Cell polarity in the Systems Medicine era: the next 10 years

• Dr Rafael Carazo Salas, University of Cambridge, UK

Biography

Dr Rafael E Carazo Salas is group leader at the Gurdon Institute and the Department of Genetics of the University of Cambridge, and an ERC Starting Independent Researcher. Trained in physics, he did a PhD in cell biology with Eric Karsenti at EMBL Heidelberg in 2001, where his work helped identify the GTPase Ran as master regulator of mitosis. He then worked with Paul Nurse as postdoctoral fellow at Cancer Research UK in London and later as Research Associate at the Rockefeller University in New York, where his work showed that motor protein-mediated self-organization is a universal pathway of microtubule control. Since 2008 his group studies the molecular networks that regulate cell morphogenesis, using inter-disciplinary functional genomics approaches.

• Dr Attila Csikász-Nagy, King's College London, UK

Biography

Dr Attila Csikász-Nagy holds a Senior Lectureship at King’s College London and serves as a group leader at the Research and Innovation Centre of Fondazione Edmund Mach in San Michele all’Adige, Italy. He received a PhD in 2000 for his work on mathematical models of cell cycle regulation. He was a postdoctoral fellow at Virginia Tech (USA), an assistant professor in Hungary and a principal investigator at The Microsoft Research – University of Trento Centre for Computational Systems Biology in Italy before taking up his double appointment in Italy and the UK. His group studies the dynamics of the regulatory networks that control cell cycle, polarized cell growth and cell to cell interactions.

• Dr Masamitsu Sato, University of Tokyo, Japan

Biography

Masamitsu Sato completed his PhD in Genetics with Masayuki Yamamoto at the Graduate School of Science, University of Tokyo in 2001. He pursued postdoctoral research with Takashi Toda in Cancer Research UK, London Research institute. He focused on the relationship of the nuclear transport machinery and microtubule formation in fission yeast mitosis. In 2006, he moved back to the Masayuki Yamamoto laboratory as an assistant professor, where he started to focus on revealing the uniqueness of the cytoskeleton in meiosis. He was awarded the Young Scientists’ Prize of the Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology of Japan in 2012.

• Professor Buzz Baum, University College London, UK

Biography

Buzz Baum is a Professor of Cell Biology at UCL’s Laboratory for Molecular Cell Biology, and a Cancer Research Senior Research Fellow. His lab explores the molecular, cellular and physical processes that give rise to the shape and polarity of isolated animal cells and cells in the context of an epithelium; and is interested in the morphological processes that go awry during cancer progression.

• Professor Brenda Andrews, The Donnelly Centre, University of Toronto, Canada
• Audio recording (mp3)
• Discussion (mp3)

Biography

Brenda Andrews is Professor and Chair of the Banting & Best Department of Medical Research within the Faculty of Medicine at the University of Toronto, where she holds the Charles H Best Chair in Medical Research.  She is also Director of the Terrence Donnelly Center for Cellular and Biomolecular Research (the Donnelly Centre), an interdisciplinary biomedical research institute with a focus on technology development for post-genome biology, functional genomics, systems & computational biology and bioengineering. 

After receiving her PhD in Medical Biophysics from the University of Toronto, Dr. Andrews obtained her early training in genetics with the late Dr Ira Herskowitz at the University of California San Francisco.  In 1991, Dr Andrews was recruited to the Department of Medical Genetics (now Molecular Genetics) at the University of Toronto.  She became Chair of the Department in 1999, a position she held for 5 years before assuming her current positions.  Dr Andrews’ current research interests analysis of genetic interaction networks in budding yeast, using automated genetics platforms that include high content microscopy for systematic analysis of cell biological phenotypes.  Specific interests in the Andrews lab include mechanisms of cell cycle control, control of cell function by kinases and other enzymes and the regulation of cell polarity and morphogenesis.  Her research is currently funded by the CIHR, the National Institutes of Health, the Ontario Research Fund, the Canadian Foundation for Innovation and the Canadian Institute for Advanced Research (CIFAR).

Dr Andrews is a Fellow of the Royal Society of Canada, Fellow of the American Association for the Advancement of Science, a Fellow of the American Academy of Microbiology and Director of the Genetic Networks Program of the CIFAR.

