Could a Vaccine for Cancer be a Reality?
How do you take out an unstoppable enemy? You don’t take the enemy head on, you take out the supply lines and the rest will take care of itself. This is not a new idea, but this not so new approach to war is being taken to an enemy on a new battlefield, your body.
Cancer in most cases can be an unstoppable force, collateral damage from chemotherapy can be, and in most cases is unacceptable. That was the thinking from a group of researchers from the Abramson Cancer Center and the Perelman School of Medicine at the University of Pennsylvania. Their idea, to attack the supply lines instead of the enemy directly.
They accomplish this feat by designing a novel DNA vaccine to kill cancer. Not by attacking tumor cells, but targeting the blood vessels that keep them alive. A happy side effect, the vaccine also indirectly creates an immune response to the tumor itself, amplifying the attack by something called epitope spreading.
[Loony hint: Epitope spreading is when your body produces proteins that cause an autoimmune response, normally your body attacks foreign invaders, but in certain cases, such as this one, your body will produce something that will cause an immune response.
In this case the cancer cells are part of the body so they normally would not be attacked. But a protein on the cancer cells has been “flagged” by the body as foreign, so the body will attack it.
In a sense it is a type of molecular mimicry which tricks the body into thinking something it made is bad and needs to be eliminated. Epitope spreading is a complex topic and this is a basic explanation of the process. If you can think of a better way to describe it please let me know.]
Now normally, when scientists have attempted something like this they targeted cells that were involved with new blood vessels, but this had the unwanted side effect of interfering with wound healing and development.
What the researchers did instead was target a specific protein [TEM1 or tumor endothelial marker 1, for those of you who want to be quizzed at the end]. TEM1 is overexpressed in the cancer cells, but is expressed very minimally in normal tissues.
“Until now there have been a lot of clinical trials using DNA vaccines to target tumors themselves, but unfortunately the results have been disappointing,” Facciabene notes. “This is a different approach which should heighten optimism for cancer vaccines in general. Moreover, based on what we’ve seen in our mouse studies, this vaccine doesn’t seem to show any significant side effects.”
There was no mention of how long the effect lasted from the vaccine [vaccines can, in certain cases lose efficacy after time, which is why you need booster shots], however this is a huge step forward for treatment of cancers.
Since the TEM1 marker is exposed in several different types of cancers this could be effective in the fight against breast cancer, lung cancer, or a number of other types of cancers that overexpress the TEM1 protein. We could very well be on the verge of a low cost cure for cancer!
Not challenged with Epitope spreading? You probably want the full study then, which you can find — here!
Facciponte J.G., Ugel S., De Sanctis F., Li C., Wang L., Nair G., Sehgal S., Raj A., Matthaiou E. & Coukos G. & (2014). Tumor endothelial marker 1–specific DNA vaccination targets tumor vasculature, Journal of Clinical Investigation, 124 (4) 1497-1511. DOI: 10.1172/JCI67382DS1