Glioblastoma exosomes
Scientists have proposed a method for noninvasive diagnosis of brain cancer based on a blood test
Scientists of the Kurchatov Institute Research Center together with other scientific organizations studied the molecular composition of exosomes secreted by glioblast cells. We are talking about the most frequent and most aggressive type of brain cancer, the diagnosis of which requires complex invasive procedures. During the study, scientists found 11 proteins in the exosomes of glioblastomas that can indicate the presence of a dangerous disease. Experts believe that this work will allow us to create new non-invasive methods of diagnosing malignant tumors based on the identification of specific cancer markers in the blood. The results of this study are published in the journal Biomedicines (Naryzhny et al., Proteome of Glioblastoma-Derived Exosomes as a Source of Biomarkers).
"The results are of particular importance because they can contribute to the development of non–invasive diagnosis of brain tumors," says the project manager, senior researcher Laboratories of protein biosynthesis of SIC "Kurchatov Institute" – PIAF Tatiana Shtam. – This is very important, because making such diagnoses requires a number of confirmatory studies, for example, a CT scan of the brain, as well as a biopsy of tumor tissues, which is impossible without surgery. Of course, it would be better to replace complex, dangerous and painful manipulations for the patient with a simple blood test. In addition, such a method will give a broader understanding of the processes occurring inside the tumor, and will allow you to adjust the treatment."
The objects studied in this work – exosomes – are microscopic vesicles (vesicles) that cells secrete into the external space. They are present in all body fluids and play an important role in the system of intercellular transport of substances and information. Exosomes can be found in cerebrospinal fluid, urine, saliva, tears and, of course, blood plasma. "It is logical to assume that the appearance of malignant cells in the body will lead to the appearance of exosomes in the plasma carrying information about this process, encrypted in the form of certain protein markers and cancer–specific nucleic acids," explained Tatiana Shtam.
In this work, experts have studied which proteins are present in the composition of exosomes secreted by glioblastomas. The experiment was carried out on five different cell lines. The molecular composition of the vesicles was determined using high-resolution mass spectrometry. As a result, scientists identified 11 common proteins in the exosomes of all five cell lines. It is noteworthy that they are produced in an increased amount in glioblastomas. Based on these data, scientists have compiled a panel of protein markers with which it is possible to establish the "origin" of exosomes: to find out whether they were produced by brain cancer cells. Some of these proteins can be considered as promising cancer markers, since their presence in blood plasma exosomes correlates with the degree of malignancy of the tumor.
At the next stage, the scientists plan to continue their research not on cell lines, but on blood samples of patients with glioblastoma.
Specialists of the V.N. Orekhovich Research Institute of Biomedical Chemistry and the Far Eastern Federal University also took part in the work.
For reference:
Glioblastoma multiforme is the most malignant form of brain tumors and one of the most aggressive types of cancer. The average survival time of patients with glioblastoma is from 12 to 15 months, and the overall two–year survival rate is on average only 26%. In this regard, early diagnosis is very important for prolonging the life of patients. Despite the efforts of the medical and scientific community, a reliable non-invasive method of early diagnosis of glioblastoma has not yet been developed.
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