Abstract

A fundamental goal of cell biology is to define the dynamic properties of proteins in the context of different cellular compartments and environments.  We have combined Synthetic Genetic Array (SGA) analysis, which automates yeast genetics, with high throughput microscopy to enable genome-scale measurements of cell biological phenotypes and quantitative read-outs of the activity of specific biological pathways. For example, to systematically evaluate protein abundance and localization in budding yeast, we developed a combined experimental and computational method to automatically generate global abundance-localization maps (ALMs) at single-cell resolution. The ALM of wild-type cells includes ~3,000 proteins (nodes) connected to one or more of 16 localization classes (hubs).  To study proteome dynamics following a genetic or chemical perturbation, we used a computational approach to map flux networks derived from ALMs and explored cellular responses to both chemical and genetic perturbations. Our analysis revealed that the proteome is regulated broadly at the level of protein abundance changes with localization changes, including mass translocation of protein complexes such as the exosome, occurring primarily in response to specific perturbations.  Flux networks provide a systems-level view and novel insight into global protein turnover and movement in eukaryotic cells.

• Professor Andre Levchenko, Johns Hopkins University, USA
• Audio recording (mp3)
• Discussion (mp3)

Biography

Professor Andre Levchenko is a biomedical engineer working in the field of Systems Biology with a particular emphasis on cell signalling, with much research relating to cell migration. He grew up in Siberia, getting his first degree at Moscow Institute of Physics and Technology. He obtained his doctoral degree at Columbia University and Memorial Sloan-Kettering Cancer Center in New York. He then did post-doctoral research at Caltech, under the guidance of several researchers, including David Baltimore. Thereafter, he moved to his present faculty position at Johns Hopkins University, where he directs the Signal Transduction and Cell-Cell Communication lab. Professor Levchenko serves on editorial boards of multiple journals and is a co-organizer of numerous conferences focused on systems and quantitative biology. He is a Fellow of AIMBE.

Abstract

Aggressive cancers, such as melanoma and glioblastoma, display strongly invasive growth and dissemination through enhanced migration into the surrounding tissue. By analyzing the motility of these cancer cells within micro- and nano-fabricated platforms designed to mimic the topography and chemical composition of tumor micro-environment, we have recently shown a number of unexpected correlative features between such simple in vitro assays and the complex in vivo tumor progression. I will present in vitro and in vivo data, including patient specific results, coupled to systems biology analysis, to demonstrate that the polarity and speed of cell migration can be a strong predictor of clinical outcomes. 

• Professor Anne Ridley, King's College London, UK

Biography

Anne Ridley obtained her BA in Natural Sciences (Biochemistry) from the University of Cambridge.  She obtained her PhD in 1989 (University of London), for her research project with Hartmut Land at Imperial Cancer Research Fund (now Cancer Research UK). She was awarded an EMBO postdoctoral fellowship to visit the laboratory of David Page (Whitehead Institute, Cambridge, MA) for a year.  She then moved back to the Institute for Cancer Research, London, to work as a postdoctoral fellow with Alan Hall.  During this time, she discovered the roles of the Rho and Rac GTPases in regulating the actin cytoskeleton.  In 1993 she started her laboratory at the Ludwig Institute for Cancer Research (University College London Branch).  She became Professor of Cell Biology at University College London in 2003, and moved to King’s College London in 2007.

• Professor Tobias Meyer, Stanford University, USA
• Audio recording (mp3)
• Discussion (mp3)

Biography not yet available

Abstract

Collective endothelial cell migration is required for blood vessel formation, for the regulation of vascular permeability, and for repair following injury. While directional signals guiding collective cell movement are thought to be transmitted mechanically from one cell to another via cell-cell junctions, little is known about how forces applied to the junction locally by one cell are sensed by its neighbor and converted into a signaling output. Using monolayers of primary human umbilical vein endothelial cells (HUVEC) as a model system, we found that endothelial cell-cell junctions were asymmetrically organized with actin-rich, filopodia-like protrusions extending from the rear of migrating cells. 3D-structured illumination fluorescence microscopy (3D-SIM) and field emission scanning electron microscopy (FE-SEM) revealed that these “actin fingers” reached into the cytoplasm of the following cell, where they were anchored to the actin cytoskeleton by junctional VE-cadherin. The highly curved membrane surfaces thus generated were selectively recognized by curvature-sensing BAR domain modules. The negative curvature sensing I-BAR module was enriched at the back of the leading cell, whereas the positive curvature sensing N-BAR module was selectively recruited to incoming actin fingers in the following cell. In search for a regulator that translates asymmetric curvature information present at cell-cell junctions into a signaling output, we identified ARHGAP29, an F-BAR and RhoGAP containing protein, as a critical component of the collective guidance machinery. The F-BAR domain of ARHGAP29 bound specifically to the positively curved surface of actin fingers and ARHGAP29 depleted cells had defects in junctional architecture and collective migration behavior. Therefore, force-induced, asymmetric membrane deformation at the endothelial cell-cell junction serves as a guidance signal by recruiting a curvature-sensing signaling component that locally impacts on RhoGTPase activities.

