40th Annual meeting

Model Organisms in Molecular Biology and Biomedical Research

Date Wednesday, April 17 - Friday, April 19, 2013
Location Hotel Marienlyst, Helsingør, Denmark
Organizers Cristina Cvitanich, Tuula Kallunki, Ulrik de Licthenberg, Steen Gammeltoft.

Meeting abstract

The 40th Anniversary Annual Meeting of the Danish Biochemical Society will focus on the crossroads of animal models and research in human biology and disease. The use of animals in genetics and pathology has a long tradition in translational research. The introduction of homologous recombination 30 years ago led to gene targeting and numerous knock-out and knock-in animals for exploration of specific gene functions in health and disease. We are proud to present a wide-ranging program, which covers a number of scientific aspects of model organisms in human diseases including developmental biology, autoimmunity, inflammation, metabolism, neurobiology and cancer. The program will include keynote lectures by three outstanding scientists, plenary presentations by national and international speakers, short talks by promising young scientists, posters, networking and social interactions.

Scientific committee: Cord Brakebusch, Birgitte Holst, Ole D. Madsen, Tuula Kallunki.

» Program

» Speakers Abstracts

Registration Information

  • Danish Biochemical Society members: 3750 Kr. (500 €), Non-members 4250 Kr. (570 €).
  • Reduced fee for Ph.D. and Master Students: Members 2750 Kr. (370 €) Non-members: 3250 Kr. (435 €).
  • Participation without accommodation: 2250 Kr. (300 €).
  • One-day participants: 1000 Kr. (135 €).
  • Exhibitors: 4.250 kr. (570 €).

Deadline for registration and abstracts: April 8, 2013.

Scholarships

Danish Society for Biochemistry and Molecular Biology is offering scholarships to Master and PhD Students and Post-doctoral fellows. These scholarships cover the registration including attendance and lodging. Send an e-mail with your application and poster abstract before April 1st, 2013 to Steen Gammeltoft: steen.gammeltoft@gmail.com

Student Discounts

Students enrolled in an undergraduate, M.S., Ph.D. or M.D. program are eligible for an additional 10 % Student Discount rate if you register before April 1st, 2013. When you sign up for the meeting, provide your supervisor's name and e-mail to receive the discount.

Free short-talks

Ph.D. students and Post-doctoral fellows are encouraged to participate and submit abstracts. Eight abstracts will be selected for oral presentation in short talks (15 min) at the meeting. For more information see the program above.

Program

Wednesday 17. April, 2013

11:00-12:00 Arrival and Registration
12:00-13:00 Lunch
13:00-17:00 Session 1: Model organisms in developmental biology
Chair: Cristina Cvitanich, Aarhus University, Denmark.
  • Ralf J. Sommer, Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany. Nematode models in evolution and development.
  • Markus Affolter, BioZentrum, Basel. Cell behavior in vascular remodeling.
  • Anne Grapin-Botton, Danish Stem Cell Centre, University of Copenhagen, Denmark. The mouse model to study pancreas development.
  • Two short talks from abstracts.
17:00-18:00 Posters
18:30-20:00 Dinner
Embo Logo
20:00-21:00 Session 2: EMBO lecture
Chair: Steen Gammeltoft, University of Copehagen, Denmark.
 
  • Matthias Mann, Max Planck Institute, Martinsried, Germany. Proteomics of whole organisms.

Thursday 18. April, 2012

08:00-09:00 Breakfast
09:00-12:00 Session 3: Model organisms in autoimmunity and inflammation
Chair: Cord Brakebusch, BRIC, University of Copenhagen.
 
  • Chantal Mathieu, Clinical and Experimental Endocrinology, Catholic University of Leuven, Belgium. Autoimmunity and inflammation in diabetes.
  • Guru Krishnamoorthy, Department of Neuroimmunology, Max Planck Institute of Neurobiology,
  • Martinsried, Germany. Modeling Multiple Sclerosis: Triggers and pathogenic processes.
  • Jens Brimnes, Alk-Abelló A/S. Animal models in respiratory allergy.
  • Cord Brakebusch, BRIC, University of Copenhagen. RAC1 in keratinocytes regulates crosstalk to immune cells by Arp2/3 dependent control of STAT1.
  • Two short talks for abstracts
12:00-13:00 Lunch
13:00-14:00 Post-lunch walk
14:00-17:00 Session 4: Model organisms in metabolism and neurobiology
Chair: Birgitte Holst, Institute for Neuroscience and Pharmacology, University of Copenhagen.
 
