1) Mesenchymal stem cells for regenerative medicine: Prof. Köller

4) Epigenetics Changes in Tumor Cells: PD Dr. Mirmohammadsadegh

3) Ionophores as selective inhibitors of tumor stem cells and first approaches to clarify the underlying mechanisms: Dr. Bühler/Prof Adamietz

Research Focus in Biochemistry of Stem Cells Faculty of Medicine

2) Regenerative Medicine in Plastic Surgery: Prof. Steinsträsser

Research Focus

Prof. Dr. rer.nat. Manfred Köller Surgical Research

University Hospital Bergmannsheil Bochum

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 (Prof. Dr. Manfred Köller)

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

Activated leukocyte

medium

Example: Osteogenic differentiation of MSC induced by supernatants of activated leukocytes

(Alizarin red staining)

Cell culture

medium

Non-Activated leukocyte

medium

Laboratory of Molecular Oncology and Wound Healing

Department of Plastic Surgery, Burn Centre

Prof. Dr. Lars Steinsträßer and Dr. Frank Jacobsen

Wound healing

Human full skin model

Gene therapy approach

Host Defense Peptides

Proteomics and

Pathophysiology

Cell seeded scaffolds Artificial skin

In vivo Models: - Rat - Mouse - Pig

Oncology of soft tissue sarcoma

Gene expression profiles, Mutation analysis, chromosome profiling

Oncolytic peptides as an alternative for

sarcoma treatment

In vivo Models: - athymic mice - syngenic (BFS-1) mice

Primary sarcoma Metastasis

In vitro and ex vivo tissue analysis

IMOSES

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!

CD44

positive

CD24

negative

breast cancer

stem-like cells

<- E-cadherin

<- vimentin

a b

a= wild type; b= epithelial)

<- keratin 18

Test system for

selective inhibitors:

two subclones from a

breast cancer cell line:

• isolated stem cells

• epithelial clone via the

transfection of keratin 18

IMOSES

0

20

40

60

80

100

120

140

MTS [OD]

0 10-7 5*10-7 10-6 5*10-6 10-5 5*10-5

Salinomycin [M]

The viability of cancer stem cells is strongly reduced by salinomycin

or narasin, whereas the epithelial clone is only marginally affected.

St

E

0

20

40

60

80

100

120

viability [MTS]

0 10-7 10-6 10-5 10-4

narasin [M]

MDA231-St

MDA231-K18

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

Hypothesis:

Tumor stem cells are more sensitive to salinomycin, due to a

less active Na+-K+-ATPase compared to somatic cells.

IMOSES

0

20

40

60

80

100

120

140

MTS [OD]

0 5*10-7 10-6 5*10-6 10-5

Salinomycin [M]

231K

231K+Hel 10-8

231K+Hel 2,5x10-8

231-St

Adding hellebrin to the epithelial cells

brings both graphs in line.

Hellebrin is a potent inhibitor of the

Na+-K+-ATPase

But qRT-PCR of Na+K+ATPase expres-

sion revealed no significant difference bet-

ween stem cells and the epithelial clone.

epithelial stem cells

E-cadherin

Na-K-ATPase

However, a significantly lower concentra-

tion of ATP was observed in the stem cells.

0

300

600

900

1200

1500

1800

MDA231-K MDA231-St

lum

inescen

ce

The Na+K+ATPase

membrane transport

is very energy consu-

ming:

3 ATP are needed for

every pair of kations.

Pathologie Bochum

Alireza Mirmohammadsadegh

Institut für Pathologie

Ruhr-Universität Bochum

www.pathologie-bochum.de

Epigenetics Changes in Tumor cells

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) -

Normal

Cancer

CpG-1 CpG-2 CpG-3

Methylation

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