CRISPR shrinks tumours in mice

Scientists from China have managed to shrink the size of tumours in mice using CRISPR/Cas9 genome-editing technology.

They used the technique to change a gene that normally promotes tumour growth into one that triggers cancer cells to die.

'[This is] a clever use of this technology to control cancer growth in mice by manipulating the expression of cancer-causing genes,' Professor Andrew Sharrocks, professor of molecular biology at the University of Manchester, who was not involved in the study, told the International Business Times.

'The really interesting aspect is that they use a system which responds to signals created by the cancer cells themselves as they grow. This then causes specific genes to switch on or off, which results in elimination of the cancer.'

'However, at this stage it is difficult to envisage how this might be applied to treating cancer in humans,' he added.

The team of researchers, led by Dr Zhiming Cai from the First Affiliated Hospital of Shenzhen University in China, modified the CRISPR/Cas9 system so that it becomes activated by a signal that normally promotes tumour growth. The activated CRISPR/Cas9 system then drives the expression of tumour suppressor genes, stopping the growth of the cancer cells.

In a separate part of the study, they used the CRISPR/Cas9 system to induce the expression of genes that trigger cell death. In both cases, when the mice were injected with cancer cells, those with the reprogrammed cells developed much smaller tumours than those who had not been treated.

The results were reported in the journal Nature Methods.

Dr Chris Lord of the Institute of Cancer Research in London, who was not involved in the research, told BBC News: 'The key to translating this technique into the clinic will be to see how specific to the tumour cell the CRISPR activation will be and how specific, in terms of genes, the CRISPR-mediated gene cutting will be.'

In a separate study published in the Journal of the National Cancer Institute, scientists at University of Dresden demonstrated that they could specifically cleave more than 80 percent of known cancer-causing mutations, without targeting healthy genes, using CRISPR/Cas9 technology.