Fig. 1: Vimentin is overexpressed in tumor endothelial cells and is present extracellularly.

a, b Vimentin mRNA (a; n = 3; qPCR) and protein (b; n = 4; flow cytometry) expression in isolated endothelial cells (EC) from human colon tumor (TEC) and normal colon (NEC). c Vimentin mRNA expression in isolated EC from human (colon, n = 13; glioma, n = 2) and murine (glioma, n = 7; melanoma, n = 2) tumors. d Proteomics analysis of human normal colon and colorectal cancer tissues for extracellular vimentin in secretome (left panel; n = 21 (normal), n = 4 (Stage I), n = 8 (Stage II), n = 5 (Stage III & IV)) and total intracellular vimentin (right panel; n = 15 (normal), n = 15 (CRC Stage I–IV)). Data are presented as mean ± SEM in a–d. p values represent paired t test (a, c, d right panel), unpaired t test (b), and one-way ANOVA (d left panel). e Immunofluorescent staining of fixated and permeabilized HUVEC (left panels) and live intact HUVEC (right panels). Inset: negative control. Representative images of at least three independent experiments are shown. f Schematic representation of vimentin localization (in green). g Western blotting of total cell lysate, ECM deposit, and secretome of HUVEC. Representative sections of at least three independent experiments are shown. h Global proteomics analysis (n = 1) of HUVEC lysate, secretome, and ECM deposit. i (Left) Proportion of known tumor EC markers (TEC, red) among externalized proteins. (Right) Secretion mechanisms among externalized proteins. j Protein–protein interaction analysis using STRING of externalized TEC markers. Opacity levels of the nodes are proportional to secretion abundance. k Effect of angiogenesis inhibitors and cytokines on vimentin secretion. Relative secretion is color-coded according to the legend right of the panel, and agent types are color-coded according to the legend below the panel. l Schematic of different cellular protein secretion pathways. m Effect of different protein secretion mediators on vimentin secretion. Legend as in k. Data are color-coded as mean values of relative secretion in k and m; numbers of samples are presented in the Source Data file. *p < 0.05 based on Kruskal–Wallis test with Dunn’s multiple comparison test correction for k and m. Source data are provided as a Source Data file.