BACKGROUND Inadequate extracellular conditions can adversely affect the environment of the ER and impinge on the maturation of nascent proteins. The resultant accumulation of unfolded proteins activates a signal transduction pathway, known as the unfolded protein response, which serves primarily to protect the cell during stress and helps restore homeostasis to the ER. PRINCIPAL FINDINGS Micr...

Microparticles (MPs) are small fragments generated from the plasma membrane after cell stimulation or apoptosis. We have recently shown that MPs harboring the morphogen Sonic Hedgehog (MPs(Shh+)) correct endothelial injury by release of nitric oxide from endothelial cells [Agouni, Mostefai, Porro, Carusio, Favre, Richard, Henrion, Martínez and Andriantsitohaina (2007) FASEB J., 21, 2735-2741]. ...

The majority of deaths from prostate cancer occur in patients with androgen-insensitive metastatic disease. An important early event in the development of the metastatic phenotype is the induction of genes that promote angiogenesis, such as vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8), which are released from tumor cells into their microenvironment. Coincident with progres...

Secreted phospholipases A2 (sPLA2s) are extracellular enzymes that catalyze the release of free fatty acids and lysophospholipids from membrane phospholipids and also bind to different receptors (e.g., PLA2R1 or integrins). To date, 12 mammalian sPLA2s have been identified, which play a critical role in pathophysiological processes including inflammation and cancer. sPLA2s activate immune cells...

Mast cells (MC) are granulated secretory cells that have long been recognized as a rich source of biologically highly active mediators such as biogenic amines, prostaglandins, leukotrienes, proteases, cytokines and chemokines. Most of their biological functions however has been rather elusive. There are now emerging data assigning these cells a relevant role in orchestrating angiogenesis, both ...

Angiogenesis, the development of new blood vessels from an existing vascular bed, is essential for the growth and spread of malignant tumors. Several endogenous angiogenesis inhibitors have been discovered and shown to suppress endothelial cell function in vitro and tumor growth in vivo. Several of these are proteolytic fragments of larger, endogenous proteins. Here we show that a Mr 50,000 pol...

During organ development and remodeling, macrophages support angiogenesis, not only by secreting proangiogenic growth factors and matrix-remodeling proteases, but also by physically interacting with the sprouting vasculature to assist the formation of complex vascular networks. Recent data further indicate that embryonic and tumor-associated macrophages express similar genetic programs, possibl...

This paper develops a simple mathematical model of the sitting of capillary sprouts on an existing blood vessel during the initiation of tumour-induced angiogenesis. The model represents an inceptive attempt to address the question of how unchecked sprouting of the parent vessel is avoided at the initiation of angiogenesis, based on the idea that feedback regulation processes play the dominant ...