The chemical structure
of the recombinant tumor necrosis α-factor of thymosine-α1 (the sequence of amino-acid residues in single-letter code) includes 185 amino-acid residues. It is written below, with the last 28 amino-acid residues on the C-end is the thymosine-alpha1 sequence:
- The molecular weight is 20.46 kDa.
The medical product has direct in vitro and in vivo antitumor effect on the different lines of tumor cells. The specter of cytotoxic and cytostatic effect on the tumor cells is the same for the product and human tumor necrosis factor alpha (TNF). However, REFNOT toxic potential is 100 times lower than that of TNF.
- A direct influence of TNF-T protein on the target tumor cell through the corresponding receptors on its surface with all complicated processes triggered inside the cell, the end result of which is the cell apoptosis (cytotoxic effect) or cell cycle arrest (cytostatic effect). In case of the latter event the cell also becomes more differentiated and expresses a variety of antigens;
- A cascade of chemical reactions, including the activation of coagulation system and local inflammatory responses determined by the TNF-T-activated endothelium cells and lymphocytes, that leads to the so-called “haemorrhagic” tumor necrosis;
- angiogenesis blocking, due to which the aggressive tumor grows new vessels slower, which results in decrease of blood supply up to the necrosis of the tumor center;
- the influence of the immune system cells, the cytotoxicity of which turned out to be closely connected with the presence of TNF molecules on their surface or the growing process/activation of those cells is connected with the response to TNF-T.
The combinations of REFNOT with IFN-alpha2 or IFN-gamma have synergistic effect.
REFNOT increases the effect of chemotherapeutic agents: actinomycin D, cytosar, doxorubicine, 5-fluorouracil, etc. against tumor cells with low response to them by eliminating their resistance. It allows considering REFNOT a chemocytostatics antitumor action modifier in case the tumor cells are resistant to multiple drugs.
REFNOT does not have cytotoxic effect on normal cells, moreover, in high concentration it even stimulates cell growth in the spleen and lymph nodes. It also amplifies production of antibodiesto T-dependent antigens, stimulates cytotoxic effect of natural killer cells against tumor cells, stimulates phagocytosis, amplifies expression of Н-2К, CD4 and CD8 antigens of I class major histocompatibility complex, being the factor of differentiation between T-helpers and T-killers.
REFNOT shows a prominent synergistic effect with antiviral activity of recombinant alpha-2 or gamma-interferons, increasing their activity against some viruses (vesicular stomatitis, encephalomyocarditis) by 100-1000 times.
The active ingredient and pharmaceutical form of the medical product have passed pre-clinical trials:
- in pharmacokinetics, toxicology (general toxic action and local irritation, immunotoxic, allergenic qualities, mutagenic activity, reproductive toxicity) in the Scientific Research Center of toxicology and hygienic rating of biological products (prof. Borovik R.V., Doctor of Medical Sciences Dyadischev N.R.), Serpukhov,
- in study of antitumor activity in vitro and in vivo (prof. Gerasimova G.K.) in Russian Cancer Research Center named after Nikolai Blokhin of the Russian Academy of Medical Sciences, Moscow,
- in study of antiviral activity combined with interferon gamma on the models of herpesvirus and cytomegalovirus infection (prof. Barinski I.F.) and infection caused by hepatitis C virus on cell cultures (prof. Deryabin P.G.) in the Research and Development Establishment of virology named after D.I. Ivanivski of the Russian Academy of Medical Sciences, Moscow.