02 December 2014

A new oncolytic virus

Destruction of tumors by M1 virus

S.Kholin, Scientific.ru

The successes of modern oncology are obvious, but until now malignant neoplasms continue to be one of the main causes of death of people on our planet. This is primarily due to the fact that the vast majority of tumor diseases are characterized by a low-symptom onset, rapid tissue damage and the appearance of metastases (secondary tumors). Therefore, in order to obtain the maximum possible positive effect, a whole complex of multicomponent treatment is required, consisting of surgical, chemotherapeutic, radiation and other methods (Mailankody et al., Comparative Effectiveness Questions in Oncology N. Engl. J. Med., 2014). However, even a timely and well-chosen scheme for combating the disease does not always guarantee the success of a complete recovery of the patient; therefore, it is necessary to find new ways to comprehensively influence tumor processes.

Not so long ago, a rather interesting direction of treatment appeared in oncological practice – the use of viruses that can not only inhibit the growth of tumors, but also destroy them. Such viruses have been called oncolytic. The fact is that each tumor consists of atypical cells whose genetic apparatus is unable to control growth, division and metabolic processes. The cytoplasm of such cells, their organelles and membranes always contain substances not peculiar to them (abnormal proteins, glycolipids, polysaccharides, etc.), and the nuclei contain altered DNA molecules. Quite often, the synthesis of some important proteins and enzymes stops in atypical cells. All these deviations from the norm allow oncolytic viruses to easily penetrate into neoplasms and destroy them without affecting the surrounding healthy tissues. To date, several similar viruses have been tested in clinical trials, in particular, good results have been obtained in the treatment of melanoma with them.

A group of scientists from China led by Yuan Lin (Identification and characterization of alphavirus M1 as a selective oncolytic virus targeting ZAP-defective human cancers, PNAS, 2014) conducted a complex study of the M1 virus; it is one of the strains of Getah-like alpha virus isolated from culicin mosquitoes living on Hainan Island of China. Getah (Geta) virus mainly affects horses and pigs; at the same time, it is practically not transmitted to humans, and when it enters the human body, it does not cause infectious diseases. In addition, M1 does not provoke pathological processes in laboratory animals (mice and rats), even with high doses. The purpose of this study was to study in detail the effect of the M1 virus on malignant tumors. To do this, scientists analyzed the features of the process of introducing the virus into the cells of surgically removed human tumors and related structural and functional changes; in parallel, all sides of the virus' impact on experimental animal tumors were observed.

As a result of the conducted genetic, immunological, biochemical and other studies, it was possible to establish that the M1 virus, getting into tumor cells, is really capable of causing their destruction. This applies to various types of tumors, including hepatocellular carcinoma, skin cancer and many others. At the same time, it was revealed that the virus has a high tropism to the atypical cells of these tumors, that is, it rushes exclusively into their cytoplasm and organelles, without going beyond the malignant neoplasm and practically without affecting healthy cells and tissues. A detailed study revealed that the M1 virus is actively introduced into cells with a deficiency of the ZAP protein and causes endoplasmic stress in them; because of this, the metabolic processes of a number of substances are sharply disrupted, and therefore further vital activity of the tumor cell becomes impossible, it dies and is destroyed (lyzed). It is important to note that treatment with the M1 virus is not accompanied by side effects and does not affect the structure and function of tissues of internal organs and the entire body. At the same time, this virus stimulates the immune system, which enhances its therapeutic effect.

Thus, it is proved that the M1 virus is capable of intensively destroying the cells of malignant neoplasms that do not contain the ZAP protein. This method of cancer treatment is very promising.

Portal "Eternal youth" http://vechnayamolodost.ru02.12.2014

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