Co-authors:
Arnold Hayer, Feng-Chiao Tsai, Lin Shao, Lydia-Marie Joubert, Eric Betzig and Tobias Meyer

• Professor Pernille Rørth, Institute of Molecular & Cell Biology, Singapore
• Audio recording (mp3)
• Discussion (mp3)

Biography

Pernille Rørth received her PhD from the University of Copenhagen, Denmark in 1993.  She worked at the Carnegie Institution for Science as an independent junior investigator and there developed the EP system for gain-of-function screens in Drosophila.  From 1998-2007, Pernille was a group leader and senior scientist at EMBL in Heidelberg, Germany, studying the regulation of cell migration and guidance, also with Drosophila as a model system.  This work has continued in Singapore, where Pernille was a senior group leader at TLL and since 2009 has been research director at Institute of Molecular and Cell Biology (IMCB).

Abstract

When cells migrate within the context of an animal, they may do so either as single cells or as interactive groups. Directed migration of single cells is well studied in vitro and to some extent in vivo, but we know much less about the regulatory mechanisms controlling group or collective migration. Recent findings that invasive movement of tumor cells derived from squamous carcinomas often occurs as collective migration underscore the importance of understanding this type of migratory behavior.  Border cells, a cluster of about 8 cells, perform a spatially and temporally controlled migration during Drosophila oogenesis and serve as a good model for directed and invasive cell migration in vivo. Border cells delaminate from an epithelium, invade the germ line and perform a directional migration to the oocyte. The Rørth lab is interested in how the cells become migratory and, once migratory, how cell and cluster movements are controlled and guided. We previously found that border cells use two receptor tyrosine kinases (RTKs), EGFR and PVR (PDGF/VEGF Receptor), as guidance receptor to perceive attractive cues produced by the oocyte.  Using live imaging of border cell migration combined with genetic analysis, we study how signaling from these RTKs is regulated and interpreted in space and time and how cell behaviors are controlled. Interestingly, guidance information is processed both at the single cell and at the group level.  Also, guidance information is polarized within the cells in a way that depends both upon the external gradients and the geometry of cells within the cluster.  Recent results from these analyses will be presented.

• Professor Inke Näthke, University of Dundee, UK

Biography

Professor Inke Näthke obtained her PhD at the University of California San Francisco and did postdoctoral work at Stanford University and Harvard Medical School before joining the faculty at the University of Dundee where she is currently the Professor of Epithelial Biology in the Division of Cell and Developmental Biology.  Her research aims to understand the earliest changes in gut tissue that accompany initiation and progression of tumours.  Work in her laboratory uses of a variety of experimental systems and techniques from single cells to whole tissue, and isolated proteins to high-resolution imaging of normal and tumour tissue.

• Professor Juha Klefström, University of Helsinki, Finland
• Audio recording (mp3)
• Discussion (mp3)

Biography

Juha Klefström PhD is an Academy of Finland Research Fellow, head of the Cancer Cell Circuitry Laboratory at the University of Helsinki and a research director in Biomedicum Functional Genomics Core. He obtained his PhD degree in molecular cancer biology from the University of Helsinki and was trained as a postdoctoral fellow at ICRF London and UCSF Comprehensive Cancer Center, San Francisco. In 2009, he briefly worked as a visiting Professor at UCSF. Klefström’s research is on the role of cell polarity pathways in cancer development and metabolic regulation of tumor cells. He is particularly focusing on the tumor suppressor gene LKB1 and therapeutically interesting proteolytic pathways specifically activated in cancer cells with polarity defects. Klefström participates in several collaborative preclinical target validation and discovery programs to translate team’s basic scientific findings into patient benefits.

