24 January 2017

Anticorrosive additives have found work in the therapy of tumors

Anna Manshina, N+1

Chinese scientists have used a substance that is usually used to prevent corrosion to fight cancer. It leads to oxygen depletion of cancer cells, removing oxygen from them, and at the same time it is safe for healthy tissues. An article about the study was published in the journal Nature Nanotechnology (Zhang et al., Magnesium silicon nanoparticles as a deoxygenation agent for cancer starvation therapy).

Cancer cells differ from healthy ones, including accelerated metabolism. Due to their rapid growth, they consume tens of times more nutrients than healthy tissues. Scientists are trying to use this feature to develop new cancer treatments based on the "starvation" of cells.

In medical practice, for example, therapy is used, which stops the development of new blood vessels of the tumor, and thereby deprives it of the influx of oxygen and glucose necessary for active development. The tumor does not die, but it does not grow and is in a "dormant" state. However, until now, little attention has been paid to the possibility of complete removal of oxygen from existing tumors. Such an impact could not just stop the growth of the tumor, but completely destroy it.

The authors of the new study decided that a powerful deoxidant can absorb oxygen in tumor cells, for example, a substance that is used in industry to remove oxygen from the surface of metals and protect against corrosion. For successful use in medicine, such a deoxidant must be biocompatible, safe for surrounding tissues and suitable for injection.

Magnesium silicide (Mg 2 Si) turned out to be a suitable candidate. This compound in an acidic environment turns into silane, which actively binds oxygen to form silicon dioxide (in fact, glass). Due to the fact that the reaction of magnesium silicide with oxygen takes place only in an acidic environment, the side effect is minimized - the neutral pH of the surrounding healthy tissues usually differs significantly from the acidified environment of the tumor.


The scheme of operation of Mg 2 Si nanoparticles. Bottom left to right: activation in an acidic environment, oxygen binding, formation of silicon dioxide aggregates. Drawing from an article in Nature Nanotechnology

In the course of their work, the scientists created injectable magnesium silicide nanoparticles and tested them on the MCF-7 breast cancer cell line. It turned out that magnesium silicide particles really cause severe hypoxia of cells. And in mice with breast cancer 4T1, the drug caused complete oxygen depletion of the tumor and its partial necrosis. Scientists also found that silicon dioxide, a byproduct of the oxygen binding reaction, forms plaques in the capillaries of the tumor that block blood flow to the tumor.

Thus, the researchers have shown the possibility of using a deoxidant to fight cancer. It is biocompatible, relatively harmless and even has an additional therapeutic effect by blocking tumor vessels. The new drug may be particularly effective for the treatment of cancers that produce most of their energy aerobically. However, before clinical trials of the drug become possible, the new substance will have to undergo a large-scale safety test on animals.

Portal "Eternal youth" http://vechnayamolodost.ru  24.01.2017

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