05 February 2018

Cancer cells are hot from nanozolot

Kirill Stasevich, "Science and Life", based on the materials of the press service of the FITC KNC SB RAS.

Gold nanoparticles could be an alternative to conventional chemo- and radiotherapy in oncology. They can be heated with a laser, and if such particles gather in a cancerous tumor, then they can be used to destroy this very tumor: malignant cells will die, unable to withstand laser heating. (As an alternative to a laser, ionizing radiation can be used, which gold particles absorb 100 times more strongly than living tissues, and under the influence of which they emit electrons that damage the DNA of cells.)

By themselves, gold nanoparticles are harmless, unlike radioactive radiation or chemotherapeutic drugs, which hit healthy tissues too. However, with nanoparticles, there is still a problem of how to get them to the right place – if they settle outside the tumor, they will not be of use. A variety of tricks are used to lead them to cancer. Earlier we wrote about how gold nanoparticles search for a tumor with the help of special antibodies that bind to cancer cell receptors; another way is to make nanoparticles look for cells with increased acidity (and in cancer cells it is just increased).

A different approach was used by researchers from the Krasnoyarsk State Medical University named after V.F. Voino-Yasenetsky, the Federal Research Center "Krasnoyarsk Scientific Center of the Siberian Branch of the Russian Academy of Sciences" (FITC KNC SB RAS), the University of Ottawa and a number of other research centers.

They provided the nanoparticles with nucleic aptamers – the so-called short nucleic acids (DNA or RNA), specially designed to bind to certain molecules. In fact, aptamers work in the same way as antibodies, specifically binding to certain cells, but in comparison with antibodies they often turn out to be more convenient: it is easier to get a very specific aptamer for some receptor than the same specific antibody.

An article in Molecular Therapy – Nucleic Acids (Kolovskaya et al., Aptamer-Targeted Plasmonic Photothermal Therapy of Cancer) describes the results of experiments with mice with Ehrlich's carcinoma, an experimental cancer tumor that grew in animals under the skin.


After the mice were injected with nanoparticles with aptamers, the tumor was irradiated with a green laser for five minutes. The tumor disappeared completely: it could not be detected either by positron emission tomography, computed tomography, or histological analysis; at the same time, healthy tissues remained intact. That is, nanoparticles with the help of aptamers really bound only to cancer cells, not paying attention to healthy ones. By themselves, the nanoparticles also did not cause any harm to the mice.

It is especially important here that the method was tested not on cell culture, but directly in a living organism. Of course, different conditions need to be selected for different tumors: for example, for those tumors that are located near the surface of the body, a green laser is enough, but if the tumor sits deep, then a red laser will be needed to warm up the nanoparticles, since it can penetrate deep into living tissues. And in the near future, the authors of the work are just going to optimize the size of nanoparticles and other conditions of the methods so that it is possible to destroy cancer cells hiding deep inside the body.

The study was carried out with the support of the Ministry of Education and Science of the Russian Federation.

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