Effect of DFO, Protease, and Lysosomal Inhibitors on Intracellular H-Ferritin and L-Ferritin Levels and H/L-Ferritin Ratios in K562 Cells
| . | H-Ferritin (ng/mg protein) . | L-Ferritin (ng/mg protein) . | H/L-Ferritin Ratio . |
|---|---|---|---|
| Before treatment | 706 ± 157 | 100.1 ± 33.1 | 7.3 ± 1.0 |
| Control | 1,010 ± 174 | 123.5 ± 36.2 | 8.4 ± 1.5 |
| DFO (100 μmol/L) | 412 ± 45 | 11.4 ± 3.8* | 38.5 ± 11.1* |
| Leupeptin (20 μg/mL) | 1,681 ± 256 | 192.5 ± 29.5 | 8.7 ± 0.2 |
| Chymostatin (100 μg/mL) | 1,887 ± 280 | 232.8 ± 23.1 | 8.2 ± 2.0 |
| Chloroquine (20 μmol/L) | 856 ± 278 | 103.6 ± 39.3 | 8.4 ± 0.7 |
| Leupeptin (20 μg/mL) + DFO (100 μmol/L) | 940 ± 455 | 110.3 ± 65.0 | 9.0 ± 1.6 |
| Chymostatin (100 μg/mL) + DFO (100 μmol/L) | 678 ± 136 | 70.4 ± 29.0 | 10.5 ± 3.3 |
| Chloroquine (20 μmol/L) + DFO (100 μmol/L) | 490 ± 62 | 23.4 ± 5.7* | 21.4 ± 2.8* |
| . | H-Ferritin (ng/mg protein) . | L-Ferritin (ng/mg protein) . | H/L-Ferritin Ratio . |
|---|---|---|---|
| Before treatment | 706 ± 157 | 100.1 ± 33.1 | 7.3 ± 1.0 |
| Control | 1,010 ± 174 | 123.5 ± 36.2 | 8.4 ± 1.5 |
| DFO (100 μmol/L) | 412 ± 45 | 11.4 ± 3.8* | 38.5 ± 11.1* |
| Leupeptin (20 μg/mL) | 1,681 ± 256 | 192.5 ± 29.5 | 8.7 ± 0.2 |
| Chymostatin (100 μg/mL) | 1,887 ± 280 | 232.8 ± 23.1 | 8.2 ± 2.0 |
| Chloroquine (20 μmol/L) | 856 ± 278 | 103.6 ± 39.3 | 8.4 ± 0.7 |
| Leupeptin (20 μg/mL) + DFO (100 μmol/L) | 940 ± 455 | 110.3 ± 65.0 | 9.0 ± 1.6 |
| Chymostatin (100 μg/mL) + DFO (100 μmol/L) | 678 ± 136 | 70.4 ± 29.0 | 10.5 ± 3.3 |
| Chloroquine (20 μmol/L) + DFO (100 μmol/L) | 490 ± 62 | 23.4 ± 5.7* | 21.4 ± 2.8* |
Cells were incubated in medium alone (control) and/or with DFO, leupeptin, chymostatin, or chloroquine for 24 hours. Leupeptin and chymostatin were added twice, at the beginning of the incubation and after 12 hours. At the end of the incubation period, the cells were washed and lysed, and total (H + L) ferritin and L-ferritin were separately determined by ELISA. H-ferritin was calculated as total minus L-ferritin. Values for cells before treatment are shown for comparison. Results are expressed as mean ± SD of 3 independent experiments run in triplicate.
P < .05: DFO at 100 μmol/L versus chloroquine at 20 μmol/L + DFO at 100 μmol/L.