. Author manuscript; available in PMC: 2016 Jul 1.

Published in final edited form as: Bioorg Med Chem. 2015 Apr 16;23(13):3542–3551. doi: 10.1016/j.bmc.2015.04.022

Table 1.

Comparison of the cell growth inhibitory effects of mono- and bis-epipodophyllotoxins and etoposide towards K562 cells and etoposide-resistant K/VP.5 cells

Compound	linker size^a	K562 IC₅₀ (μM)	K/VP.5 IC₅₀ (μM)	RR^b	mean NCI-60 cell GI₅₀ (μM)
6a	3	1.27	13.3	10.5	ND
6c	8	0.103	0.556	5.4	ND
6d	10	0.026	0.156	6.0	ND
7a	3	0.525	7.5	14.2	ND^c
7b	6	0.041	0.88	21.5	3.7
7c	8	0.016	0.115	7.4	ND
7d	10	0.044	0.114	2.6	0.47
7e	12	0.067	0.549	8.2	ND
Etoposide^d	-	0.163	2.50	15.4	12^d

Number of methylene groups linking the two piperazine groups.

RR is relative resistance (K/VP.5 IC₅₀) K562 IC₅₀). The K562 and K/VP.5 IC₅₀ values are averages from experiments carried out on two separate days.

1-dose NCI-60 data for this compound is given in Supplemental Figure 3

NCI mean GI₅₀ data from 38 experiments (http://dtp.nci.nih.gov/compare).

ND is not determined.