Mature and progenitor endothelial cells perform angiogenesis also under protease inhibition: the amoeboid angiogenesis

Abstract

BackgroundControlling vascular growth is a challenging aim for the inhibition of tumor growth and metastasis. The amoeboid and mesenchymal types of invasiveness are two modes of migration interchangeable in cancer cells: the Rac-dependent mesenchymal migration requires the activity of proteases; the Rho-ROCK-dependent amoeboid motility is protease-independent and has never been described in endothelial cells.MethodsA cocktail of physiologic inhibitors (Ph-C) of serine-proteases, metallo-proteases and cysteine-proteases, mimicking the physiological environment that cells encounter during their migration within the angiogenesis sites was used to induce amoeboid style migration of Endothelial colony forming cells (ECFCs) and mature endothelial cells (ECs). To evaluate the mesenchymal-ameboid transition RhoA and Rac1 activation assays were performed along with immunofluorescence analysis of proteins involved in cytoskeleton organization. Cell invasion was studied in Boyden chambers and Matrigel plug assay for the in vivo angiogenesis.ResultsIn the present study we showed in both ECFCs and ECs, a decrease of activated Rac1 and an increase of activated RhoA upon shifting of cells to the amoeboid conditions. In presence of Ph-C inhibitors both cell lines acquired a round morphology and Matrigel invasion was greatly enhanced with respect to that observed in the absence of protease inhibition. We also observed that the urokinase-plasminogen-activator (uPAR) receptor silencing and uPAR-integrin uncoupling with the M25 peptide abolished both mesenchymal and amoeboid angiogenesis of ECFCs and ECs in vitro and in vivo, indicating a role of the uPAR-integrin-actin axis in the regulation of amoeboid angiogenesis. Furthermore, under amoeboid conditions endothelial cells seem to be indifferent to VEGF stimulation, which induces an amoeboid signaling pattern also in mesenchymal conditions.ConclusionHere we first provide a data set disclosing that endothelial cells can move and differentiate into vascular structures in vitro and in vivo also in the absence of proteases activity, performing a new type of neovascularization: the “amoeboid angiogenesis”. uPAR is indispensable for ECs and ECFCs to perform an efficient amoeboid angiogenesis. Therefore, uPAR silencing or the block of its integrin-interaction, together with standard treatment against VEGF, could be a possible solution for angiogenesis inhibition.Electronic supplementary materialThe online version of this article (10.1186/s13046-018-0742-2) contains supplementary material, which is available to authorized users.

microRNA-378a-5p iS a novel positive regulator of melanoma progression

“…Through its interaction with integrins, we previously reported that uPAR is able to affect melanoma invasion, migration and response to therapy 33 . We also demonstrated that the M25 linear peptide was able to uncouple uPAR from integrins thus affecting its functions 33,34 . On the basis of these evidences, we reasoned that inhibition of uPAR functions with M25 peptide could produce functional effects similar to those obtained with uPAR silencing by means of si-uPAR.…”

“…Inhibition of uPAR-integrin interaction was obtained with the M25 peptide (STYHHLSLGYMYTLN), previously identified in a phage display library 55 and produced by PRIMM srl (Milan, Italy). Its sequence spans an exposed loop on the ligand-binding surface of integrin α chain and uncouples the interaction of the α-chain of integrin with uPAR, thus impairing uPAR functions 33,34 .…”

EGFR/uPAR interaction as druggable target to overcome vemurafenib acquired resistance in melanoma cells

“…In this paper we provide a strong evidence that the well known and characterized uPA receptor (uPAR) acts not only as a promoter of proliferation, invasiveness and angiogenesis in melanoma and other cancer cell lines [[42], [43], [44], [45]] but also as a factor contributing to the development of drug resistance. Indeed, we found a remarkable direct association between uPAR and EGFR co-expression levels and vemurafenib responsiveness inV600E BRAF mutated melanoma cells.…”

“…As a matter of fact, uPAR is a glycosylphosphatidylinositol-anchored membrane protein which associates with integrins and RTKs such as EGFR to form a potent signaling complex [31,37,45]. uPAR is overexpressed in many human malignancies including melanomas [[46], [47], [48], [49]] and is associated with a worse prognosis especially among breast cancer and esophageal carcinomas.…”

The novel chromatin architectural regulator SND1 promotes glioma proliferation and invasion and predicts the prognosis of patients

“…Our results reveal that SND1 facilitates the proliferation and invasion of glioma cells. We identified RhoA, a small GTPase implicating cancer proliferation, apoptosis, angiogenesis, migration, and invasion, [11][12][13][14] as a potential target of SND1 through human GBM mRNA profiling and bioinformatics analyses. The regulatory mechanism and biologic effects of SND1 and RhoA were also determined.…”