One of the most remarkable scientific breakthroughs since the mapping of the human genome has been CRISPR, an acronym that stands for “clustered regularly interspaced short palindromic repeats.” It is a technique that allows scientists to make precision edits to any DNA and was discovered when studying the immune system of bacteria. The potential of CRISPR is huge, enabling researchers to cut, copy and replace sections of DNA, and use it for a variety of purposes – from treating genetic disorders such as cystic fibrosis to modifying plants that provide sufficient food for the world’s growing population.
Today’s edition of Science features a series of freely-available articles by Jon Cohen who recently visited China. Most people, when thinking of CRISPR and China, recall the controversial actions of biophysicist He Jiankui who used the technology to alter the DNA of two human embryos that would become twin girls. However, as Cohen emphasises, the country’s scientists have established an enviable reputation, challenging the dominance of America. This applies to both patent applications (USA = 872, China = 858) and journal papers published in 2018 (USA = 898, China = 824), although China lags in the number of citations.
Earlier this week, National Public Radio (NPR) in the USA published an exclusive article about a patient, Victoria Gray (seen left, © NPR), who has been treated for sickle cell disease. She is the first publicly identified person involved in a study applying CRISPR technology to a genetic disorder. In the procedure, doctors used cells from Gray’s own bone marrow, genetically modified the cells using CRISPR to produce foetal haemoglobin, and then infused billions of these cells into her blood stream. It will take months, perhaps years, before doctors know whether the treatment has been effective, but Gray is optimistic: “This gives me hope if it gives me nothing else.”
In the field of breast cancer research, CRISPR has thus far been used primarily as a diagnostic tool – identifying dangerous mutations – but in time it is hoped that the technology will play an important therapeutic role. Cancer cells that circulate in the blood are often self-homing, returning to the original tumour site. In an animal model, Khalid Shah in Boston has used a Trojan horse approach, using CRISPR to modify breast cancer cells, and then inserting molecules to initiate cell death. His team plans to implement the technique in human clinical trials in the next few years.
It’s fascinating to realise that 30-year-old basic science research on the bacteria Escherichia coli could have such far-reaching implications for humankind.