Table 1.
SSTR2 binding constants and uptake fractions of gallium‑68-, lutetium‑177-, copper‑64-, and copper‑67-labeled TATE variants measured in intact MPC cells
| TATE variant | RN | A m | K d a | B max a | Uptake fraction b | ||
|---|---|---|---|---|---|---|---|
| [MBq/nmol] | [nmol/L] | [pmol/mg protein] | n c | [%] | n d | ||
| DOTA | 68Ga | 26.8 ± 0.27 | 2.92 ± 0.78 | 1.18 ± 0.39 | 4 | 87 ± 1.9 | 3 |
| 177Lu | 26.7 ± 1.17 | 2.94 ± 0.52 | 1.21 ± 0.24 | 5 | 73 ± 2.2 | 5 | |
| 64Cu | 23.2 ± 1.35 | 0.97 ± 0.17 † | 0.46 ± 0.05 * | 8 | 61 ± 4.6 | 5 | |
| NODAGA | 64Cu | 25.0 ± 0.97 | 1.78 ± 0.34 | 0.47 ± 0.04 * | 6 | 64 ± 4.1 | 6 |
| 67Cu | 18.2 | 2.55 (2.12-2.98) | 0.82 (0.79-0.85) | 1 | 54 (52-55) | 1 | |
| NODAGA-cLAB4 | 64Cu | 26.7 ± 0.71 | 2.72 ± 0.52 | 0.60 ± 0.08 | 4 | 72 ± 6.3 | 3 |
| 67Cu | 24.0 | 2.74 (1.90-3.59) | 0.61 (0.56-0.66) | 1 | 61 (59-62) | 1 |
(Am) molar activity at incubation start; (RN) radionuclide; a binding constants were measured at free radioligand concentrations between 0.3-40 nmol/L; non-specific binding was assessed in presence of 1 nmol/L acetyl-TATE; b non-acid-releasable radioligand fraction, values normalized to specifically bound radioligand after initial exposure to a free concentration of 25 nmol/L; number of independent experiments (n) each performed in c triplicate or d sextuplicate; data presented as means ± standard error (n > 3) or confidence interval of 68 % (n < 3); significance of differences compared to [177Lu]Lu‑DOTA-TATE: * p < 0.05, † p < 0.01