b-AP15  (Synonyms: NSC 687852)

For deubiquitinase inhibition assays, 19S regulatory particle (5 nM), 26S (5 nM) UCH-L1 (5 nM), UCH-L3 (0.3 nM), USP2_CD (5 nM) USP7_CD (5 nM) USP8_CD (5 nM) or BAP1 (5 nM) is incubated with DMSO or b-AP15 and monitored the cleavage of ubiquitin-AMC (1,000 nM) using a Wallac VICTOR Multilabel counter or a Tecan Infinite M1000 equipped with 380 nm excitation and 460 nm emission filters^[1].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Cell viability is monitored by either the fluorometric microculture cytotoxicity assay or the MTT assay. For the MTT assay, cells are seeded into 96-well flat-bottomed plates overnight and exposed to drugs, using DMSO as the control. At the end of incubations, 10 µl of a stock solution of 5 mg/mL MTT is added into each well, and the plates are incubated 4 hours at 37°C. Formazan crystals are dissolved with 100 µL 10% SDS/10 mM HCl solution overnight at 37°C. Absorbance is measured using an enzyme-linked immunosorbent assay (ELISA) plate reader at 590 nm^[2].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Mice^[1]
For the squamous carcinoma model, 1×10⁶ FaDu cells are subcutaneously injected into the right rear flank of female SCID mice. Tumor growth is measured by the formula length×width²×0.44. When tumors have grown to a size of approximately 200 mm³ (defined as day 0), mice are randomized to receive either vehicle (n=10) or b-AP15 (n=15) at 5 mg per kg of body weight by daily subcutaneous injection. For the colon carcinoma model, we subcutaneously injected 2.5×10⁶ HCT-116 colon carcinoma cells overexpressing Bcl2 into the right flank of female nude mice. We treated mice with 5 mg of b-AP15 per kg of body weight by intraperitoneal injection. For the lung carcinoma model, we subcutaneously injected 2×10⁵ LLC cells into the right rear flank of female C57/B6 mice. When tumors had grown to a size of approximately 50 mm³ (defined as day 0), we randomized mice to receive either vehicle (n=4) or b-AP15 (n=4) at 5 mg per kg of body weight intraperitoneally, with a treatment cycle consisting of 2 d of treatment followed by 2 d of rest (2 d on, 2 d off) for 2 weeks.

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

• [1]. D'Arcy P, et al. Inhibition of proteasome deubiquitinating activity as a new cancer therapy. Nat Med. 2011 Nov 6;17(12):1636-40.  [Content Brief]

  [2]. Wang X, et al. The 19S Deubiquitinase Inhibitor b-AP15 is Enriched in Cells and Elicits Rapid Commitment to Cell Death. Mol Pharmacol. 2014 Jun;85(6):932-45.  [Content Brief]

  [3]. Tian Z, et al. A novel small molecule inhibitor of deubiquitylating enzyme USP14 and UCHL5 induces apoptosis in multiple myeloma and overcomes bortezomib resistance. Blood. 2014 Jan 30;123(5):706-16.  [Content Brief]