CRISPR Gene-Editing Trials Begin in Human Cancer Patients
For the first time ever, the CRISPR-Cas9 gene-editing technique is being utilized in human test trials, specifically in patients with lung cancer. On October 28, 2016 a group of Chinese scientists operating out of Sichuan University delivered cells modified through CRISPR in an attempt to reverse the progression of a patient’s aggressive lung cancer.1 In the past, other gene-editing techniques have been brought to clinical trials such as this, but none as simple, productive or efficient.3 If trials result in overwhelming success, the technique will likely catalyze the introduction of gene-editing into the cancer clinic environment as a new means of treatment.2 It is also important to consider the competitive nature of science in China and the United States; these types of developments will only further advance progress, quicken the pace of discovery, and improve treatment efficiency.1 The CRISPR technique is only just starting to take hold in clinical trials, with plans for treating bladder, prostate and renal cancers all currently being pursued with haste.1
Considering the risks we are taking by injecting genetically modified cells into the human body, it is best to have an understanding of exactly how the process works in order to better predict possible problems that may arise. The CRISPR technique, formally known as CRISPR-Cas9, incorporates both a DNA-cutting enzyme and a molecular guide that tells the enzyme where to cut DNA when administered to immune cells from the recipient’s blood.1,2 Specifically, the guide tells the enzyme to cut out and disable a gene that codes for a particular protein: PD-1. This protein is significant in that it is responsible for limiting the immune response in cells;cancer takes advantage of PD-1 to allow for uninhibited growth.1,2 Thus, the purpose of CRISPR is to shut off the cell’s ability to produce any PD-1, making it a legitimate contender against cancer cells. Immune cells are first isolated from the patient’s blood, made incapable of producing PD-1 through CRISPR, and finally reintroduced into the body after cells have been cultured. Without PD-1, these cells are, in theory, capable of defeating cancer.1,2
With the emergence of CRISPR into clinical trials, oncologists have a variety of opinions on the viability, safety and efficiency of such a technique. The primary concern for researchers is that of patient safety; currently, initial trials seem to have had minimal issues, but as treatment progresses for months and more injections are administered, we enter unknown territory. It is unknown what kind of adverse effects may appear after patients have been exposed to genetically modified cells for extended periods of time, and the efficacy of the treatment itself is still being questioned.1,2 Gene-editing is a controversial technique in itself, and the rapid increase in biotech research may be a considerable ethical concern, as scientists fear that we may be doing too much without realizing the implication of such changes in the human genome. Oncologist Naiyer Rizvi of Columbia University Medical Center in New York City is one of many skeptics of the procedure, stating it is “a huge undertaking and not very scalable.”1 Bioethical, efficacy and scalability concerns surround the CRISPR technique, but only further research and time will tell us whether or not the injections are safe, or even beneficial, for the treatment of cancer in the human body.
1Cyranoski, David. “CRISPR Gene-Editing Tested In a Person for the First Time”. Scientific American. November 15, 2016. https://www.scientificamerican.com/article/crispr-gene-editing-tested-in-a-person-for-the-first-time/
2 Irving, Michael. “CRISPR-Cas9 gene-editing tool used in first human trial”. New Atlas. November 15, 2016. http://newatlas.com/crispr-gene-editing-first-human-trial/46453/
3Reardon, Sara. “Gene-editing method tackles HIV in first clinical test”. Nature. March 5, 2014. http://www.nature.com/news/gene-editing-method-tackles-hiv-in-first-clinical-test-1.14813