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Angiogenesis

List of -TEMs -PEMs -NEMs

TEMs TEM1 TEM2 TEM3 TEM4 TEM5 TEM6 TEM7 TEM8 TEM9 TEM10 TEM11 TEM12 TEM13 TEM14 TEM15 TEM16 TEM17 TEM18 TEM19 TEM20 TEM21_1 TEM21_2 TEM22 TEM23 TEM24 TEM25 TEM26 TEM27 TEM28 TEM29 TEM30 TEM31_1 TEM31_2 TEM32 TEM33 TEM34 TEM35 TEM36 TEM37 TEM38 TEM39 TEM40 TEM41 TEM42 TEM43 TEM44 TEM45 TEM46

Summary -Overview of TEMs -extracellular TEMs -intrac. & membrane TEMs -TEM tissue distribution

Supplementary -SAGE -Seq.analysis Methods

FAQ

Summary of Croix et al

New solutions to an old question

   Tumor angiogenesis is a process of clinical relevance, thus the molecular steps involved are of particular interest. Traditional approaches to link altered gene expression to the clinical phenotype were mostly focused on the analysis of single gene effects. Recently developed high true put approaches have provided a way to study functional relationships on a multifactorial bases, allowing the characterization of a process, a network rather than a gene, a nodal point of a network. Such techniques have increasingly been used in the description of angiogenesis, mostly relying on in vitro endothelial systems that allow a controlled switch between different phenotypical steps.

The publication that initiated this protein study

   A SAGE-analysis performed by Croix et al, aimed at uncovering genes expressed differentially in tumor-associated versus normal endothelium. Such genes supply a molecular basis for understanding the process of angiogenesis and are of potential interest for the development of anti-angiogenic cancer therapies. The approach taken by the researchers in their study is outlined in the following:

1. Isolation of endothelial cells from tissue specimens is a difficult task as the cells of interest constitute only a small fraction of the cells in a particular tissue.Human colon cancer was chosen for the study for its high incidence, and angiogenesis dependent growth. Negative selection of non-endothelial cells was achieved in multiple steps applying mechanical and immunological techniques. Positive selection of endothelial cells was based on immunological methods.

2. SAGE analysis of the obtained material results in the generation of SAGE-libraries for non-endothelial and endothelial cells containing around 96 000 tags each (corresponded to over 16 000 transcripts each). Differentially expressed tags were classified as follows:

• PEMs, pan endothelial markers. They are expressed preferentially in tumor-associated and normal endothelium compared to other cell-types. A total of 93 tags matching this category have been published.

• TEMs, tumor endothelial markers. They are expressed preferentially in tumor-associated compared to normal endothelium. A total of 46 tags matching this category have been published.

• NEMs, normal endothelial markers. They are expressed preferentially in normal compared to tumor-associated endothelium. A total of 33 tags matching this category have been published.

   Besides the advantages that are common to the SAGE analysis, the use of in vivo material isolate from normal and tumor tissue allows an unbiased characterization of an angiogenic endothelium transcription profile.