(a) Representative bright field (BF) images of in vitro sprouting assay using HUVEC and BP+shCtr or HUVEC and BP+shTie2 co-culture spheroids, respectively. (b) Quantification of average sprout length in in vitro sprouting assay using HUVEC-BP shTie2 co-culture spheroids normalized to HUVEC-BP shCtr co-culture spheroids. (c) Representative images of in vivo plug assay sections using HUVEC-BP shCtr and HUVEC-BP shTie2 co-culture spheroids stained for CD34. (d) Quantification of microvessel density (MVD) in CD34-stained plugs using HUVEC-BP shTie2 co-culture spheroids normalized to HUVEC-BP shCtr co-culture spheroids. Scale bars: 100 μm (a), 50 μm (c). Data are shown as mean±s.d. Statistics were performed using one-way ANOVA (b) and Mann–Whitney U test (d). **P<0.01, ***P<0.001.