Ural Federal University: New Fluorophores Can Help Fight Cancer

Scientists from the Ural Federal University and the Ural Branch of the Russian Academy of Sciences have created new fluorescent chemical compounds (fluorophores) for photodynamic therapy of cancerous tumors, the newest method of treating cancerous diseases. The compound is suitable for the simultaneous diagnosis of tumor processes by staining affected tissues and their further treatment by destroying tumor cells without harming healthy ones. The results of the primary research are presented in the journal Dyes and Pigments.

The synthesis of these fluorophores is notable for its low cost, due to the availability of all derivatives in the composition, as well as the absence of impurities that could lead to side effects. The efficacy of the fluorophore was tested on HeLa cells used as a model of cervical cancer. Scientists are now testing how the new compound interacts with other types of cancer cells.

Fluorophores are chemical compounds that emit visible light (photoluminescence) when exposed to ultraviolet or visible light. They are capable of spreading through biological tissues and staining cells subject to inflammatory processes. Thus, the new compound interacts with biomolecules of body tissues and, when exposed to ultraviolet or visible radiation, stains the areas where the tumor is growing. This makes it possible to determine the size of the tumor in the body and delineate its borders. During experiments, scientists found that the new fluorophore has a dual function: it not only stains diseased areas, but also begins to destroy them.

“Initially, we investigated only the dyeing properties of the compound. The compound is able to accumulate in certain parts of the cell – the cell membrane and reticulum (intracellular organoid responsible for protein folding), and when exposed to ultraviolet or visible radiation, it lights up the infected areas with a bright green color. However, it turned out that the fluorophore further acts as a photosensitizer. That is, under the influence of optical radiation, it begins to interact with the surrounding cellular environment (oxygen, water, etc.) and generates free radicals, the so-called reactive oxygen species. These active particles interact chemically with the affected cells, starting their destruction with little or no effect on healthy cells. This is called photodynamic therapy; it is a new prospective method of cancer treatment with high efficiency and minimal side effects,” says Grigory Zyryanov, co-author of the study and Professor of the Department of Organic and Biomolecular Chemistry at UrFU.

Scientists used heterocyclic chemistry techniques to create two experimental samples. Chemists synthesized a fluorophore based on naphthoxazole, a derivative of the oxazole compound used in the synthesis of medicines and biochemicals, and a naphthalene fragment used as a platform and so-called antenna for more effective perception of optical irradiation by the molecule. Additionally, the chemists added to the compound fragments of pyrene and anthracene, polynuclear aromatic hydrocarbons that have a high fluorescence response, that is, a bright glow. The compound containing pyrene showed the greatest fluorescent and anticancer activity.

“Pyrenees are very often used for bioimaging, anthracenes less often. These compounds are promising for many reasons, including that we were able to show that a pyrene-containing compound begins to glow even when exposed to visible light, and this can be seen even with the naked eye. This is very convenient, including, for example, for surgical interventions, when it is still necessary in treatment,” Grigory Zyryanov explains.