Soluble VEGFR-1 (sVEGFR-1) acts both as a decoy receptor for VEGFs and as an extracellular matrix protein for 51 integrin. A sVEGFR-1-derived peptide that interacts with 51 integrin promotes angiogenesis. However, canonical signal downstream integrin activation is not induced, resulting into lack of focal adhesion maturation. We performed a gene expression profile of endothelial cells adhering on sVEGFR-1 compared to that of cells adhering on fibronectin, the principal 51 integrin ligand. Three protein kinase-C substrates, adducin, MARCKS, and radixin were differently modulated. Adducin and MARCKS were less phosphorylated whereas radixin was higher phosphorylated in sVEGFR-1 adhering cells, the latter leading to prolonged small GTPase Rac1 activation and induction of a pathway involving the heterotrimeric G protein 13. Altogether, our data indicated endothelial cell acquisition of an highly motile phenotype when adherent on sVEGFR-1. Finally, we indicated radixin as accountable for the angiogenic effect of 51 integrin interaction with sVEGFR-1 that in turn depends on an active VEGF-A/VEGFR-2 signaling.
Endothelial cell adhesion to soluble vascular endothelial growth factor receptor-1 triggers a cell dynamic and angiogenic phenotype.
Specimen part
View SamplesRecessive dystrophic epidermolysis bullosa (RDEB) is a genodermatosis characterized by fragile skin forming blisters that heal invariably with scars. It is due to mutations in the COL7A1 gene encoding type VII collagen, the major component of anchoring fibrils connecting the cutaneous basement membrane to the dermis. Identical COL7A1 mutations often result in inter- and intra-familial disease variability, suggesting that additional modifiers contribute to RDEB course. Here, we studied a monozygotic twin pair with RDEB presenting markedly different phenotypic manifestations, while expressing similar amounts of collagen VII. Genome-wide expression analysis in twins' fibroblasts showed differential expression of genes associated with TGF- pathway inhibition. In particular, decorin, a skin matrix component with anti-fibrotic properties, was found to be more expressed in the less affected twin. Accordingly, fibroblasts from the more affected sibling manifested a profibrotic and contractile phenotype characterized by enhanced -smooth muscle actin and plasminogen activator inhibitor 1 expression, collagen I release and collagen lattice contraction. These cells also produced increased amounts of proinflammatory cytokines interleukin 6 and monocyte chemoattractant protein-1. Both TGF- canonical (Smads) and non-canonical (MAPKs) pathways were basally more activated in the fibroblasts of the more affected twin. The profibrotic behaviour of these fibroblasts was suppressed by decorin delivery to cells. Our data show that the amount of type VII collagen is not the only determinant of RDEB clinical severity, and indicate an involvement of TGF- pathways in modulating disease variability. Moreover, our findings identify decorin as a possible anti-fibrotic/inflammatory agent for RDEB therapeutic intervention.
Monozygotic twins discordant for recessive dystrophic epidermolysis bullosa phenotype highlight the role of TGF-β signalling in modifying disease severity.
Specimen part, Disease
View SamplesPrecociously disseminated cancer cells may seed quiescent sites of future metastasis if they can protect themselves from immune surveillance. However, there is little knowledge about how such sites might be achieved. Here we present evidence that prostate cancer stem-like cells (CSC) can be found in histopathologically negative prostate draining lymph nodes (PDLN) in mice harboring oncogene-driven prostate intraepithelial neoplasia (mPIN). PDLN-derived CSC were phenotypically and functionally identical to CSC obtained from mPIN lesions, but distinct from CSCs obtained from frank prostate tumors. CSC derived from either PDLN or mPIN used the extracellular matrix protein Tenascin-C (TNC) to inhibit T cell receptor-dependent T cell activation, proliferation and cytokine production. Mechanistically, TNC interacted with 51 integrin on the cell surface of T cells, inhibiting reorganization of the actin-based cytoskeleton therein required for proper T cell activation. CSC from both PDLN and mPIN lesions also expressed CXCR4 and migrated in response to its ligand CXCL12, which was overexpressed in PDLN upon mPIN development. CXCR4 was critical for the development of PDLN-derived CSC, as in vivo administration of CXCR4 inhibitors prevented establishment in PDLN of an immunosuppressive microenvironment. Taken together, our work establishes a pivotal role for TNC in tuning the local immune response to establish equilibrium between disseminated nodal CSC and the immune system.
Tenascin-C Protects Cancer Stem-like Cells from Immune Surveillance by Arresting T-cell Activation.
Specimen part
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