Immune evasion is critical to the growth and survival of cancer cells. This is especially pertinent to transmissible cancers, which evade immune detection across genetically diverse hosts. The Tasmanian devil (Sarcophilus harrisii) is threatened by the emergence of Devil Facial Tumour Disease (DFTD), comprising two transmissible cancers (DFT1 and DFT2). The development of effective prophylactic vaccines and therapies against DFTD has been restricted by an incomplete understanding of how allogeneic DFT1 and DFT2 cells maintain immune evasion upon activation of tumour-specific immune responses. In this study, we used RNA sequencing to examine tumours from three experimental DFT1 cases. Two devils received a vaccine prior to inoculation with live DFT1 cells, providing an opportunity to explore changes to DFT1 cancers under immune pressure. Analysis of DFT1 in the non-immunised devil revealed a 'myelinating Schwann cell' phenotype, reflecting both natural DFT1 cancers and the DFT1 cell line used for the experimental challenge. Comparatively, immunised devils exhibited a 'dedifferentiated mesenchymal' DFT1 phenotype. A third 'immune-enriched' phenotype, characterised by increased PDL1 and CTLA-4 expression, was detected in a DFT1 tumour that arose after immunotherapy. In response to immune pressure, mesenchymal plasticity and upregulation of immune checkpoint molecules are used by human cancers to evade immune responses. Similar mechanisms are associated with immune evasion by DFTD cancers, providing novel insights that will inform modification of DFTD vaccines. As DFT1 and DFT2 are clonal cancers transmitted across genetically distinct hosts, the Tasmanian devil provides a 'natural' disease model for more broadly exploring these immune evasion mechanisms in cancer.

Item Type:	Refereed Article
Keywords:	Tasmanian devil, Devil Facial Tumour Disease, transmissible cancer, cancer vaccine, epithelial-to-mesenchymal transition, mesenchymal plasticity
Research Division:	Biological Sciences
Research Group:	Zoology
Research Field:	Animal cell and molecular biology
Objective Division:	Environmental Management
Objective Group:	Terrestrial systems and management
Objective Field:	Control of pests, diseases and exotic species in terrestrial environments
UTAS Author:	Patchett, AL (Dr Amanda Patchett)
UTAS Author:	Tovar, C (Dr Cesar Tovar Lopez)
UTAS Author:	Blackburn, NB (Dr Nicholas Blackburn)
UTAS Author:	Woods, GM (Professor Gregory Woods)
UTAS Author:	Lyons, AB (Associate Professor Bruce Lyons)
ID Code:	143856
Year Published:	2021
Web of Science® Times Cited:	5
Deposited By:	Menzies Institute for Medical Research
Deposited On:	2021-04-07
Last Modified:	2021-05-05
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