. Author manuscript; available in PMC: 2012 Jan 1.

Published in final edited form as: Cancer Chemother Pharmacol. 2010 Mar 20;67(1):83–92. doi: 10.1007/s00280-010-1287-z

Table 1.

Summary of DOX IC₅₀ values for cell growth inhibition in ng/mL

	Co-incubation			Pre-incubation

[VPA], mM	0	0.5	1.0	0	0.5	1.0
Abrams	60	24.3	13	74.6	26.1	10.3^*
D17	17	10	9	758	193^*	66^*
SAOS2	225.5	117.4^*	120^*	111	64.7^*	53.4^*
SJSA1	104	109.7	77.06	271.3	134.3^*	92.4^*

Cells were plated in 96-well plates and treated with DOX ranging from 0–1,000 ng/mL (Abrams, D17, SAOS2) or 0–3,000 ng/mL (SJSA1). Relative viable cell numbers were determined by Alamar blue reduction and fluorescence detection. For co-incubation, cells were treated for 48 h with VPA and DOX. For pre-incubation, cells were treated with VPA for 48 h prior to 48 h incubation in VPA and DOX. There are larger reductions in IC₅₀ with VPA pre-incubation than co-incubation, with synergism seen only after pre-incubation in three of four cell lines.

synergistic interaction (P < 0.05) determined by Bliss analysis as described in Methods