  • Jens Juul Holst, Institute of Biomedicine and Novo Nordisk Centre of Metabolism. Animal models in gut hormone biology.
  • Anders Nykjær, Institute for Biomedicine, Aarhus University. SorCS1, encoded by the Alzheimer's
  • Disease and type 2 diabetes susceptibility gene SORCS1, is a potent regulator of peripheral insulin sensitivity
  • Nils Færgeman, Institute of Molecular Biology, University of Southern Denmark. Dissection of Lipid and
  • Energy Metabolism in the yeast Sacchromyces cerevisiae and the nematode C. elegans.
  • Birgitte Holst, Institute for Neuroscience and Pharmacology, University of Copenhagen. Gut peptides in transgenic mice.
  • Two short talks from abstracts
17:00-18:00 Session 5: Posters and Exhibition
18:00-19:00 Session 6: Keynote lecture
Chair: Eva Arnspang Christensen, University of Southern Denmark.
 
  • Jeff W Lichtman, Molecular and Cellular Biology, Centre for Brain Science, Harvard University, Cambridge, USA. Bio imaging of model organisms.
19:00-21:00 Banquet
21:00-01:00 Party and dance with dj

Friday 19. April, 2012

08:00-09:00 Breakfast
FEBS logo
09:00-10:00 Session 7: THE FEBS NATIONAL LECTURE
Chair: Tuula Kallunki, Danish Cancer Institute.
 
  • Erwin F. Wagner, Genes, Development and Disease Group, CNIO Madrid, Spain. Inflammation and Cancer: Lessons from AP-1(Fos/Jun)-dependent Mouse Models and Humans
10:00-12:00 Session 8: Model organisms in cancer
Chair: Tuula Kallunki, Danish Cancer Institute.
  • Heidi Hahn, Department of Human Genetics, Göttingen Graduate School for Neurosciences, Biophysics and Molecular Biosciences, Germany. The Patched knockout mouse: a model to study pathogenesis and new treatment options of Hedgehog/Patched-associated cancer.
  • Mikaela Egeblad, Cold Spring Harbor Laboratories, USA. Illuminating the influence of the tumor
  • microenvironment on drug resistance and metastasis.
  • Two short talks from abstracts.
12:00-13:00 Sandwiches and soft-drinks
13:00 Departure

Sponsors

Cancer Logo Novo nordisk logo Leo Pharma logo

Secretariat and vendor contact

Vivian Juhl, Danish Biochemical Society. Tel: 50723667. vivian.dyrup.juhl@gmail.com

Abstract

Session 1. Model organisms in developmental biology

Nematode models in evolution and development.

Ralf J. Sommer, Max-Planck Institute for Developmental Biology, Tübingen, Germany. ralf.sommer@tuebingen.mpg.de

Nematodes are the largest animal phylum that is best characterized by species richness, numerical abundance and ecological omnipresence. Comprising of free-living as well as parasitic species, several nematodes became important model systems in modern biology. Most importantly, Caenorhabditis elegans has been at the forefront of research in modern developmental biology, genetics, neurobiology and genomics. After reviewing the state of the art research platforms in C. elegans I will expand to the possibility to develop other nematode species as comparative models for development and evolution. We have developed the distantly related Pristionchus pacificus as a model system in development, but also ecology and evolutionary biology. Among other topics, comparative evolutionary developmental biology (evo-devo) can indicate the conservation (or non-conservation) of the mechanistic principles observed in the selected group of model organisms.

Detailed investigations of vulva formation revealed that developmental mechanisms differ strongly between C. elegans and P. pacificus. I will describe our work on vulva development, providing an example for developmental system drift. While evo-devo results in fundamental insight into the evolution of developmental mechanisms, it also necessitates a synthesis with other areas of evolutionary biology: Synthesis with "population genetics" can reveal how phenotypic evolution is initiated at the micro-evolutionary level and synthesis with "evolutionary ecology" can add an ecological perspective to these evolutionary processes. These case studies will highlight the importance of integrative approaches in modern evolutionary biology.

