What you need to know about this game-changing gene–editing technique
By Charles Weaver, Jennifer Murar Maxon, RN
The year 2016 was undoubtedly full of lessons and surprises, including a pivotal milestone involving a very controversial issue: gene editing in a living person. Researchers from China recently announced that they began treatment using gene editing on a patient with advanced cancer, and researchers from the United States announced plans to follow suit in early 2017.
Although various forms of genetic manipulation have been around for decades, the actual implementation of precision gene editing in the treatment of a living person is a first.
For the past few years, researchers have been brimming with enthusiasm as the fairly new gene-editing technique, referred to as CRISPR, which stands for clustered regularly interspaced short palindromic repeats, has swiftly infiltrated research labs worldwide, becoming a game changer in the field of genetics. Meanwhile international scientific and bioethics communities are closely monitoring the “CRISPR craze” to enforce the adopted ethical standards to which all scientists are to adhere.
Although CRISPR has exponentially advanced the prospects of gene editing—leaving it poised with the potential to possibly revolutionize healthcare and medicine in the near future—time will be the ultimate judge in revealing its effectiveness and long-term outcomes through future generations.
Manipulating the Genetic Code
The idea of purposefully manipulating a human’s genetic code tends to evoke an emotional response in almost everyone, whether it stems from intrigue, hope, fear, or a combination thereof. There also exists an underlying vague apprehension in many, based on the notion that humans tinkering with life-altering genetic codes just because they can sets us on a path through uncharted territory.
Conversely, parents of a terminally ill child with no further treatment options, or individuals with an inherited disease that is robbing them of their independence and dignity, or even those who watch a loved one suffer and are desperate for their relief may feel a dire sense of urgency to expedite the availability of therapy using genetics, as it represents a last bit of real hope for their situation.
It is against the backdrop of all of these questions and emotions that scientists are forging a path to learn more about how genetic manipulation will factor into our health as we move forward.
What Is Gene Editing?
Gene editing, also called genomic editing, is a type of genetic engineering in which very specific and targeted pieces of a gene are altered with precision.
Every living organism’s genetic code has a primary component known as DNA. DNA is essentially composed of four different molecules called nucleic acids; these nucleic acids occur in different sequences—for a length of an approximate 6 billion in consecutive order.
A gene is a piece of DNA that may comprise a few or up to hundreds of thousands of nucleic acids. It is the differences in the DNA sequences that create all the variances among individuals and organisms—or the differences between a healthy cell and a cancer cell.
During a gene-editing process, very specific DNA sequences can be removed and specific new DNA sequences can be inserted into a gene at a precise location. The newly inserted DNA sequence becomes part of the organism’s genetic code and has the potential to be passed on to the organism’s offspring and future generations.
An important distinction of gene editing that sets it apart from other types of genetic engineering is its precision, by which very specific and targeted DNA sequences can be removed and added. Furthermore, unlike different genetic-engineering methods, such as those often used in the production of genetically modified products, gene editing does not include the introduction of foreign genetic material from a different species or organism.
What Is the CRISPR Technique?
Gene editing was invented and practiced in labs in the 1970s; since then researchers have refined the process. It is the development of one of the newest types of gene-editing techniques, however, referred to as CRISPR, short for clustered regularly interspaced short palindromic repeats, that is responsible for the recent explosion of research and excitement in gene editing worldwide.
The CRISPR technique possesses the traits needed to launch gene editing into a real-world setting: fast results, efficiency, precision, affordability, and reproducibility. The older gene-editing methods were time-consuming and expensive and required many more resources than CRISPR does.
The CRISPR technique basically involves a two-prong strategy. First researchers determine very specific DNA sequences that they wish to target (i.e., a sequence associated with the development of cancer). Next a preprogrammed microscopic “guide” is used to search for the precise DNA sequence slated for manipulation. Once the guide finds the particular DNA sequence, it communicates to a different protein, which acts like a surgeon’s scalpel to cut out the sequence. A new sequence of DNA is then placed where the old sequence once resided.
