Effects of 4-S-CPG, SLC7A11-specific siRNA, NAC, and AsA on cytotoxicity of GA analogs in A549 cells 4-S-CPG (50 μM) was used to suppress SLC7A11 transport activity. siRNA was used to downregulate SLC7A11 expression. The effects of the GSH precursor and antioxidant NAC (1 mM) and the prooxidant AsA (1 mM) were also tested on the cytotoxicity of GA analogs. IC50 values in micromolar are shown for each drug in the presence or absence of 4-S-CPG, siRNA, NAC, or AsA. Values in the rows marked “-Fold” are -fold reversal, which is the IC50 for the cytotoxic drug in control cells divided by that in inhibitor-treated cells. When IC50 was higher than the maximum concentration used, it is denoted as “> maximum concentration,” and the -fold changes were calculated using the maximum concentration. Results represent mean ± S.D. of at least three experiments.
NSC # | 122750 | 658514 | 661581 | 330507 | 707545 | ||
|---|---|---|---|---|---|---|---|
| Name | GA | 17-AAG | 17-DMAG | 17-AEP-GA | 17-DMAP-GA | ||
| CC | –0.57 | –0.46 | –0.50 | –0.10 | 0.06 | ||
| –4-S-CPG | 0.026 ± 0.00 | 2.5 ± 0.51 | 0.35 ± 0.05 | 0.086 ± 0.01 | 0.15 ± 0.00 | 0.072 ± 0.01 | 0.31 ± 0.02 |
| +4-S-CPG | 0.004 ± 0.00 | 1.6 ± 0.40 | 0.12 ± 0.01 | 0.062 ± 0.00 | 0.14 ± 0.02 | 0.082 ± 0.00 | 0.34 ± 0.04 |
| -Fold | (7.1)* | (1.6)* | (3.0)* | (1.4) | (1.1) | (0.89) | (0.94) |
| –siRNA | 0.025 ± 0.00 | 5.9 ± 0.33 | 0.92 ± 0.13 | 0.03 ± 0.00 | 0.10 ± 0.00 | 0.030 ± 0.00 | 0.11 ± 0.01 |
| +siRNA | 0.013 ± 0.00 | 2.8 ± 0.11 | 0.51 ± 0.03 | 0.04 ± 0.00 | 0.10 ± 0.01 | 0.017 ± 0.00 | 0.083 ± 0.03 |
| -Fold | (1.8)* | (2.1)* | (1.8)* | (0.9) | (1.0) | (1.8) | (1.4) |
| –NAC | 0.026 ± 0.00 | 2.0 ± 0.35 | 0.45 ± 0.05 | 0.033 ± 0.00 | 0.090 ± 0.01 | 0.057 ± 0.01 | 0.14 ± 0.01 |
| +NAC | >6.25 | >16.7 | >16.7 | 0.030 ± 0.00 | 0.24 ± 0.01 | 0.15 ± 0.05 | 0.26 ± 0.02 |
| -Fold | (<0.0042)* | (<0.12)* | (<0.027)* | (1.1) | (0.37)* | (0.42) | (0.54)* |
| –AsA | 0.029 ± 0.00 | 1.9 ± 0.18 | 0.35 ± 0.03 | 0.026 ± 0.00 | 0.088 ± 0.01 | 0.047 ± 0.01 | 0.11 ± 0.00 |
| +AsA | 0.012 ± 0.00 | 0.063 ± 0.00 | 0.051 ± 0.00 | 0.038 ± 0.00 | 0.11 ± 0.01 | 0.057 ± 0.01 | 0.28 ± 0.04 |
| -Fold | (2.5)* | (30)* | (6.8)* | (0.69)* | (0.78) | (0.82) | (0.41)* |
CC, Pearson correlation coefficients between compound potency and SLC7A11 expression
↵* P < 0.05 versus controls without adding inhibitors or siRNA