KILL SWITCH
Nanorobots with hidden ‘lethal weapons’ destroy cancer cells and stop tumours spreading, scientists say
It is one of several major cancer breakthroughs in the last few years
SCIENTISTS have developed nanorobots with hidden "lethal weapons" that can kill cancer cells.
The tiny machines stopped tumours from spreading without harming surrounding healthy tissue in a promising trial in mice.
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The researchers, from the Karolinska Institutet in Sweden, hope the technology can be used to the same effect in humans.
Yang Wang, a researcher in the Department of Medical Biochemistry and Biophysics, said: "We now need to investigate whether this works in more advanced cancer models that more closely resemble the real human disease.
";We also need to find out what side effects the method has before it can be tested on humans."
The scientists previously developed structures that can organise so-called death receptors on the surface of cells, leading to cell death.
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These exhibited six peptides (amino acid chains) assembled in a hexagonal pattern.
"This hexagonal nanopattern of peptides becomes a lethal weapon," lead author Professor Björn Högberg said.
"If you were to administer it as a drug, it would indiscriminately start killing cells in the body, which would not be good.
"To get around this problem, we have hidden the weapon inside a nanostructure built from DNA."
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The art of building nanoscale structures using DNA is called 'DNA origami' and is something the team has been working on for years.
Now, they have used the technique to create a ‘kill switch’ that is activated under the right conditions, sparing healthy cells.
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"We have managed to hide the weapon in such a way that it can only be exposed in the environment found in and around a solid tumour," Prof Högberg said.
"This means that we have created a type of nanorobot that can specifically target and kill cancer cells."
The key is the low pH, or acidic microenvironment, that usually surrounds cancer cells, which activates the nanorobot’s weapon.
PROMISE FOR FUTURE TREATMENT
In test tube analyses, the researchers were able to show that the peptide weapon is hidden inside the nanostructure at a normal pH of 7.4, but that it has a drastic cell-killing effect when the pH drops to 6.5.
They then injected the nanorobot into mice with breast cancer.
This resulted in a 70 per cent reduction in tumour growth compared to mice given an inactive version of the nanorobot.
As well as testing whether this could produce the same results in humans, the researchers plan to investigate whether it is possible to make the nanorobot more targeted by placing proteins or peptides on its surface that specifically bind to certain types of cancer.
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This targeted approach could lead to more effective and less toxic cancer treatments in the future.
The study was published in the journal .
Other cancer breakthroughs
IT’S a worrying fact that more than half of us will get cancer in our lifetime.
Each year around 385,000 people are diagnosed and 167,000 lives are lost to the disease in the UK . . . and experts have warned of an alarming new surge in the young.
But, in the face of rising cases, there is good news — the future of cancer care looks brighter.
Personalised medicine
Perhaps the most exciting new avenue of research is tailoring medicine to treat a patient’s cancer based on their own tumour’s genetic make-up.
Professor Lawrence Young, an oncologist who has been working in cancer research for 40 years, says: “We’ve learnt that by profiling the genetics, you almost get a barcode for an individual’s cancer.
“Just because somebody’s got the same stage and grade of cancer, doesn’t mean it should be treated the same, or with a particular combination of drugs.”
The NHS announced in May that it would trial personalised cancer vaccines designed by biotech giants BioNTech and Genentech.
Some 10,000 patients in England are set to get their very own disease-busting jab by 2030, through the NHS Cancer Vaccine Launch Pad.
Immunotherapy
Dubbed the “biggest breakthrough since chemo”, immunotherapy harnesses the power of the immune system to fight cancer.
Antibodies seek out and mark the diseased cells for destruction but spare surrounding healthy tissue, unlike chemotherapy or radiotherapy.
Prof Young says: “We’ve known for 100 years the body tries to fight cancer with the immune system but it doesn’t really work.
“Cancer cleverly learns how to get around the immune response. It can switch off the way the immune system recognises it – but these antibodies can switch it back on again.
“Antibodies are effective alone, but where they are most effective is in combination with another type of immunotherapy.”
Keytruda (pembrolizumab) brings cancer cells out from hiding.
It has been approved for treating several cancers on the NHS, including melanoma, cervical, breast and lung cancer. But its use could be extended to bowel cancer.
Targeted cancer drugs
These work more precisely to stop cancer cells from dividing and growing, while limiting damage to healthy cells – and their uses are expanding.
Prof Young says: “This is targeting the machinery of the genetic mutations that drive cancer.
“Some are targets we’ve known about for years but were difficult, until recently, to develop drugs for.
“The normal growth of our cells is controlled by switches which become mutated and permanently switched on in cancer cells.
“Now, after years of research, we have targeted drugs which can switch off these growth signals.”
Kinase inhibitors are targeted drugs – small molecules that stop certain enzymes involved in cancer growth.
Lorlatinib, branded as Lorviqua, is used for a handful of patients with ALK-positive non-small cell lung cancer.
But after “groundbreaking” results in May, campaigners hope it will become a lifeline for the 350 people in the UK who are diagnosed with this type of cancer each year.
Blood tests
Early diagnosis is still the best weapon against cancer and its devastating impacts.
Blood tests are becoming increasingly sensitive in spotting the disease.
Prof Young says: “Current blood tests aren’t that great. For example, we measure the proteins PSA, for prostate cancer, or CEA, for ovarian cancer, but they’re not very specific.
“We want to do our best to cure cancer with early diagnosis, and with these interesting blood tests it might be possible to identify cancer early and remove it before we get too far.”
These new blood tests can “identify minuscule amounts of DNA shed from tumour cells into the blood”, Prof Young says.
The NHS has been trialling the Galleri blood test in England and Wales, using 140,000 volunteers so far, and will continue until 2026.
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