Epithelial morphogenesis and cell polarity

Lead Research Organisation: MRC Cell Biology Unit

Abstract

Epithelial cell polarity specification and maintenance is a key problem in cell biology. The vast majority of cancers in human originate from epithelia (i.e. Breast, Colon, Lung, Kidney, etc.) and a major hallmark of tumourogenesis is a progressive loss of epithelial cell polarity. We are studying this problem using the fruit fly Drosophila melanogaster, coming with an unparalleled genetic toolbox, and thus allowing us to manipulate the function of virtually every single gene present in its genome. While up to 80% of the genes associated with diseases in human are conserved in Drosophila, they are often present as one single gene, which is ideal to study a gene function, as very little redundancy is present. Using this approach, we are making significant progresses toward characterizing the molecular basis for establishing and maintaining epithelial cell polarity. This is particularly relevant for better tackling the process of tumorogenesis and metastasis, as these are characterized by a loss of epithelial cell polarity.

Technical Summary

The regulation of Epithelial cell polarity specification and maintenance is a key problem in cell biology. The vast majority of cancers in human originate from epithelia (i.e. Breast, Colon, Lung, Kidney etc.) and a major hallmark of tumourogenesis is a progressive loss of epithelial cell polarity. This eventually leads to Epithelial to Mesenchymal (EMT) cell transition a key step toward cell metastasis activity. Epithelial cell specification presents the converse step (i.e. Mesenchymal to Epithelial transition, MET). Better understanding the molecular mechanisms and signalling pathways required for promoting MET is therefore a key step toward a better understanding of EMT.||To tackle this question in vivo, we are using the genetically amenable Drosophila melanogaster. While up to 80% of the genes associated with diseases in human, are conserved in Drosophila, they are often present as one single locus, which is ideal as very little redundancy is present. So far this approach has allowed us to characterize the function of the conserved tumour suppressor PTEN, during epithelial apical membrane morphogenesis. PTEN is mutated in more than 50% of cancers in human. In epithelial cells, PTEN is recruited at the developing zonula adherens (za) through direct binding to the conserved polarity gene Par3/Baz. Our work in Drosophila has now been confirmed and validated in mammalian epithelial cells, by two other independent groups. Since then, we have tried to better characterize the PTEN/Par3 interface and in particular we have focussed our work on the problem of za morphogenesis and maintenance. The za is the principal membrane domain for the cells to form an epithelial sheet, as this domain is responsible for cell-cell anchorage. We believe that we have now solved a number of key open questions in this field of research. In particular, we have recently solved the molecular basis for Par3 requirement during za assembly in epithelial cells. Par3 and PTEN are also key genes for directed cell migration and we propose that in pathological conditions such as cancer, defect in their regulation in epithelial cells (i.e. phosphorylations/localization), and are likely to have a profound impact toward cell metastasis.

Publications

10 25 50
 
Description COB meeting grant
Amount £4,000 (GBP)
Funding ID EA1005 
Organisation Company of Biologists 
Sector Charity/Non Profit
Country United Kingdom
Start 05/2015 
End 06/2015
 
Description EMBO post doc long term fellowship
Amount £266,236 (GBP)
Organisation European Molecular Biology Organisation 
Sector Learned Society
Country European Union (EU)
Start 10/2007 
End 09/2008
 
Description Multi-user equipment grant
Amount £290,000 (GBP)
Funding ID 108427/z/15/z 
Organisation Wellcome Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 10/2014 
End 09/2019
 
Description National Cancer Institute of Canada
Amount £23,000 (GBP)
Organisation Canadian Cancer Society 
Department Canadian Cancer Society Research Institute
Sector Academic/University
Country Canada
Start  
 
Title Antibodies 
Description Transgenic fly lines and antibodies 
Type Of Material Antibody 
Year Produced 2008 
Provided To Others? Yes  
Impact Significant number of publications from other groups using these reagents. 
 
Title Transgenic fly lines 
Description Transgenic fly lines and antibodies related to PTEN and epithelial polarity proteins 
Type Of Material Model of mechanisms or symptoms - non-mammalian in vivo 
Year Produced 2008 
Provided To Others? Yes  
Impact Significant number of publications from other research groups have used these reagents 
 
Description Cell competition 
Organisation Medical Research Council (MRC)
Department MRC Cell Biology Unit
Country United Kingdom 
Sector Academic/University 
PI Contribution Expertise with Drosophila genetics and epithelial morphogenesis.
Collaborator Contribution The lab of Yasusuki Fujita at the LMCB has been providing us with technical expertise regarding vertebrate epithelial cell biology. This nicely complemented our work using Drosophila genetics.
Impact PMID: 17682048 PMID: 19287376
Start Year 2006
 
