Altering Food and Light Schedules Affects Cancer Genes in Mice

Altering Food and Light Schedules Affects Cancer Genes in Mice

A new study has found that altering food schedules and
light/dark exposure in mice modified the expression of
circadian clock genes and genes involved in carcinogenesis
and tumor progression.

The circadian clock regulates the approximate 24-hour
cycles of many animals, including mammals. It has been
reported that tumors grow faster in animals with a
disrupted circadian clock--which happens, for example, in
chronic jet lag--but the molecular mechanism is unclear.

Francis Lévi, M.D., Ph.D., of the French National Institute
of Health and Medical Research (INSERM) and
University Paris XI at Paul Brousse Hospital in Villejuif,
France, and colleagues compared the expression patterns of
circadian clock and cell cycle genes in the livers and tumors
of mice synchronized by normal light and dark schedules
(normal circadian clock) or with schedules designed to
simulate chronic jet lag in humans (disrupted circadian
clock). They found that meal timing reversed the disrupted
circadian clock gene expression patterns and slowed tumor
growth in chronic jet lagged mice. The authors conclude
that the altered light/dark or feeding schedules modified the
expression of circadian clock genes and genes involved in
carcinogenesis and tumor progression.