The microscopic guides and “scalpels” are engineered in a laboratory but are made of biological materials that already exist in human cells, circumventing the introduction of foreign material. They are simply injected into the patient or subject in the same manner in which a vaccination is given, and they work together in the body to complete their task. As the CRISPR method evolves, it continues to be refined and is providing even greater precision with faster results—while becoming less expensive. In fact, any scientist with basic skills and a few hundred dollars can implement CRISPR. Orders for specific guides can be placed online and received within a few days, as well as an order of “designer” guides to find newly discovered sequences.
The CRISPR technique has been integrated into the scientific community at lightning speed, NS researchers are overwhelmingly hopeful about the technique’s prospects, including the transformation of healthcare and medicine, biofuels, food production and storage, species’ traits, and biosystems, to name a few. And although CRISPR is already being used in some types of farming and food production—and has been studied extensively in human cells in the laboratory—its appearance in the treatment of living humans is a historic milestone.
The rapid pace with which CRISPR has led to gene editing in humans, as well as massive research efforts involving many different areas of focus, has left unanswered questions, unknown consequences, and varied concerns in its wake. The business, legal, regulatory, and bioethics sectors are attempting to sort out and clarify novel issues associated with CRISPR in a responsible manner.
Patent ownerships and licensing rights involving different parts of the CRISPR method are being legally evaluated in courtrooms, and initial public offerings for businesses hoping to capitalize on the “CRISPR craze” are popping up in anticipation of its far-reaching possibilities. International meetings have been called to develop protocols of scientific ethics for the use and monitoring of gene editing, and international watchdog groups vow to report any suspected unethical behavior.
Governments of various countries have established different rules as to where their funding in gene editing will be allocated. The US federal government will not fund gene-editing research on embryos, unlike the governments of China and the United Kingdom.
What Does This Mean for Cancer?
Because precise gene-editing therapy is being evaluated in humans for the very first time, the main focus of these early-phase clinical trials is to provide a methodical understanding and evaluation of the safety of this type of therapy.
If results from these trials indicate that gene editing does indeed appear safe, the future in the treatment and prevention of cancer using the CRISPR method holds immeasurable promise. Researchers are hopeful that CRISPR will allow for the correction of very specific DNA sequences that are known to make a person susceptible to developing cancer, ultimately eliminating the risk of cancer for that person in their lifetime.
Or, if a person does get cancer, researchers anticipate that in the future they will be able to determine precisely which DNA sequences need to be eliminated, corrected, or inserted to shut down the growth of existing cancer cells and cure the disease. Due to the precision of CRISPR, the hope is that a cure can be obtained without the toxic side effects associated with the standard types of therapy available today.
Furthermore, researchers believe that the CRISPR method will allow them to determine exactly which types of therapy will work for each patient according to the cancer’s genetic traits, or they will be able to manipulate cancer cells to respond to certain types of therapy with pinpoint precision.
The current clinical trial evaluating CRISPR in China involves genes edited specifically to stimulate certain pathways in immune cells to be able to detect existing cancer cells and ultimately mount an immune attack against them.
The initial clinical trials for gene editing will include patients with advanced types of cancers for which there are most likely no other available treatment options. From there, if gene editing proves safe, advancements into further trials to evaluate its effectiveness will continue, followed by a comparison of effectiveness against standard therapies.
As the CRISPR Story Unfolds
As with all new advancements in human history, the way in which gene editing will shape the future remains unknown. Unlike many other milestones, however, gene editing encompasses an element that requires caution, as altering genetic code will have repercussions for generations. Fortunately, researchers have stated that the possibility of reversing an error made with CRISPR is plausible, as they could, in theory, remove any DNA sequences that had been mistakenly inserted and correct the mistake.
Nonetheless the progression of gene editing in clinical trials will not be hurried. The ethics and scientific committees are strictly enforcing guidelines, and researchers, to the best of their ability, are allowing no room for error in their work.
All of this taken into consideration, CRISPR has undoubtedly launched a new era for the way in which diseases, including cancer, will be treated. Considering the days of nothing more than surgery, chemotherapy, and radiation as options for cancer, finding a cure suddenly seems as though it could someday become a reality.
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