Cell behavior in vascular remodeling

Anna Lenard, Lukas Herwig, Yannick Blum, Alice Krudewig, Loic Sauteur,  Elin Ellertsdottir, Heinz-Georg Belting and Markus Affolter. Biozentrum?University of Basel, Klingelbergstrasse 50 / 70, Basel, Switzerland. Markus.Affolter@unibas.ch

To form interconnected networks of endothelial tubes, sprouting vessels of the developing vasculature have to connect to each other, a process referred to as anastomosis. Upon blood flow, certain connections are stabilized, while other disappear, a process referred to as pruning. To better understand cell behavior during anastomosis and pruning, we studied how angiogenic sprouts connect to give rise to a fully lumenized vessel (DLAV) in different regions of the zebrafish embryos. To monitor cell behavior and lumen formation concomitantly, we generated novel transgenic fish lines expressing eGFP-fused version of the AJ/TJ protein ZO1 or deletion version of the AJ protein VE-cadherin under indirect control of an endothelial-specific enhancer using the Gal4 system. We found that during anastomosis, tip cells reach each other via filopodial extensions and subsequently establish new contact points by localizing eGFP-ZO1 and VE-Cad to such site of contact. These point-like initial contact sites subsequently elaborate into loop-like structures, suggesting that a pre-apical spot is enlarged into a larger apical membrane compartment between two tip/fusion cells. In 60% of the cases we recorded in vivo, we find that the lumen subsequently extends and grows through the former tip cells from the proximal-most position towards the novel, more distal apical side of the tip/fusion cell. This cell hollowing process is dependent on the previous lumenization of the participating sprouts, suggesting that apical membrane growth and invagination into the tip/fusion cell are driven by plasma pressure. Eventually, cell rearrangements lead to multicellular vascular tubes, a process that involved cell splitting. We also find that a second mechanism is involved in vessel anastomosis. In this scenario, the novel apical membrane patches and the pre-luminal space they surround are brought together through cell rearrangements and eventually establish direct contact, resulting in lumen coalescence and the formation of an extracellular lumen embedded in a regular, multicellular tube. Somewhat to our surprise, we find that vessel pruning represent very much "reverse fusion", and first results from our analyses of pruning will be presented.

Thus, endothelial cells are rather plastic during the process of anastomosis and can connect using distinct mechanisms and generate tubes of different architectures. Pruning appears to be a reversal of fusion, a finding which seems to involve endothelial cell-self fusion in live embryos.

The mouse model to study pancreas development

Anne Grapin-Botton, DanStem, University of Copenhagen, 3B Blegdamsvej, 2200 Copenhagen N, Denmark. anne.grapin-botton@sund.ku.dk

The mouse model is widely used to study organ development, in particular how cells become specified, differentiate and organize into tissues, many decisions that are reproducibly orchestrated in a species and often conserved between species. Understanding our cells´ history is intrinsically interesting but it is also important to engineer these cells for replacement therapy or drug testing, to understand how gene networks lead to cell functionality and to uncover the preferred pathways used in reprogramming. The mouse model, although complex and costly has the advantage of being close to human and amenable to genetics.

These principles can be illustrated on the development of the pancreas. Using mouse genetics, we and others have studied the role of diffusible signals, transcription factors and other proteins in the development of this organ, including the differentiation of the beta cells that produce insulin. This has generated insight into the genetics of certain forms of diabetes as well as protocols to produce pancreatic cell types in vitro from pluripotent stem cells.

Our recent work shows that the control of cell differentiation in the pancreas is tightly associated to the architecture of the organ and that the position of pancreas progenitors in a tridimensional structure forming ducts is important for their differentiation. While imaging helps us to visualize this architecture, mouse genetics allows us to define the genes that control it. This is complemented by three dimensional in vitro systems where cell architecture can be deconstructed and manipulated.

Session 2: THE EMBO LECTURE

High resolution, quantitative mass spectrometry for near comprehensive detection of the proteome

Matthias Mann. Max Planck Institute of Biochemistry, 82152 Martinsried, Germany. Novo Nordisk Foundation Institute for Protein Science, Copenhagen, Denmark. mmann@biochem.mpg.de

Mass spectrometry-based proteomics, particularly in a quantitative and high resolution format, has become a very powerful technology to study gene expression at it ‘end point' - the level of proteins.

