Mapping the extracellular and membrane proteome associated with the vasculature and the stroma in the embryo.

In order to map the extracellular or membrane proteome associated with the vasculature and the stroma in an embryonic organism in vivo, we developed a biotinylation technique for chicken embryo and combined it with mass spectrometry and bioinformatic analysis. We also applied this procedure to implanted tumors growing on the chorioallantoic membrane or after the induction of granulation tissue. Membrane and extracellular matrix proteins were the most abundant components identified. Relative quantitative analysis revealed differential protein expression patterns in several tissues. Through a bioinformatic approach, we determined endothelial cell protein expression signatures, which allowed us to identify several proteins not yet reported to be associated with endothelial cells or the vasculature. This is the first study reported so far that applies in vivo biotinylation, in combination with robust label-free quantitative proteomics approaches and bioinformatic analysis, to an embryonic organism. It also provides the first description of the vascular and matrix proteome of the embryo that might constitute the starting point for further developments.

[Mechanisms of cancer angiogenesis]. / Mechanizmy angiogenezy nowotworowej.

The early stages of tumor growth are independent of blood vessels. When a tumor reaches a volume of approximately 2 mm3, it requires an oxygen and nutrient supply, like other tissues. Satisfaction of the metabolic demands of tumor tissue occurs through neovascularization, which is also called tumor angiogenesis. The best-characterized mechanism of new vessel formation is endothelial cell sprouting. This three-step process involves dilation of a preexisting vessel and basement membrane degradation as well as endothelial cell proliferation and migration, which lead to the restoration of vessel continuity. Eventually, a new vascular basement membrane is deposited and proliferating pericytes are recruited to stabilize the newly formed vessels. Other examples of tumor neovascularization are intussusceptive and glomerular angiogenesis. Since endothelial cell recruitment, proliferation, and migration is not required, they proceed faster and at lower energetic costs. These types of angiogenesis predominate in the colon, stomach, thymus, and skin cancers as well as gliosarcomas mulitiforme. Moreover, tumors can also be fed by co-opting host vessels or by forming "pseudovessels" in angiogenesis mimicry. All the processes mentioned in this review are not mutually exclusive; on the contrary, they are closely connected in many cases.Therefore, effective anticancer therapies should not only focus on diminishing the activity of proangiogenic factors targeted during vessel sprouting, but include the great variety of vessel factors.

[Atelocollagen as a potential carrier of therapeutics]. / Atelokolagen jako potencjalny nosnik terapeutyków.

Collagen is a very abundant protein that makes up about 25% of the total protein in animal organisms. Of the 28 types of collagen described so far, type I is the most common. Applying collagen in medical treatment is dangerous and may be harmful to patients due to its high immunoreactivity and the risk of contamination with viruses or prions. The immunogenicity of collagen I can be significantly reduced by digestion with pepsin, resulting in the release of telopeptides containing mostly antigenic epitopes. The major product of the digestion is called atelocollagen, which was used for the first time in tissue engineering already in the 1970s. Recent data indicate that due to its rare properties, such as low immunogenicity, liquid state at 4 degrees C, and solid state at 37 degrees C as well as its strong positive charge (pI 9), it may be used as a carrier of negatively charged proteins and nucleic acids. In addition, such complexes of atecollagen/therapeutics are easy to obtain and, depending upon the concentration of atelocollagen, they may be used to provide therapeutics to the organism locally or in a systemic manner. In this review the practical application of atelocollagen used as a carrier of proteins and nucleic acids (plasmids, antisense oligodeoxynucleotides, and siRNA) to treat inherited diseases and cancers is critically discussed. The observations described indicate that it is an optimal vehicle to transport medication which may be used in vivo with very limited risk. Therefore, atelocollagen has the potential to contribute significantly to the further development of gene therapy.