杏吧原创

OUR bodies are electric. It鈥檚 not just our brains and hearts 鈥� almost every cell has an electrical charge, and hacking it might be a way to treat cancer. Researchers have used light to shift the charge of cancer cells in frogs, making them healthy again.

It鈥檚 some way off being a human therapy, but this is the first use of聽a technique called optogenetics to target cancer, opening up the possibility of treatments that don鈥檛 use toxic drugs. 鈥淭his is聽just聽the beginning,鈥� says at Tufts University, Massachusetts. 鈥淲e hope we have a new strategy for reprogramming cell activity聽鈥� we鈥檙e cracking the bioelectric code.鈥�

Nerve cells use electricity to transmit signals. They do this by聽letting ions flow into or out of the cell through channels in their membranes, often triggering similar changes in neighbouring cells. Other cells also communicate in this way, using their ion channels to share information about their function or movement, says Levin.

This communication seems to be important when cells divide to repair damage. But uncontrolled cell division can lead to cancer, and when a cell loses some of its negative charge, it seems to help tumours to spread. These findings have raised a tantalising prospect: could we target these electrical signals to stop cancer?

Treatments that target ion channels are already being tested聽鈥� one such drug seems to have kept a man鈥檚 brain tumour . However, the drug had toxic side effects, so he聽stopped taking it.

Instead of using drugs to target聽ion channels, Levin鈥檚 team聽is using optogenetics. This technique involves injecting a聽gene into cells that makes a light-sensitive protein. Shining a聽laser on these newly sensitive cells can then alter their behaviour in different ways, depending on the protein used.

鈥淲e hope we have a new strategy for cancer 鈥� we鈥檙e cracking the bioelectric code鈥�

To see if optogenetics can change the flow of ions into a cell聽to revert it to a non-dividing state, Levin鈥檚 team have turned to聽frog embryos, which are particularly easy to work with. They inserted a gene that predisposes animals to cancer, adding a gene for a light-activated ion channel at the same time.

A week later, the tadpoles had聽hatched and developed tumours. While not exactly the same as human cancers, these tumours had many of the same properties, growing, spreading and forming their own blood supply in a similar way.

When the team pointed a laser at the tadpoles, around a third of the tumours stopped developing. This is an impressive result for a cancer treatment, says at the University of聽York, UK, although he says it is聽hard to know how large the effect would be in humans.

In the tadpoles, cells that had聽been cancerous looked healthy again, and were absorbed back into other body tissues. 鈥淭hey鈥檝e reprogrammed the cancer cells, by altering the electrical status of聽the cell,鈥� says聽 at聽Loyola University Chicago. 鈥淭hey are not聽cancer cells anymore.鈥�

If the approach works in humans, breast and skin cancers might be targeted first, as they are聽easy to shine a laser on. Levin聽hopes his approach will eventually offer an alternative to standard cancer drugs. We might find that drug-free treatments have fewer side effects, he says.

Gentile agrees. Cancer drugs that kill dividing cells don鈥檛 work perfectly, and the side effects can be worse than the disease itself in some cases, he says. 鈥淟evin has shown that you don鈥檛 need to kill the cells聽鈥� you can take them back to a normal state.鈥�

This article appeared in print under the headline 鈥淏ioelectric cancer hack鈥