Fig. 5

Differential protein-level expression of drug targets is confirmed in VMOs and TNBC VMTs with and without treatment. A Tie2 staining of VMO and B MDA-MB-231 VMT shows differential expression. Vessels are red, tumor is green, and Tie2 protein is blue. Scale bars = 200 μm. C Zoom view of VMO stained with anti-Tie2 antibody. Scale bar = 100 μm D Zoom view of MDA-MB-231 VMT without treatment (control) stained with anti-Tie2 antibody. E Zoom view of MDA-MB-231 VMT treated with 10 nM razuprotafib and stained for Tie2. F Quantification of Tie2 protein expression in VMO, control MDA-MB-231 VMT, and razuprotafib-treated MDA-MB-231 VMT. G Phosphorylated ErbB3 (pHER3) staining of VMO and H HCC1599 VMT shows differential expression. Vessels are red, tumor is green, and pHER3 protein is blue. Scale bars = 200 μm. I Zoom view of VMO stained with anti-pHER3 antibody. Scale bar = 100 μm. J Zoom view of HCC1599 VMT without treatment (control) stained with anti-pHER3 antibody. K Zoom view of HCC1599 VMT treated with 100 nM sapitinib and stained for pHER3. L Quantification of HER3 protein phosphorylation in VMO, control HCC1599 VMT, and sapitinib-treated HCC1599 VMT. M Secondary-only IgG control VMO. Scale bar = 200 μm. N Secondary-only IgG control MDA-MB-231 VMT. Scale bar = 200 μm. O Secondary-only IgG control HCC1599 VMT. Scale bar = 200 μm. ns not significant, ***\(p < 0.0001\)