Due to be tested in August, the gene editing CRISPR technique will be used in attempt to treat patients suffering from lung cancer. The team led by oncologist Lu Yuo, based in Sichuan University’s West China Hospital in Chengdu, are on the verge of being the first in the world to inject patients with cells modified using CRISPR- Cas9 gene editing technology.
The clinical trial was given approval from the hospital’s review board in early July. The team will enrol patients who have metastatic (cancer that has spread from where it first started to another part of the body) non-small cell lung cancer, and whom haven’t had success with chemotherapy, radiation or other therapies, Nature reported.
As it stands, CRISPR is off limits in the UK and is considered a controversial topic, with doubts that it could result in ‘designer babies’ if exploited. However, the limits of CRISPR are unknown, from changing the colour of mouse fur to designing malaria free mosquitoes and pest resistant crops to correcting a plethora of genetic diseases such a sickle cell anaemia.
Lu’s team will carefully extract immune cells called T cells from the blood of the enrolled patients. Using Clustered, Regularly Interspaced, Short Palindromic Repeat technology or CRISPR-Cas9 for short, a molecular guide able to identify and target specific genetic sequences will be paired on a chromosome using an enzyme (Cas9) to cut the chromosome as that particular spot. This results in a gene being ‘knocked out’. The gene in question encodes a protein called PD-1, also known as programmed cell death protein 1 that is normally checks the cell’s capacity to launch an immune response, to prevent it from attacking healthy cells.
The newly engineered cells will then be multiplied and reintroduced back into the patient’s bloodstream, circulate and hopefully, home in on the cancer.
In the previous few years, antibodies have been used by scientists to knock out the PD-1 gene but CRISPR- Cas9 technology appears to bring a bigger glimmer of hope. By contrast, knocking out the gene blocks PD-1 with greater certainty, while multiplying the cells increases the chance of a response. “It will be much more powerful than the antibodies,” says Timothy Chan, who carries out clinical research in immunotherapy at Memorial Sloan Kettering Cancer Center in New York.
What could be the risks?
CRISPR is well known to cause gene edits at the wrong place in the genome, which could potentially cause some harmful effects. As in this case it is T cells that will be targeted, Chan worries an autoimmune response will be triggered as these cells are involved in various immunological mechanisms in a non-specific way.
Some scientists think China sometimes move too fast when it comes to CRISPR technology, but Lu says this is because her team are experienced with clinical trials and cancer research. “I hope we are the first,” she says. “And more importantly, I hope we can get positive data from the trial.