Accurate expression changes can now be measured for the entire yeast proteome and for a very large fraction (more than 10,000 proteins) of mammalian proteomes. This will be illustrated using a recent project on 11 commonly used mammalian cell lines. We also pursue, rapid, ‘single shot' analysis, which can now quantify nearly the entire yeast proteome in a few hours. Our group is now interested in applying these technologies to the rapid classification of cancer patients and first examples of these efforts will be presented. 

Our laboratory extensively uses quantitative proteomics data not only for protein expression measurement but also for the detection of specific protein interactions. In this format, protein quantification (by SILAC labeling or in a label-free format) is applied to distinguish background binders from true binders. By quantification of binders to bait molecules vs. a control bait, the need for stringent washes is reduced and transient binders can still be detected. We will describe application of our generic workflow to interactions with specific DNA elements in the genome (such as GWAS derived SNPs or QTLs), RNA structures, post-translational modifications as well as to stimulus dependent interactions in signaling pathways.

Furthermore, MS-based proteomics can analyze post-translational modifications on a very large scale - for example, more than 50,000 phosphorylation sites can readily be detected in a cell line. Here we describe the current state of the technology as developed in our institute with an emphasis on recent developments in instrumentation and computational proteomics.             

Session 3: Model organisms in autoimmunity and inflammation

Vitamin D and inflammation: the case of type 1 diabetes

Chantal Mathieu, Clinical and Experimental Endocrinology, UZ Herestraat 49, 3000 Leuven. chantal.mathieu@uzleuven.be

Type 1 diabetes is an autoimmune disease where beta-cells are destroyed by autoimmune T lymphocytes, but where also inflammatory cytokines like IL1, IFNg and TNFa  contribute to beta-cell damage via inflammation-induced apoptosis. Receptors for the active form of vitamin D, 1,25-dihydroxyvitamin D (1,25(OH)2D3- VDR)) are present in cells throughout the immune system and many immune celltypes can also synthesize 1,25(OH)2D3 under influence of inflammatory signals. Finally, also the target cell of type 1 diabetes, the beta-cell itself, carries VDR. In the immune system, vitamin D enhances antimicrobial actions of macrophages, but reduces inflammation, measured as production of inflammatory cytokines like IL1, TNFa and IL6. It renders dendritic cells tolerogenic and induces a regulator cell phenotype in T lymphocytes, while suppressing T cell proliferation. Beta-cells are protected from cytokine-induced apoptosis and dysfunction. In addition, chemokine production by beta-cells under immune attack is suppressed. In animal models (NOD mouse), protection against autoimmune diabetes is seen upon treatment with high doses of vitamin D or 1,25(OH)2D3, whereas in case of vitamin D deficiency increased prevalences of diabetes are observed.  Disruption of the VDR does not alter diabetes risk as long as hypocalcemia is avoided.

Modeling Multiple Sclerosis: Triggers and pathogenic processes

Gurumoorthy Krishnamoorthy, Max Planck Institute of Neurobiology, Am Klopferspitz 18, Martinsried, Germany. guru@neuro.mpg.de

Multiple sclerosis (MS), an autoimmune disorder of the central nervous system, results from a combined influence of genetic and environmental factors. Experimental autoimmune encephalomyelitis (EAE) induced in susceptible rodents is the commonly used model to study MS pathogenesis. Classic EAE models use either immunization with myelin antigens or transfer of pathogenic effector T cells in naïve recipient animals. However, these models are not suitable to study the factors that trigger autoimmune disease. Recently, spontaneous EAE models resembling MS have been created by transgenic expression of myelin-reactive T cell receptors. Using these models, we have studied the factors that initiate pathogenic immune processes leading to spontaneous nervous system autoimmunity. These studies highlighted the importance of normal gut microbiota in triggering MS-like disease. Gut microbiota activated myelin-specific T cells to differentiate into pro-inflammatory TH17 cells which further resulted in the recruitment and activation of myelin-reactive B cells to produce pathogenic autoantibodies. Together, these findings identify a key role for the intestinal microbiota in shaping early pathogenic events in spontaneous CNS autoimmunity.

