Beating cancer is one of humanity's greatest challenges and figuring out how to deal with these turncoat cells in our body continues to be a global priority. We have come a long way over the last century yet we have not yet won the fight. It is why researchers continue to find new approaches to kill these rogue cells and ensure a healthier life.
Until about ten years ago, the only weapons we had against this internal enemy were surgery, chemicals and radiation. But around that time, researchers began a quest to use more natural means to identify these antagonistic agents and rid them. Two very different strategies were initiated in the process. One relied on repurposing an already known enemy while the other utilized our own internal defense forces.
The first to emerge was a practice now known as virotherapy. As the name implies, the goal was to train viruses to seek out solely cancer cells. Upon finding them, these tiny pathogens would enter the cell and begin their usual course of destruction. The practice gained significant success over the years and certain viral options gained approval for widespread use.
The second focused on figuring out how to use our immunity to target cancer cells. This method, called immunotherapy was much more difficult as it required using the immune system and in particular antibodies to identify double-crossing cells while leaving others alone. Successes were seen and thanks to one particular case, former President Jimmy Carter, immunotherapy became a valid route for treatment.
As antibody-based therapy progressed, researchers discovered a different means to accomplish this daunting task. This time, the soldiers were not antibodies but front line members of the immune system known as T-cells. They could be extracted from the body and modified such that they became single-assignment soldiers. Then, when they were delivered back to the bloodstream, they would carry out their orders. This process, called chimeric antigen receptors (CAR) T-cell therapy was given the green light for clinical trials and successes were promising.
The successes of virotherapy and immunotherapy have opened the door to explore other avenues to increase the weaponry in our medical arsenal. For a group of Japanese researchers, the next step appears to be finding a way to get these two different approaches to work together. They have recently figured out exactly how to achieve this valiant goal. As they point out, the key is to develop a biological Trojan Horse.
The key to their approach was a certain type of T-cell known as HOZOT. For anyone who speaks Japanese, the name gives away the origin of the line - the umbilical cord (hozo). These cells were first discovered in 2007 although their true purpose wasn't learned until 2010 when they were found to have a unique capability. They could enter cancer cells. While at the time, this was considered a tool for the future, for the researchers, this suggested they could harness a well-known and effective strategy of war.
The research team surmised they could genetically modify HOZOT cells such that they could produce cancer-killing viruses. In essence, they imagined creating a Trojan Horse. In this scenario, cancer cells would welcome the HOZOTs inside only to find out a lethal enemy had just passed through the cellular gates. The construction of the right "horse" took time but eventually, the team constructed the perfect invader. All that was needed was to test it on cancer cells.
In the lab, the horse worked like a charm, effectively killing several different cancer types. As expected, the HOZOTs were granted access to the cell followed by a vicious attack from the virus. When the system was made more complicated with the addition of molecules found in blood, there was no change.
The next step was to test the HOZOTs in mice. The process was no different than any other cancer treatment test yet the results were by no means normal. Just like in the petri dishes, the cancer cells in the mice were attacked and killed. Over the course of only two weeks, the tumours shrunk, stopped metastasizing, and revealed scars of war in the form of dead tissue. The mice appreciated the effort as they lived longer than controls.
While the HOZOT method worked, the authors admit this is just the first step. They have shown the promise of the Trojan Horse in the fight against this disease. Now it is up to researchers to take hold of this tool and being to develop even better biological routes to improve treatment outcomes. However, for all cancer fighters, this is certainly good news. The arsenal against this serious opponent may grow and help us to finally overwhelm this disease such that it will eventually lose more battles than it wins.
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