Sci Adv: Still staying up late? Scientists have found that circadian rhythm disorders can damage the immune response and accelerate the proliferation of cancer cells!

The study of circadian rhythm is of great significance in medicine and plays an important role in promoting the basic theoretical research of biology.
a recent study showed that chronic jet lag alters the micro-environment around tumor cells, making it more beneficial to tumor growth and hindering the body's natural immune defenses.
the study was led by Carla Finkielstein, an associate professor at Virginia Tech's Franlin Institute for Life Sciences, and Diego Golombek, a professor at the National Kilmes University in Argentina, and published in the October 14 issue of the journal Science Advances, entitled "Circadian developments tumor-immune microenvironmentions.
Scientists have previously shown that frequent cross-time zones, as well as shift work, are associated with an increased risk of cancer, but it is unclear how circadian rhythm disorders reduce the body's ability to inhibit the growth of cancer cells on a molecular scale.
Finkielstein said: "One of the important conclusions of this study is that if someone has a congenital disease, such as melanoma, and in this case is working shifts or changing the time zone regularly, the body's immune system is weakened and the growth of the tumor increases.
study also helps explain why tumors prevail when a person is exposed to chronic stress conditions with environmental and biological clock disorders.
cells in the human body have their own set of molecular clocks, including a range of genes, proteins, and signaling chemicals that determine the rate at which cells grow, divide, and decay.
in cancer cells, these biological clocks are often altered, allowing the tumor to set its own rapid, unlimited rate of proliferation.
body's main biological clock is located in the brain, regulated by external light, and sends signals to synchronize peripheral clocks throughout the body.
When our perception of day and night becomes confused by irregular light and dark intervals, our internal clocks and environments are disturbed, which, as this study shows, can have subtle and significant consequences at the cellular level.
researchers wanted to know how chronic jet lag affected the micro-environment around cancer cells, and studied two groups of mice injected with melanoma cells.
the first group as a control, exposed to normal circadian rhythms: 12 hours of light and 12 hours of darkness.
group simulated chronic jet lag, with light and dark exposure offset for six hours every two days, the equivalent of roaming 21 time zones per week.
month, the scientists observed that mice in the chronic jet lag group had about three times as many tumors as the control group.
the characteristics of tumor growth and animal survival under the chronic jet lag schedule, they also tested the microennity around the tumor, as well as samples of the spleen and liver that produce immune cells.
found that the immune systems of the two groups of mice responded differently to tumors.
, for example, in chronic jet lag groups, levels of different types of immune cells, such as macrophages, are reversed, making them more likely to promote tumor growth.
, the rhythms of other immune cells and molecules, including cytokines, are disrupted.
even if the tumor did not spread to nearby organs, such as the liver or spleen, the scientists observed that changes in the immune system's circadian rhythms in both organs were suppressed.
Two different methods of time biology were used to study the effects of circadian rhythm disorders on tumor growth and immune rhythms, and found a link," said Golombek, a researcher.
the body needs optimal rhythms of immune cells and immune body fluid factors to inhibit the rapid growth of tumors.
but when circadian rhythms are permanently disrupted, they can be damaged, reversed, or completely disappeared, which may help explain why the tumors in mice in the chronic jet lag group are significantly larger.
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