Cancer will be put on the counter
Scientists have discovered a mitochondrial "counter" of cell divisions capable of detecting cancer cells
BFU Press Service
An international group of scientists, led by Konstantin Popadyina, a professor at the Institute of Living Systems of the I. Kant BFU and a senior scientist at the Federal Polytechnic University of Lausanne, has discovered a way to quickly identify potentially dangerous cells that, by dividing rapidly, can cause cancer (or cancer metastases).
The results of the research can be read in the Bioarchive (Mikhaylova et al., Mitochondrial mutational spectrum provides an universal marker of cellular and organizational longevity).
"The research began with the fact that we tried to understand the mutations occurring in the DNA of mitochondria," says Konstantin. "It should be noted that the mitochondria, which are in each of our cells, have their own separate genome, which is seriously different from our main, nuclear, genome. Firstly, the mitochondrial genome is inherited only through the maternal line, secondly, it has a lot of copies, and thirdly, it mutates quite quickly - about ten times faster than the nuclear genome. And, thanks to these features, mitochondria are a kind of marker for the development of cell lines. Simply put, by observing the mitochondria, we can conclude from which specific cell the rest of the cells of a particular tissue in our body originated. This connection has been traced for a long time, but we decided to go further and check whether mitochondrial mutations are related to the functional features of tissues."
According to Konstantin, in the process of studying different types of cancer-affected tissues, it turned out that in slowly dividing cells, out of 12 possible types of transformation of one nucleotide into another (from A to T, from A to G, from A to C, from T to A and eight other possible substitutions), the type of mutation significantly prevails, in which the nucleotide A (adenine) is replaced by the nucleotide G (guanine).
"It turns out that mutations "from A to G" mark long-lived cells. This surprised us, and we decided to continue the study at another level – we began to analyze the mutagenesis of the mitochondria of eggs: women who gave birth, relatively speaking, at 20 and 40 years old, – continues Popadin. Since eggs do not divide after embryonic development, the age of fertilization of a woman (the age of birth of a child) is equal to the age of the egg. It turned out that in the case of 40-year-old mothers, mutations of the "A to G" type significantly prevail in the mitochondria. That is, with age, eggs accumulate mutations and mainly "from A to G".
At the next stage, scientists investigated mutations of mitochondria of different animals. In particular, mice, elephants and whales. In the last two species, the life expectancy of eggs is very long (tens of years). Strikingly, a predominance of mutation was found in the mitochondria of elephants and whales, when nucleotide A is replaced by nucleotide G.
"And when we received the results of studies at three different levels, we concluded that we had discovered the rules for mutating mitochondria," the researcher explains. – If a cell divides slowly, then it will have a lot of mutations from A to G. We can say that a kind of counter works inside us, which shows how long the cell lived, – The chemical mechanism of the transformation of nucleotide A into nucleotide G is not yet fully clear (some hypotheses are being tested by the authors at the moment) but it is obvious that such a "mitochondrial counter" can be used for early cancer diagnosis."
"Theoretically, it is possible to examine individual cells from the tissue and by the number of mutations "from A to G" determine the potentially most dangerous cell (with a minimum number of mutations "from A to G"), whose rapid division can cause cancer or metastasis. And since we can find it, it means that in the future there will be a way to quickly neutralize it," the scientist is sure.
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