Background
CC-292, formerly known as AVL-292, is an orally active, potent irreversible small molecule inhibitor of BTK with IC50 of 0.5 nM and EC50 of 8 nM. [1]
The B cell receptor (BCR) signaling pathway plays an important role in the fate and function of B cells by modulating cellular selection, maturation, proliferation, and production of antibody.
BTK, which is a tyrosine kinase member of the Tec kinase family, is a unique therapeutic target among kinases in the pathway BCR signaling. Studies showed that loss of gene function mutations of BTK in humans consequently leads to X-linked agammaglobulinaemia (XLA), characterized by a complete lack of B cells, low concentrations of serum Ig, and recurring infections, which implies that BTK is required in the development and immunoglobulin production of B cells. CC-292 inhibits BTK by the formation of a covalent bond with Cys481 residue. [2]
The inhibitory activity of CC-292 has been examined in immunoblot analysis, which showed that CC-292 potently inhibits auto-phosphorylation in human naive primary B cells. Furthermore, CD69 upregulation tested by ?ow cytometry tracking also exhibited a dose-dependent reduction in CD69 expression with increasing levels of CC-292 in vitro. Covalent probe analysis of human B cells coupled with enzyme linked immunosorbent assay (ELISA) quanti?cation methods illustrated 42% BTK occupancy in a 1h incubation with CC-292 of 10 nM. [1, 2]
Studies in vivo for CC-292 has been conducted. CIA model in mice was orally treated with CC-292, which demonstrated a positive correlation between BTK occupancy and inhibition of the disease. In addition, CC-292 was assessed with clinical trials, which showed a T1/2 of 1.9h and suggested efficacy in B-NHL, WM, and CLL patients. [2]
参考文献:
[1].Evans E K, Aslanian S, Karp R, et al. Inhibition of Btk with CC-292 provides early pharmacodynamic assessment of activity in mice and humans[J]. Journal of Pharmacology and Experimental Therapeutics, 2013, 346(2): 219-228.
[2].Aalipour A, Advani R H. Bruton tyrosine kinase inhibitors: a promising novel targeted treatment for B cell lymphomas[J]. British journal of haematology, 2013, 163(4): 436-443.
Protocol
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Cell experiment:
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Cells are incubated in serum-free RPMI media for 1-1.5 hours. Isolated human B cells are incubated with Spebrutinib at a final concentration of 0.001, 0.01, 0.1 and 1 μM. Ramos cells are incubated with 0.1 nM-3 μM Spebrutinib. Cells are then incubated in the presence of compound for 1 hour at 37°C. Following incubation, cells are centrifuged and resuspended in 100 μL of serum-free RPMI and BCR is stimulated with addition of 5 μg/mL α-human IgM. Samples are centrifuged, washed in phosphate-buffered saline (PBS), and lysed in 100 μL of Cell Extraction Buffer plus 1:10 (v/v) PhosSTOP Phosphatase Inhibitor and 1:10 (v/v) Complete Protease Inhibitor. Antibodies used for immunoblot analysis include P-PLCγ2, PLCγ2 (3871; CST), Syk (2712; CST), P-Syk (2710; CST), Btk, P-Btk, and Tubulin. Membranes are scanned on a Li-Cor Odyssey scanner using infrared fluorescence detection[1].
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参考文献:
[1]. Evans EK, et al. Inhibition of Btk with CC-292 provides early pharmacodynamic assessment of activity in mice and humans. J Pharmacol Exp Ther. 2013 Aug;346(2):219-28.
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