Abstract

During the development of epithelial structures, cells exit from the cell cycle to become quiescent at the appropriate time and place. These developmentally controlled epithelial cell cycle exits lay foundation for epithelial tissue organization, which is important for differentiated epithelial organ function. Recent evidence suggests that loss of these control mechanisms render epithelial tissues tumor‐prone. However, little is known about the molecular machineries that establish the epithelial cell cycle restriction and sustain the epithelial quiescence. We have systematically interrogated the impact of loss of epithelial integrity control on normal and Myc oncogene-driven proliferation in three-dimensional mammary epithelial cultures, which become quiescent after completing acinar morphogenesis in matrix. Human homologues of Drosophila genes involved in epithelial integrity were silenced by lentiviral shRNA approach, which pinpointed regulators of apical polarity, Wnt and Hippo pathways and actin dynamics in establishment of epithelial proliferation restriction. Furthermore, an integrated computational analysis and functional cooperation assays with Myc define a sub-set of genes with tumor suppressor properties, particularly suggesting a role for PAR genes in control of epithelial proliferation suppressive environment. The present findings provide a framework for analysis of tumor suppressor functions at the intersection of epithelial integrity and proliferation control. 

• Professor Jonathan Clarke, King's College London, UK
• Audio recording (mp3)
• Discussion (mp3)

Biography

Professor Jon Clarke is currently the Head of the Department of Anatomy at Kings College London. He has a long-standing interest in understanding the development and function of the vertebrate nervous system. He trained with Alan Roberts to study the sensory and locomotor circuitry of Xenopus embryo spinal cord, Nigel Holder to study the regenerating axolotl nervous system, and Andrew Lumsden to study the development of chick embryo brain. His lab now uses the zebrafish embryo to understand morphogenesis and neurogenesis in a vertebrate brain.

Abstract

We use the advantageous optical quality of the zebrafish embryo to study the development of cell polarity and its relation to morphogenesis in vivo. In particular we are interested in understanding the cellular and sub-cellular events that underlie the development of neuroepithelial polarity and lumen formation in the neural tube. Our recent work explores the role of cell division, cell-cell interactions and cell-ECM interactions in these processes. In a wider context the regulation of neuroepithelial polarity is likely to play an important role in the control of asymmetric (self-renewing) divisions during embryonic and adult neurogenesis.

• Dr Sandrine Etienne-Manneville, Institut Pasteur, France

Biography

Sandrine Etienne-Manneville is Directrice de Recherche at the CNRS and part-time professor at Ecole Polytechnique (Palaiseau, France). She studied cell Biology and biochemistry at the Ecole Normale Supérieure in Paris and obtained her PhD in Immunology in 1998, working on the regulation of leukocyte infiltration in the central nervous system. After four years of postdoctoral fellowship in the laboratory of Prof A.Hall at the MRC-LMCB in London, she entered the CNRS as a member of D. Louvard’s team at the Curie Institute (Paris, France) in 2003. In 2006, she moved to the Pasteur Institute (Paris, France) to become an independent group leader. The 5-year group “Cell Polarity and Migration, she initiated has recently been as promoted as a Pasteur Unit “Cell Polarity, Migration and Cancer”.

• Professor Xin Lu, University of Oxford, UK
• Audio recording (mp3)
• Discussion (mp3)

Biography

Xin Lu studied Biochemistry at Sichuan University, before an MSc at Cancer Research at Peking Union Medical School in Beijing. She was awarded an IARC WHO fellowship to join the Imperial Cancer Research Fund in London in 1986, studying for her PhD under Birgit Lane. She was awarded British Society of Cell Biology “Young Cell Biologist of 1989” for her PhD work. She then moved to Dundee University for postdoctoral training with Sir David Lane. In 1993 she joined the Ludwig Institute for Cancer Research (LICR), Imperial College, and was appointed Director of the LICR London Branch (then at UCL) in 2004. She moved the unit to Oxford in 2007. In recognition of her outstanding work she was elected an EMBO Fellow in 2011, Fellow of the Royal College of Pathology in 2007, and named Ninth James Gibson Visiting Professor of the University of Hong Kong the same year. Her research team is one of the world’s major research groups studying the regulation of the tumour suppressor p53, whose function is lost in most human cancers. In particular, her group has identified a key family of proteins, the ASPP family, that promote and inhibit tumour growth by associating with p53.

