A cancer study has achieved a breakthrough by showing that sick cells may be able to split themselves up to recover, instead of dying, when the body is exposed to chemotherapy – all by disabling a process that communicates the news of death.
The University of Colorado Cancer Center study, published in the journal Cell Reports, talks of a process called autophagy, wherein cells devour parts of themselves when faced with some external stressor. But while autophagy is not a new concept, its study has not yet been thorough enough for it not to amaze scientists with new properties.
The term comes from the Greek expression “to eat oneself” and described a process, wherein the little bits of a cell, autophagosomes, trap dangerous or surplus material and transport it elsewhere for the purpose of being recycled into energy or immune protection, whenever the organism runs low.
But autophagy can be manipulated. The process could either be fine-tuned enough, or the materials that work with it could also be targeted. What the team found using the ovarian cancer model is that “cancer cells may [still] be able to rescue themselves from death caused by chemotherapies,” as the deputy director of the CU Cancer Center, Andrew Thorburn, puts it.
This is done by cheating the cell into thinking it’s not really dead. In the moments of death, the mitochondrial cell walls are stripped away and proteins are released – something called MOMP by scientists.
MOMP is an indicator of death. Increased autophagy means the autophagosomes are able to capture the released proteins and revive a dead cell before it’s robbed of all its protein.
Thorburn explains that by inhibiting autophagy, “you’d make this less likely to happen, i.e. when you kill cancer cells they would stay dead.”
To prove this, the researchers focused on PUMA – a regulator of cell death. By removing this regulator, they showed that high autophagy can be used to create a special cell death, which kills off bad material, but allows for the creation of a new cell in its place with deposits of protein. In effect, the team are regulating tumor growth itself by inducing high autophagy.
In future, they believe that by employing the newly discovered “molecular mechanism whereby cell fate can be determined by autophagy” and finding new targets in the cell to regulate, they can create different inhibitor medicines for different types of cancer.