Focus goes on developing new, more targeted cancer treatments
Boron neutron therapy isn't new, but advances in medical science mean it might be commonly used in future. Photo / Getty Images
Many traditional cancer treatments damage healthy cells along with the malignant ones, and the focus now is on developing new, more targeted therapies. At the University of Auckland, Paul Harris and his team are working on one potential solution.
Boron neutron capture therapy isn’t new, exactly. Its potential was recognised back in the 1930s but for a long time it was far too challenging to deliver.
This type of radiation treatment involves a patient having an infusion of a non-toxic drug containing atoms of boron-10. The tumour is then irradiated with low-energy neutrons, many of which are absorbed by the boron, triggering a nuclear reaction and obliterating the targeted cells.
“The biggest challenge has been that you needed a nuclear reactor to generate these neutrons,” says Harris. “So, you had to have a hospital that was next to a nuclear power station to actually do this technique.”
The game-changer has been the development of neutron accelerators that are powered by electricity and can be scaled down in size. “Now the chemistry needs to catch up,” says Harris. “We have to find better ways of getting the boron into cancer cells. The compounds we have at the moment are nowhere near as advanced as they will have to be. You need them to be selective and not go into your normal cells, obviously.”
In some countries, such as Japan, boron neutron capture therapy is already being used for cancers of the head, neck and skin, and at Tokyo’s Edogawa hospital the cutting-edge treatment is being trialled with breast cancer. “But it tends to be used as a last-chance treatment when all other options have failed,” says Harris.
His team is focused on creating a peptide that will act like a Trojan horse, tricking cancer cells into letting boron-10 atoms inside so that the neutrons target only them and not the healthy cells.
Many cancers over-express a particular surface protein, and this peptide has been designed to bind onto it, then get inside the cell.
Harris says: “The question is, if we add boron to that peptide will it still bind with the protein and be internalised? Because if that doesn’t work it’s dead in the water, really. With medicinal chemistry, it is always a possibility that when we add something to a molecule it won’t play ball any more; it is one of those things that is difficult to predict.”
At the moment, researchers are trialling various peptides, and Harris hopes to know in the next few months which is the most effective boron-carrier.