Carfilzomib displays preferential in vitro inhibitory potency against the ChT-L activity in the β5 subunit, with over 80% inhibition at doses of 10 nM and above and little or no effect on the PGPH and T-L activities at doses up to 100 nM. Carfilzomib decreases the viability of ANBL-6, RPMI 8226 cells, U266 and KAS-6/1 cells with an IC50 less than 5 nM. Carfilzomib overcome Dex resistance, in that MM1.R cells reveals an IC50 of 15.2 nM, less than the value of 29.3 nM for parental MM1.S cells. Co-treatment with carfilzomib and HDACIs leads to synergistic induction of cell death in various mantle cell lymphoma lines and primary mantle cell lymphoma cells. Combined treatment with carfilzomib or ONX0912 with vorinostat in HF-4B and Granta cells sharply increases caspase activation, PARP cleavage, JNK activation, MnSOD2 induction, and DNA damage.