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It's like someone has pressed fast-forward on the gene-editing field: A simple tool that scientists can wield to snip and edit DNA is speeding the pace of advancements that could lead to treating and preventing diseases.
Findings are now coming quickly, as researchers can publish the results of their work that's made use of the tool, called CRISPR-Cas9.
The tool, often called CRISPR for short, was first shown to be able to snip DNA in 2011. It consists of a protein and a cousin of DNA, called RNA. Scientists can use it to cut DNA strands at very precise locations, enabling them to remove mutated parts of genes from a strand of genetic material.
In the past year alone, dozens of scientific papers from researchers around the world have detailed the results of studies — some promising, some critical — that used CRISPR to snip out and replace unwanted DNA to develop treatments for cancer, HIV, blindness, chronic pain, muscular dystrophy and Huntington's disease, to name a few.
"The pace of basic research discoveries has exploded, thanks to CRISPR," said biochemist and CRISPR expert Sam Sternberg, the group leader of technology development at at Berkeley, California-based Caribou Biosciences Inc., which is developing CRISPR-based solutions for medicine, agriculture, and biological research.
Although it will be a few more years before any CRISPR-based treatments could be tested in people, "hardly a day goes by without numerous new publications outlining new findings about human health and human genetics that took advantage" of this new tool, Sternberg told Live Science.
Of course, humans are not the only species with a genome. CRISPR has applications in animals and plants, too, from disabling parasites, like those that cause malaria and Lyme disease, to improving the crop yields of potatoes, citrus and tomatoes.
"[CRISPR] is incredibly powerful. It has already brought a revolution to the day-to-day life in most laboratories," said molecular biologist Jason Sheltzer, principal investigator at the Sheltzer Lab at Cold Spring Harbor Laboratory in New York. Sheltzer and his team are using CRISPR to understand the biology of chromosomes and how errors associated with them may contribute to cancer.
“I am very hopeful that over the next decade gene editing will transition from being a primarily research tool to something that enables new treatments in the clinic,” said Neville Sanjana, of the New York Genome Center and an assistant professor of biology, neuroscience and physiology at New York University.
Here, we take a look at the recent advances in the fights against 10 diseases that demonstrate CRISPR's capabilities, and hint at things to come.
CancerSlide 2 of 21
A cure for cancer has alluded humankind since the Greek physician Hippocrates, who lived between 460 and 370 B.C., coined the word for this disease: karkinos. But because cancer, like many diseases, results from a mutation in a person's genome, researchers say it's possible that a CRISPR-based treatment could one day slow the speed at which a tumor spreads, or perhaps reverse the disease completely.
Some early work in this area is happening already in China, where regulations governing the use of gene editing in humans are more relaxed than they are in the United States.
In October 2016, a lung cancer patient in China became the first of 10 people in the world to receive an injection of cells that had been modified using CRISPR, the journal Nature reported. The researchers, led by oncologist Dr. Lu You at Sichuan University in Chengdu, modified the immune cells taken from the patient's own blood and disabled a gene that produces a protein that cancer cells normally hijack in order to divide and multiply. The hope is that without the protein, the cancer cells won’t multiply and the immune system will win out.
Research teams in the United States are also eyeing ways to use CRISPR to fight cancer. Dr. Carl June, director of translational research at the Abramson Cancer Center at the University of Pennsylvania, and his colleagues received approval in June 2016 from the National Institutes of Health to conduct a clinical trial on 18 cancer patients in late stages of melanoma (a skin cancer), sarcoma (a cancer of soft tissue) and multiple myeloma (a cancer of the bone marrow), according to a statement from the university. For this clinical trial, researchers will use CRISPR to alter three genes in patients' own immune system cells, in hopes of getting those cells to destroy the cancer cells in their bodies.Slide 3 of 21
HIVSlide 4 of 21
Eradicating HIV, the virus that causes AIDS, has been an uphill battle. Not only does the virus infect the very immune cells in the body that attack viruses, but it's also a notorious mutator. After HIV hijacks a cell in the body and begins to replicate, it generates many genetic variations of itself, which helps it evade drug therapies. This drug resistance is a huge problem in treating people who are infected with HIV, according to the World Health Organization.
CRISPR has HIV lined up in its sight, though. In May 2017, researchers at Temple University and the University of Pittsburgh used CRISPR to snip the virus from the cell it was infecting, shutting down the virus's ability to replicate. This use of the technique, which was tested in three different animal models, was the first time researchers had demonstrated a way to eliminate HIV from infected cells, according to the researchers, led by Chen Liang, a virologist at McGill University in Montreal. They reported the results of their study in the journal Molecular Therapy.Slide 5 of 21
Huntington's diseaseSlide 6 of 21
About 30,000 people in the United States have an inherited condition called Huntington's disease, a fatal genetic disorder that causes nerves in the brain to deteriorate over time, according to the Huntington's Disease Society of America. Symptoms include personality changes, mood swings, unsteady gait and slurred speech.
The condition results from a faulty gene that becomes larger than normal and produces a larger-than-normal form of a protein called huntingtin, which then breaks into smaller, toxic fragments that accumulate in neurons, disrupting their function, according to the National Institutes of Health.
But in June 2017, scientists reported in The Journal of Clinical Investigation that they had reversed the disease in lab mice that had been engineered to have a human mutant huntingtin gene in place of a mouse huntingtin gene. Su Yang, a Postdoctoral Fellow in the department of human genetics at Emory University in Atlanta, and Renbao Chang, at the Institute of Genetics and Developmental Biology at the Chinese Academy of Sciences, used CRISPR to snip out part of the mutant huntingtin gene that produces the toxic bits.
After they did that, the number of toxic fragments decreased in the mice's brains, and the neurons began to heal. The affected mice regained some of their motor control, balance and grip strength. Although their performance on certain tasks was not as good as that of healthy mice, the results showed the potential of CRISPR to help fight this condition.
In a statement, the scientists stressed that more rigorous studies need to be conducted before such a therapy could be used in humans.Slide 7 of 21
Duchenne muscular dystrophySlide 8 of 21