Animal Models in Respiratory Allergy

Jens Brimnes, Alk-Abelló A/S, Bøge Allé 6, 2970 Hørsholm, Denmark. Jens.Brimnes@alk.net

Specific immunotherapy is an effective treatment of pollen and house dust mite induced rhinitis and asthma. Traditionally, specific immunotherapy has been done by repeated subcutaneous administrations of small amounts of specific allergen to the sensitized subject. Although this form of treatment is an effective therapeutic option, there has over the last 15 years been an increasing interest in developing more convenient alternatives to subcutaneous injections in order to improve safety and patient compliance. These include the oral, nasal, bronchial and sublingual routes of administration. Especially sublingual immunotherapy (SLIT) has been the focus of many clinical studies and has now been demonstrated to be a safe and clinically effective treatment.

We have developed several different animal models displaying the hallmarks of human rhinitis and asthma, such as sneezing, decreased lung function, eosinophilia and a Th2-like immune response. Most animal models of allergy are reactive against the model antigen ovalbumin, but we have also developed models that react towards more clinically relevant allergens such as grass pollen and house dust mites. Using these animal models we have demonstrated that SLIT treatment in experimental animal models leads to a similar effect compared to human allergic patients.

Furthermore, we have shown that the dose as well as duration and frequency of treatment are critical parameters for a successful treatment. Finally we have investigated the mechanisms underlying the effect of SLIT and identified regulatory T-cells as key players in the effect of SLIT treatment.

RAC1 in keratinocytes regulates crosstalk to immune cells by Arp2/3 dependent control of STAT1

Esben Pedersen1, Zhipeng Wang1, Alanna Stanley2, Karine Peyrollier1, Lennart M. Rösner3, Thomas Werfel3, Fabio Quondamatteo2, Cord Brakebusch1

1Biomedical Institute, BRIC, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark; 2Anatomy Unit, NUI Galway, University Road, Galway Ireland,; 3Dept. of Dermatology and Allergology, Hannover Medical School, Hannover, Germany.

Crosstalk between keratinocytes and immune cells is crucial for the immunological barrier function of the skin and aberrant crosstalk contributes to inflammatory skin diseases. Using mice with a keratinocyte-restricted deletion of the RAC1 gene we found that RAC1 in keratinocytes plays an important role in modulating the interferon (IFN) response in skin. RAC1 mutant mice showed increased sensitivity in an irritant contact dermatitis model, abnormal keratinocyte differentiation, and increased expression of immune response genes including the IFN signal transducer STAT1.

Loss of RAC1 in keratinocytes decreased actin polymerization in vivo and in vitro  and caused Arp2/3 dependent expression of STAT1, increased interferon sensitivity and upregulation of aberrant keratinoctye differentiation markers. This is inhibitable by the AP-1 inhibitor tanshinone IIA.  Loss of RAC1 makes keratinocytes hypersensitive towards inflammatory stimuli both in vitro and in vivo, suggesting a major role for RAC1 in regulating the crosstalk between the epidermis and the immune system.

Session 4: Model organisms in metabolism and neurobiology

Animal models in gut hormone biology.

Jens Juul Holst, Institute of Biomedicine and Novo Nordisk Centre of Metabolism, University of Copenhagen, Denmark. jholst@sund.ku.dk

Abstract to be announced.

SorCS1, encoded by the Alzheimer's Disease and type 2 diabetes susceptibility gene SORCS1, is a potent regulator of peripheral insulin sensitivity

Karen Marie Pedersen, Mads Kjølby, Simon Glerup, Christian Vægter, and Anders Nykjaer. The Lundbeck Foundation Research Centre MIND, Aarhus University, Denmark. AN@biokemi.au.dk

