Safety mechanism
A trigger for removing unnecessary cells has been discovered, which can protect against cancer
Georgy Golovanov, Hi-tech+
The removal of some cells from the body is an important part of the development of the embryo in animals. And in mature tissues, this process occurs daily. For example, the cells of the intestinal walls are updated every few days. One of the ways to get rid of unnecessary cells is extrusion, when they are squeezed out of the tissues without damaging the remaining layer. Biologists from MIT have found out that this process is triggered when cells cannot reproduce themselves through division.
Article by Dwivedi et al. Replication stress promotes cell elimination by extrusion published in the journal Nature – VM.
"Cell extrusion is a cell removal mechanism used by various organisms: sponges, insects, and humans," explained Robert Horowitz, professor of biology and head of the study. – The discovery that extrusion is triggered by a malfunction in DNA replication was unexpected and allows us to take a fresh look at possible treatments for certain diseases, in particular cancer."
In the 80s Horowitz was one of the first to study the process of programmed cell suicide - apoptosis. Later, he made another discovery: if, due to a genetic mutation, excess cells are not destroyed by apoptosis, they are removed by extrusion - something like a safety mechanism. However, how this mechanism is triggered remained a mystery, writes MIT News.
In order to uncover it, scientists from MIT examined over 11,000 genes of C.elegans nematodes. Gradually, they were able to identify the genes responsible for cell extrusion. To their surprise, many of these genes were involved in the cycle of cell division. It turned out that when cells cannot reproduce themselves, stuck in this phase, they are waiting for extrusion.
The C.elegans embryo (green) squeezes out a cell (purple cell in the center of the image) during development.
"Replication stress is one of the characteristic features of precancerous and cancerous cells," explained Dwivedi, the first author of the article. "Our discovery suggests that the extrusion of cells that experience replication stress is a potential mechanism for tumor suppression."
The fact that cell extrusion is present in such a large number of animal species, from sponges to mammals, led scientists to assume that it developed as a very early form of getting rid of unnecessary cells, which was later replaced by apoptosis.
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