New weapon to combat cancer: light

Scientists have discovered a simple and practical way to kill cancer cells by using light to steer immune cells to attack the tumours.

Researchers at the University Rochester Medical Centre describe their method as similar to “sending light on a spy mission to track down cancer cells.”

Immunotherapy is different from radiation or chemotherapy. Instead of directly killing cancer cells, immunotherapy tells the immune system to act in certain ways by stimulating T cells to attack the disease.

But the problem is that immunotherapy can cause the immune system to overreact or under-react, said Minsoo Kim, a professor at the university. Her laboratory conducted a study to understand and develop light-sensitive molecules that could efficiently guide T cells towards tumours.

Virus used

They discovered that a molecule called channelrhodopsin, active in algae and is light sensitive, could be introduced to the immune system via a virus and activated to control the T cell response to cancer. They also tested an LED chip in mice, which could eventually be implanted in humans.

The team evaluated their methods in mice with melanoma on the ears.

The animals wore a tiny battery pack that sent a wireless signal to the LED chip — allowing researchers to remotely shine light on the tumour and surrounding areas, giving T cells a boost for their cancer-killing function.