UCD PhD student Aisling O'Connor has won much praise for her research into a light-based treatment for cancer, writes Dick Ahlstrom.
Shining a bit of light on a problem can have wonderful effects in the area of cancer treatment. A combination of specialised chemicals and a beam of light are enough to destroy cancer cells completely while leaving healthy tissue intact.
New research in the area of "photodynamic therapy" (PDT) last week won first prize in the 2007 Conway Research Medal competition at University College Dublin. Second-year PhD student Aisling O'Connor claimed the gold medal and with it a cheque for €300.
O'Connor was one of 10 finalists taking part in the Conway Institute of Biomolecular and Biomedical Research annual Festival of Research at UCD's O'Reilly Hall. Participants are asked to present a talk on their research to an audience, so it is as much about being able to describe the work well as about the research itself.
PDT is all about combining a photosensitive chemical with a light source, explains O'Connor. "We inject a drug that is sensitive to light at a specific wavelength. When you shine the light, the drug is activated," she explains. "It produces large amounts of 'singlet oxygen'."
The free oxygen is highly reactive and it begins to fix onto cell structures and disrupt it, eventually causing the cell to die.
She has conducted in-vitro and in-vivo tests of the specialised chemical group known as chelated tetraaryl-azadipyrromethanes (ADPMs).
The object is to regulate the dose carefully and to use the right kind of light. The ADPMs respond to near-infrared light at between 680 and 690 nanometres, so it is highly specific, she explains. "We use a red light because it can easily penetrate the skin."
The key is to get the drug selectively to the site of a tumour. "The drug preferentially accumulates in the tumour," she says and is taken up less well by healthy tissues. This means that when the light source is applied there is virtually no "collateral damage" to normal surrounding tissues.
"You should have no affect on normal cells. In our tests, the animals were completely well soon after the treatment," she says.
The system looks very promising given the cell death seen in the in-vitro tests was close to the body's own method for removing unwanted cells, known as apoptosis. This is a highly regulated system whereby the waste products produced by the dying cell are mopped up by white blood cells.
The cell death seen in in-vivo tests was more necrotic, or uncontrolled, but O'Connor put this down to the white cells being unable to keep up with the rapid tumour cell death rate. Even so, the animals were completely well and suffered no ill-effects after treatment.
She will now begin to treat another cancer, this time using a model for breast cancer. Although the tumours will be deeper inside the body, the infrared light will be able to reach the tumour and trigger the ADPMs, she says.
O'Connor's work is funded by Science Foundation Ireland and by a UCD Ad Astra Research Scholarship. Her research is overseen by Prof William Gallagher, Dr Annette Byrne, Dr Donal O'Shea and Dr Margaret Magee.
Second prize in the Gold Medal competition went to Shane Gannon and third prize went to Radka Saldova and Kristine Nyhan.