Characterisation of primitive stem cell-like canine cancer cells: identification of therapeutic targets through genomics

Lead Research Organisation: University of Edinburgh
Department Name: Veterinary Clinical Studies


Cancer has emerged as a major cause of morbidity and mortality in the dog, with an estimated incidence of 1 in 4. Despite advances in conventional chemotherapy and radiation, complete cures for most cancer types remains elusive, the challenge being to develop highly targeted therapies that kill cancer cells but leave normal cells healthy. For decades the scientific community has accepted a model that most cells in the body have the capacity to undergo genetic changes that ultimately result in them becoming cancerous. However, there has been a recent challenge to this model that suggests that the ability to become a cancer cell is restricted to specific tissue stem cells. These cells give rise to cancer stem cells that drive the production of daughter tumour cells. Daughter cells have the potential to be killed by conventional chemotherapy and radiation in contrast to cells with stem cell capabilities, which are largely resistant to such therapies. The implications of this are immense as it suggests that current therapeutic strategies are not targeting the root of the cancer, the cancer stem cell. There is a growing body of evidence that cancer is a true stem cell disease. Researchers in human medicine have identified putative cancer stem cells from a diverse range of cancers such as breast, colon, pancreas and brain. We have recently applied similar methodologies to the dog and identified a sub-set of cells in bone cancer that have stem cell characteristics. This proposal aims to further characterize these cells and will seek to identify novel signalling pathways in these cells that have the potential to be a therapeutic target. This study will inform the veterinary oncology community of potentially new ways to kill cancer cells. Further, it has the potential to inform similar studies in people and help to further advance the field of stem cell biology.

Technical Summary

For decades the advances in molecular techniques has allowed us to continually dissect the mechanisms of carcinogenesis, most work focusing on the accepted model of multistage carcinogenesis underpinned by progressive genetic changes that drive malignant transformation. In this model, any cell in the body has the potential for malignant transformation. More recently, attention has focused on an alternative model where transformation takes place in a tissue stem cell, becoming a cancer stem cell (CSC) and giving rise to a tumour composed mostly of daughter cancer cells and a small number of CS cells that drive tumour growth and expansion. Proof that cancer stem cells exist as a phenotypically different population of cancer cells requires isolation of different populations of cancer cells and demonstration that one or more groups are efficient at producing tumors while other groups lack this ability. However, these cells cannot be definitively called cancer stem cells until it is possible to demonstrate that a single transplanted cancer cell can give rise to a diverse population of cancer cells within a tumour. Using 'sphere' assays we have isolated cancer cells from cell lines and clinical cases that express markers (e.g. Nanog, Oct 3/4) indicative of a primitive phenotype. We have demonstrated that these cells can be passaged multiple times and are phenotypically distinct from daughter populations. This proposal aims to further characterize these cells in vitro and in vivo. In particular we will evaluate to ability of these cells to form tumours in NOD-SCID mice and use microarray to study specific transcriptomic profiles. Finally, we will use the array data, information from the published canine genome sequence, and RNAi to identify and validate potential targets in these cells for therapeutic intervention


10 25 50
Description We refined and characterised a number of markers and techniques for purifying cancer stem cells in dogs.We characterised these cells in terms of their resistance to radiation and chemotherapy. From this we identified major differences in DNA damage pathways in these cells which contribute to survival of the cancer.We used array technology to analyse the transcriptional profile of cancer stem cells versus "normal" cancer cells and mesenchymal stem cells. From this we have identified a short list of candidate genes that have the potential to be targeted therapeutically.We identified one specific gene that is massively up-regulated in cancer stem cells in bone cancer in dogs and is of major significance therapeutically. This has implications for the management of cancer in dogs, and also could have an impact on human medicine, specifically the treatment of osteosarcoma in children.

Update as of January 2016. As previously noted we identified a key gene COX-2 which we consider to be very important in tumour initiation. Since the end of the great we secured funding for a PhD student to study the role of COX-2 in tumour initiation. In addition, we secured a Daphne Jackson Fellowship for a scientist returning after significant maternity leave to work on COX-2 in cancer. Additional findings from the microarray study has also identified key pathways in EGFR signalling that are also required in cancer stem cell signalling. We have recently submitted a manuscript for publication (in review) based on these findings.
Exploitation Route These finding will have an implication for the veterinary healthcare sector. The papers we have already published have gained a lot of interest (downloads and cites) and it will support a greater understanding of basic mechanisms of cancer in veterinary species (and potentially the role of these genes in pluripotency). Interestingly, much of our data implicates the products of these genes playing a major role in the effects of conventional treatments (chemotherapy and radiation) and could have a more direct impact on how we manage veterinary patients. Equally, this information is important for human medicine.
Sectors Healthcare,Pharmaceuticals and Medical Biotechnology

Description The work in this grant has a major impact for veterinary medicine. However, more widely it has provided direct evidence that natural cancers in dogs provide a more optimal therapeutic model for the development of cancer treatments in people. One of the key advantages being that it reduces the number of experimental animals being used and may provide a more rapid and reproducible model system in the linear drug development pathway. An example of this is highlighted by the fact that it has led to a key industrial collaboration with an Italian biotechnology company developing drugs for humans. We have recently submitted a major grant to MRC based on using the dog model with this company to develop a new antibody targeted therapy for cancer.
Sector Healthcare
Impact Types Societal,Economic

Description Further funding: Pilot investigation into the in vitro effect of mavacoxib (trocoxil) on canine cancer cell lines
Amount £9,000 (GBP)
Organisation Zoetis 
Sector Private
Country United States
Start 05/2012 
End 06/2013
Description Returnning Scientist Scheme
Amount £58,000 (GBP)
Organisation University of Surrey 
Department Daphne Jackson Trust
Sector Charity/Non Profit
Country United Kingdom
Start 08/2015 
End 08/2017
Description University of Edinburgh Studentship
Amount £75,000 (GBP)
Organisation University of Edinburgh 
Sector Academic/University
Country United Kingdom
Start 09/2013 
End 09/2016
Description Arthur Willis Distinguished Speaker Lecture entitled Can comparative biology inform rational cancer drug development? 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Sparked discussion

Development of early stage collaborations in Canada
Year(s) Of Engagement Activity 2013
Description British Society of Veterinary Pathology 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Sparked discussion and debate

Requests for information about our work
Year(s) Of Engagement Activity 2014
Description International Conference UNAM University Mexico City 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact > 100 people attended from various international countries. I made two state of the art presentations on stem cell biology and set cells in disease.
Year(s) Of Engagement Activity 2016
Description Invited Talk, University of Hokkaido, Japan 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Sparked discussion afterwards

Supported development of MOU to provide exchange for postgraduate and undergraduate students
Year(s) Of Engagement Activity 2014
Description Medical detective Series 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Talked sparked discussion and debate

Interest in our work from a variety of sources
Year(s) Of Engagement Activity 2011