Scientists harness light therapy to target and kill cancer cells in world first
Scientists have successfully developed a revolutionary cancer treatment that lights up and wipes out microscopic cancer cells, in a breakthrough that could enable surgeons to more effectively target and destroy the disease in patients.
A European team of engineers, physicists, neurosurgeons, biologists and immunologists from the UK, Poland and Sweden joined forces to design the new form of photoimmunotherapy.
Experts believe it is destined to become the world’s fifth major cancer treatment after surgery, chemotherapy, radiotherapy and immunotherapy.
The light-activated therapy forces cancer cells to glow in the dark, helping surgeons remove more of the tumours compared with existing techniques – and then kills off remaining cells within minutes once the surgery is complete. In a world-first trial in mice with glioblastoma, one of the most common and aggressive types of brain cancer, scans revealed the novel treatment lit up even the tiniest cancer cells to help surgeons remove them – and then wiped out those left over.
Trials of the new form of photoimmunotherapy, led by the Institute of Cancer Research, London, also showed the treatment triggered an immune response that could prime the immune system to target cancer cells in future, suggesting it could prevent glioblastoma coming back after surgery. Researchers are now also studying the new treatment for the childhood cancer neuroblastoma.
“Brain cancers like glioblastoma can be hard to treat and, sadly, there are too few treatment options for patients,” the study leader, Dr Gabriela KramerMarek, told the Guardian. “Surgery is challenging due to the location of the tumours, and so new ways to see tumour cells to be removed during surgery, and to treat residual cancer cells that remain afterwards, could be of great benefit.”
The ICR’s team leader in preclinical molecular imaging added: “Our study shows that a novel photoimmunotherapy treatment using a combination of a fluorescent marker, affibody protein and near-infrared light can both identify and treat leftover glioblastoma cells in mice. In the future, we hope this approach can be used to treat human glioblastoma and potentially other cancers, too.”
The therapy combines a special fluorescent dye with a cancer-targeting compound. In the trial in mice, the combination was shown to dramatically improve the visibility of cancer cells during surgery and, when later activated by near-infrared light, to trigger an anti-tumour effect.
Scientists from the ICR, Imperial College London, the Medical University of Silesia, Poland, and the Swedish company AffibodyAB believe the novel treatment could help surgeons more easily and effectively remove particularly challenging tumours, such as those in the head and neck.
The joint effort was largely funded by the Cancer Research UK Convergence Science Centre at the ICR and Imperial College London – a partnership that brings together international scientists from engineering, physical and life sciences specialisms to find innovative ways to tackle cancer.
“Multidisciplinary working is critical to finding innovative solutions to address the challenges we face in cancer research, diagnosis and treatment – and this study is a great example,” said Prof Axel Behrens, the leader of the cancer stem cell team at the ICR and scientific director of the Cancer Research UK Convergence Science Centre.
“This research demonstrates a novel approach to identifying and treating glioblastoma cells in the brain using light to turn an immunosuppressive environment into an immune-vulnerable one, and which has exciting potential as a therapy against this aggressive type of brain tumour.”
After decades of progress in treating cancer, the four main forms in existence today – surgery, chemotherapy, radiotherapy and immunotherapy – mean more people who are diagnosed with the disease can be treated effectively, and large numbers can live healthily for many years.
However, the close proximity of some tumours to vital organs in the body means it is vital new ways to treat cancer are developed so doctors can overcome the risk of harming healthy parts of the body. Experts believe that photoimmunotherapy could be the answer.
When tumours grow in sensitive areas of the brain such as the motor cortex, which is involved in the planning and control of voluntary movements, glioblastoma surgery can leave behind tumour cells that can be very hard to treat – and which mean the disease can come back more aggressively later.
The new treatment uses synthetic molecules called affibodies. These are tiny proteins engineered in the lab to bind with a specific target with high precision, in this case a protein called EGFR – which is mutated in many cases of glioblastoma.
The affibodies were then combined with a fluorescent molecule called IR700, and administered to the mice before surgery. Shining light on the compounds caused the dye to glow, highlighting microscopic regions of tumours in the brain for surgeons to remove. The laser then switched to near-infrared light, which triggered anti-tumour activity, killing the remaining cells after surgery.
“Photoimmunotherapies could help us to target the cancer cells that can’t be removed during surgery, which may help people live longer after their treatment,” said Dr Charles Evans, the research information manager at Cancer Research UK. He cautioned that there were still technical challenges to overcome, such as reaching all parts of a tumour with near-infrared light, but added that he was “excited to see how this research will develop”.