Adrenomedullin blockade induces regression of tumor neovessels through interference with vascular endothelial-cadherin signalling.
The cellular and molecular mechanisms by which adrenomedullin (AM) blockade suppresses tumor neovessels are not well defined. Herein, we show that AM blockade using anti-AM and anti-AM receptors antibodies targets vascular endothelial cells (ECs) and vascular smooth muscle cells (VSMCs), and induces regression of unstable nascent tumor neovessels. The underlying mechanism involved, and shown in vitro and in vivo in mice, is the disruption of the molecular engagement of the endothelial cell-specific junctional molecules vascular endothelial-cadherin (VE-cadherin)/β-catenin complex. AM blockade increases endothelial cell permeability by inhibiting cell-cell contacts predominantly through disruption of VE-cadherin/β-catenin/Akt signalling pathway, thereby leading to vascular collapse and regression of tumor neovessels. At a molecular level, we show that AM blockade induces tyrosine phosphorylation of VE-cadherin at a critical tyrosine, Tyr731, which is sufficient to prevent the binding of β-catenin to the cytoplasmic tail of VE-cadherin leading to the inhibition of cell barrier function. Furthermore, we demonstrate activation of Src kinase by phosphorylation on Tyr416, supporting a role of Src to phosphorylate Tyr731-VE-cadherin. In this model, Src inhibition impairs αAM and αAMR-induced Tyr731-VE-cadherin phosphorylation in a dose-dependent manner, indicating that Tyr731-VE-cadherin phosphorylation state is dependent on Src activation. We found that AM blockade induces β-catenin phosphorylation on Ser33/Ser37/Thr41 sites in both ECs and VSMCs both in vitro and in vivo in mice. These data suggest that AM blockade selectively induces regression of unstable tumor neovessels, through disruption of VE-cadherin signalling. Targeting AM system may present a novel therapeutic target to selectively disrupt assembly and induce regression of nascent tumor neovessels, without affecting normal stabilized vasculature.
Aix Marseille Université, CRO2, UMR_S 911, Faculté de Médecine, Marseille, France.|Inserm, U911-CRO2, Marseille, France.
Ghizlane
G
Khalfaoui-Bendriss
Aix Marseille Université, CRO2, UMR_S 911, Faculté de Médecine, Marseille, France.|Inserm, U911-CRO2, Marseille, France.
Nadège
N
Dussault
Aix Marseille Université, CRO2, UMR_S 911, Faculté de Médecine, Marseille, France.|Inserm, U911-CRO2, Marseille, France.
Samantha
S
Fernandez-Sauze
Aix Marseille Université, CRO2, UMR_S 911, Faculté de Médecine, Marseille, France.|Inserm, U911-CRO2, Marseille, France.
Caroline
C
Berenguer-Daizé
Aix Marseille Université, CRO2, UMR_S 911, Faculté de Médecine, Marseille, France.|Inserm, U911-CRO2, Marseille, France.
Romain
R
Sigaud
Aix Marseille Université, CRO2, UMR_S 911, Faculté de Médecine, Marseille, France.|Inserm, U911-CRO2, Marseille, France.
Christine
C
Delfino
Aix Marseille Université, CRO2, UMR_S 911, Faculté de Médecine, Marseille, France.|Inserm, U911-CRO2, Marseille, France.
Mylène
M
Cayol
Aix Marseille Université, CRO2, UMR_S 911, Faculté de Médecine, Marseille, France.|Inserm, U911-CRO2, Marseille, France.
Philippe
P
Metellus
Aix Marseille Université, CRO2, UMR_S 911, Faculté de Médecine, Marseille, France.|Inserm, U911-CRO2, Marseille, France.
Olivier
O
Chinot
Aix-Marseille Université, CNRS, UMR 7273, Institut de Chimie Radicalaire (ICR) Marseille, France.
Kamel
K
Mabrouk
Aix Marseille Université, CRO2, UMR_S 911, Faculté de Médecine, Marseille, France.|Inserm, U911-CRO2, Marseille, France.|AP-HM, CHU Nord, Service de Transfert d'Oncologie Biologique, Marseille, France.
Pierre-Marie
PM
Martin
Aix Marseille Université, CRO2, UMR_S 911, Faculté de Médecine, Marseille, France.|Inserm, U911-CRO2, Marseille, France.|AP-HM, CHU Nord, Service de Transfert d'Oncologie Biologique, Marseille, France.
L'Houcine
L
Ouafik
D053607:Adrenomedullin / Q000378:metabolism*; D000818:Animals; D004730:Endothelium, Vascular / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D018919:Neovascularization, Physiologic / Q000502:physiology*; D010766:Phosphorylation; D015398:Signal Transduction; D051176:beta Catenin / Q000378:metabolism*
D051176:beta Catenin; D053607:Adrenomedullin
VE-cadherin; adrenomedullin; angiogenesis; tumor neovessels; β-catenin