Irreversible DNA Damage Inflicted by Alcohol Ups Cancer Risk
Bad news for those of you hoping to score a good happy hour this weekend.
By Puritanical standards, alcohol is considered a vice- a widely acceptable one at that. But still, it is something that we are all better off avoiding in excess. Every year, its consumption is responsible for the deaths of around 88,000 people in the US alone.
Also, evaluating alcohol’s impact through the lens of biology has now painted a rather terrifying picture- researchers at the MRC Laboratory of Molecular Biology, Cambridge, have found that alcohol causes irreparable damage in the DNA of stem cells, enhancing the risk of developing cancer, and costing some hard drinkers “more than just a hangover”.
“How exactly alcohol causes damage to us is controversial,” said Prof Ketan Patel, who led the work at the MRC Laboratory of Molecular Biology in Cambridge. “This paper provides very strong evidence that an alcohol metabolite causes DNA damage [including] to the all-important stem cells that go on to make tissues.”
The study builds on previous work that had pinpointed a breakdown product of alcohol, called acetaldehyde, as a toxin that can damage the DNA within cells
. However, these earlier studies had relied on extremely high concentrations of acetaldehyde and used cells in a dish rather than tracking its effects within the body.The study in discussion, however, demonstrates how acetaldehyde slices through DNA, causing permanent damage, if the effects of the toxin are not neutralised by two natural defence mechanisms. The first tier of defence clears away the acetaldehyde and the second repairs the DNA damage.
The researchers experimented with mice bred without ALDH2 or FANCD2, to see what happens to blood stem cells (known as haemopoetic stem cells (HSCs)) when these mice are exposed to alcohol.
They found alcohol caused major DNA damage which stopped the HSCs from producing new blood cells. The experiments were not set up to see if the mice developed cancer.
This damage to the stem cells destroyed their ability to create fresh blood cells, which is their major function in the body, the researchers explain, and it may lead to the development of further mutations. “Our work definitively shows that external factors, like drinking alcohol, can damage DNA in blood stem cells, meaning it could also damage DNA in other types of stem cells,” Patel said. “While we didn’t look at whether these mice got cancer or not, previous studies have show that the type of DNA damage we saw in these mice can considerably increase the risk of cancer.”
Commenting on the findings, Magdalena Zernicka-Goetz, Professor of Mammalian Development and Stem Cell Biology at Cambridge, said: “This is beautiful work which puts our finger on the molecular basis for the link between alcohol and increased cancer risk and stem cells. Very important.”
Prof Malcolm Alison, Professor of Stem Cell Biology at the Barts Cancer Institute, Queen Mary University of London, added : “Drinkers beware: most of our organs and tissues have stem cells, immortal cells that replenish cells lost through the likes of old age throughout our lives, and the haematopoietic (blood stem cell) system is no exception.”
Susannah Brown, Senior Science Programme Manager (Research Evidence) of the World Cancer Research Fund said: “Our research shows the more people drink, the greater the risk they have of developing cancer. 24,000 cases of cancer a year could be prevented in the UK if nobody drank alcohol.
“World Cancer Research Fund has many tips for cutting down on alcohol, including drinking out of smaller glasses, diluting drinks such as swapping pints for a spritzer and to aim to keep at least a few days each week alcohol-free.”
