TABLE 1.
Binding affinities of different ligands for human BRS-3, GRP, and NMB receptors in various cells
Cells were incubated with 50 pM 125I-[d-Tyr6, βAla11, Phe13, Nle14]Bn-(6–14) for 40–60 minutes at 21°C and binding was determined as described under Materials and Methods. For each ligand, a dose-response curve was performed with concentrations from 1 pM to 1 μM. Data are expressed as the concentration causing half-maximal inhibition of saturable binding. Results were calculated from the dose-response curves shown in Figs. 1 and 2 using a nonlinear regression curve-fitting program (Prism). Results are mean ± S.E.M. from at least four experiments, and >10,000 = IC50 >10,000 nM.
| Ligand | IC50 (nM) |
|||||
|---|---|---|---|---|---|---|
| hBRS-3 |
hGRP-R |
hNMB-R |
||||
| Balb 3T3 | NCI-N417 | Balb 3T3 | HuTu-80 | Balb 3T3 | NCI-H1299 | |
| GRP | >10,000 | >10,000 | 0.23 ± 0.02 | 0.13 ± 0.01 | 246 ± 39 | 127 ± 11 |
| NMB | >10,000 | >10,000 | 57.4 ± 5.9 | 66.4 ± 5.6 | 0.07 ± 0.01 | 0.60 ± 0.11 |
| Peptide #1 | 2.52 ± 0.51 | 2.76 ± 0.41 | 0.26 ± 0.01 | 0.05 ± 0.01 | 1.55 ± 0.15 | 6.00 ± 2.12 |
| MK-5046 | 18.8 ± 0.2 | 17.7 ± 0.2 | >10,000 | >10,000 | >10,000 | >10,000 |
| Bantag-1 | 1.59 ± 0.52 | 1.05 ± 0.55 | >10,000 | >10,000 | >10,000 | >10,000 |