Abstract
Aberrant extra-vascular expression of VE-cadherin has been observed in metastasis associated with Vasculogenic Mimicry (VM); we have recently shown that in VM prone (VM+) tumor cells VE-cadherin is mainly in the form of pVE-cadherin in Y658 allowing an increased plasticity that potentiates VM development. As excessive VE-cadherin phosphorylation is regulated by the phosphatase VEPTP in endothelial cells in the current study we analysed its role in this aberrant phenotype in malignant tumor cells. We show that human malignant melanoma cells VM+, also express VE-PTP although at lower levels than endothelial cells. The complex VE-PTP/VE-Cadherin/p120-catenin act as a safeguard to prevent VE-cadherin degradation by autophagy. Indeed, silencing of VE-PTP results in complete degradation of VE-cadherin with the features of autophagy and increases the global p120 tyrosine phosphorylation status. In summary, we show that VE-PTP is involved in VM formation and disruption of VE-PTP/VE-Cadherin/p120 complex results in enhanced autophagy in aggressive VM+ cells.
