Download Research Focus in Biochemistry of Stem Cells - Ruhr

Research Focus in Biochemistry of Stem Cells
Faculty of Medicine
1) Mesenchymal stem cells for regenerative medicine: Prof. Köller
2) Regenerative Medicine in Plastic Surgery: Prof. Steinsträsser
3) Ionophores as selective inhibitors of tumor stem cells and first approaches
to clarify the underlying mechanisms: Dr. Bühler/Prof Adamietz
4) Epigenetics Changes in Tumor Cells: PD Dr. Mirmohammadsadegh
Research Focus
Prof. Dr. rer.nat. Manfred Köller
Surgical Research
University Hospital Bergmannsheil Bochum
Surgical Research (Prof. Dr. Manfred Köller)
Major research topics
Harvest and cultivation of mesenchymal stem cells
Differentiation of MSC
Interaction of MSC with biomaterials
Autologous plasma clot carrier matrices
for bone fracture healing and
neuroregeneration
Interaction of MSC with nanoparticles
Surgical Research, Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil, Bochum
Mesenchymal stem cells for regenerative medicine
Clinical success of stem cell research is related to clinically
important answers
How to make stem cells morph into the cell type needed
(is that really needed ??)
How to ensure the survival of stem cells ?
How to home stem cells to sites
of injury ?
What is the optimal application
method under clinical conditions ?
MSC cultured on a porous calcium phosphate
particle for fracture healing (calcein-AM / PI- stain)
Mesenchymal stem cells for regenerative medicine
Clinical Strategies
Example: Osteogenic differentiation of MSC induced by supernatants of activated leukocytes
(Alizarin red staining)
Cell culture
medium
Non-Activated leukocyte
medium
Activated leukocyte
medium
Laboratory of Molecular Oncology
and Wound Healing
Department of Plastic Surgery, Burn Centre
Prof. Dr. Lars Steinsträßer and Dr. Frank Jacobsen
In vivo Models:
- Rat
- Mouse
- Pig
Human full skin model
Proteomics
and
Pathophysiology
Wound
healing
Host Defense Peptides
Gene therapy approach
Cell seeded scaffolds
Artificial skin
In vivo Models:
- athymic mice
- syngenic (BFS-1) mice
In vitro and ex vivo tissue analysis
Oncology of
soft tissue
sarcoma
Oncolytic peptides as an
alternative for
sarcoma treatment
Primary sarcoma
Gene expression profiles,
Mutation analysis, chromosome profiling
Metastasis
Ionophores as selective inhibitors of tumor stem cells and first
approaches to clarify the underlying mechanisms.
Na+K+ATPase activity might be the crucial factor.
Dr. H. Bühler, Institut für Molekulare Onkologie, Strahlenbiologie und Experimentelle
Strahlentherapie (IMOSES), Klinikum Marienhospital
The stem cell hypothesis in cancer:
„Tumors and recurrences originate from tumor stem cells“
We need specific therapeutic agents!
a
b
<- E-cadherin
CD24
negative
<- vimentin
CD44
positive
breast cancer
stem-like cells
IMOSES
<- keratin 18
a= wild type; b= epithelial)
Test system for
selective inhibitors:
two subclones from a
breast cancer cell line:
• isolated stem cells
• epithelial clone via the
transfection of keratin 18
The viability of cancer stem cells is strongly reduced by salinomycin
or narasin, whereas the epithelial clone is only marginally affected.
MTS [OD]
140
viability [MTS]
120
120
100
100
80
80
60
E
MDA231-St
MDA231-K18
60
40
40
20
St
20
0
0
0
0
10-7
5*10-7
10-6
5*10-6
10-5
10-7
10-6
5*10-5
10-5
10-4
narasin [M]
Salinomycin [M]
both are ionophors for monovalent kations, e.g. Na+ und K+
intracellular K+ ist essential for the cell
a Na+/K+-gradient has to be maintained against the interstitial fluid
the main player is the enzyme Na+-K+-ATPase
IMOSES
Hypothesis:
Tumor stem cells are more sensitive to salinomycin, due to a
less active Na+-K+-ATPase compared to somatic cells.
Adding hellebrin to the epithelial cells
brings both graphs in line.
But qRT-PCR of Na+K+ATPase expression revealed no significant difference between stem cells and the epithelial clone.
MTS [OD]
140
E-cadherin
120
100
80
Na-K-ATPase
60
40
20
0
231K
231K+Hel 10-8
231K+Hel 2,5x10-8
231-St
0
5*10-7
epithelial
10-6
5*10-6
10-5
Salinomycin [M]
However, a significantly lower concentration of ATP was observed in the stem cells.
Hellebrin is a potent inhibitor of the
Na+-K+-ATPase
1800
The
Na+K+ATPase
membrane transport
is very energy consuming:
3 ATP are needed for
every pair of kations.
luminescence
1500
1200
900
600
300
IMOSES
stem cells
0
MDA231-K
MDA231-St
Pathologie Bochum
Epigenetics Changes in Tumor cells
Alireza Mirmohammadsadegh
Institut für Pathologie
Ruhr-Universität Bochum
www.pathologie-bochum.de
Epigenetic gene-silencing events and tumorigenesis
Study of heritable changes in gene expression or
cellular phenotype caused by mechanisms other
than changes in the underlying DNA sequence
Epigenetic gene silencing
&
Epigenetic gene activation
Advances in molecular techniques to study DNA methylation
- Pyrosequencing (Quantitative positional methylation analysis) -
Methylation
CpG-3
CpG-2
CpG-1
Normal
Cancer
Molecular mechanisms of epigenetic gene silencing and activation during
tumor progression
Tumorigenesis
Gene Silencing
Courtesy: Baylin SB (2005) DNA methylation and gene silencing in cancer Nat Clin Pract Oncol 2