Description Ect2- Cdc42 and Mitotic rounding 
Organisation University College London
Department MRC Laboratory for Molecular Cell Biology (LMCB)
Country United Kingdom 
Sector Academic/University 
PI Contribution We have provided biochemical evidence that the GEF Ect2 binds to Par6 and Cdc42 in Drosophila
Collaborator Contribution The Baum lab has identified a major role for Ect-2 during mitotic cell rounding and remodelling of epithelial polarity in this particular context.
Impact Ect2/Pbl Acts via Rho and Polarity Proteins to Direct the Assembly of an Isotropic Actomyosin Cortex upon Mitotic Entry André Rosa, Evi Vlassaks, Franck Pichaud, Buzz Baum Dev Cell. 2015 March 9; 32(5): 604-616. doi: 10.1016/j.devcel.2015.01.012 PMCID: PMC4359025
Start Year 2014
 
Description Phosphoinositol lipids and Epithelial polarity 
Organisation University of Oxford
Department Department of Physiology, Anatomy and Genetics
Country United Kingdom 
Sector Academic/University 
PI Contribution Our research team designed and implemented nearly all the experiments that were subsequently published.
Collaborator Contribution Contributed key reagents, including transgenic Drosophila strains that were instrumental for the success of this research project.
Impact High profile scientific publication PMID: 16431366
Start Year 2006
 
Description Rhodopsin expression 
Organisation New York University
Country United States 
Sector Academic/University 
PI Contribution Provided electron microscopy analysis of a number of Drosophila retina samples. Intellectual contribution through on going discussions.
Collaborator Contribution This is mostly my group providing expertise.
Impact Two high profile peer reviewed publications. PMID: 17785526 PMID: 18433293
Start Year 2006
 
Description Role of Pak4 during epithelial membrane differentiation 
Organisation Memorial Sloan Kettering Cancer Center
Department Cell Biology Program
Country United States 
Sector Academic/University 
PI Contribution Discovery that Drosophila pak4 is regulates the epithelial polarity gene network.
Collaborator Contribution Identification of the epithelial protein Par6 as a substrate for Pak4
Impact This collaboration has consisted in capitalising on Drosophila genetics to determine exactly where Pak4 fits in the existing network of epithelial polarity genes. In my lab, this has meant establishing and studying the relevant Par6 and Pak4 transgenic animals. Corresponding paper submitted Oct 2015
Start Year 2014
 
Description Super Resolution imaging 
Organisation National Physical Laboratory
Country United Kingdom 
Sector Academic/University 
PI Contribution Working together with NPL toward establishing a regional user platform for super resolution imaging.
Collaborator Contribution NPL assembles experimental super resolution system.
Impact The setting up of a core facility for super resolution at UCL is now well underway.
Start Year 2011
 
Description Tissue Growth 
Organisation Cancer Research UK
Department Cancer Research UK London Research Institute (LRI)
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution Analysis of a number of tumor suppressors 's effect on cell shape and cell sorting during organogenesis.
Collaborator Contribution Increased understanding and expertise in this particular field of research.
Impact Peer reviewed publication and increased connection with key labs working at the LRI (CRUK) on the particular question of tissue growth regulation. This collaboration has led to the setting up of a bi-weekly joint meeting between my group members and that of my collaborators at the LRI. PMID: 19531586
Start Year 2008
 
Description Transcriptomic analysis of retinal development 
Organisation Catholic University of Louvain
Country Belgium 
Sector Academic/University 
PI Contribution Expertise with analysing particular genotype in the developing drosophila retina.
Collaborator Contribution Have conducted an extensive survey of the genes whose transcription is regulated during retinal development in Drosophila.
Impact MS in preparation to be published in 2016
Start Year 2013
 
Description BBC4 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Contributing to the making of "what Darwin didn't know". Aired on BBC 4 in 2009.

Raised the profile of my lab in the institute and contributed to promote people's interest toward the use of model organism to study Cell Biology.
Year(s) Of Engagement Activity 2009
 
Description MRC centenary celebration day at UCL 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? Yes
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact hundreds of people visited our workshop

New contact with local schools that will feed in our 'local school visit program'
Year(s) Of Engagement Activity 2013
 
Description Open day for a local school 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact approximately 25 pupil each year. Access to our fly facility including microscopes.

Overall feedbacks are very positive.
Year(s) Of Engagement Activity 2007,2009,2011,2013,2015
 
Description Seminar to a panel of Layperson 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? Yes
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Gave a short talk follow by taking questions from a panel of Layperson that had been assembled by the MRC.

n/a
Year(s) Of Engagement Activity 2009