AsianScientist (Sep. 3, 2012) – The outlook for Tasmanian devils appears even worse following new research published in PLoS One.
Devil Facial Tumor Disease (DFTD), a naturally occurring contagious cancer which is transmitted between devils when they bite each other, has already decimated 85 percent of the population since its appearance in 1996, killing in excess of 100,000 animals.
Short of a cure, scientists are removing the sick animals and quarantining healthy devils in case the wild population dies out.
The research looked at telomere changes over time in DFTD cells. Telomeres are repeated sequences on the ends of chromosomes that have been compared to the protective plastic on the end of a shoelace. In the same way, the primary role of the telomeres is to protect the end of the chromosomes from fraying.
During normal cell division telomere length shortens until a critical length is reached, at which point the cell can no longer divide. In human cancer cells, telomeres do not get shorter but are maintained by an enzyme called telomerase.
“We have discovered that DFTD is able to survive indefinitely because the ‘caps’ at the ends of their chromosomes are being replenished, essentially preventing aging in this cell line,” said senior author Dr. Kathy Belov from the University of Sydney.
Not only did the researchers confirm the ‘immortality’ of the DFTD cancer cells, they also discovered that both the length of the telomere and the activity of the telomerase have been increasing over time in the devils.
Nobody has previously found that the activity of telomerase can increase over time in a species and future studies will need to test if this leads to an increased rate of cell division in the devils.
“In the meantime we need to redouble our efforts to protect this species from extinction. We have found that the tumor is not going to die out, meaning that our major hope at the moment lies in removing the devils from the path of DFTD. The captive breeding program is essential to save this iconic species from disappearing completely,” said lead author Beata Ujvari, a postdoctoral research fellow in the Faculty of Veterinary Science.
The article can be found at: Ujvari B et al. (2012) Telomere Dynamics and Homeostasis in a Transmissible Cancer.
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Source: University of Sydney; Photo: jomilo75/Flickr/CC.
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