Cell Binding and Internalization Data of Compounds
| Compound | Specifically cell surface–bound* | Specifically internalized* | IC50 (nM)† Free ligands | 69/71Ga-labeled compounds |
|---|---|---|---|---|
| Glu-urea-Lys-(HE)1-HBED-CC-IRDye800CW | 3.00 ± 1.42 | 3.27 ± 1.83 | 28.41 ± 14.39 | 35.57 ± 22.83 |
| Glu-urea-Lys-(WE)1-HBED-CC-IRDye800CW | 6.47 ± 3.69 | 13.77 ± 8.50 | 43.70 ± 14.12 | 56.80 ± 17.10 |
| Glu-urea-Lys-(HE)3-HBED-CC-IRDye800CW | 8.30 ± 3.93 | 6.45 ± 3.36 | 51.29 ± 11.84 | 69.98 ± 22.88 |
| Glu-urea-Lys-HBED-CC-(HE)3-IRDye800CW | 6.26 ± 1.49 | 3.70 ± 0.51 | 41.74 ± 18.26 | 52.21 ± 7.33 |
↵* 68Ga-labeled compounds. Specific cell uptake was determined by blockage using 500 μM 2-PMPA. Data are percentage applied radioactivity bound to 105 cells.
↵† Radioligand: 68Ga-PSMA-10 (dissociation constant, 3.8 ± 1.8 nM (25); cradioligand, 0.75 nM [c = concentration]).
Data are expressed as mean ± SD (n = 3). Affinity to PSMA and internalization properties of compounds were determined in vitro using PSMA-positive cells (LNCaP). For all compounds, PSMA-specific internalization was detected, as well as high binding affinity to PSMA (in low nanomolar range) not significantly dependent on complexation.