Nanoparticles for radiosensitization therapy of cancer

Scientists from the Institute of Macromolecular Chemistry (IMC CAS) have conducted research on self-assembled nanoparticles for radiotherapy oncological diseases. The journal Free Radical Biology and Medicine recently published the results of an almost five-year study gathering researchers across the IMC CAS, the First Faculty of Medicine Charles University, The Center for Advanced Preclinical Imaging (CAPI), and the Stanford School of Medicine.

Radiotherapy, along with chemotherapy, belongs to the most commonly used method in the treatment of cancer. Some types of tumors respond better to the treatment, while some more aggressive ones often represent challenges due to low treatment response. Hypoxic cancer cells (cells present in regions with a less oxygenated environment) belong to the group of cells that has a low treatment response. As a result of insufficient access to oxygen, these cells have altered metabolism, resulting in increased resistance to treatment. Resistivity toward radiation and chemical treatment of hypoxic cancer cells represent one of the main challenges in cancer treatment, currently.

The results of new study indicate that newly developed diselenide nanoparticles behave as powerful radiosensitizers, meaning that they can maximize radiation treatment to prevent tumor growth and further recurrence. Researchers designed and studied a chemical drug that required the use of less traditional characterization methods due to the nanoparticle’s “exotic” nature. "The instrumentation used for physicochemical characterization were focusing on the diselenide linker and fluorinated core of the self-assembly nanoparticles, for example, nuclear magnetic resonance of 77Se, 17F, or solid-state NMR was applied for studying the relaxation of fluorine atoms in an oxygenated atmosphere. Techniques such as cryo-TEM, DLS, MS/ESI, and MALDI-TOF were used to determine the physicochemical behavior of fluorinated diselenide nanoparticles. The research suggests that our nanoparticles amplify the outcome of radiation treatment by influencing intracellular redox systems after internalization into cells. That required to confirm these results by the detection and quantification of reactive oxygen species using fluorescence and photoluminescence. As a reasonable part of the experimental process, the treatment of the cell cultures grown in an environment with reduced oxygen content to induce hypoxia in tumor cells was performed. It was interesting to work with devices that were able to deliver a therapeutic dose using X-rays or cobalt 60 as a radiation treatment option" explains Dr. Miroslav Vetrik from the Department of Supramolecular Polymer Systems.

"The most beneficial to me personally, was the possibility to manage and participate in all the steps of the research, from the design, synthesis, properties determination, performing in vitro studies using hypoxic cells, and conducting in vivo studies across all participating research institutions. Mastering the techniques describing the system from radiation oncology point of view was challenging because it is different compared to nuclear chemistry, which belong to my field of study. This approach allowed me to better understand the biochemistry of hypoxic tumor cells, which we can apply in further research," adds Dr. Vetrik.

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