2008 WINNER

By Arron Rodrigues
Oundle School

Winner of the 15-19 category

Can we cure cancer with laser precision?

For every 5,000 drugs that enter pre-clinical testing in the US, on average only five are ever tested on humans, and only one approved for use. This puts into context the many “magic bullet” treatments that we hear about in the media. However, as a result of promising lab results, Nanospectra Biosciences has gained approval to “commence a human trial in patients with head and neck cancer” this year using “AuroLase™ Therapy”.

The pioneering research was led by Dr Jennifer West at Rice University in Texas, before the technology was licensed to Nanospectra, based in Houston. West’s laboratory exposed mice with cancerous tumours to tiny “nanoshells” and a special laser, which beams light similar to that used in your TV remote. The results were remarkable – the cancerous cells were eliminated in only 10 days.

A tumour consists of an area of rapidly and uncontrollably dividing cells, which is invisible to the body’s defence system. As the body cannot destroy them, untreated tumours grow larger, “squashing” vital organs. Tumours also develop their own blood vessels, drawing blood away from these organs. Unfortunately, cancerous tumours often lead to death. One in three people in the UK will be diagnosed with cancer – a fact which emphasises the importance of finding more effective treatments as soon as possible.

Chemotherapy, a common treatment for cancer, uses drugs that destroy rapidly dividing cells, in particular the cancerous ones. However, cells in the intestine and scalp also have a high turnover. Consequently, chemotherapy kills these healthy cells, too, with debilitating side-effects – diarrhoea and hair-loss. So replacements for current cancer treatments are long overdue: science writer Kevin Kelleher has remarked that “today’s best cancer treatments destroy tumour cells with about as much precision as an atomic bomb”.

Enter the nanoshell, which has enormous potential to provide more targeted treatment of cancerous tumours. It consists of a core made of silica, the main chemical in sand, surrounded by a thin gold shell. This gold coating was chosen because it is “biocompatible”, meaning that it is unlikely to be attacked by the body’s defences.

The most extraordinary thing about these incredible balls is their size: only 120 nanometres. To put this into perspective, if you were to blow up a cell of the body to the size of a football, a nanoshell would be half the size of a grain of sand. It can pass into the tumours from the bloodstream, because the blood vessels running through the tumours are “leaky”.

In treatment, the laser is shone on to the body, passing straight through all the cells without any harmful effects. Each nanoshell, however, acts as both a lens and a mirror: two thirds of the light from the laser is absorbed and converted into heat energy, while the remaining third is reflected, enabling doctors to locate the tiny balls. As the nanoshells accumulate near cancerous cells in tumours, the heat energy creates huge holes – the contents spill out and the cancerous cell dies.

This method may seem as haphazard and unfocussed as the present chemotherapy regimes, but fear not. Another paper was published late last year by Dr West’s lab. In this study, the researchers attached “targeting molecules” to each of the nanoshells. This new technique enabled the nanoshells to identify and latch on to cancerous cells, thereby reducing the risk of nanoshells accumulating in other organs.

Andre Gobin, who worked on this project, is very optimistic: “We can use one single particle to accomplish two tasks,” he explains, meaning that the nanoshells both locate and treat cancerous tumours. But scientists who study the effects of nanoparticles on the body continue to urge caution. Professor Vicki Stone, of Napier University in Edinburgh, maintains that the risks could outweigh the benefits. As yet, the effect of nanomedicines on the human body is relatively unknown, compared to conventional medicines.

Dr West claims that when testing the modified nanoshells on mice with cancerous tumours, the cancer was “completely destroyed”. Five months later, the mice were healthy and showed no signs of tumours.

Clearly, this result demonstrates the huge potential for “Aurolase™ Therapy” to save lives; but it must pass numerous, rigorous trials before entering our hospitals. There is still a long way to go for nanomedicines, but exciting times lie ahead. Finding a cure for cancer has proven to be one of the most colossal challenges in modern medicine – but it may yet be conquered by the smallest of solutions.