New research into the way the Tasmanian devil facial tumour disease is spread has solved a long held mystery regarding the iconic species.
Tasmanian devils are a rare host of transmittable cancers because tumours usually exclusively grow where their cells of origin derive from. How the disease became transmittable has puzzled scientists since the discovery of the disease.
All collected tumour samples are nearly genetically identical and presumably derive from a single cell or origin.
A research collaboration between the CeMM Research Centre for Molecular Medicine of the Austrian Academy of Sciences, the Vienna University of Veterinary Medicine and the Medical University of Vienna has revealed molecular mechanisms that are crucial for the transmissibility of the tumour.
CeMM research co-author Lindsay Kosack said the research could play an important role for the treatment of the disease in infected devils.
“Our experiments show for the first time that the excessive activation of ERBB receptions and STAT3 proteins play a key role in the transmissibility of the Tasmanian devil’s facial tumour,” Mr Kosack said.
“We showed in further experiments that the inhibition of ERBB receptors with a drug can selectively kill the cancer cells,” Mr Kosack said.
Trowunna Wildlife Sanctuary director Androo Kelly said the findings build on a body of research into how the tumour cell works and for the first time answers a long held question of why the devils have no immune response to the cancer.
“It is probably the first time it has been revealed how the cell is implanted into another devil’s face,” Mr Kelly said.
Mr Kelly said the findings of this research were fascinating in terms of academic knowledge, however they will not have any direct management impacts on the devils in Tasmania.
The devil population in Tasmania is in recovery and will not need to implement the use of a vaccine program, he said.
“Tasmanian devils are showing resilience and an evolutionary response.”
Mr Kelly said there was a large insurance population in the wild of thousands of devils and that the species was no longer on the verge of extinction.
“The devils are showing they don’t need any more intervention.”
Mr Kelly said the research may have practical responses to cancer in humans down the track.
In collaboration with the Universities of Cambridge, Southampton, Toronto and Tasmania, the study found the receptor molecules, the ERBB receptors, on the cancer cells show massively increased activity.
This activity triggers a biochemical reaction within the cells that eventually activates STAT3 proteins which alters the cell’s genetic program and results in an extensive rebuild of the cell.
The number of molecules that serve as identification for the immune system are reduced, proliferation is accelerated and factors allowing for the growth of cancer cells on a healthy devil are created.
CeMM principal investigator Andreas Bergthaler said the aggressive biting behaviour of the animals seems to play an important role in tumour transmission.
Mr Bergthaler said the the study was significant not only for the devils, but for human cancer research.
“99.1 per cent of the Tasmanian devil’s STAT3 are identical to the human protein and many of the genes that are activated by STAT3 in the animals are also active in human cancers,” Mr Bergthaler said.
“The biological principles of invasion of new tissues are also crucial for non-transmittable tumours. Scientific aspects of cancer, contagious diseases and inflammatory processes can be studied with this rare phenomenon.”
Mr Bergthaler said it was unlikely, but not impossible, that a human cancer would become transmissible.
“Aside from the molecular mechanisms that would need to evolve humans are genetically much more diverse and resistant than the isolated population of the Tasmanian devils.”
“Nevertheless, a better molecular understanding of this rare disease can provide valuable insights on fundamental biological mechanisms of cancer development.”