April 7, 2014
Zombie Cancer Cells
Zombies are everywhere these days. Well, not really “everywhere,” or else we would find ourselves facing a true zombie apocalypse straight out of The Walking Dead. But in terms of media and entertainment, zombies seem to be the next big thing. I suppose this is a good thing, as vampires have really seemed to lose their bite (ha!) in terms of being scary thanks to all the romantic interpretations of them that have sprung up over the last few years (I’m looking at you, Twilight). Zombies tend to lack any relatable qualities, and thus they have become the next “horror creature” to take center stage in the media. We have television shows, movies, books, videogames, and even fundraising events all themed around these walking, flesh eating, corpses. In the medical field, there have also been some recent developments centered around cannibalistic reanimation, namely in one of the worst places we would ever think to find it – in cancer cells.
A recent discovery made by the University of Colorado Cancer Center shows that the cellular process of autophagy – a process of cellular recycling in which organelles known as autophageosomes take in extra or dangerous material and transport it to the cell’s lysosomes to be disposed of – may enable cancer cells to revive and multiply instead of dying when being treated with chemotherapies. Autophagy, which comes from the Greek “to eat oneself,” is a lot like taking apart a Lego model. It breaks down unneeded components into basic building blocks composed of either energy or protein which it can then later use to survive times of low energy or so that it can keep itself safe from poisons and pathogens. What the researchers found is that if autophagy is not working as it should, if it is either working too efficiently or if the target that regulates it is not functioning properly, cancerous cells may use it to rescue themselves.
To better illustrate what this means, the researchers put together a short film to illustrate what they have found. When viewed, it shows a mitochondrial cell wall as it is broken down and the cell’s mitochondria are shown releasing proteins in a process called mitochondrial outer membrane permeabilization (or MOMP), which is a common marker of cell death. Then, showing what can happen with high autophagy, it shows a cell encapsulating and digesting these proteins before MOMP can keep the cell wall dead. As this goes on, viewers can see the cancer cell recover and continue to divide, spreading the cancer. Like a zombie, the cancer cell revived itself from the dead and went on to infect other cells. According to a statement by Andrew Thorburn, PhD, deputy director of the CU Cancer Center, “The Implication here is that if you inhibit autophagy you’d make this less likely to happen, i.e. when you kill cancer cells they would stay dead.”)
Thorburn and fellow researchers also found that autophagy depends on the target PUMA to regulate cell death. When PUMA is not present, inhibiting autophagy is pointless as without the communicating action of PUMA, the cancer cells will continue to survive. This finding has some very important implications. Firstly, it shows how autophagy controls cell death and secondly, it reinforces the clinical potential of inhibiting autophagy to sensitize cancer cells to chemotherapy.
According to Thorburn, “Autophagy is complex and as yet not fully understood. But now that we see a molecular mechanism whereby cell-fate can be determined by autophagy, we hope to discover patient populations that could benefit from drugs that inhibit this action.”
Our world is scary enough without zombie-cancers eating away at our insides. For all our sakes, I wish continued luck to the research being done by Andrew Thorburn and his associates.
Image Credit: Thinkstock