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Dr Kenneth Ewan

Dr Kenneth Ewan

Research Associate

School of Biosciences

Email:
ewankb@cardiff.ac.uk
Telephone:
+44 (0)29 20879073
Location:
Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX

I am a cell biologist with interests in the Wnt pathway, drug discovery and 3D tissue organoids. The projects I am currently working on are: 1) Small molecule inhibitors of the WNT signalling pathway; 2) Characterisation of RNA binding protein HnRNPa1 as a negative regulator of the WNT pathway; 3) Live, label free imaging of 3D tissue organoids using CARS microscopy

I obtained my BSc. from the University of Sydney, Sydney Australia in Genetics, Biochemistry and Microbiology in 1987 and my Ph.D from the Department of Physiology, University of Western Australia in 1995 on the topic of somitic cell migration. Following short research positions at the University of Sydney and at the Max Planck Institute of Biophysical Chemistry in Germany, I commenced a postdoc with Dr. Barcellos-Hoff at the Lawrence Berkeley National Laboratory, California, USA in 1999. Here, I worked on the role of TGF-β1 in the mammary gland finding that a) ovarian hormones estrogen and progesterone induce activation of TGF-β1 in the ER/PR positive cells of the mammary gland resulting in inhibition of their proliferation and b) TGF-β1beta1 mediates the cellular response to ionising radiation induced DNA damage via the activation of p53.

I joined Cardiff University in the laboratory of Professor Trevor Dale in 2004.

2018

2017

2016

2015

2010

2008

2006

2005

2002

2000

Teaching

2018-Journal Club for Masters Students  (BI4003): – Assessing the ability of Masters level students to understand and interpret research papers.

2007-2014-Lecturing –Animal Development Module (BI2350): One lecture on head mesenchyme and pharyngeal cleft development and one lecture on the development of the urogenital system.

Student Supervision

2018 Supervised a student from the Johannes Gutenberg University of Mainz for a project investigating the effect of Wnt pathway inhibitors on Axin1 and Axin1/Axin2 deficient liver-derived organoids.

2018: Co-supervised a Masters level Erasmus research student from the University of the Basque Region on the effect of porcupine inhibitors on the growth of liver-derived organoids. The student subsequently enrolled in a Ph.D program.

2011-2012: Direct supervision of a Masters level Erasmus research student for 3 months: Project was “Wnt inhibitors and intestinal crypt organoids”. The student subsequently enrolled in a Ph.D program.

2009: Direct supervision of undergraduate student for 3-month final year research project: Research title was “Interaction of Fus with b-catenin”. The student subsequently undertook a graduate-entry medicine degree.

2005: Direct supervision of two undergraduate students for 3-month final year research projects: Research titles were 1) “Wnt pathway inducers”, 2) “Intersection of Wnt and inositol signalling pathways”. One student subsequently completed a Ph.D degree.

Small Molecule Inhibitors of the WNT Signalling Pathway

Oncogenic deregulation of the Wnt signalling pathway is a causal factor in the initiation of cancer in a diverse range of tissues including the colon, breast and liver. To identify small-molecule inhibitors of Wnt signaling as potential therapeutics, a diverse chemical library at the Cancer Research UK Centre for Cancer Therapeutics was screened using a transcription factor reporter cell line in which the activity of the pathway was induced at the level of Disheveled protein. A series of deconvolution studies was used to focus on three compound series that selectively killed cancer cell lines with constitutive Wnt signalling. Activities of the compounds included the ability to induce degradation of β-catenin that had been stabilized by a glycogen synthase kinase-3 (GSK-3) inhibitor. A lead compound series from the cell-based screen was used in a full drug discovery project with Merck Serono and the Institute of Cancer Research as partners. Optimised variants of the compound were highly potent inhibitors against its molecular targets (CDK8/CDK19). Unfortunately, inhibiting CDK8/CDK19 had toxic effects that precluded moving to clinical studies. My role included determining the drug efficacy in reversing intestinal hyperplasia and inhibiting tumour xenograft growth in in vivo models, assaying drug efficacy in inhibiting growth of hyperplasic intestinal and tumour 3D organoids in culture, determining the drug effect on intestinal stem cells in vivo and assisting the development of a protein target identification strategy. Subsequently, I have been testing small molecule Wnt inhibitors in collaboration with Merck in the Axin1 deficient mouse system liver both in vivo and using liver-derived organoids.

Characterisation of RNA Binding Protein HnRNPa1 as a Negative Regulator of the WNT Pathway

β-catenin is a crucial canonical Wnt signalling pathway transactivation component whose turnover is aberrantly regulated in different cancers. From loss-of function genomic screens, we identified the RNA-binding protein HnRNPa1 as an inhibitor of β-catenin protein abundance and Wnt reporter activity. This raised the possibility that β-catenin abundance is regulated at the level of expression as well as by the turnover complex. HnRNPa1 abundance does not regulate transcription, mRNA stability, splicing or turnover. However, translation of a luciferase-β-catenin gene fusion construct was altered by HnRNPa1 knockdown but not when the construct was mutated to block HnRNPa1 interaction. HnRNPa1 is normally localised in the nucleus but nuclear-cytoplasmic shuttling of HnRNPa1 was previously shown to be increased by FGF-2 signalling. We found that FGF-2 addition increases β-catenin protein abundance but not that of the luciferase-β-catenin gene fusion construct with mutated HnRNPa1 binding sites. HnRNPa1 is a component of an FGF-2 mediated pathway that regulates β-catenin abundance via translation.

Live, Label Free Imaging of 3D Tissue Organoids Using CARS Microscopy

The abundance of biology that can be studied in 3D cell culture has the potential to revolutionise technical approaches in personalised medicine and drug discovery. However, current methods for the quantitative analysis of cells in 3D have lagged behind those for less complex 2D systems (e.g. high content microscopy) due to problems in biomarker identification, detection, validation and quantification. CARS microscopy has emerged in the last 10-15 years as a powerful label-free multi-photon technology for rapid imaging of living cells and tissues with high 3D spatial resolution and quantitative chemical specificity. Protein, DNA and lipid signatures can be detected by CARS imaging. We are using hyperspectral Coherent Anti-Stokes Raman Spectroscopy (CARS) label-free microscopy as a tool for analysing cellular heterogeneity in live 3D organoids, particularly cell type and cell cycle status.

2018: Member of Organising Committee for Engineering and Biosciences Forum. This forum brought together researchers in the School of Biosciences and the School of Engineering for talks on collaborative projects and included a "speed-dating" networking session.

2016-18: Chair of Biosciences Research Staff Group Committee.The committee articulates issues that are raised by and associated with research staff. I also attended the Research Committee as the Research Staff representative.  In 2017 and 2018, I organised, with other members of the Research Staff Committee, a Research Day that had technique and Technology Hub related networking opportunities and career-related talks.

2015-18: Seed Corn grant assessor and assessment committee chair. This School of Biosciences funding initiative is for small project proposals by Research Staff. I was an assessor in 2015-16 and chaired the assessment committee in 2017-18.

2016: Participation in the European Cancer Stem Cell Research Institute Open Day: communication of research to the lay public.

2008-16: Member of Biosciences Research Staff Group Committee.

External profiles

Research links