Abstract

Cell polarity and proliferation are processes that play key roles in development. Loss of cell polarity and increased cellular proliferation are hallmarks of human cancer. The identification of molecules that are involved in the control of these processes is, therefore, important for our better understanding of tumour development and progression. p53 was recently found to be important in controlling the mammary epithelial stem cell pool. We have subsequently shown that ASPP2, a regulator of p53 and binding partner of many other proteins, is an important player in the regulation of cell polarity due to its ability to bind and regulate Par-3.

ASPP2 is a member of the evolutionarily conserved ASPP family of proteins, which also consists of ASPP1 and iASPP. We have previously shown that ASPP1 and ASPP2 specifically stimulate the apoptotic function of p53, while iASPP specifically inhibits it. Importantly, iASPP is the most conserved member of the ASPP family, and C. elegans iASPP is capable of substituting for human iASPP in all of the assays performed in human cells. Detailed analysis of ASPP2-deficient mice has demonstrated that ASPP2 is a novel haploinsufficient tumour suppressor. Deficiency of p53 and ASPP2 results in synthetic lethality, suggesting that ASPP2 and p53 interact genetically. Furthermore, ASPP2 co-operates with p53 to suppress tumour growth in vivo, explaining why p53’s ASPP2 contact residues are mutated in human cancer with a relatively high frequency. Importantly, ASPP2-deficient mice exhibit a major defect in that there is a loss of cell polarity, accompanied by increased proliferation. This observation and the mechanisms involved will be discussed in detail.

• Professor Ira Mellman, Genentech, USA
• Audio recording (mp3)
• Discussion (mp3)

Biography

Ira Mellman received his AB degree from Oberlin College and his PhD degree in genetics from Yale University School of Medicine.  He was a postdoctoral fellow and later Assistant Professor at The Rockefeller University, working with the late Ralph M Steinman, the 2011 Nobel Prize winner in Physiology or Medicine.  Dr Mellman joined the faculty of the Yale University School of Medicine in 1981 as an Assistant Professor in the Department of Cell Biology, which was then headed by Nobel Laureate Dr George E Palade, whom he eventually succeeded as chair.  Dr Mellman has also been a long-time Member of the Ludwig Institute for Cancer Research and also served as Scientific Director of the Yale Comprehensive Cancer Center.  The recipient of many honors, named lectures, and awards, including Yale’s prestigious Sterling Professorship, Dr Mellman is a member of the US National Academy of Sciences, a fellow of the American Association for the Advancement of Arts and Sciences, an elected foreign member of the European Molecular Biology Organization (EMBO).  He also served as Editor-in-Chief of the Journal of Cell Biology and as a member of the editorial boards of Cell, The JCB, The Journal of Experimental Medicine, and EMBO Journal.  Dr Mellman is the scientific founder of CGI Pharmaceuticals, Inc. and Athersys, Inc, and an advisor to research institutes and foundations around the world.

Dr Mellman’s work has contributed numerous fundamental concepts to our current understanding of cell biology and immunology, beginning with the discovery, definition, and naming of a “new” organelle, the endosome.  Extending this work, his laboratory has also elucidated the mechanisms by which epithelial cells polarize to form tissues and initiate cancer, and revealed the remarkable cell biological mechanisms underlying how dendritic cells act to initiate immune responses.

Dr Mellman began at Genentech in 2007, assuming the position of Vice President of Research Oncology.  Placed in charge of the largest therapeutic area in Genentech’s research organization, Dr Mellman is responsible for leading all aspects of oncology research and advancing both antibody and small molecule drug candidates into the clinic. The development of immunotherapeutic approaches to cancer is now a key feature of Genentech’s activities.

