Table 3.

Ara‐G and YC137 augmented growth inhibition effects of ara‐C on HL‐60/AD cells

	IC50 (μM)
	HL‐60/AD	RR
Ara‐C	2.70 ± 0.59	34.0
Ara‐C + Ara‐G	0.40 ± 0.14	4.0
Ara‐C + YC137	0.17 ± 0.19	4.3
Ara‐C + Ara‐G + YC137	0.07 ± 0.01	1.4

Cells were incubated with a given nucleoside analog with or without co‐incubation with 10 μM ara‐G or 2.5 μM YC137 for 72 h. The IC₅₀ was determined using the XTT assay. RR, relative resistance calculated as the ratio of the IC₅₀ of HL‐60/AD cells relative to that of HL‐60 cells. Ara‐C, cytarabine; Ara‐G, 9‐β‐d‐arabinofuranosylguanine. Values for IC₅₀ are the means ± SD.