Biochemical potency of CB-1158 against arginase and NOS activity

CB-1158, IC50 (nM)
Purified enzyme assay
 Recombinant human Arg186 (±25)
 Recombinant human Arg2296 (±5)
 Recombinant bovine endothelial NOSN/A
 Rat cerebellar neuronal NOSN/A
 Recombinant murine inducible NOSN/A
Cell lysate assay
 Human granulocyte lysate178 (±28)
 Human erythrocyte lysate116
 Human hepatocyte lysate158 (±23)
 Cancer patient plasma122 (±32)

Mean IC50 values in nanomolar for CB-1158 inhibition of purified recombinant arginases or native arginases in cell lysates or cancer patient plasma. Standard deviations are indicated in parentheses. Recombinant Arg1 assays (N = 3) were performed in duplicate wells in the presence of 160 μM L-arginine. Recombinant Arg2 assays (N = 2) were performed in triplicate wells with 20 mM L-arginine. Arginase activity assays using human granulocyte lysate (N = 3), human erythrocyte lysate (N = 1), human hepatocyte lysate (N = 4), and cancer patient plasma (N = 5) were performed in duplicate wells with 160 μM L-arginine. Purified NOS enzyme activity was assayed in the presence 50 μM CB-1158, which showed no inhibitory activity against the three NOS isoforms

N/A not applicable