Quirks & Quarks

Cancer cells 'hibernate' to hide from chemotherapy

Scientists were able to inhibit the hibernation-like state, allowing chemo to again be effective

Scientists were able to inhibit the hibernation-like state, allowing chemo to again be effective

Scientists discovered that cancer cells that develop a resistance to chemotherapy go into a hibernation-like state survive the treatment, just like bears hibernate to wait out the winter. (Chris Hondros / Getty Images)

Chemotherapy drugs can work wonders, especially early in a person's treatment, but over time, they may stop working. Researchers have found a reason why: cancer cells can enter a state akin to hibernation to avoid the toxic onslaught of the drugs.

Scientists at the Princess Margaret Cancer Centre in Toronto were trying to figure out how cancer cells apparently become resistant to chemotherapy when they made the discovery.

Dr. Catherine O'Brien, the senior author of the study and Canada Research Chair in Translational Research in Colorectal Cancer, explained that this kind of resistance to chemotherapy is broadly seen with chemotherapy treatment for different types of cancer.

Chemotherapy works by essentially poisoning cancer cells, which grow more quickly than most normal cells, and thus absorb a lot of the toxic drugs.

Dr. O'Brien said she expected to see a certain subtype of cancer cell to be responsible for this chemotherapy-evading behaviour, but was surprised when she found that all the cancer cells developed this ability.

In an interview with Quirks & Quarks host Bob McDonald, she said it was like the cancer cells were acting as a single organism.

Dr. Catherine O’Brien from the University Health Network's Princess Margaret Cancer Centre in Toronto is the senior author of the study. (University Health Network)

That led her to investigate what type of cellular processes could result in cells being able to lay low while chemotherapy drugs are present. 

She found that the cells entering a hibernation-like state, called "diapause." In animals like deer and mice, this state allows embryos to pause their development if they encounter nutritionally poor environments. 

Though the underlying processes are similar, unlike hibernation, diapause only occurs in undifferentiated cells that haven't yet matured — or differentiated — into cells such as skin, muscle, and nerve cells.

During diapause the cancer cells use a process called "autophagy," in which they essentially start eating themselves, the way a hibernating animal might live off stored fat.

Dr. O'Brien found that when she gave cancer cells that were in this diapause state autophagy-inhibitors, she could reverse chemotherapy-resistance and kill the cancer cells.

Produced and written by Sonya Buyting.

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