M-3258

M-3258 is an inhibitor of the immunoproteasome subunit large multifunctional peptidase 7 (LMP7, IC50 = 4.1 nM). It is selective for LMP7 over the 20S proteasomal catalytic subunits beta1, -beta2, and -beta5 (IC50s = >10,000, 2,519, and >10,000 nM, respectively), as well as LMP2 and proteosome subunit beta type 10 (PSMB10, IC50s = >10,000 nM for both). It increases ubiquitinated protein levels (EC50 = 1,980 nM) and induces apoptosis in MM.1S multiple myeloma cells (EC50 = 420 nM). M-3258 (10 mg/kg per day) reduces tumor volume in U266B1, OPM-2, and RPMI-8226 mouse xenograft models of multiple myeloma.Formal Name: B-[(1R)-2-(3-benzofuranyl)-1-[[(1S,2R,4R)-7-oxabicyclo[2.2.1]hept-2-ylcarbonyl]amino]ethyl]-boronic acid. CAS Number: 2285330-15-4. Molecular Formula: C17H20BNO5. Formula Weight: 329.2. Purity: >98%. Formulation: (Request formulation change), A solid. Solubility: DMSO: 30 mg/ml. lambdamax: 248 nm. SMILES: OB(O)[C@@H](NC([C@H]1[C@@](CC2)([H])O[C@@]2([H])C1)=O)CC3=COC4=CC=CC=C34. InChi Code: InChI=1S/C17H20BNO5/c20-17(13-8-11-5-6-15(13)24-11)19-16(18(21)22)7-10-9-23-14-4-2-1-3-12(10)14/h1-4,9,11,13,15-16,21-22H,5-8H2,(H,19,20)/t11-,13-,15+,16+/m1/s1. InChi Key: RFQDLTYXNINJON-OYNZBZHQSA-N.