A new study published in the journal PLOS Biology suggests that the way that experts approach optimizing cancer treatment may need to be rethought to include factors relating to the biological, or “circadian,” clock.
We all have a biological clock, which is tasked with helping us to maintain our daily cycles of rest and activity by running in sync with the cycles of light and dark in our environment. Another natural cycle in our body is “the cell cycle,” which controls the multiplication of our body’s cells.
Both the cell cycle and biological clock can be disrupted by cancer. In fact, in many cancers, a dysfunctional cell cycle enables the tumor to multiply uncontrollably.
Experts know that the biological clock plays a role in regulating time-dependent processes within the body, including metabolism, DNA repair, and the cell cycle. And in the new study, researchers from Charité-Medical University in Berlin, Germany, explored whether or not the biological clock may also be able to suppress tumors.
The researchers tested their hypothesis in mice by altering levels of a protein called RAS, which is known to control the cell cycle and is dysfunctional in approximately a quarter of all human tumors.
In this mouse study, the researchers discovered that RAS also controls the cycles of the biological clock, or “circadian rhythms,” by influencing two proteins called INK4a and ARF.
It is important to remember that this study was conducted in mice, so we do not know for sure how these results might apply to humans.
Still, the researchers believe that this finding demonstrates the influence of the biological clock over how cells multiply, suggesting that the biological clock has a potential function as a cancer-preventing mechanism.
“Based on our results,” explains Dr. Angela Relógio, from Charité-Medical University, “it seems to us that the clock is likely to act as a tumor suppressor, and that it is of advantage for cancer cells to circumvent circadian control.”
She adds, “One cannot stop wondering whether disrupted circadian timing should be included as a next potential hallmark of cancer.”
Dr. Relógio — whose surname, appropriately, translates to “clock” in Portuguese — says that the team’s findings show that it may be relevant to consider the effects of internal time as part of cancer treatment.
These results also correspond with some other recent studies suggesting that resetting a person’s biological clock by adjusting sleeping and waking times — a process known as “chronotherapy” — may help to optimize the therapeutic effects of cancer treatments.