Cells are seeded at a density of 4×10⁴/mL, cultured for 24 h, then treated with 0.06 to 6 μM Tosedostat (CHR-2797) for 24 h. After treatment, 5×10⁴ cells are washed with PBS and seeded in 100 μL Cys/Met-free RPMI 1640 containing Tosedostat, supplemented with 10% dialyzed FBS. 1.5 μCi [³⁵S]Cys/Met (>1,000 Ci/mmol) is added, and incubation continued for 1 h at 37°C. Cells are captured onto 96-well GF/B filter plates and washed twice with PBS before precipitation with 10% ice-cold trichloroacetic acid (TCA) for 1 h at 4°C. Precipitated proteins are washed four times with ice-cold 10% TCA and air-dried for 1 h. UltimaGold scintillation cocktail is added and allowed to mix for 1 h before scintillation counting using a scintillation counter^[1].

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

Leukemic cells are washed and suspended in phosphate buffered saline (PBS). 100 μL of cell suspension (1×10⁵ cells/mL) is mixed with 100 μL of Tosedostat (CHR-2797) (0.01 to 10 μM) and 200 μM L-alanine 4-methyl-coumaryl-7-amide (ala-MCA) in a 96 well plate in duplicate. The aminopeptidase activity is measured by detecting the fluorescent 7-amino-4-methylcoumarin (MCA) liberated from the cleavage of ala-MCA by cellular aminopeptidases (excitation 355 nm, emission 460 nm)^[2].

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

A breeding colony of NOD/SCID IL2R gamma^null mice are used in this study. The mice are inoculated subcutaneously in the right flank with 2×10⁶ H929 myeloma cells in 50 μL RPMI-1640 and 50 μL Matrigel^TM Basement Membrane Matrix Growth Factor Reduced. The mice are assigned into the following four treatment groups (10 animals per group): no treatment, Tosedostat 75 mg/kg, CHR-3996 30 mg/kg, and Tosedostat 75 mg/kg with concomitant CHR-3996 30 mg/kg. Tosedostat is administered daily by intra-peritoneal injection beginning four days after the tumour cells are inoculated. Caliper measurements of the longest perpendicular tumour diameters (length) and width are performed every other day to estimate the tumour volume^[3].

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

• [1]. Emma M Smith, et al. The combination of HDAC and aminopeptidase inhibitors is highly synergistic in myeloma and leads to disruption of the NFκB signalling pathway. Oncotarget. 2015 Jul 10;6(19):17314-27.  [Content Brief]

  [2]. Krige D, et al. CHR-2797: an antiproliferative aminopeptidase inhibitor that leads to amino acid deprivation in human leukemic cells. Cancer Res. 2008 Aug 15;68(16):6669-79.  [Content Brief]

  [3]. Jenkins C, et al. Aminopeptidase inhibition by the novel agent CHR-2797 (tosedostat) for the therapy of acute myeloid leukemia. Leuk Res. 2011 May;35(5):677-81.  [Content Brief]

  [4]. Smith EM, et al. The combination of HDAC and aminopeptidase inhibitors is highly synergistic in myeloma and leads to disruption of the NFκB signalling pathway. Oncotarget. 2015 Jul 10;6(19):17314-27.