TABLE 1.
Effect of GS-Nitroxide JP4-039 Added before or after Irradiation on the Radiosensitivity of Fanconi Anemia D2–/– and G–/– Cell Lines
| Cell line | D0 (Gy) | ñ |
|---|---|---|
| FancG –/– (PD326) | 1.2 ± 0.3 | 9.4 ± 1.5 P = 0.001* (compared to FancG) |
| Tempol + PD326 before | 1.2 ± 0.1 | 14.7 ± 1.4 P = 0.01* (compared to PD326) |
| JP4-039 + PD326 before | 1.1 ± 0.2 | 20.5 ± 4.5 P = 0.02* (compared to PD326) P = 0.001* (compared to PD326 + Tempol) |
| PD326 + Tempol after | 1.1 ± 0.1 | 14.8 ± 1.5 P = 0.01* (compared to PD326) P = 0.001* (compared to FancG + Tempol) |
| PD326 + JP4-039 after | 1.1 ± 0.1 | 20.5 ± 4.5 P = 0.02* (compared to PD326) P = 0.03* (compared to FancG +J P4-039) |
| FancG restored | 1.2 ± 0.1 | 2.2 ± 0.5 |
| Tempol + FancG before | 1.3 ± 0.2 | 7.2 ± 0.7 P = 0.001* (compared to FancG) |
| JP4-039 + FancG before | 1.3 ± 0.1 | 20.5 ± 4.5 P = 0.002* (compared to FancG) |
| FancG + Tempol after | 1.0 ± 0.2 | 7.2 ± 0.7 P = 0.001* (compared to FancG) |
| FancG + JP4-039 after | 1.1 ± 0.1 | 6.8 ± 0.6 P = 0.001* (compared to FancG) |
| FancD2 –/– (PD20F) | 1.4 6 0.2 | 2.0 ± 0.7 P = 0.03* (compared to FancD2) |
| Tempol + PD20F before | 1.5 ± 0.3 | 4.5 ± 1.8 P = 0.02* (compared to PD320F) |
| JP4-039 + PD20F before | 1.7 ± 0.1 P = 0.04* (compared to PD320F) |
1.9 ± 0.3 |
| PD20F + Tempol after | 1.5 ± 0.3 | 4.0 ± 1.1 |
| PD20F + JP4-039 after | 1.6 ± 0.3 | 6.2 ± 0.7 P = 0.01* (compared to PD20F) |
| FancD2 restored | 1.0 ± 0.1 | 4.7 ± 2.2 |
| Tempol + FancD2 before | 1.1 ± 0.1 P = 0.06* (compared to Tempol + PD20F) |
5.1 ± 1.0 |
| JP4-039 + FancD2 before | 1.1 ± 0.1 P = 0.0009* (compared to JP4-039 + PD20F) |
7.6 ± 0.6 P < 0.0001* (compared to JP4-039 + PD20F) P = 0.04* (compared to FancD2) |
| FancD2 + Tempol Post | 1.2 ± 0.1 | 4.7 ± 1.2 |
| FancD2 + JP4-039 Post | 1.2 ± 0.1 | 7.8 ± 0.5 P = 0.02* (compared to FancD2) |
Notes. FancG, FancG –/– (PD326), FancD2 and FancD2–/– (PD20F) cells were irradiated with 0 to 8 Gy. The cells were plated in 4-well tissue culture plates and incubated in a high CO2 incubator for 8 days, and colonies of greater than 50 cells were counted. The data were analyzed by the linear-quadratic and single-hit, multitarget models; the D0 and ñ are shown. FancG transgene-restored cells were more radiosensitive than FancG–/– cells [decreased shoulder on the survival curve (ñ)], while FancD2–/– cells were more radiosensitive than transgene-restored FancD2 cells. The data are the average of three separate experiments on 3 separate days. Tempol or JP4-039 was added before or after irradiation and the D0 and ñ for each cell line were calculated as described in the Methods. Means ± SD of D0 and ñ in each group are shown. P values were calculated for the comparison between two groups with the two-sided two-sample t test. Significant P values are indicated by an asterisk. Each experiment was carried out a minimum of three times.