Effect of Chloroquine on Anthracycline Sensitivity in U-937 and U-A10 Cells
| Drug . | U-937 (IC50) . | U-A10 (IC50) . | Fold Resistance . |
|---|---|---|---|
| Chloroquine (μmol/L) | 56.5 ± 8.2 | 23.2 ± 4.6 | 0.41 |
| Daunorubicin (ng/mL) | 8.4 ± 0.5 | 293 ± 23 | 35 |
| Daunorubicin/chloroquine | 9.8 ± 0.6 | 11.9 ± 2.4 | 1.2 |
| Doxorubicin (ng/mL) | 9.5 ± 0.8 | 683 ± 89 | 72 |
| Doxorubicin/chloroquine | 11.1 ± 2.0 | 66.7 ± 2.9 | 6.0 |
| Drug . | U-937 (IC50) . | U-A10 (IC50) . | Fold Resistance . |
|---|---|---|---|
| Chloroquine (μmol/L) | 56.5 ± 8.2 | 23.2 ± 4.6 | 0.41 |
| Daunorubicin (ng/mL) | 8.4 ± 0.5 | 293 ± 23 | 35 |
| Daunorubicin/chloroquine | 9.8 ± 0.6 | 11.9 ± 2.4 | 1.2 |
| Doxorubicin (ng/mL) | 9.5 ± 0.8 | 683 ± 89 | 72 |
| Doxorubicin/chloroquine | 11.1 ± 2.0 | 66.7 ± 2.9 | 6.0 |
The sensitivity of the parental U-937 and the doxorubicin-selected U-A10 cell lines to chloroquine, daunorubicin, and doxorubicin was determined in a standard MTT assay after 96 hours of drug exposure. Shown is the average (±the standard mean) IC50 value from three experiments each performed in quadruplicate. The effect of chloroquine on anthracycline cytotoxicity was determined by adding the lysosomotropic agent to a final concentration of 10 μmol/L just before adding the anthracycline. The fold resistance is calculated from the ratio of the IC50 of U-A10 cells/the IC50 of U-937 cells.