Zombie Apocalypse Attacks Human Cells
A number of media outlets have recently reported on a phenomenon that’s being called “zombie cancer cells”—with headlines such as ‘Zombie cancer cells can resurrect, get cured by eating themselves’ and ‘Zombie Cancer Cells ‘Rescue’ Themselves Before Death, May Complicate Chemotherapy Treatments’—suggesting that some kind of zombie apocalypse has invaded medical science. Although it may sound like something out of a sci-fi movie, there is real research to back up these reports.
What are zombie cells?
The premise of “zombie cancer cells” is based on the idea that zombies, after dying, are able to return from the grave. Similarly, scientists have found that certain cancer cells, after being killed by chemotherapy or other cancer treatments, may be able to overcome death. The scientific term for this process is called autophagy, which is derived from the Greek term meaning “to eat oneself.” When cells undergo autophagy, they break down into individual building blocks of energy and protein. Although the process sounds detrimental, it actually helps healthy cells because it allows them to turn waste into energy, which they can then use to survive during starvation or times of stress.
Zombie cells and chemotherapy
In a recent study, scientists from the University of Colorado Cancer Center examined the role of autophagy in cancer cells while testing a chemotherapy drug called TRAIL. As expected, they saw the tumor cells begin to break down. However, researchers then saw that the autophagy kicked into a higher gear—called high autophagy—and the cells began to recover the components which they had previously shed. So while autophagy is beneficial for healthy cells, it is harmful when it occurs in cancer cells. Even though the TRAIL drugs would typically have killed the cancer cells, the cells were able to use the recovered components to restore their original functions. The cancer cells then were able to continue dividing and reproducing—essentially, they began to die but through autophagy were able to come back to life.
The study’s researchers then tested whether inhibiting cells from entering autophagy would increase the effectiveness of chemotherapy and allow the cancer cells to die. Specifically, they focused on the role of PUMA—a regulator of cell death. They found that when PUMA, a type of protein, was present, they were able to inhibit the process of autophagy and the cancer cells would die. When PUMA was absent, however, the cancer cells continued to survive.
The findings, published in the journal Cell Reports, demonstrate how PUMA acts as the mechanism by which autophagy controls cell death. Researchers said that understanding this mechanism is significant, as autophagy remains largely understood within the science community. With further trials, the inhibition of autophagy may prove to be an effective clinical practice when administering chemotherapy or other cancer treatments, researchers said. They concluded that by identifying new targets in cancer cells to regulate, in addition to PUMA, they may be able to create different inhibitor medicines for different types of cancer.