Researchers have found that the concentration of oxygen has a significant impact on the spread of cancer cells.
Understanding of the spread of cancer cells throughout the body is advancing. Biologists from Johns Hopkins University in Baltimore (USA) have discovered that low oxygen levels can trigger the production of proteins, RhoA and ROCK1, which help spread breast cancer cells, as reported the Medical News Today website. The lack of oxygen would lead to a series of events that would transform breast cancer cells from rigid and stationary cells to mobile and invasive, promoting the migration of metastases.
It was previously known that high levels of RhOA and ROCK1 proteins gave cancer cells the ability to move and spread, making it worse for patients already suffering from breast cancer. But this is the first time that a study, published in Proceedings of the National Academy of Sciences the journal of the American Academy of Sciences, identifies the presence of high levels of these proteins in cells.
A lack of mechanical oxygen
Dr. Gregg Semenza, professor of medicine at the John Hopkins School of Medicine, details this discovery: “When the cells of the tumor multiply, the interior of the tumor is less and less supplied with oxygen”. The growth of the tumor requires a lot of energy, and therefore a lot of oxygen. “The lack of oxygen activates ” factors produced by hypoxia ” [les protéines qui régulent l’absence d’oxygène ou HIF, comme RhoA ou ROCK1, ndlr] which themselves activate genes that help cells adapt to the lack of oxygen ”.
The famous “lack of oxygen” is therefore not an environmental but a mechanical factor, due to the very development of the tumor.
For example, Dr Daniele Gilkes, who is one of the lead authors of the study, found that when breast cancer cells were exposed to low levels of oxygen, they moved significantly more than those exposed to normal oxygen levels. Likewise, the level of RhoA and ROCK1 increased under conditions of hypoxia, and decreased under normal conditions.
Stop the spread of tumors
This discovery is of major importance. Indeed, as Daniele Gilkes explains: “We have succeeded in lowering the mobility of breast cancer cells by using genetic ‘tricks’ that lower HIFs. Now that we understand the mechanism at play, we hope that clinical trials will be set up to see if drugs that inhibit HIF expression could have the dual benefit of blocking the production of RhoA and ROCK1 and preventing metastasis in women with breast cancer ”. Especially by having access to a database, the researchers realized that women with high levels of RhoA and Rock1 had a higher risk of dying from breast cancer than others.
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