Fig. 4

Invasion behaviour after irradiation. a The area occupied by invading cells surrounding the solid spheroidal core was measured by image analysis and plotted as function of invasion day. Indicated are means ± SD from 5 independent experiments with each 6–8 replicates. Sidak’s test following two-way ANOVA was used to detect significant differences between the means of 3 or more independent groups. A p value ≤ 0.05 was considered statistically significant. Single, double and triple asterisks indicate significant differences with p-values of < 0.05, < 0.01 and < 0.001, respectively. b Maximum invasion radius measured from spheroid centroid on days 7 and 14 after irradiation with 5 Gy or mock-treatment and embedding. Data from 7–12 spheroids per data point (except for BT474 + HDF, day 7: 4 spheroids) are shown as swarm plot, together with mean and SD. Unpaired, two-tailed Students’ t-test was performed with Graphpad Prism8. A p value ≤ 0.05 was considered statistically significant. Single asterisk indicates significant difference with p-value of < 0.05