Human lymphoma cells
= When chemotherapy is used for lymphoma, the chromosomes of cancer cells are abnormally increased and the cells themselves are often enlarged.
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Cancer cells’ resistance to chemotherapy is an old headache for scientists.
Research has shown that could be an important clue in crushing this treatment resistance of cancer cells.
The point is that when a hostile environment is created by chemotherapy or the like, cancer cells enter a kind of’hibernation state’ that extremely inhibits self-division and energy consumption, neutralizing the therapeutic effect.
In this case, the cancer cells acted like a whole organism, incorporating survival strategies conserved in many mammals during evolution.
This is the first time that cancer cells have been proven in medical science to evade chemotherapy using mammalian evolution programs.
Scientists have also suggested a treatment strategy to prevent the recurrence of cancer by intensively targeting the cancer cells hiding in this slow division state.
The study was conducted by scientists at the Princess Margaret Cancer Center in Toronto, Canada, and a related paper was published in the journal Cell on the 7th (local time).
Fatty acids (red) play an important role in the regeneration of epithelial cells in the lining of the intestine.
However, it has been reported that if there is too much dietary fat in the intestine, stem cells (green) increase, increasing the risk of colon cancer.
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By administering chemotherapy to human colon cancer cells isolated on a petri dish, the research team stopped growth and induced a’slow division’ state that uses little nutrients.
As long as chemotherapy was used, cancer cells continued to maintain this condition.
Cancer cells used an “embryonic survival program” conserved in more than 100 mammals to switch to a low-energy mode.
This program is a survival strategy that safeguards the embryos inside the body when faced with extreme environments such as high or low temperatures, or lack of food.
Then, when the external environment improves, the embryo that has stopped growing resumes normal development, and there is no problem with the offspring of the female.
Dr. Catherine O’Brien of the cancer center (adjunct professor of surgery at the University of Toronto Medical School) said, “It seems that cancer cells have intercepted the survival strategy of mammals that humans don’t have in the process of evolution.” Explained that it will switch to a’slow division’ state.
The researchers found that cancer cells induced by slow division using chemotherapeutic drugs had very similar gene expression characteristics compared to mouse embryos in a state of growth arrest.
Both slow-dividing cancer cells and mouse embryos that stopped growing required the activation of a cellular process called autophagy.
Cells that lack nutrients break down proteins or other cellular components on their own to survive, which is called autophagy.
The research team confirmed that cancer cells cannot survive if autophagy is suppressed with a small molecule substance.
Cancer cells that could not hide in the hiding place of’slow division’ because autophagy stopped, could not avoid chemotherapy.
Dr. O’Brien said, “When cancer cells are hidden by slow division, that is, genetic mutations do not occur and are still vulnerable to chemotherapy, we must focus on cancer cells.”