The biological clock regulates the body's daily rhythms, including sleep, hormone secretion, tissue repair, and immune system monitoring. When this system is disrupted by night work, frequent travel across time zones, or irregular sleep patterns, the body's natural defenses are weakened, creating an environment conducive to cancer growth and spread.
A team from the College of Arts and Sciences at Texas A&M University, led by Dr. Tapasri Roy Sarkar, has revealed the biological mechanisms that link sleep disorder to cancer growth.
The researchers conducted an experiment on two groups of genetically modified animal models susceptible to aggressive breast cancer:
The first group lived according to a natural light cycle.
The second group was exposed to a disrupted light cycle that caused a disruption in the biological clock.
Cancer symptoms appeared earlier in the disrupted group, at 18 weeks, compared to 22 weeks in the normal group. The tumors were also more aggressive and more likely to spread to the lungs, while the disruption to the circadian rhythm weakened the immune system, which helped the cancer cells survive and grow.
The researchers focused on a protein called LILRB4, which is known to suppress the immune response. Under normal conditions, this protein protects tissues from excessive inflammation, but it becomes dangerous when overactive in cancer, acting as a "switch off" for the immune system.
When researchers targeted LILRB4, they observed a decrease in tumor growth and spread even under disrupted circadian rhythms, opening up prospects for targeted therapies for aggressive breast cancers.
The study indicates that disruption of the circadian rhythm not only increases the risk of developing cancer but also contributes to its progression. Future research aims to explore how to reverse the effects of circadian rhythm disruption in humans, particularly night shift workers and frequent travelers, to improve overall health and reduce cancer risk.
The study was published in the journal Oncogene.
