Projektleiter und Institution
Prof. Dr. Andrea Tannapfel, Universitätsklinik Leipzig, Institut für Pathologie
Prof. Dr. Adrian Gillissen, Robert-Koch-Klinik, Klinikum „St. Georg”, Leipzig
Prof. Dr. Dr. Wataru Yasui, Hiroshima University, Department of Molecular Pathology
Stipendiatin
Cornelia Köhler
DNA methylation is a crucial component of the epigenetic control of gene activity
through the regulation of chromatin state. It has been found that DNA methylation
is required for protecting chromosomes and it is involved in recognition of parental
DNA strands during mismatch repair [1]. DNA methylation also plays a very important role in regulating the spatial distribution
of gene expression [2]. A number of factors involved in this process, such as methyl-binding proteins and
histone-deacetylases have been identified [3]. Similar to other somatic genome alterations present in cancer cells, including
gene deletions and gene mutations, DNA methylation changes often affect gene function;
methylation of CpG dinucleotides clustered into CpG islands encompassing the transcriptional
regulatory region of genes has been associated with transcriptional “silencing“ of
many critical genes in cancer cells. Unlike other somatic genome alterations in cancer
cells, however, DNA methylation changes typically do not disrupt DNA sequence. For
this reason, somatic changes in DNA methylation in cancer cells are thought to be
potentially reversible “epigenetic“ genome lesions, rather than irreversible “genetic“
genome alterations [4].
If suitable CpG markers are identified that are selectively hypermethylated in lung
cancer (LC) but not in normal epithelium. They could be potential markers useful in
classifying LC and defining subgroups of patients, as well as lend themselves to diagnosis
of occult disease or recurrence. The detection of methylation of particular sets of
genes could help select patients that respond well to certain drugs. Importantly,
these studies will interact with preclinical and early clinical studies underway for
compounds that reverse methylation-induced transcriptional silencing and thus have
tremendous potential for translation to the clinic [5].
To additionally define epigenetic modifications and order of epigenomic events at
CpG islands on a global scale, a microarray system that combines gene expression,
DNA methylation, and DNA-protein interaction analyses comparing results from lung
cancer tissue with specimens from healthy bronchi/lung tissue will be employed in
the network as platform technique [6].
Our study represents a genomic approach that is capable of dissecting the complex
hierarchy of transcriptional controls orchestrated by the epigenomic machinery. This
integrated microarray system allows for both the identification of individual genes
and a systematic analysis of the relationship among the epigenetic machinery, promoter
targets, and downstream responses regulated by the epigenome.
We plan to generate array data in the lab of Professor Yasui, Hiroshima, Japan, which
is an internationally accepted and well-known experts in the field of methylation/acetylation.
He is willing to generate the biological as well as bioinformatory data of our project.
Within the network, the applicant is collecting tumour specimen of patients with LC.
The analysis will take place in the Hiroshima lab.
Data validation and candidate methylation screening will be the second part of the
project and take place in Leipzig (Institute of Pathology and St. George Medical Center,
Robert-Koch-Hospital).
The objectives will be at follows:
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Identification of epigenitically altered genes for targeted therapy of lung cancer.
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Screening for possible methylation targets in Hiroshima/Japan using microarrays and
sequencing. Implementing these methods in Leipzig and subsequent biological assessment
in lung cancer specimens.
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Identification of methylated genes in lung cancer responsible for tumorgenesis with
the intent of therapeutic intervention by reversing methylation, thereby reactivating
the silenced gene.
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Comparing these data with healthy bronchopulmonary tissue.
The program has three integral parts which take place in Japan and Leipzig. The applicant
has to learn the microarray technique in the Yasui lab, using tumour specimen from
Germany (tumour bank Robert-Koch-Hospital).
All patients with bronchial carcinoma (NSCLC and SCLC) will be included as far as
tumour tissue can be obtained and written consent of voluntary participation is obtained.
We expect about 70 % NSCLC and 30 % SCLC. Using the tumour bank of the Robert-Koch-Hospital
500 patients may be included over time once specimen collection and documentation
of these patients are already in place. Once the NSCLC is expected to be the majority
the patients will be statistically divided in three groups: a) NSCLC (Stadium I-IIIA),
b) NSCLC (Stadium IIIB-IV), c) SCLC.
The identified candidate genes will be assessed in a large series of tumour. The biological
relevance (is the identified gene a tumour suppressor?) will be analysed in the Institute
of Pathology. The identified gene will be transfected into a cell culture system to
be able analyse possible effects on cell cycle and marker expression.
The project was designed as a collaboration project to obtain data from Leipzig's
patients using the Japanese chip technology and biostatistics (Abb. [1]). The project as described above does already exist for gastrointestinal tumors.
Thus, lung tumor specimen will be newly included in an already existing international
scientific network collaboration effort. Therefore, the network will be expanded by
a new organ tumour (lung cancer), using an already existing methodological platform.
The advances of these complex techniques will be transferred to both German partners.
The pre-existing network will be further expanded covering pulmonary oncology as well.
Fig. 1 Project description (see text for details) in which the scholarship will be embedded.
