Page URL:

Elephants' 'zombie gene' may give cancer insights

20 August 2018
Appeared in BioNews 963

For their large body size, elephants should get cancer a lot more often than they do – now a new study has found out why. And this may help in our understanding of cancer.

Researchers at the University of Chicago in Illinois suggest that elephants have evolved to protect themselves from cancer by resurrecting a copy of an ancient tumour suppressor gene LIF6, that had become dormant. They call it a 'zombie gene'.

'It might tell us something fundamental about cancer as a process. And if we're lucky, it might tell us something about how to treat human disease,' senior author Dr Vincent Lynch told the New York Times.

The LIF6 gene can kill cells in response to DNA damage and prevent the accumulation of errors in the genome that lead to uncontrolled cell proliferation and, therefore, tumour formation.

The gene is expressed by the cells of most mammals, including humans, where it is usually present as a single copy. The ancestors of the modern elephant accumulated ten copies of the LIF gene, known as pseudogenes – dormant genes whose functionality is lost. Among these extra copies, elephants appear to have brought one of them back to life.

'I was sitting at my computer, and I thought: "let me just look at the elephant genome and see if they have extra tumour suppressors",' said Dr Lynch, senior author of the study and an evolutionary biologist. 'It turns out they have lots. And then I had something to tell the class.'

The finding may help explain an observation known as the 'Peto paradox' that has long puzzled scientists. Large animals, like elephants, have more cells than small animals: a higher number of cells means a higher number of cell divisions, which increases the chances of acquiring cancer-related mutations.

This applies within members of the same species, but paradoxically not across species. In other words, taller humans are more likely to develop tumours than shorter ones, but elephants are not more susceptible to tumours than humans.

Previous studies identified other genes that help fight tumours, of which copies seemed to have accumulated during the evolution of the elephant lineage. One of these genes is p53 – often described the 'guardian of the genome'. Analysing 53 different mammalian genomes, Lynch's team found that p53 activated the expression of LIF6 in elephant cells in vitro in response to DNA damage. The LIF6 proteins then triggered the release of toxic molecules from the mitochondria of the cells, causing cell death.

The results 'offer up another avenue of research, another piece of the puzzle, in how nature decreases cancer, and could help us in finding creative ways to treat and perhaps one day prevent cancer' said paediatric oncologist, Dr Joshua Schiffman at the University of Utah in Salt Lake City, who has also studied cancer in elephants and was not involved in the study.

The new research was published in Cell Reports.

A Zombie LIF Gene in Elephants Is Upregulated by TP53 to Induce Apoptosis in Response to DNA Damage
Cell Reports |  14 August 2018
Elephants Have a Secret Weapon Against Cancer
The Atlantic |  15 August 2018
The ‘Zombie Gene’ That May Protect Elephants From Cancer
New York Times |  14 August 2018
'Zombie gene' could be why so few elephants die of cancer
Popular Science |  16 August 2018
29 March 2021 - by Anna Wernick 
A set of immune cell genes ramp up their expression after death, a new study has revealed...
18 January 2021 - by Dr George Janes 
Existing drugs could treat as many as one in five glioblastomas, a new study has found...
24 June 2019 - by Dr Lea Goetz 
The rapid annual regrowth of deer antlers is down to a combination of cancer-linked genes and tight regulation of them by tumour-suppressing genes, finds a new study. The results may offer a new avenue for cancer treatment research in humans...
25 February 2019 - by Hugo Wolfe 
Scientists who have decoded the great white shark genome for the first time may have uncovered clues which could help develop human cancer treatments...
14 January 2019 - by Isobel Steer 
Twenty-four genes strongly associated with monogamy in males have been discovered from analysing the genomes of ten animal species...
18 December 2017 - by Dr Loredana Guglielmi 
Scientists in the USA have found a novel non-coding gene that alters proliferation in cancer cells to help tumour development...
6 November 2017 - by Julianna Photopoulos 
Scientists have found 27 new tumour suppressor genes...
30 November 2015 - by Dr Jane Currie 
Scientists have used genome-editing technology to identify a core set of 1580 genes that are essential to human life...
4 August 2014 - by Daryl Ramai 
Scientists at the Children's Nutrition Research Center, USA have shown that epigenetic changes alone could cause cancer....
30 August 2011 - by Kyrillos Georgiadis 
A group of Irish scientists has discovered that a supposedly 'dead' pseudogene is, in fact, active. The gene, DHFRL1, was long thought to be inactive, however new research, published in the US Proceedings of the National Academy of Sciences, suggests this is not the case...
to add a Comment.

By posting a comment you agree to abide by the BioNews terms and conditions

Syndicate this story - click here to enquire about using this story.