Cancer, Development and the Multifunctional Wilms Tumour Gene, WT1

Lead Research Organisation: University of Edinburgh

Abstract

Wilms tumour is a kidney cancer that is quite common in children during the first 5 years of life. It is clearly a remarkable example of cancer arising through the normal processes of development going wrong. In order to understand how the tumour develops with a view to better treatments, we have to understand the processes of normal kidney development and how these go awry on the route to tumorigenesis. We are studying a Wilms tumour predisposition gene, WT1, mutations in which result in Wilms tumour but may also lead to other life-threatening kidney diseases and abnormalities of the sexual organs. We have shown that this gene is vital for normal kidney, testis and ovary development and one of our major goals is to understand how WT1 controls differentiation of these tissues and why disease develops when the gene is mutated. We have shown that WT1 is necessary for cells to divide and to prevent differentiation in certain tissues such as blood vessels of the heart. We propose to dissect WT1s role in these processes and to test the idea that it may play a major role in stem cell maintenance, tissue repair and in adult cancer. We have also shown WT1 is a remarkable example of a single gene encoding multiple proteins that may differentially regulate gene expression both in the nucleus and in the cytoplasm. One of our major goals is to understand these functions and how they control normal development and disease. We are taking a multidisciplinary approach to our work and are trying to set-up novel systems in culture to test the function of WT1 and associated genes.

Technical Summary

Mutations in the Wilms tumour suppressor gene, WT1, may lead not only to the eponymous childhood kidney cancer, but also to severe glomerular nephropathy and gonadal dysgenesis, including sex reversal. In order to understand the mechanisms underlying these conditions with a view to novel therapies, we must elucidate the roles of WT1 in normal genitourinary development and establish mouse models that mimic the human diseases as closely as possible. Our studies so far indicate that whereas WT1 is essential for terminal differentiation of the kidney nephron, consistent with its role as a tumour suppressor, in other tissues such as heart, great vessels and liver, WT1 appears to play the reverse role, i.e. maintaining vascular and other progenitors in an undifferentiated state. In these cases, we suggest it is necessary to shut off WT1 function for cells to terminally differentiate. Our findings provide a basis for the growing view that WT1 may act as an oncogene in some common adult cancers where it is highly expressed.||We aim to continue to dissect the roles of WT1 in normal kidney development. We are using a conditional WT1 model to dissect roles for WT1 in different stages of nephron development. We have strong data to support a model where in condensing mesenchyme WT1 directly activates WNT4, the essential signalling molecule in the epithelialization of the nephron. We are extending this with analyzing the downstream pathways of WNT4 in this process, and new models (in vitro and in vivo) to understand the role of beta-catenin mutations in Wilms tumors. We re hoping combined all this will help us to develop a mouse model for Wilms tumors. We are also testing the hypothesis that WT1 maintains progenitor cells in an undifferentiated state in the heart, liver and some specific neurons. Furthermore, we will use cellular and whole animal models to rigorously test the hypothesis that WT1 is an oncogene in adult cancers and to dissect the mechanisms and pathways involved. In this context a major development is the role we have identified for WT1 in regulating epithelial to mesenchymal transitions by direct regulation of Snail.||In order to understand the roles of WT1 in development and disease, we must understand its function at the biochemical and cellular levels. The WT1 gene encodes multiple protein isoforms, each including 4 C2H2 zinc fingers. There is a considerable body of evidence that WT1 acts as a transcription factor. However, work mainly from this group suggests that some WT1 isoforms regulate gene expression at the post-transcriptional level. We propose to use a variety of approaches to identify target genes and RNAs directly regulated by WT1 in the nucleus and cytoplasm and will dissect the function of different isoforms in post-transcriptional processes.||Parts of the programme on kidney development in particular can now be placed in a broader context as they have strong links with the EU FP6 programme, EUREGENE, and with the NIDDK Genitourinary Atlas programme, PI Duncan Davidson. With our EUREGENE colleagues, we will be exploring new approaches to studying genetic pathways underlying nephrogenesis and to model kidney anatomy in 3D with the help of OPT. The ultimate aim is to build a 4D genitourinary atlas and database which can be used to formulate new hypotheses and to facilitate translational research.

Publications

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Cano E (2016) Extracardiac septum transversum/proepicardial endothelial cells pattern embryonic coronary arterio-venous connections. in Proceedings of the National Academy of Sciences of the United States of America

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Hohenstein P (2014) LINking microRNAs, kidney development, and Wilms tumors. in Genes & development

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International Consortium For Blood Pressure Genome-Wide Association Studies (2011) Genetic variants in novel pathways influence blood pressure and cardiovascular disease risk. in Nature

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McGregor RJ (2016) In Vivo Assays for Assessing the Role of the Wilms' Tumor Suppressor 1 (Wt1) in Angiogenesis. in Methods in molecular biology (Clifton, N.J.)

 
Description EuReGene 
Organisation Helmholtz Association of German Research Centres
Department The Max Delbrück Center for Molecular Medicine (MDC)
Country Germany 
Sector Academic/University 
PI Contribution My team has contributed intellectually to the Consortium; we have developed new imaging tools for analysing the kidney; we have developed new animal models and cell lines. Finally we have ellucidated some of the molecular pathways controlling kidney development. We have also develooped new DNA vectors for rapid genetic manipulation in mice.
Collaborator Contribution EuReGene is an FP6 Integrated Project coordinated by Professor Thomas Willnow. Its goal is to dissect the mechanisms underlying kidney development and physiology and to create a kidney atlas. EuReGene involves partners in 8 different European countries. The different partners bring different and complementary skills to the project.
Impact 19014667. Several additional papers are in preparation
Start Year 2006
 
Description The role of WT1 in mesothelial and cardiovascular development. 
Organisation University of Malaga
Country Spain 
Sector Academic/University 
PI Contribution My group has demonstrated the mechanisms controlling the formation of cardiovascular progenitor cells, using studies in whole animals, at the cellular and molecular levels.
Collaborator Contribution Professor Ramon Munoz Chapuli, our collaborator, has brought considerable intellectual contribution to the project. He has also carried out a great deal of skilled embryological, anatomical and histopathological analysis.
Impact 20023660
 
Description Media reporting of our findings on fat stem cells 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact We published a paper showing that the developmental origins for the "bad" (visceral) fat cells are different than for the "good" subcatenous fat. Furthermore we identified the stem cells for visceral fat and ways that these are regulated. The University of Edinburgh and the MRC put out a press release which aroused wide spread media interest, both on TV and national and international newspapers.
Year(s) Of Engagement Activity 2014
 
Description Public Lecture Botanic Gardens Edinburgh entitled "Genetics and New Fortune Telling" 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact This lecture was part of the MRC Centenary celebrations. I gave a wide-ranging talk on human genetics and the implication of human genome sequencing
Year(s) Of Engagement Activity 2014