Abstract

Lkb1, also known as Par-4 or Stk11, is an ancient gene involved in asymmetric cell division in early embryogenesis.  More recently, it has been implicated in the regulation of cellular energy, proliferation, and epithelial cell polarity.  Lkb1 is also a potent tumor suppressor, frequently mutated or lost in lung and pancreatic cancer, and also the gene responsible for most cases of Peutz-Jeghers disease, characterized by benign hamartoma formation and a nearly complete pre-disposition to cancer.  Despite extensive study, little is known about how Lkb1 contributes to tissue morphogenesis or cancer.  Much the same is true for the wide range of genes are clearly appreciated as controlling oncogenesis:  little is known about their mechanisms of action at the cell biological level or indeed about their relative contributions to the initiation vs the maintenance of the oncogenic state.  We have devised a new approach to this problem to study the role of Lkb1 in a physiological tissue context, but to do so ex vivo under conditions that permit experimental manipulation and observation of living epithelia at the morphological, biochemical, and genetic levels.  The approach has enabled us to approach the goal of reconstituting cancer initiation in tissue culture, and has already cast some surprising light on what is and what is not required to create an early oncogenic or oncogenic-like state.

• Dr Anatole Chessel, University of Cambridge, UK

Biography

Anatole Chessel was trained in applied mathematics for mechanics in the Ecole Centrale de Marseille and he did a Master’s degree in applied mathematics for machine learning and image analysis at the Ecole Normale de Cachan, both part of the Grandes Ecoles system in France. He did his PhD in the French Marine Institute (IFREMER, Brest) and a first post-doc in Rennes (INRIA) and Paris (Institut Curie) before joining the group of Rafael Carazo-Salas in Cambridge in July 2010. His interdisciplinary scientific focus has increasingly shifted towards image analysis for cell biology, with the view that image analysis, rather than simply a helpful tool to ease biologists’ life, is a fundamental component of modern cell and systems biology research. His current projects, all in close interaction with experimental biologists, are aimed at clarifying the regulation of cellular polarity in S pombe by: a) seeking to reconstruct the polarity-regulating network, using high-throughput/high-content microscopy; and b) characterizing the fine spatial organization of polarity-regulating proteins at the cell periphery, using time-lapse/super-resolution microscopy and novel statistical image analysis methods.

• Dr James Dodgson, University of Cambridge, UK

Biography

Dr James Dodgson is a post-doc in the lab of Rafael Carazo Salas, based at the Gurdon Institute, University of Cambridge. Currently he is involved in two projects; firstly investigating the physical arrangement of polarity factors at the cortex (a paper has recently been accepted by Nature Communications) and secondly examining at a systems level how a single-cell reaches its polarized state through a high-content localization dependency screen. Unifying the projects is the use of fission yeast as a model system and the intensive use of advanced image based methods. He has become particularly interested in the application of super-resolution and other new imaging techniques. He first became interested in cell polarity during his PhD at the University of Sussex, which involved studying the dimorphic switch of fission yeast to a highly polarized pseudo-hyphae state.

• Dr Marco Geymonat, University of Cambridge, UK

Biography

Marco Geymonat is a post-doc in Rafael Carazo-Salas’ lab, based at the Gurdon Institute, and a teaching assistant in the department of Genetics at the University of Cambridge.  During his scientific career he has been interested in the interface between cell cycle and cell polarity. His work using budding yeast, carried out at the National Institute for Medical Research, lead him to characterise a daughter specific protein implicated in the coordination between mitotic exit and establishment of polarity. His project in Cambridge is centred on the study of shape and polarization control using the fission yeast S pombe as model organism. He has developed a cell cycle/cell polarity biomarker that will allow us, with the use of advanced image based methods, to identify genes implicated in the coordination between those two processes. He is also interested in a cell cycle regulated polarity factor that specifically localises at the non-growing end and has growth inhibition activity.  

• Dr Federico Vaggi, Fondazione Edmund Mach, Italy

Biography

Federico Vaggi is a researcher at FEM in San Michele All'Adige.  He received his PhD in Molecular Oncology from the European Institute of Oncology in Milan in 2010 under the supervision of Dr. Ciliberto studying models of filopodia formation in multiple cell lines.  He carried out his post-doc at COSBI, where he used graph theory and modeling approaches to study cell polarity using fission yeast as a model organism.  His main research interests are focused on the use of computational tools to study complex systems in biology, including ODE/PDE/particle-based models, graph theoretical approaches and machine learning.  Currently, he is working on network inference to study the proteins that control polarity in fission yeast, L-systems based approaches to model duct formation in human breast tissue, and collaborating on the modeling of p53 kinetics in an ex-vivo system.