interaction inhibitor (Cas 92–78–4, Merck Millipore) was also diluted in DMSO at a concentration of 20 mM as stock solution. Recombinant mouse IL-1β/IL-1F2 (R&D systems) were prepared at a concentration of 10 μg ml⁻¹ in sterile PBS with 0.1% bovine serum albumin. Ten millimolar ready to use MG132 solution (Sigma) was purchased. Pterosin B was synthesized by Intelium Corp. (Supplementary Fig. 5a). Pterosin B was dissolved in DMSO at a concentration of 100, 200 and 300 mM for in vitro experiments and 900 mM for mouse experiments to prepare stock solution. These solutions were diluted with culture medium for in vitro experiments.

A 10 µM chloroquine solution (2x) (Sigma Chemical Co., St. Louis, MO, USA), a 10 mM MG132 solution (2x) (Sigma Chemical Co., St. Louis, MO, USA), and a 25 µM EMD638683 solution (2x) (Cayman Chemical Co., Ann Arbor, MI, USA) were prepared in PBS (137 mM NaCl, 2.7 mM KCl, 8 mM Na₂HPO₄, and 2 mM KH₂PO₄) from concentrated solutions diluted in dimethyl sulfoxide (DMSO) to achieve a final DMSO concentration of 0.02%. Indeed, the additional effects of proteasome inhibitors on cell cycle progression and induction of apoptosis are well-known. However, the concentration and duration of incubation we used had the desired effect of inhibiting the chymotrypsin-like activity of the proteasome [41 (link)].