Table 1.
Sensitivity of HL‐60 cells and HL‐60/ara‐C60 cells to anticancer agents
| IC50 (μM) | |||
|---|---|---|---|
| HL‐60 | HL‐60/ara‐C60 | RR | |
| Ara‐C | 0.0800 ± 0.0030 | 4.9100 ± 0.2300 | 61.0 |
| dFdC | 0.0040 ± 0.0002 | 0.1200 ± 0.0300 | 30.0 |
| 2CdA | 0.0700 ± 0.0060 | 17.10 ± 2.8200 | 244.0 |
| Ara‐G | >1000 | >1000 | – |
| Ara‐C + Ara‐G | 0.1000 ± 0.0800 | 0.2300 ± 0.0500 | 2.3 |
| CPT‐11 | 0.0080 ± 0.0002 | 0.0400 ± 0.0040 | 5.0 |
Cells were treated with each agent for 72 h, followed by the determination of IC50 using the XTT assay. RR, relative resistance calculated as the ratio of the IC50 of HL‐60/ara‐C60 cells relative to that of HL‐60 cells. Ara‐C, cytarabine; dFdC, gemcitabine; 2CdA, cladribine; CPT‐11, irinotecan; ara‐G, 9‐β‐d‐arabinofuranosylguanine; ND, not determined due to insensitivity to ara‐G. Values for IC50 are the means ± SD.