Mounting evidence suggests that good sleep is critical to many aspects of our health. Circadian rhythms regulate the sleep-wake cycle in everything from mammals to fruit flies to plants, and keeps them synced up to the 24-hour cycle of the Earth’s rotation. In humans, circadian rhythms can be disrupted by chronic jet lag and shift work. New research indicates that disrupting these rhythms has negative consequences for both tumor size and microenvironment in mice.
Researchers led by Dr. Carla Finkielstein at the Virginia Tech Carilion School of Medicine and Dr. Diego Golombek at the National University of Quilmes have been studying the effects of sleep dysregulation in mice who are injected with melanoma cells. In their new study, “Circadian disruption promotes tumor-immune microenvironment remodeling favoring tumor cell proliferation“, published in Science Advances, they found that circadian disruption causes a host of changes in these mice, including increased tumor growth rate.
Mice in the experimental group were subjected to conditions equivalent to traveling across 21 time zones in a week. After a month of these conditions, their tumors were found to be three times the size of those of the mice in the control group. The jet lagged mice’s macrophages were also more accepting of tumor growth.
This work could have important implications for humans, too. “A key takeaway from this study is that if someone has a proliferative disorder, in this case melanoma, doing shift work or regularly changing time zones could exacerbate the problem by dampening immune system response to tumor growth,” said Finkielstein. You can read more about the paper at Genetic Engineering & Biotechnology News.