All of us have to deal with the looming threat of developing cancer during our lifetime, no matter how good our genetics are, or how healthy our lifestyle is. Despite major improvements to the way that we treat and even cure cases of cancer, the reality today is that not all types of cancer are treatable, in many cases there’s the likelihood that one day it will return even after full remission, and chemotherapy in particular comes with potential life-long health issues. Of the most promising new and upcoming treatments, immunotherapy, is decidedly among the most interesting.
With this approach, it is the body’s own immune system that is taught to attack those cancer cells, requiring little more than a few tweaks to T-cells harvested from the patient’s body, after which they’re sent on their merry cancer-killing way. Yet as simple as this sounds, finding the right characteristics which identify the cancerous cells, and getting a solid and long-lasting immune response is a tough challenge. Despite highly promising results with immunotherapy treatment for non-solid cancers like leukemia – that have resulted in almost miraculous cures – translating this success to other cancer types has so far remained elusive.
New research now shows that changing some characteristics of these modified (chimeric antigen receptors, or CAR) T-cells may be key to making them significantly more long-lived and effective within a patient’s body. Is this the key to making immunotherapy possible for many more cancers?
One of the human body’s greatest features is its natural antivirus protection. If your immune system is working normally, it produces legions of T-cells that go around looking for abnormalities like cancer cells just to gang up and destroy them. They do this by grabbing on to little protein fragments called antigens that live on the surface of the bad cells and tattle on their whereabouts to the immune system. Once the T-cells have a stranglehold on these antigens, they can release toxins that destroy the bad cell, while minimizing collateral damage to healthy cells.
This rather neat human trick doesn’t always work, however. Cancer cells sometimes mask themselves as healthy cells, or they otherwise thwart T-cell attacks by growing so many antigens on their surface that the T-cells have no place to grab onto.
Medical science has come up with a fairly new method of outfoxing these crafty cancer cells called CAR T-cell therapy. Basically, they withdraw blood from the patient, extract the T-cells, and replace the blood. The T-cells are sent off to a CRISPR lab, where they get injected with a modified, inactive virus that introduces a new gene which causes the T-cells to sprout a little hook on their surface.
This hook, which they’ve dubbed the chimeric antigen receptor (CAR), allows the T-cell to chemically see through the cancer cells’ various disguises and attack them. The lab multiplies these super soldiers and sends them back to the treatment facility, where they are injected into the patient’s front lines.