Cancer remains one of the biggest causes of death worldwide. In the United States, it kills more people than any other causes except heart disease.
And it remains an unfortunate reality that many forms of cancer treatment, while much improved in recent decades, have downsides.
Radiotherapy can be effective at killing cancer cells, but it is also harmful to healthy tissue. Chemotherapy, meanwhile, often has unpleasant side effects, and again there is the problem that healthy cells die along with cancer cells.
Surgery does not always remove the whole tumour, and it can be hard to tell whether the cancer has spread across the body.
Little wonder, then, that thousands of researchers the world over are working on new ways to diagnose and treat cancer.
A key area concerns nanoparticles. These are tiny, usually spherical particles that are often as small as one-thousandth the width of a human hair.
At the Nanotech Dubai conference in October, a group of Germany-based scientists presented results that showed how effectively nanoparticles could kill cancer cells.
They reported laboratory tests in which nanoparticles, in this case bubble-like “vesicles” made from fat molecules, delivered anti-cancer drugs directly to cancer cells. The nanoparticles had molecules attached that made them combine with cancer cells.
When the particles, filled with a cancer-killing substance called doxorubicin, were applied to cervical cancer cells, more than 90 per cent of the cancer cells died just three days later. Without the nanoparticles, doxorubicin alone killed barely half the cancer cells in the same time.
The results were similar for intestinal cancer cells: 87 per cent of the cancer cells were killed when the anti-cancer agent was delivered with nanoparticles; but without them, almost half survived.
And nanoparticles can be designed to target only cancer cells, rather than healthy ones.
“You can both increase the effectiveness [of the drug] and reduce the side effects,” said Mont Kumpugdee-Vollrath, a professor at the Beuth University of Applied Sciences in Berlin. She was part of the team, including researchers from Fraunhofer Institute for Applied Polymer Research, that carried out the work.
“We’ve shown successfully that it can work.”
The research is still at an early stage, with clinical trials in the distant horizon. But the researchers are looking into the possibility of patenting their type of vesicle, which has a particular chemical composition that could be manipulated to alter its effectiveness.
Many other researchers are exploring the uses of nanoparticles against cancer. A team at Cornell University in the US have been studying gold and iron-oxide nanoparticles that, crucially, give off heat when infrared light is shone on them.
Antibodies attached to the nanoparticles guide them to the cancer cells, then the infrared light makes them heat up, killing the cancer cells without harming the surrounding healthy tissue.
This technique, according to Professor Carl Batt, who leads the Cornell group, could allow cancer to be treated with only “very localised treatment”.
“Our goal is to develop a treatment that is benign without being activated, and the particles that heat up [are] targeted towards the cancer cell,” he said.
“In theory, any type of cancer where we can define a targeting molecule would be treatable with this approach.”
Using another technique, University of Georgia scientists have employed nanoparticles that target the mitochondria – the tiny organelles within cells that produce the energy that powers them – of breast cancer cells.
When lasers activate the nanoparticles, the way the cells function is disrupted. These “activated” cancer cells can be used, via another type of cell, to stimulate the immune system, which can then identify and destroy the cancer cells.
Ultimately, it could offer ways of creating a cancer vaccine, or of treating late-stage breast cancer that has spread across the body.
As well as new ways of treating cancer, nanoparticles offer hope for improving diagnosis.
For example, nanoparticles that home in on cancer cells and are visible near infrared light, offer a potential way of determining the size and location of tumours.
For now, much of this is pie in the sky. Even the US National Cancer Institute admits that the use of nanotechnology for treating cancer is “largely in the development phase”.
Still, some drugs that employ nanotechnology are already available. Among them is Doxil, which has been used to treat ovarian cancer since 1995. Doxil employs nanoparticles that contain doxorubicin – essentially the same mechanism that was trumpeted in Dubai in October.
As research continues, the use of nanoparticles is likely to become more widespread, even though only a fraction of the laboratory discoveries will ever become real-world drugs.
Funding is a major constraint. Clinical trials, notes Prof Batt, are “expensive and time-consuming” – costing up to 1,000 times the expense of the initial discovery of a drug. In many cases, the hard part, in terms of cost and time, is not so much finding a drug that treats cancer effectively, but finding one that does so while being safe for use on patients. A cancer-treatment drug is of no use if it also shuts down the spleen.
In the case of Prof Batt’s gold and iron-oxide nanoparticles, he estimates that an achievable safe drug is still many years away – if it ever even makes it to market.
That quest for funding, according to Prof Kumpugdee-Vollrath, is one reason why researchers were keen to present their findings in Dubai.
“Abu Dhabi and Dubai are new cities and we think maybe we’ll … find an interesting partner,” she said. “In Europe, everybody knows us or we know them.
“We’re looking to progress this work, but it’s a question of money and we have to find funding from a third party.”
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