D3 potentiates NGF in protecting TrkA-expressing cell lines from apoptosis by binding to the IgC2 domain of the receptor
| Treatment | 4-3.6 Cells | HEK293-TrkB/TrkA Chimera | ||
|---|---|---|---|---|
| OD | % Protection | OD | % Protection | |
| 1 Untreated | 64 ± 7 | 0 ± 2 | 32 ± 5 | 0 ± 4 |
| 2 1 nM NGF | 412 ± 24 | 100 ± 6 | 350 ± 12 | 100 ± 4 |
| 3 10 pM NGF | 205 ± 19 | 40 ± 5 | 88 ± 8 | 18 ± 5 |
| 4 10 μM D3 | 95 ± 9 | 8 ± 2 | 69 ± 7 | 9 ± 3 |
| 5 10 μM C59 | 76 ± 4 | 2 ± 1 | 30 ± 7 | −1 ± 2 |
| 6 10 μM D3 + 10 pM NGF | 255 ± 14 | 55 ± 3 | 165 ± 11 | 42 ± 5 |
| 7 10 μM C59 + 10 pM NGF | 209 ± 17 | 41 ± 4 | 90 ± 9 | 21 ± 6 |
4-3.6 cells or HEK293 cells expressing TrkB/TrkA IgG-C2 chimeric receptor were treated with the indicated ligands for a total of 72 h. Survival was measured by MTT assays. Percentage protection was calculated as in Table 4. Shown is the OD from one experiment, mean ± S.E.M. (n = 4). Percent protection was averaged from six (4-3.6 cells) or three (293-IgG-C2 chimera) independent experiments.