Highlighted during the Covid-19 pandemic, mRNA had already been studied for several years to fight cancer, and several studies are underway on the subject.
Messenger ribonucleic acid, better known as messenger RNA or mRNA. This term was greatly popularized with the Covid-19 pandemic, because it is the name of the molecule that made it possible to quickly create effective vaccines against this virus, which spread in a few weeks on the planet.
But before being used against SARS-CoV-2, messenger RNA had been studied for several years already, and was notably considered as a potential treatment against cancer. The pandemic has had the positive side effect of allowing laboratories to move forward more quickly on this subject.
The American laboratories Moderna and Merck announced last Wednesday that they had entered into an agreement to jointly develop and market an mRNA vaccine against skin cancer. The bosses of BioNTech have for their part raised the possibility that an mRNA vaccine against cancer will be available “before 2030”.
What is messenger RNA again?
mRNAs “serve as a pattern during the manufacture of proteins”, explains Inserm. These molecules are produced from our DNA, it is “a photocopy of the page of the genome where the instructions for producing a given protein are written”. An mRNA is therefore in a way a construction plan transmitted to a cell, which will tell it how to produce the protein it needs.
In the context of vaccines against Covid-19, an mRNA coding for the Spike protein was used and injected, because it is this protein that allowed the virus to enter our cells.
After the vaccine, with the plan given by the mRNA, “our cells then make this protein and ‘present’ it on their surface. The immune system recognizes it as if it were carried by the virus itself and activates the mechanisms of defense and the memory response”, explains Inserm. The immune system will therefore be able to recognize the virus if the organism is infected in the future.
The same technique as that against Covid-19
When we talk about an mRNA vaccine against cancers, we are not only talking about preventive techniques, as is the case with Covid-19, but also about curative methods: it is not a question of preparing the system for a potential infection, the disease is already there and it must be fought.
However, mRNA remains used for the same principle: “to ensure that representative samples of cancer cells are exposed to immune cells”, explains the ARC Foundation for cancer research.
“We take cells from the tumor and we will study the sequences, that is to say the identity card of these tumors”, explains Alain Ducardonnet, cardiologist and health consultant for BFMTV.
“We will then synthesize the mRNA and we will inject it into the body, and there we will somehow give the information to the immune cells to specifically attack the images that the mRNA brings. So they will attack the tumor cells specifically.”
Cancer more difficult to apprehend
The whole difficulty with cancer lies in finding the protein to reproduce in order to successfully fight the tumour. Viruses are thus “carriers of certain characteristics which indicate to the immune system that they are enemies”, explains on ARTE Mustafa Diken, immunologist.
But “cancer is different because cancer cells come from our own cells and normally, at first glance, the immune system cannot always identify that it is an enemy,” he explains.
It is indeed necessary “to ensure that this targeting cannot mount the immune system against healthy cells which would also express the protein coded by the vaccine mRNAs”, underlines the ARC Foundation. The researchers are therefore trying to target “some of the genetic mutations present in cancer cells” which “directly affect the nature of the proteins produced by these cells.”
On the other hand, each cancer acts differently, and affected individuals have a different immune response, which leads to a demand for personalized responses.
mRNA associated with other methods
Several dozen studies are currently underway on the subject, as the pandemic has brought the mRNA method to light and increased the number of funding devoted to it.
“Some RNA-drugs in development are designed to directly target the fundamental processes of cancer: proliferation, acquisition of resistance to treatment, formation of metastasis, etc”, explains the League against cancer, “others aim rather the permissive environment that supports the development of cancer and acts, for example, by activating the anti-cancer immune response.”
It remains very difficult at the moment to give the release date of a treatment and mRNA, although revolutionary in its approach, is not a miracle answer and may not be enough on its own. Immunotherapies “could therefore, obviously, in the long term, be associated with possible vaccine strategies. They are moreover already integrated into current vaccination trials against cancers”, writes the Arc Foundation.
Beyond cancer, treatments using mRNA could “allow the personalized management of a large number of diseases, such as genetic diseases in particular”, explains Palma Rocchi, biologist, research director at Inserm. “It’s a real revolution for the medicine of tomorrow.”