SorCS1 is a member of the Vps10p-domain receptor family, which also comprises sortilin, SorLA, and SorCS2 and -3. The receptors predominate in distinct neuronal populations and are functionally and genetically linked to a variety of neurodegenerative and psychiatric disorders including Alzheimer's disease (SorLA and SorCS1), frontotemporal dementia (sortilin), and bipolar disease, schizophrenia, and ADHD (SorCS2). Surprisingly, outside the nervous system the receptors exhibit critical roles in a variety of metabolic processes. For instance, sortilin is strongly linked to dyslipidemia and risk of cardiovascular disease by regulating hepatic lipoprotein export. Recently, single nucleotide polymorphisms in SORCS1 were associated with risk of type 2 diabetes in humans, rats and mice. However, the molecular mechanism underlying this association remains unknown. We find that SorCS1 is expressed in skeletal muscle and adipose tissue, but not in liver, where it exists in several splice variants encoding receptor isoforms with an identical extracellular domain but with distinct cytoplasmic tails. Mice deficient in SorCS1 expression develop age-dependent insulin resistance characterized by increased plasma glucose and insulin levels and blunted insulin receptor activation. In cell lines and primary myocyte cultures, SorCS1 physically associates with the insulin receptor to stabilize its active confirmation and facilitate insulin signaling. Curiously, overexpression of a soluble product of SorCS1 is able to fully restore insulin sensitivity in diabetic mouse models.

Dissection of Lipid and Energy Metabolism in the yeast Sacchromyces cerevisiae and the nematode C. elegansDissection of Lipid and Energy Metabolism in the yeast Sacchromyces cerevisiae and the nematode C. elegans

Nils Færgeman, Department of Biochemistry and Molecular Biology, University of Southern Denmark. nils.f@bmb.sdu.dk

Stable isotope labeling by amino acids combined with mass spectrometry is a widely used methodology to quantitatively examine metabolic and signaling pathways in yeast, fruit flies, plants, cell cultures and mice. We have used this methodology combined with phospho-proteomic analyses to examine how the yeast Saccharomyces cerevisiae and the nematode C. elegans respond to functional loss of central metabolic regulators and to changes in their nutritional status. Our results provide evidence for key enzymes involved in lipid- and energy metabolism are dynamically phosphorylated, which modulate their metabolic activity. By subsequent bioinformatics and functional analyses, we have identified signaling hub proteins, kinases, and networks, which are involved in mediating the global cellular response to changes in their nutritional status. Collectively, the present study shows that quantitative phospho-proteomics in combination with molecular genetics applied on genetic tractable model organisms provide valuable tools to identify novel regulatory mechanisms of lipid- and energy metabolism.

Gut peptides in transgenic mice.

Birgitte Holst, Institute for Neuroscience and Pharmacology, University of Copenhagen.

Abstract to be announced.

Session 6: KEYNOTE LECTURE

Imaging the connectome.

Jeff W. Lichtman, Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02134 USAjeff@mcb.harvard.edu

Connectional maps of the brain may have value in developing models of both how the brain works and how it fails when subsets of neurons or synapses are missing or misconnected. Such maps might also provide detailed information about how brain circuits develop and age.  I am eager to obtain such maps in neonatal animals because of a longstanding interest in the ways neuromuscular circuitry is modified during early postnatal life as axonal input to muscle fibers is pruned. Work in my laboratory has focused on obtaining complete wiring diagrams ("connectomes") of the projections of motor neuron axons in young and adult muscles. Each data set is large and typically made up of hundreds of confocal microscopy stacks of images which tile the 3dimensional volume of a muscle.  As a first step to analyze these data sets we developed computer assisted segmentation approaches and to make this task easier, have developed second generation "Brainbow" transgenic mice that in essence segment each axon by a unique fluorescent spectral hue. Once the axons are segmented, we have been able to graph the connectivity matrices that result.  This effort has led to new insights into the developmental processes which help the mammalian nervous system mold itself based on experience.  Analysis of these complete muscle connectomes show a striking single axis gradient of connectovity that we think is related to the ordered ranking of neural activity in axons (the "size principle" of Henneman).  In brain however, as opposed to muscle, the high density of neuropil is overwhelming, which has precluded using the confocal optical approaches that have worked in the peripheral nervous system because there are too many neural processes in each optical section. We have thus developed of lossless automated physical sectioning strategy that generates thousands of ultra thin (~25 nm) sections on a firm plastic tape. We have developed a thin-section scanning electron microscopy approach to visualize these sections at 3nm lateral resolution. This method makes large scale serial microscopic analysis of brain volumes more routine. We are now focused on developing an automated pipeline to trace out neural circuits in brains using this technique.

Session 7: THE FEBS NATIONAL LECTURE

Inflammation and Cancer: Lessons from AP-1(Fos/Jun)-dependent Mouse Models and Humans.

