I can’t say I share this passion with too many other people, but I am always excited by news that RNA is being put to good use fighting disease. Perhaps a bit of background is in order here. You may probably be aware that in nearly every one of the trillion cells in your body, several very long strands of DNA are tucked tightly inside the nucleus. Over the course of your lifetime, your DNA doesn’t change that much — that’s usually good news because DNA is your body’s instruction manual. Among other things it spells out the precise instructions your cells use to create the enzymes that run all of the processes in your body.
However, two things can go wrong: either you inherit a mutation in your DNA from your parents or your DNA becomes damaged during your lifetime from exposure to mutagenic agents like too much UV radiation or the toxins in cigarette smoke. If these teeny errors in your DNA happen to affect the enzymes that are tasked with protecting your body from tumours, then you could be in serious trouble — and you could develop cancer.
Most cancer therapies are based on trying to nuke out the tumour itself — zapping it with radiation to kill it; hitting it with drugs to slow down its cell division; surgically excising the tumour to prevent its cells from spreading. However, many of these approaches can be toxic to other parts of the body and often don’t manage to totally destroy the tumour. If one cell is left behind, the tumour can grow again because it is so adept and multiplying and taking over.
A new line of research into stopping cancer in its tracks involves mucking about with cancerous cells on the genetic level. Remember how I told you that DNA contains the instructions necessary for producing and maint
Here’s the fun part. DNA is a double-stranded molecule (the famous “double helix”). But RNA has only one strand. That means another RNA molecule is able to bind to the RNA produced by your body. One this binding has occurred, the RNA is inactivated.aining all the molecular machinery that makes your cells tick? Well, that’s only part of the picture. When the DNA is “decoded” by your cells to make proteins, an intermediary molecule, called RNA, is generated. This RNA is an exact copy of the DNA but made using a different chemical (RNA, natch). The RNA is the actual “instruction manual” for making a protein.
In a study out of Princeton University looked at bone cancer, which is especially painful and nasty. In about 70 per cent of patients with late-stage cancer, tumour cells divide and then squeeze their way into the bone. This invasion is called metastasis. These rogue cells take over a type of bone cell called an osteoclast which is normally responsible for breaking down old and damaged bone material. When the cancer cells hijack the osteoclasts, they cause them to go into overdrive, dissolving normal bone tissue willy-nilly. The result: fractures, nerve damage and extreme pain.
Enter the Princeton researchers. They noticed that certain proteins in the osteoclasts that had been hijacked were producing abnormally large amounts of certian proteins that direct the bone destruction process. So the researchers injected small amounts of RNA — called microRNAs (or miRNA for short) right into the bones of sufferers. These little pieces of RNA bound swiftly to the RNA that corresponds to the overactive protein, silencing them. Because the RNA was targeted specifically to these proteins, the rest of the body was unaffected.
To their delight, the researchers announced that the bones that had been injected with miRNAs showed much less evidence of damage than bones that had not been treated.
This result shows that we are getting ever closer to the promise of personalized medicine: treating people with methods that are specifically tailored to their genetic makeup.