Light Hybrid Molecule Treatment Stops Tumor Growth in Mice

This is a form of therapy where active ingredients target the tumors only, leaving the rest of the body untouched thus reducing the drug's toxicity.

In this case, the potentially highly effective treatment is achieved by a combination of modern photodynamic therapy with the latest methods of targeted drug delivery.

"Photodynamic therapy is a cancer treatment method that uses a combination of special preparations -- photosensitizers and light with waves of a certain length," said Mikhail Green, one of the authors of the new study, Sc.D. in Chemistry, Head of the Department of Chemistry and Bioactive Compounds, MIREA.

"Photosensitizers tend to accumulate in the tumor and when exposed to light with a certain wavelength contribute to the formation of a special form of oxygen, which destroys cancer cells. In addition to destroying cancer cells, photodynamic therapy destroys cancer in two other ways. First, photosensitizers can damage the blood vessels in the tumor, thus disrupting the flow of nutrients to it. Second, they can activate the immune system, causing it to attack cancer cells."

Combining deliverers with photosensitizers

To engineer the novel treatment, researchers combined a magnetic nanoparticle, known as the deliverer, with a cancer cell-killing molecule-photosensitizer to produce a hybrid whose movement can be tracked and measured through MRI. However, for the treatment to be effective the organs needed to be irradiated when the concentration of the drug in the tissues is at its peak. 

This took further work and analysis by the scientists. "Even at the theoretical stage, we have suggested that the optimal time of exposure to light can be determined by the intensity of the signal on the MRI image and the data obtained after the introduction of the hybrid "magnetite + photosensitizer" is 60-100 minutes," said Maksim Abakumov, one of the coauthors, Head of NUST MISIS Laboratory Biomedical Nanomaterials.

"Next, we conducted a series of preclinical tests on three groups of mice for 21 days. The first group received radiation after 30 minutes after injection of the test drug, the second one -- for 60-100 minutes, the third -- after 3 hours or more. As a result, almost all mice from the second group demonstrated stop in tumor growth, which proved the correctness of the proposed hypothesis".

Now the team is planning on initiating clinical trials for the innovative potentially life-saving hybrid treatment. The current study is published in Pharmaceutics journal.