Erwin F. Wagner. Genes, Development and Disease Group, CNIO Madrid, Spain. ewagner@cnio.es

Abstract to be announced.

Session 8: Model organisms in cancer

The Patched knockout mouse: a model to study pathogenesis and new treatment options of Hedgehog/Patched-associated cancer

Heidi Hahn, Institute of Human Genetics, University Medical Center Göttingen, Germany. hhahn@gwdg.de

The Hedgehog signaling cascade is a key signaling pathway in embryonic development. It also plays a pivotal role in tumorigenesis when it is reactivated in adult tissues. Abnormal Hedgehog signaling in cancer can be categorized as ligand-dependent (paracrine or autocrine) or mutation-driven i.e. ligand-independent. Whereas the former mode of hyperactive hedgehog signaling can be found in a variety of tumors, mutations in key regulatory components of the Hedgehog pathway (e.g. PTCH) are responsible for aberrant hedgehog signaling activity in basal cell carcinoma and medulloblastoma. The latter cancers are also found in Ptch knockout mice, which thus provide an excellent model to study the pathogenesis of these tumors and to use them in preclinical studies. In addition to basal cell carcinoma and medulloblastoma, these mice also develop rhabdomyosarcoma. Indeed, when we screened human rhabdomyosarcoma for aberrant Hedgehog signaling activity we found an association with the embryonal subtype of this tumor entity. Therefore, Ptch knockout mice also provide a model to study rhabdomyosarcoma biology, the cellular origin of this tumor and in the responsiveness to Hedgehog pathway inhibitors.

Illuminating the influence of the tumor microenvironment on drug resistance and metastasis

Elizabeth Nakasone, Juwon Park, Miriam Fein, Tim Kees, Jae-Hyun Park, Mario Shields, Robert Wysocki, Mikala Egeblad. Cold Spring Harbor Laboratories, USA. egeblad@cshl.edu

Like organs, solid tumors are composed of cancer cells and stroma, which includes the extracellular matrix, fibroblasts, cells of the vascular system, and immune cells. We study how the tumor stroma - the microenvironment - influences drug resistance and metastasis. We use mouse models of breast and pancreatic cancer together with confocal microscopy of tumors of living mice. This allows us to follow - in real-time - how for example cancer cell survival and migration are influenced by e.g., vascular drug delivery and immune cell infiltration.

Classical chemotherapy has been used for decades but surprisingly little is known about how cancer cells in intact tumors respond to it. We have used in vivo confocal imaging to study responses to anti-cancer drugs, such as the chemotherapeutic drug doxorubicin. We revealed that the microenvironment participates in regulating drug-induced cell death through effects on drug penetration. Treatment also led to a new microenvironment: activation of the chemokine receptor CCR2 on monocytes led to recruitment of the monocytes after chemotherapeutic treatment. The infiltration of these cells contributed to chemoresistance and relapse after treatment with doxorubicin or cisplatin.

The prognosis of metastatic cancer is poor. The metastatic process is dynamic and characterized by the ability of cancer cells to move through tissues and from one part of the body to another. Confocal imaging can follow such dynamic processes in real-time. We are studying differences between the microenvironments of tumors formed from the metastatic 4T1 and the non-metastatic 4T07 cell lines, isolated from the same breast tumor. We have identified chemokines that specifically are secreted by metastatic cancer cells and these leads to chemokine receptor-dependent infiltration of specific innate immune cells. Ongoing studies are addressing how the chemokine-chemokine receptor signaling axis between cancer cells and myeloid-derived cells drive metastasis using imaging windows over primary tumor and lungs.

In conclusion, confocal imaging of intact tumors in live mice with breast or pancreatic tumors reveals a complex contribution of the microenvironment - and opportunities for therapeutic targeting - to drug sensitivity and metastatic capabilities of cancer cell.

References

Nakasone, E.S., et al. (2012) Imaging tumor-stroma interactions during chemotherapy reveals contributions of the microenvironment to resistance. Cancer Cell, 21(4):488-503.

Nakasone, E. S, et al., Live imaging of drug responses in the tumor microenvironment in mouse models of breast cancer. JoVE, in press.

Fein, M. R., and Egeblad, M. Caught in the Act: Revealing the Metastatic Process by Live Imaging. Dis. Model. Mech., in press.