This could usher in a wondrous era for genetic science, but risks also loom ahead.
Crisper, better gene editing
CRISPR first crept into the public eye in 2012 when researchers found a way to transform it from a bacterial shield (which is what it is, naturally) to a gene editing tool. Not long after that, its massive potential quickly became evident. By 2014, 600 research papers mentioned it and now, a quick Google Scholar search reveals over 30,000 articles mentioning CRISPR.
The acronym stands for Clustered regularly interspaced short palindromic repeats, which are basically segments of prokaryotic DNA containing short, repetitive base sequences. They’re very important because they enable targeted genetic modifications — basically, through some customization, they allow researchers to operate a “genetic scissors” which can edit genes with unparalleled precision. The method works both in humans, as well as in other organisms, and the applications are almost limitless. You can inactive certain genes that cause serious conditions and diseases, you can modify yeasts used to make biofuels, enhance crops, modify mosquitoes to prevent them from transmitting diseases — the sky’s the limit. To make things even better, CRISPR is significantly cheaper and easier to use than other gene editing techniques.
The pace at which CRISPR research has developed is stunning and despite a general reluctance to carry out genetic human trials, a flurry of them are right around the corner. Interestingly, China seems eager to lead the way.
For China, it’s important to establish itself as a leader in science (an area in which it has had lots of struggles, despite its recent economic success), but China also has less strict regulations when it comes to gene editing and research in general — up to the point where ethics is often a concern.
The first gene-editing trial in humans started in 2009. Doctors extracted immune cells from people with HIV and disabled the CCR5 receptor which allows this virus to enter cells. After this, they re-inserted the modified cells into the patients, and this seemed to keep HIV in check. This was hailed as a great success, but gene therapy remained expensive and inaccessible. This is where CRISPR enters the stage.
The first CRISPR human trial started in October 2016 at the West China Hospital in Chengdu. Researchers harvested cells from a patient suffering from lung cancer and removed a gene called PD-1 — which cancer cells use to “trick” the body into not attacking them. If it is disabled, then the body might recognize and kill off the cancer cells. However, there is a risk of other cells attacking themselves, which is really not what you want to see. That trial is set to finish in 2018 so we won’t know what’s happening until then, but in the meantime, several other trials are set to go.
Over a dozen human CRISPR trials will take a jab at PD-1, in an attempt to finally break down cancer’s defense mechanisms. These trial will focus on breast, prostate, bladder, esophageal, kidney, colorectal, and Epstein-Barr virus-associated cancers. If successful, it could be a massive breakthrough — but that’s not the only angle scientists are taking.
Different teams want to use the method to figure out how to defeat HPV, the human papillomavirus. Most HPV infections cause no symptoms and resolve spontaneously, but sometimes they cause lesions which increase the risk of cancer of the cervix, vulva, vagina, penis, anus, mouth, or throat. Since it’s estimated that around 12% of all women globally are infected at all times, that’s 460 million women carrying a virus which can increase the risk of cancer. It’s considered a ticking time bomb, a massive risk constantly looming over. What researchers want to do now is apply a gel containing DNA coding for CRISPR to destroy the viral genes of HPV, thus rendering it unable to turn into cancerous lesions.
“Targeting HPVs seems a sensible approach if they can deliver the genome-editing components to sufficient numbers of cells,” says Robin Lovell-Badge of the Crick Institute in the UK.
Another four trial studies will attempt to make the body better at killing cancerous cells, through various mechanisms, in China and in the US. All in all, twenty CRISPR trials are starting in 2017 or early 2018, and these trials could help millions. However, researchers also warn of some of the dangers associated with CRISPR. Even as precise as the method is, it often induces hundreds of unwanted mutations. So far, in mice, the mutations seem to not have any negative effect but the risks also have to be considered. As groundbreaking as the benefits can be.