Gene Therapy And MICRO-PIGS! YOU FUCKING LOVE SCIENCE!
First an anecdote from the early days of my biotech career. Sherman, set the way-back machine to the year 1999. Shakespeare in Love wins best picture. Napster debuts and so does the Euro. Back then I worked for one of the few "big" biotechs of that time and was part of the team that brought potential drug or company acquisitions to the executives for their review. This one particular time, we were pitching a drug that helped cystic fibrosis patients with their frequent infections. It didn't treat the underlying disease at all, but helped manage it. Everyone on the executive team thought it was a good drug to bring to our company, except for one of the founders. His comment was, "Cystic fibrosis? Gene therapy will cure it in five years!" We were one of the early companies looking at gene therapy to cure disease and had a fairly advanced program using gene therapy to target hemophilia. Guess what? It's 2018 and gene therapy hasn't cured cystic fibrosis. However, to paraphrase a certain cancer-causing company's ad, we've come a long way, baby.
So, what IS gene therapy? I'm glad you asked!
Gene therapy is a catch-all bucket for various technologies used to manipulate genes in various ways. The "therapy" part is when it's used to try and treat genetic diseases, but the techniques can be used in other fun ways! More on that later, but the headline IS a bit of a spoiler. Let's talk approaches first and then we can do a greatest hits of current targets for the approaches. Yes, there will be micro-pigs, or "marranitos."
You're sick because you have a whacked gene that's either not making the protein it's supposed to, or just making mierda. Remember PRIONS? There are essentially three approaches: 1) Inactivating a gene that's fucked up; 2) Replacing a gene that's fucked up; 3) Inserting a totally new gene into someone.
Inactivating a Gene That's Fucked Up
This technique is good for diseases like Huntington's where some copies of the gene are okay and making the appropriate protein, but some copies are going nuts and making shitty proteins that screw up nerve cells in the brain. These will break down over time leading to movement, thinking and psychiatric problems. Gene silencing also has different approaches depending where along the path from DNA to actual final product, the protein, you want to stop the process. Ionis Pharmaceuticals has a drug on the market using the "antisense" approach to gene silencing and is a leader in the field. Fun fact about Ionis, they changed their name from Isis Pharmaceuticals after a more famous ISIS kinda screwed the name for them.
Replacing a Gene That's Fucked Up
Again, you can do this a variety of ways. My old company, looking to cure hemophilia, tried using viruses. We took a virus and inserted a human gene into it. The way viruses get you sick is first, you don't wash your hands and rub your eyes, getting the virus into you. Then, the little pendejo finds one of your cells of interest, injects its DNA (sometimes RNA, depending what kind of virus) into the cell, the DNA combines into YOUR DNA but is now also coding for more viruses! It's a shitty life cycle, but one that scientists saw and went, "Hey! We can use that!" So, all you need to do is create a modified virus that is still infective but won't get you sick and that now carries a human gene of interest, say the one that codes for blood clotting factor VIII, which is missing in hemophilia A patients. Inject into a patient and let the virus replicate and insert the gene that's missing. Easy, peasy, Lemon Squeezy! ... Except, the gene is pretty big compared to what the DNA loop of a virus can store, your immune system likes to attack viruses, you need some organs to get the gene more than others ... and now you see why we haven't cured hemophilia via gene therapy yet.
However, a drug named Strimvelis has cured ADA-SCID, more famously known as "Bubble-boy Syndrome," via a different gene replacement technique. In this case, they extract stem cells from the patient and modify THOSE cells to produce the missing enzyme which in turn fixes the immune system problem. One treatment, and the kids are cured! The cost? About € 600,000 for the one-time treatment, and a bargain … but drug pricing is a whole other article!
Inserting a Totally New Gene
This is where the shit gets bananas.
Genome editing, baybee. You've probably heard of CRISPR-Cas9 in the news. Without getting into the sciency details (which you can get here in a really good primer from Andrew Pollack at the "failing" New York Times), it's a revolutionary technology for gene editing. Compared to what we had in the bronze age of biotech (1990s), it's way faster, cheaper, more accurate and efficient than other approaches. It's the Prius of gene editing. It can get a little ethically dicey, though. Most gene therapies focus on cells that won't pass down the modification to the patient's kids. CRISPR has the ability to modify ova and sperm. Ethics of modifying unborn generations is a whole OTHER article! Gene editing to treat human disease is "off like a prom dress!" to quote my favorite soccer announcer, Ray Hudson. There are several companies gearing up for human testing in a variety of genetic maladies, including cystic fibrosis. See how I set that up in Act I and paid it off here?
Okay, okay. You've been patient with me but we all know you really wanted to hear about mini-pigs, so here you go. The craziest things being tried with CRISPR and other gene editing tricks:
Chinese researchers disabled a growth hormone receptor gene and created a pig that maxes out at 30 lbs. Originally, they planned to sell them as pets, but raised eyebrows in China has THAT on hold.
Chinese researchers (again!) deleted the myostatin gene from beagles resulting in basically, the Captain America of dogs.
American researchers (finally!) modify the little pendejos to not spread malaria. Sounds good, but this is also the beginning of decent horror movie I could write where the insects become giant and sentient.
Japanese researchers did the myostatin beagle thing to fish, because we want more meat on our fish.
American researchers (Stanford. "Yuck!" says this Berkeley grad) have been able to modify coral in the first steps towards creating tougher versions that could survive climate change.
So that's it for this week, kids. Since you followed me to the end, here's a fun sci-fi book I read by Annalee Newitz who co-founded IO9. Autonomous is about gene editing, robots and sex. What else do you want?!
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I am a biochemist MexiCAN. I also write screenplays, ever hoping to get one made.
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