A new study, published in the journal Cell, reveals that cancer cells have learned to adapt an ancient evolutionary mechanism to survive the harsh chemotherapy. They have learned to hibernate like bears in winter to survive through periods when the source is scarce, ScienceAlert reported.
Princess Margaret scientist Dr. Catherine O'Brien and team discovered that cancer cells enter a state of sluggish and slow-dividing state when they are under threat due to chemotherapy. They have the ability to transition into this state of "rest" until the threat is removed.
Understanding the hibernation of cancer cells could play a significant role in future research about cancer. It is as important as knowing how cancer cells evade and stand up to drug treatments towards defeating them for good because often they can return even after staying dormant for several years after treatment.
Failure in therapy Linked to Hibernating Cancer Cells
According to ScienceAlert, preclinical research on human colorectal cancer cells revealed that they could slow down into low-maintenance and be in a "drug-tolerant persister" (DTP) state to survive. Their evolved behavior explains how some therapies failed and also explained the tumor relapses.
Researcher and surgeon Catherine O'Brien, from the Princess Margaret Cancer Center, said that "the tumor is acting like a whole organism, able to go into a slow-dividing state, conserving energy to help it survive."
The researchers noted that the cancer cells stopped expanding, so they required very little nutrients to carry on living when chemotherapy drugs were present. More so, they said that the survival strategy was seen in all cancer cells.
The researchers tried using xenografts of colorectal cells on different sets of mice. When tumors started growing, they began administering chemotherapy treatment for eight weeks. They observed that the tumors became small but began to grow again when the treatment was stopped.
Then they grafted the cancer cells into different mice and repeated the treatment. The results were similar, and the findings remain consistent, wherein cancer cells entered the DTP state.
What is the Drug-Tolerant Persister (DTP) State?
The DTP state is the cell version of the hibernation in animals during winter. It is also called embryonic diapause, in which the mice embryos fall back on their emergency survival mode. It allows many animals to put embryonic development on pause until environmental conditions become favorable.
According to a recent study, cancer cells have seemed to be doing a similar trick. But another link between the DTP and embryonic diapause is autophagy, a biological mechanism in which cells eat themselves for nutrients as a way to survive.
Unique Therapeutic Opportunity
According to Science Daily, Dr. O'Brien found that cancer cells did not survive when autophagy was inhibited. She said that this gives experts a unique therapeutic opportunity. They have to target and inhibit the autophagy process from breaking the hibernation or DTP state and killing the cancer cells for good.
"It is a new way to think about resistance to chemotherapy and how to overcome it," said co-senior author of the study and professor Dr. Ramalho-Santos.
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