Table 1.

Radiation parameters of the four human tumour cell lines, for VRL and VFL; mean values ± standard error.

Cell line	Conc. (nM)	IC-value*	N	Mean MID	Mean ID50	Mean DEF	Mean CI
	VRL
ECV304	0		13	3,23 ± 0,14	2.71 ± 0.15
	4	IC15	8	2,45 ± 0,24a	1.88 ± 0.23a	1.49 ± 0.13	0.89 ± 0.01	slight synergism
	6	IC30	9	2,10 ± 0,21a	1.56 ± 0.16a	1,97 ± 0,26	0,77 ± 0,01	moderate synergism
CAL-27	0		9	3,23 ± 0,12	2.99 ± 0.12
	2,5	IC45	9	2,22 ± 0,20a	1.68 ± 0.19a	1,92 ± 0,24	0,69 ± 0,01	synergism
	3,5	IC75	8	1,81 ± 0,24a	1.33 ± 0.17a	2,49 ± 0,41	0,51 ± 0,01	synergism
MCF-7	0		19	3.26 ± 0.12	2.80 ± 0.16
	3	IC20	17	2.66 ± 0.17a	2.00 ± 0.15a	1.48 ± 0.05	0.93 ± 0,02	additivity
	4	IC55	11	2.55 ± 0.28a	1.94 ± 0.21a	1.47 ± 0.10	0.78 ± 0,04	moderate synergism
H292	0		16	3,69 ± 0,10	2.91 ± 0.10
	3	IC10	15	3,18 ± 0,18	2.51 ± 0.16	1,19 ± 0,06	0,97 ± 0,02	additivity
	4	IC20	5	2,59 ± 0,27a	2.00 ± 0.22a	1,36 ± 0,06	0,83 ± 0,04	moderate synergism
	VFL
ECV304	0		5	3.18 ± 0.25	2.46 ± 0.28
	30	IC10	5	2.12 ± 0.26	1.56 ± 0.16	1.57 ± 0.11	0.84 ± 0.01	moderate synergism
	50	IC25	5	1.66 ± 0.08a	1.26 ± 0.05a	1.93 ± 0.14	0.71 ± 0.01	moderate synergism
CAL-27	0		5	3.24 ± 0.13	2.81 ± 0.17
	25	IC40	4	2.48 ± 0.23	2.01 ± 0.26	1.41 ± 0.09	0.98 ± 0.04	additivity
	30	IC70	4	1.63 ± 0.06a	1.22 ± 0.05a	2.29 ± 0.23	0.57 ± 0.02	synergism
MCF-7	0		4	4.00 ± 0.34	3.18 ± 0.26
	30	IC40	4	3.07 ± 0.38	2.29 ± 0.29	1.42 ± 0.13	0.77 ± 0.01	moderate synergism
	40	IC60	4	1.93 ± 0.16a	1.48 ± 0.14a	2.24 ± 0.08	0.54 ± 0.01	synergism
H292	0		4	5.16 ± 0.36	4.42 ± 0.31
	30	IC10	4	4.55 ± 0.64	3.55 ± 0.46	1.29 ± 0.14	1.27 ± 0.12	additivity
	40	IC40	3	3.60 ± 0.21a	3.03 ± 0.20a	1.53 ± 0.02	0.77 ± 0.03	moderate synergism

N = number of experiments

MID = mean inactivation dose

ID50 = radiation dose causing 50% growth inhibition

DEF = Dose Enhancement Factor

CI = Combination Index

^a p < 0.01 compared to control (0 nM VFL)

* IC-value represents the concentration of VRL or VFL causing a specific percentage of inhibition of cell growth