9/1/2016 4:44:33 PM
|written By : Staff Reporter|
A handful of large studies of cancer risk factors have found that working the night shift boosts the chances of developing cancer. MIT biologists have now found a link that may explain this heightened risk.
In humans and most other organisms, a circadian clock governed by light regulates the timing of key aspects of human physiology, by controlling cellular activities such as metabolism and division. In a study of mice, the MIT team found that two of the genes that control cells’ circadian rhythms also function as tumor suppressors.
Loss of these tumor suppressors, either through gene deletion or disruption of the normal light/dark cycle, allows tumors to become more aggressive. “It doesn’t matter how you disrupt the clock — both ways, loss of it seems to drive tumorigenesis,” said Thales Papagiannakopoulos, a former postdoc at MIT’s Koch Institute for Integrative Cancer Research and the lead author of the study, which appears in the July 28 issue of Cell Metabolism.
In humans, the central circadian clock is located in the brain’s suprachiasmatic nucleus (SCN), which receives information about light levels from the retina. The SCN communicates this information to cells in the body through hormones and other signaling molecules.
“Cells need the light cue, which is like a reset button for the clock. When you lose that cue, you lose the normal rhythms in every cell in your body,” says Papagiannakopoulos, who is now an assistant professor of pathology at New York University School of Medicine.