Humans aren't the only biological systems capable of breaking generational cycles: The cells that make us are, too. New research shows that cells detect when their parent had difficulty dividing and then stop dividing themselves. This process could help mitigate cancer and the origination of genetic disorders, both of which can be triggered by dysregulated cell division.
Most of us learned in school that cells reproduce via mitosis, the process by which one cell copies its contents and splits into two cells. Mitosis consists of a chain of events, each of which features its own checks to ensure that things like DNA replication and chromosome allocation are done correctly. An error at any given step could severely affect the body's development, immune system, genetic expression, and more.
Researchers at the University of California San Diego and the Okinawa Institute of Science and Technology found that cells recognize when their parent had a difficult time passing these checkpoints. To prevent further issues with mitosis down the line, those cells will stop dividing. While a similar process has been known to occur with retinal cells, this new study, published Thursday in the journal Science, reveals that generational cell cycles can be broken within more than just our eyes.
Through their research, developmental biologists and molecular scientists found that cells throughout the body are capable of "timing" a parent's mitosis. They do this using a three-protein biochemical pathway the scientists refer to as a "mitosis stopwatch." Through this pathway's memory function, cells develop a report of how long each step of mitosis has taken. This report carries from one cellular generation to the next.
Depending on how long it took for their parent to undergo mitosis, a pair of daughter cells might stop dividing altogether. The researchers think this is the body's effort to safeguard us from the cancers and disorders that might result from dysfunctional mitosis. Even a mitosis delay of 20 minutes is enough for daughter cells to call it quits.
"Our research suggests that measuring mitosis time is a mechanism that was developed as a way to protect us," Karen Oegema, a cell biology professor at UC San Diego, said in a statement. "Essentially, it’s another tumor-suppression function tied to [the proteins'] job to protect against problematic cells."
The mitosis stopwatch isn't foolproof. Oegema and her colleagues found that in tumors, the stopwatch often failed, allowing cells to continue their problematic division patterns and produce cancerous lumps. Still, without our knowledge, our cells might regularly "choose" to end their own generational lines in favor of the systems to which they belong. With further research, the insight hidden within cell proteins could help us devise innovative treatments for cancer and other conditions.
