Cancer cells are able to hibernate as “bears in the winter” when attacked by a threat such as chemotherapy treatment, according to a new study – seemingly embracing the mechanism used by some animals (although they have long been lost in humans) to survive through times when resources are scarce. .
Knowing just how cancers escape and resist drug treatments is an important part of working towards the cause for good, which is why understanding can play an important role. on this winter’s sleep behavior in future research. Cancers can often return after they are dormant or appear to disappear for several years after treatment.
Preclinical study of human colorectal cancer cells showed that they were able to slow into a “tolerant maintenance” (DTP) state with minimal maintenance, which helped explain some failures in treatment and tumor recurrence.
“Immersion acts as a whole organism, capable of entering a slowly decomposing state, conserving energy to help it survive,” says the researcher and surgeon Catherine O’Brien, of the Princess Margaret Cancer Center in Canada.
“There are examples of animals entering a state that are easily moved back and stand up to harsh environments. Cancer cells seem to have co-opted the same state to craft for their the benefit of survival. “
Collecting human colorectal cancer cells in a petri dish and exposing the cells to chemotherapy, the researchers watched the colorectal cancer cells enter the same hibernation state, in a coordinated manner, when chemotherapy drugs were present. The cells stopped expanding, which meant they needed very little nutrients to survive.
These observations also “fit a mathematical model where all cancer cells, and not a small subgroup, have the equipotent potential to be DTPs”, indicating that the strategies may survival see that in all cancer cells.
Researchers used xenografts of colorectal cancer cells on different sets of mice. As soon as the mice developed tumors of certain sizes, the researchers treated the mice with routine chemotherapy regimens. Scientists observed very little tumor growth in mice receiving treatments during eight weeks. When treatment stopped, tumor growth began again.
Cancer cells removed from the tumors after a period of regeneration were reintroduced into different mice and re-treated. The recovered cells were sensitive to treatments, and their growth stopped and began in the same way, results that were consistent with cancer cells entering a DTP state.
This DTP state is very similar to a hibernation-like state called embryonic diapause in which embryos mice fall back as a form of emergency survival. Embryonic diapause enables many animals, including mice, to stop initial development until more favorable environmental conditions.
Here, cancer cells were found performing a similar trick. Another link between the DTP state and embryonic diapause is the reliance on a biological mechanism called autophagy, in which cells essentially feed themselves to find the nutrients they need. Autophagy occurs naturally in the body as a means of cleansing waste, but in this case cancers are used to survive.
“We never knew that cancer cells were like sleeping bears,” said oncologist Aaron Schimmer, of the Princess Margaret Cancer Center. “This study also tells us how to target these sleeping bears so that they do not hibernate and wake up to come back later, unexpectedly.”
“I think this will be an important reason for drug resistance, and it will explain something we didn’t have a good understanding of before.”
By targeting and inhibiting the autophagy process, the researchers were able to break the hibernation state (or DTP) and kill the cancer cells for good with chemotherapy. This could be one way to treat cancer tumors that are against conventional treatments in the future.
Scientists already know a number of other ways in which cancers can hide in the body, so this new study contributes to a growing body of evidence about how you can detoxify cancer cells. who are opposed to taking drugs and conventional procedures.
“This will give us a unique therapeutic opportunity,” O’Brien said. “We need to target cancer cells while they are in this slow, vulnerable state before they can get the genetic mutations that move against drugs.
“It’s a new way of thinking about resisting chemotherapy and how to get over it.”
The research was published in Cell.