Scientists develop 'dual-purpose' cancer nanoparticles

In collaboration with the Press Association

US researchers have developed 'dual-purpose' microscopic nanoparticles, one-billionth of a metre in size, that could be used both to precisely deliver drugs to cancer cells and then to help monitor their effects.

The system has only been tested in animals so far, but with promising results.

A team at the University of Michigan used the nanoparticles to treat brain tumours in mice. Brain tumours are hard to treat using conventional drugs as it can be difficult to get the drugs across what is known as the blood-brain barrier.

"Thinking outside the box is a must for developing brain cancer treatments," said study author Professor Alnawaz Rehemtulla.

"Drugs don't get into the brain when delivered in the normal way, which explains in part why some current treatments for brain tumours are generally not effective."

Average survival for mice treated with the nanoparticles was 33 days - compared to 13 days when the drug was delivered intravenously.

The nanoparticles contain a light-sensitive cancer drug, Photofrin, together with iron oxide which is used as a 'contrast agent' to make cells and tissues more visible on an MRI scan.

By combining the drug with a contrast agent, researchers were able using imaging techniques to determine whether the drug actually reached the tumour.

This technique could have the potential to diagnose brain tumours early, as well as to help researchers determine when to deliver a drug or when to administer the next dose.

Photofrin works by attacking a tumour's blood supply, starving cancer cells of oxygen and nutrients. The drug has previously been shown to work against throat, bladder and skin cancers. But it can also cause damage to healthy tissues, especially the skin.

If nanoparticle delivery proves to be safe in humans, it will allow researchers to re-examine previously developed drugs that were discarded because they caused too many dangerous side effects in patients.

The study is published in the journal Clinical Cancer Research.