The proteasome is a multicatalytic proteinase complex with a highly ordered ring-shaped 20S core structure. Proteasome Subunit β5 is a component of the 20S core proteasome complex involved in the proteolytic degradation of most intracellular proteins. Proteasome Subunit β5 displays a chymotrypsin-like activity.
Carfilzomib is a proteasome inhibitor, specifically inhibiting the chymotrypsin-like (ChT-L) activity at the β5 subunits of the core 20S proteasome[3]. According to a report, extracts from multiple myeloma ANBL-6 cells were exposed to increasing concentrations of carfilzomib and assayed for 20S catalytic activities. Carfilzomib displayed preferential in vitro inhibitory potency against the ChT-L activity in the β5 subunit, with over 80% inhibition at the dose of 10 nM and little or no effect on the PGPH and T-L activities at doses up to 100 nM. In an ELISA assay utilizing cell extracts from ANBL-6 cells, designed to identify subunit binding, short exposure to Carfilzomib at the concentration as low as 0.1 μM exhibited preferential binding specificity for the β5 constitutive 20S proteasome. Based on a WST-1 assay, the inhibitory IC50s of Carfilzomib against multiple myeloma ANBL-6 and RPMI8226 cells were both less than 5 nM, with the drug incubation time of 24h. In a caspase activity assay, ANBL-6 cells were exposed to a 1-hour pulse of 100 nM Carfilzomib and allowed to recover for 8 hours. The results indicated that Carfilzomib increased caspase-3 activity approximately 6-fold, and caspase-8, caspase-9 activity approximately 4-fold[4].
In a mouse model of bone marrow disseminated multiple myeloma established by intravenous injection of 5TGM1-GFP cells into KaLwRij mice, Carfilzomib was intravenously administrated at the dose of 3 mg/kg daily for 2 days. The treatment of Carfilzomib significantly decreased tumor burden as measured by serum levels of the clonotypic antibody IgG2b and by percentage of bone marrow or spleen GFP-expressing tumor cells. Protection from tumor-induced bone loss was also observed by microCT[5].
Carfilzomib 细胞研究
细胞系
浓度
检测类型
检测时间
活动说明
数据源
1483
200 nM
Apoptosis Asssay
24 h
induce the cell apoptosis co-treatment with ONX 0912
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