Fig. 2: Loss of ephrinB2 in both the cancer cells and the vasculature inhibits tumor growth while knockdown of EphB4 promotes tumor growth progression in orthotopic and xenograft models of HNSCC.
From: EphB4 and ephrinB2 act in opposition in the head and neck tumor microenvironment
Accelerated tumor growth is observed following knockdown of EphB4 on cancer cells in (a) Moc2 [n = 9 (control sh); n = 10 (EphrinB2 sh, EphB4 sh], b Ly2 (n = 10/group), c CUHN013 [upper panel: n = 6 (control sh); n = 6 (EphB4 sh), lower panel: n = 16/group] and d MEER [n = 7 (control); n = 10 (EphB4 KO)] models. Tumor volume data are shown in the form of spaghetti plots to present tumor growth of individual mice for the respective groups in a time-dependent manner. The groups in a–d are annotated based on the tumor cells implanted in the C57BL/6 mice. Dot plots are also shown to present tumor volumes on day 19 (Moc2), day 24 (Ly2), day 22 (CUHN013), and day 33 (MEER) post tumor implantation. a–c EphrinB2 knockdown in the Moc2 tumors reduced tumor growth, whereas, in Ly2 or CUHN013 tumors, ephrinB2 manipulation on cancer cells failed to show a similar effect. e Conditional deletion of ephrinB2 on the vasculature results in a modest decrease in Moc2 tumor growth in EFNB2fl/flTie2-Cre-ERT (n = 7) mice compared to the controls (n = 8) as shown by temporal growth curves and by dot plots at day 17 post-tumor implantation. The group annotation refers to the Moc2 control tumors implanted in either littermate controls (left) or EFNB2fl/flTie2-Cre-ERT mice (right). f Knockout of ephrinB2 in both the tumor cells and the vasculature [Moc2 ephrinB2 KO + EFNB2fl/flTie2-Cre-ERT mice (n = 10)] results in a maximal decline in tumor growth compared to the control counterparts (n = 11) in vivo in a time-dependent manner. Dot plots are shown on day 25 post-implantation. The groups correspond to the Moc2 control tumors implanted in littermate controls (left) or Moc2 ephrinB2 KO tumors implanted in EFNB2fl/flTie2-Cre-ERT mice (right). Data are shown as mean ± SEM. The color key for groups shown in histogram plots (a–f) is the same as depicted in the respective spaghetti plots. (g, h) IncuCyte in vitro assay shows an effect on tumor cell growth following downregulation of EphB4 and ephrinB2 in CUHN013 (g) and Moc2 (h) cell lines (n = 6/group). The experiments were replicated two times. Statistical significance was analyzed by performing two-sided Student’st-test or ANOVA. The Dunnett post-hoc test was used after ANOVA where multiple experimental groups were involved. p-values are indicated for figures a *p = 0.029, b *p = 0.04, c ****p ≤ 0.0001, d ***p = 0.0006, e *p = 0.023, f–h ****p ≤ 0.0001.
