08 October 2012

Together against cancer

Magnetic nanoparticles will trigger apoptosis without penetrating cancer cells

Roman Ivanov, "Compulenta"

Nanoparticles can be used as remote-controlled magnetic switches that cause the death of cancer cells, according to scientists from Yonsei University (South Korea). The main actors of the technique are zinc–doped magnetic iron oxide nanoparticles with antibodies attached to them to one of the external receptors of colon cancer cells.

When activated by a magnetic field, the antibodies interact with the DR4 receptor and trigger an external apoptosis program.

Signaling pathways are the basis of all cellular processes, such as information exchange, growth, metabolism, as well as apoptosis (a cell death program that is triggered when certain signals are received by receptors). Apoptosis stands guard over normal cellular processes, not allowing them to get out of control as a result of cellular failures. Recently, signaling pathways of the so-called external apoptosis have been discovered.

It turns out that there are special receptors on the surface of cells, the activation of which by special signaling molecules from the outside allows you to launch a program of cell death. This discovery dramatically spurred the creation of new anti-cancer drugs based on biochemical ligands capable of interacting with "deadly" receptors. Unfortunately, all the ligands obtained so far have too short half-lives in blood plasma, and as a result, most of the injected drug disintegrates before it reaches its target.

To solve this problem, Korean scientists turned to nanotechnology. It turned out that the addition of magnetic abilities will allow you to control the signaling process remotely, using an external field. This, according to the authors, makes it possible to accurately position nanoparticles in the patient's body and thereby ensure the selective interaction of the drug only with malignant cells. The efficiency of the method was demonstrated by the example of a Danio fish.

So what's the point here? The main thing is the multivalence of the biochemical ligand, which is necessary for the activation of apoptosis from the outside. It is precisely such ligands, due to their multivalent nature, that cannot survive in blood plasma. Antibodies, on the contrary, are monovalent ligands that have no difficulty getting to the target. That's just they can't start apoptosis alone. It is necessary to find a way to assemble several monovalent ligands at one receptor. This method was the external magnetic field paired with magnetic nanoparticles.

The use of magnetic particles with the corresponding antibody on an ordinary embryo of a Danio fish
led to a change in the development of the embryo in the case of the application of an external magnetic field (illustration NPG).

More information about the results of the study can be found in the journal Nature Materials: Cho et al., A magnetic switch for the control of cell death signaling in in vitro and in vivo systemsPrepared based on the materials of Chemistry World: Magnetic nanoparticles zap cancer.

Portal "Eternal youth" http://vechnayamolodost.ru08.10.2012

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