COH000 is a covalent and irreversible inhibitor of small ubiquitin-like modifier (SUMO)-activating enzyme and inhibited SUMOylation (IC50: ~ 0.2 μM in vitro).

SUMO activating enzyme:0.2 μM (cell free)

COH000在体外平均IC50约为0.2 μM的条件下抑制了SUMOylation，但在相同条件下，即使浓度高达100 μM，在以Ubc13介导的多聚泛素化试验中也未能抑制泛素化。COH000处理诱导了HCT-116细胞中的凋亡。通过转染过表达SAE2，凋亡水平降低；而当在HCT116细胞中敲除SAE2时，凋亡水平增加。

当肿瘤变得可触及时，携带肿瘤的Es1e/SCID小鼠接受了COH000或对照剂的治疗，为期14天。COH000显著抑制了肿瘤生长，并且显著降低了肿瘤组织中SAE2的水平。

Briefly, SAE, Ubc9, GST-SUMO and His6-RanGap-1 proteins were expressed and purified as described previously.Assay buffer contained 50 mMTris-HCl pH 7.4, 0.3 mM DTT, 10 mM MgCl2, and 0.005% Tween-20. The assays were conducted using 1536-well, white plates. 2 μL of Mixture 1, containing 12.5 nM SAE and 100 nM His6-RanGap-1 in the assay buffer was mixed with 70 nl of 2 mM compounds dissolved in DMSO. Then 2 μL of Mixture 2, containing 20 mM ATP, 12.5 nM E2 and 30 nM GST-SUMO in assay buffer, was added. After incubation for 90 min at room temperature, 1 μl of pre-mixed Ni acceptor beads and Glutathione Donor beads, at 10 μg/ml each, was added. After incubation for 60 min at room temperature, readings were made on a BMG LabtechPheraStar in an AlphaScreen mode (Ex: 680 nm; Em: 570 nm).

Cell proliferation was measured using a CellTiter 96 AQueous One Solution Cell Proliferation Assay (MTS-based) after COH000 or its analog (54 or 55) treatment at the indicated concentrations and the time points. Briefly, cells were incubated with 20 mL of CellTiter 96 AQueous reagentafter the treatment and incubated at 37C until color development. Absorbance measurements were performed using a SpectraMax M5 reader. For assays measuring anti-proliferation effects, all values were normalized to the vehicle treatment. All values are represented graphically as mean ± standard deviation (STDEV) from three independent samples (n=3).

Mice were housed in a controlled environment (12-h light/12-h dark cycle) with access to waterand fed a standard diet generally from 6 to 8 weeks of age. Body weight was measured weekly and food intake was monitored. For colorectal cancer xenograft with COH000 treatment, HCT116 cells were s.c. injected into a plasma esterase-deficient SCID mouse strain (Es1e/SCID), male, 8-10 weeks. When the tumors became palpable, COH000 was administered subcutaneously peritumoral injection once a day at a dose of 10 mg per kilogram of body weight. Mice in the control group received equal volumes of vehicle (5% DMSO, 30% solutol in PBS). Tumor volume was measured until the endpoint was reached. Mice were euthanized using CO2 inhalation and tumors were excised.