Table 2.
IC50 values of the FAPi probes against FAP and the related serine proteases (PREP, DPP4, DPP8, DPP9). Data are described as the mean with standard deviation (n=3 for FAP and n=2 for PREP and the DPPs)
| Compound | IC50 (µM) | IC50 (nM) | |||
|---|---|---|---|---|---|
|
|
|
||||
| DPP4 | DPP8 | DPP9 | PREP | FAP | |
| DOTA.(SA.FAPi)2 | 0.44±0.06 | 1.33±0.11 | 0.96±0.15 | 0.42±0.02 | 0.78±0.05 |
| [natGa]Ga-DOTA.(SA.FAPi)2 | 0.51±0.09 | 1.44±0.16 | 0.78±0.07 | 0.92±0.07 | 1.05±0.07 |
| DOTAGA.(SA.FAPi)2 | 0.40±0.07 | 0.42±0.04 | 0.16±0.02 | 0.39±0.02 | 0.92±0.06 |
| [natGa]Ga-DOTAGA.(SA.FAPi)2 | 0.70±0.11 | 0.87±0.08 | 0.19±0.01 | 1.60±0.16 | 0.90±0.06 |
| [natLu]Lu-DOTAGA.(SA.FAPi)2 | 0.63±0.07 | 0.41±0.03 | 0.18±0.02 | 0.56±0.04 | 1.54±0.15 |
| [natGa]Ga-DOTA.SA.FAPi | >1 | N/A | >1 | 8.7±0.9a | 1.4±0.2a |
| [natLu]Lu-DOTA.SA.FAPi | >1 | N/A | >1 | 2.5±0.4a | 0.8±0.2a |
| UAMC1110 | >10 | 10.1±0.6b | 4.7±0.4b | 1.8±0.01 | 0.43±0.02a |
a
IC50 for FAP and PREP from Moon et al. [10].
b
The IC50 value of UAMC-1110 for DPP9 (4.7±0.4 μM) is slightly lower compared to what was published before (>12 μM) [2]. This is due to introducing of a new measurement method in combination with new human recombinant DPP9 (instead of bovine DPP9). The IC50 of UAMC1110 for DPP8 was determined as a part of this study.