Danio fish instead of mice

The Future of Personalized Chemotherapy

Anna Kerman, XX2 century, based on the materials of MedicalXspress: Zebrafish larvae could be used as 'avatars' to optimize personalized treatment of cancer

Malek danio-rerio with a malignant tumor
(marked in red), grown from the patient's cells.

A group of scientists from Portugal for the first time demonstrated the possibility of using the fry of the aquarium fish Danio rerio as an object for testing various approaches to the treatment of malignant neoplasms. If the results of the study are confirmed, soon doctors will begin to quickly and safely select the optimal therapy for specific patients. The work was published online in the Proceedings of the National Academy of Sciences (Single-cell functional and chemosensitive profiling of combinatorial colorectal therapy in zebrafish xenografts).

To date, the effectiveness of prescribed chemotherapy is usually not tested on an individual level. Doctors prescribe medications based on the results of large-scale clinical trials. Personalized tests, during which doctors transplant tumor cells to mice and already test different drugs on them, are available only in large clinics and specialized medical centers.

Mice belong to mammals, so they are quite close to us from an evolutionary point of view. As a rule, the results of the "treatment" of experimental mice predict the patient's response to a particular therapy with high accuracy. However, such a study takes too much time – tumors in the mouse body take several months to grow and form. If the results of the new work carried out under the leadership of Rita Fior and Miguel Godino Ferreira are confirmed, then over time the mice may be replaced by danio fry. In this case, the development of a personalized treatment regimen will take less than two weeks.

In previous studies, it has already been shown that danio-rerio fish are a good model for pharmacological experiments. However, the authors of the new work were able to demonstrate for the first time that danio fish and mice respond to treatment in the same way. "Using the same drugs, we obtained similar results in both danio fry and mice," explains Miguel Godino Ferreira.

Interestingly, the researchers were not only able to prove a certain "similarity" between the danio fry and mice. They also found that a single mutation in the RAS gene (it is known that it often mutates in oncological diseases) able to change the response to treatment.

At the last stage of the work, the researchers created "avatars" of five real patients with colorectal cancer. To do this, tumor cells were transplanted to fry. After the operation, all patients underwent chemotherapy. The same "treatment" was "prescribed" to fish. Two experimental animals did not receive an adequate response to chemotherapy, and patients whose "avatars" were these fish soon relapsed. Conversely, the "avatars" of patients who achieved remission responded well to therapy. Thus, scientists were able to correctly predict the outcome of treatment in 4 out of 5 cases.

Of course, the scale of this study is too small to talk about the applicability of the new method in clinical practice. Therefore, now the authors of the work are preparing for the next stage of trials involving hundreds of patients. It will take about two years. Ideally, scientists would like to create a technique similar to existing tests for antibiotic sensitivity, but applicable in oncology.

Portal "Eternal youth" http://vechnayamolodost.ru  31.08.2017