The objectives of the working group of Pool-Zobel are to improve colon cancer prevention by diet by disclosing associated molecular mechanisms and to develop biomarkers for human intervention studies (http://www2.uni-jena.de/biologie/ieu/et/).

The group is investigating the effects of apple ingredients (apple extract, isolated apple compounds and fermented apple extract) in colon cell lines and in primary human colon cells obtained from colon tissue removed during surgery. A number of endpoints are investigated in the cells, which include cell proliferation, expression of genes of biotransformation (cDNA micro array, real-time PCR and protein expression) and antigenotoxic properties.

Outside of the network, the group also works in a number of areas of basic research. Among others, human cells of different origin (colon, breast, prostate, leucocytes) are being characterized for their susceptibility to cancer risk factors (comparison of detoxification systems, sensitivity towards carcinogens). Here, it is of additional interest to elucidate also how the cells respond to different compounds and phytoprotectants associated with the human diet (e.g. EGCG and other chatechins from green tee, phytohormones from soy like genistein and daidzein or butyrate and propionate from fiber fermentation). They are studied for their potential to modulate gene expression, especially for genes which gene products may contribute to cancer chemoprevention. Such work in the field of molecular nutrition research/molecular toxicology is also important for studying apple compounds in the forthcoming project.

The Böhmer group (http://www2.uni-jena.de/med/zbio) has extensive expertise in the characterization of signal transduction chains, and with respect to mechanisms of gene regulation. In the framework of the previous network activities, reporter-gene assays for several signalling pathways and the isolation of functional promoters for relevant genes were established. A major focus of the work was the functional characterization of DEP-1, a protein-tyrosine phosphatase and a recently identified tumor suppressor in the colon, which can be induced in LT97 adenoma cells by apple constituents and their fermentation products, and in further colon epithelial cell lines by butyrate.

In future work, investigation of the mechanism of expression regulation shall be carried out for of a limited number of genes whose induction by apple constituents has previously been established. Their suitability as biomarkers will also be tested. A promoter of DEP-1 has been cloned which will allow efficient analysis of expression control. Another gene of particular interest encodes the enzyme GST-T2 for which promoter constructs are likewise available. With the help of reporter assays different components of apple extracts will be analysed for their role in expression regulation of these genes. Further, promoter elements which confer the regulation shall also be identified.

Outside the network the group has mainly worked on the regulation of signal transduction in normal and cancer cells by protein-tyrosine phosphatases and by tyrosine kinase inhibitors.

The research group Wölfl (http://ipmb.uni-hd.de/) is involved in development and application of methods for »Functional Genomanalysis«. One focus is the optimized use of genome wide gene expression profiling and the application of proteinarrays for the detection of changes (immediate changes) on protein level, in particular the activation of signalproteins. These methods are used to study changes of cellular regulation and of cellular metabolism in response to external signals and in difference between »healthy« and »disease« cells with the aim to find significant changes, which allow identification of underlying cellular mechanisms and of »Biomarkers«. In the present part of the project we collected and analyzed gene expression profiles of human colon-epithelia samples and from tissue culture models. With this work some potential new »Biomarkers« were identified.

In the ongoing work we will focus on the comparison of the cellular regulation of various tissue culture systems in response to apple extracts and related molecules. A particular focus will be the analysis of changes in signalpathway activation with phsophorylation specific antibody arrays. Combined with the analysis of gene expression profiles this should lead to an elucidation of he interplay between signaling pathways in response to the treatment with apple extracts (or fermentations products).

Outside of the network we are involved in various research networks using our methods for functional genome analysis in the study of diseases and in drug screening. Other research topics are: the development of biosensors for toxicity testing, in particular genotoxicity, and the development of miniaturized assay systems for bio-analytics.

Period: 1.7.2005 – 31.6.2009