Despite successful treatments, there are several instances where a person relapses with cancer. It turns out that cancer cells hibernate to avoid getting killed by chemotherapy.
As further development and research are underway to find a way to battle cancer, researchers are unlocking many secrets about the deadly disease. One of those mysteries now unlocked is how cancer cells behave when exposed to many cancer therapies, primarily chemotherapy.
Chemotherapy - the best bet yet
Chemotherapy is a drug treatment that uses potent chemicals that can kill off the rapidly multiplying cancer cells. It is one of the most prevalent cancer treatments since the chemicals promptly destroy cancer cells. However, one of the downfalls of chemotherapy is that it is quite painful for the person, and powerful substances induce cellular changes in the body, most often seen in the hair follicles.
Chemotherapy undergoers grow back curls known as ‘chemo-curls’ since they change the hair follicles’ shape. The treatment can also damage the healthy DNA within your body. Nevertheless, it is one of the most effective cancer treatments currently out there.
Cancer Cells 'Can' Hibernate in the Body to Avoid Chemotherapy
Researchers in a recent study made the shocking discovery that cancer cells can hibernate to withstand treatments. The research was done by researchers from the Princess Margaret Cancer Centre, Canada. Different cancers have different relapse rates. Some of the undetected cancer cells can remain in the body for years before deciding to divide and grow again. But how exactly do these cancerous cells go into hibernation is a mystery for many oncologists and researchers.
In the study, they found out some of the ways that cancer cells use to hide and avoid chemotherapy. Cancer cells can hide in fatty tissue or achieve a cancer-immune system equilibrium (they do this by remaining silent and not causing any internal disruption) to avoid being killed. Scientists, however, have no good idea about how this equilibrium works.
The research revealed that all cancer cells ‘could’ enter into periods of dormancy, similar to animals during hibernation, as a survival method, to go undetected by chemotherapy. The preclinical research was done on human colorectal cancer cells.
Researchers observed that chemotherapy enabled cancer cells to enter into a slow-division state in a laboratory-controlled environment. The way the cancer genes were expressed during this state was quite similar to the mouse embryos, where these embryos enter a state of hibernation know as embryonic diapause.
More than a hundred mammalian embryos can go into an embryonic diapause. From the mighty bears to the squeaky mice, this diapause is believed to get activated when the organism’s environmental conditions are unfavorable. The embryonic diapause also delays the embryo’s development until the conditions become better for it.
How Do Cancer Cells Hibernate?
One of the primary characteristics of embryonic diapause is a process known as ‘autophagy’. Autophagy is the body’s ability to clean up or ‘eat away’ unnecessary cells or proteins to help repair other body cells. This enables the body to function during unfavorable conditions like starvation.
This new investigation found out that cancer cells use autophagy to go into a ‘hibernation’ state. This helps the cells to go undetected by chemotherapy and thus successfully avoid it. However, when researchers inhibited the cancer cells’ ability to go into autophagy, chemotherapy was discovered by the cancer cells, and it virtually destroyed them.
Aaron Schimmer from the Princess Margaret Cancer Centre said that this system nearly resembles a bear’s hibernation during winters. Schimmer also said that autophagy could also help scientists discover why some people don’t respond well to chemotherapy.
The research has labelled these hibernating cancer cells as ‘drug-tolerant persisters’ (DTPs), and the model designed by the scientists reveals that all cancer cells may have the capacity to turn in DTPs.
Catherine O’Brien, a scientist at the same institute as well as one of the lead researchers of its study, said, “The tumour is acting as a bion, able to go into a slow-dividing state, preserving energy to support its survival. There are examples of animals inscribing into a reversible and slow-dividing state to withstand harsh environments. It resembles that cancer cells have craftily co-opted this same state for their endurance benefit.”
This research may soon encourage drug developments that can inhibit the cancer cells’ potential to turn into DTPs by reducing or removing their autophagy potential, making them more susceptible to cancer treatments and lowering the relapsing percentage of certain types of cancers. The study was issued in the Journal Proceedings of Cell.