CD93 maintains endothelial barrier function and limits metastatic dissemination
Kalyani Vemuri, Beatriz de Alves Pereira, Patricia Fuenzalida, Yelin Subashi, Stefano Barbera, Luuk van Hooren, Marie Hedlund, Fredrik Pontén, Cecilia Lindskog, Anna-Karin Olsson, Roberta Lugano, Anna Dimberg
Kalyani Vemuri, Beatriz de Alves Pereira, Patricia Fuenzalida, Yelin Subashi, Stefano Barbera, Luuk van Hooren, Marie Hedlund, Fredrik Pontén, Cecilia Lindskog, Anna-Karin Olsson, Roberta Lugano, Anna Dimberg
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Research Article Oncology Vascular biology

CD93 maintains endothelial barrier function and limits metastatic dissemination

Abstract

Compromised vascular integrity facilitates extravasation of cancer cells and promotes metastatic dissemination. CD93 has emerged as a target for antiangiogenic therapy, but its importance for vascular integrity in metastatic cancers has not been evaluated. Here, we demonstrate that CD93 participates in maintaining the endothelial barrier and reducing metastatic dissemination. Primary melanoma growth was hampered in CD93–/– mice, but metastatic dissemination was increased and associated with disruption of adherens and tight junctions in tumor endothelial cells and elevated expression of matrix metalloprotease 9 at the metastatic site. CD93 directly interacted with vascular endothelial growth factor receptor 2 (VEGFR2) and its absence led to VEGF-induced hyperphosphorylation of VEGFR2 in endothelial cells. Antagonistic anti-VEGFR2 antibody therapy rescued endothelial barrier function and reduced the metastatic burden in CD93–/– mice to wild-type levels. These findings reveal a key role of CD93 in maintaining vascular integrity, which has implications for pathological angiogenesis and endothelial barrier function in metastatic cancer.

Authors

Kalyani Vemuri, Beatriz de Alves Pereira, Patricia Fuenzalida, Yelin Subashi, Stefano Barbera, Luuk van Hooren, Marie Hedlund, Fredrik Pontén, Cecilia Lindskog, Anna-Karin Olsson, Roberta Lugano, Anna Dimberg

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Figure 7

CD93 regulates MMP9 levels in vitro as well as in primary and metastatic sites.

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CD93 regulates MMP9 levels in vitro as well as in primary and metastatic...
(A) Immunofluorescence images of MMP9 (green) in control mLECs (Mock and siCtrl) and mLECs silenced for CD93 (siCD93-4 and siCD93-5) with/without VEGF (10 ng/mL, 5 minutes). Actin and nuclei were visualized by phalloidin (red) and Hoechst (blue). Scale bars: 20 μm. (B). Quantification of MMP9 levels in mLECs. *P < 0.05, **P < 0.01 by 1-way ANOVA with Tukey′s multiple-comparison test (3 independent experiments). (C) Real-time qPCR showing Mmp9 mRNA levels in control mLECs (mock and siCtrl) and CD93-silenced mLECs (siCD93-4 and siCD93-5) with/without VEGF (3 independent experiments). **P < 0.01, ***P < 0.001 by 1-way ANOVA with Tukey′s multiple-comparison test. (D) Immunofluorescent staining of MMP9 (green) and CD31 (red) in HCmel12 primary tumor from wild-type and CD93–/– mice. Scale bars: 20 μm. (E) Quantification of the area covered by MMP9 normalized to the CD31+ area in wild-type (n = 5) and CD93–/– (n = 7) HCmel12 primary tumor tissue. (F) Immunofluorescent staining of MMP9 (green) and CD31 (red) in metastatic lungs from wild-type and CD93–/– mice. Metastatic lesion of mCherry-HCmel12 tumor cells (TC, gray) are defined by dotted line. Scale bars: 20 μm. (G) Quantification of the area covered by MMP9 around the lung metastatic lesion normalized to the CD31+ area in wild-type (n = 9) and CD93–/– (n = 9) lung metastatic lesions. All immunofluorescence quantifications were performed in a minimum of 4 fields of view/sample. AU, arbitrary units. *P < 0.05; **P < 0.01; ***P < 0.001 by 2-tailed t test (E and G). Values represent mean ± SEM.