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With the aim to investigate structure-functional relations of DSIP, 11 DSIP analogues were tested on antimetastatic activity, among them five new analogues, differing in positions 2 and 6 of the DSIP amino acid sequence were synthesized by the solid-phase method using Fmoc-approach. Experiments on C57B1 mice with metastatic Lewis lung carcinoma showed some analogues to be more efficient as antimetastatic agents then DSIP after i.v. (50 micrograms/kg) administration. Normalization of neuroendocrine status and activity of peritoneal, alveolar and spleen macrophages after the DSIP and some analogues injections in mice with metastatic Lewis lung carcinoma took place. Antimetastatic action of DSIP derivatives is considerably affected by structural changes, especially in the N-terminal part. Conformational factors rather than enhanced enzymatic resistance are essential for antimetastatic response.

In staphylococcal infection the changes in functional ability of macrophages occur: their oxygen-depending bactericidity and adenosine-desaminase activity are depressed 5-nucleotidase ability increases. Introduction of homologous alpha-IFN in the dose of 1 x 10(3) u/mouse leads to enhancing macrophage bactericidity of the animals infected, inhibits their 5-nucleotidase activity and enhances adenosine desaminase one. Influence of alpha-IFN on the activity of adenosine metabolism enzymes in macrophages can be considered one of the most important mechanisms of its modulating effect in bacterial infections.

A new fungal strain, Trichoderma sp., discovered in Moscow, produces the antitumor enzyme, lysine-oxidase, which demonstrates an anti-invasive effect in vitro and anti-metastatic activity in vivo. Maximal inhibition of the in vitro invasion of MM1 clone cells was obtained when the tumor cells were pretreated with 2.5 mU/ml of lysine-oxidase; the pretreatment caused a 1.9-times reduction in cell growth and a 1.6-times reduction in the invasive capacity. We studied its anti-metastatic effect on the spreading Lewis lung carcinoma (3LL) in mice from which the primary tumor had been removed. The administration of the enzyme (50 U/kg, i.v.) significantly decreased not only the extent but the number of lung metastases, as compared with the untreated mice. In addition to that, the lysine-oxidase treatment considerably increases the life-span of mice from which the primary tumor had been removed (200 days after 3LL implantation, lysine-oxidase treatment caused surviving of 50% mice in experimental group).

The influence of ceruloplasmin on cell proliferation in regeneration liver of the rat has been studied. Ceruloplasmin stimulates cell proliferation in regeneration liver increasing functional activity of the mononuclear phagocytes.

The influence of a new antitumor enzyme L-lysine alpha-oxidase on Lewis lung carcinoma spreading was studied in mice in which primary tumor had been removed. The enzyme was found to significantly decrease the extent and number of lung metastases as compared to mice which hadn't received L-lysine alpha-oxidase. This was matched by recovery of alveolar macrophages functional activity, as assessed by adenosine deaminase and 5' nucleotidase levels in these cells. Moreover, antimetastatic and cytostatic effect was confirmed by the measuring of polyamine concentration in mice erythrocytes.

An antimetastatic effect associated with macrophage activation by liposome-encapsulated glucosaminylmuramyldipeptide was found to enhance in malnourished mice with the Lewis lung carcinoma. These changes were not matched by further increase in the functional activity of macrophages. It has been suggested that enhancement of the antimetastatic effect in malnourished animals is due to the inhibition of neovascularization necessary for the beginning of metastatic exponential growth. The induction of neovascularization may be caused by the tumor necrosis factor, main product of activated macrophages.

The influence of drugs improving sympathoadrenal system status on natural killer (NK) functional activity was studied in lung cancer patients. The activity of adenosine-metabolizing enzymes (adenosine deaminase and 5'-nucleotidase) in NK cells was found significantly altered, suggesting the involvement of this phenomenon in decreasing NK activity under tumor growth. Pharmacological correction of sympathoadrenal system status was followed by an increase in NK functional activity in lung cancer patients.

In mice with metastasizing tumors that received a reduced (by 30-40%) daily ration, suppression of neovascularization processes and normalization of macrophage function were recorded: activity of macrophages in the area of the metastatic growth increased, while activity of macrophages suppressing T-lymphocytes in the spleen was decreased. It has been suggested that these effects play a role in the phenomenon observed by the authors--suppression of the metastatic processes in the test mice kept on a reduced food ration.

Data on the participation of macrophages in the control of tumour growth and metastatic spreading are presented. Information about the macrophage activation and secretion of soluble cytotoxic factors is given. Certain biochemical mechanisms related to the antimetastatic activity of macrophages are presented. A conclusion is drawn on the possibility of macrophages to stimulate the tumour growth in certain cases. This possibility should be taken into account during the antimetastatic therapy with macrophage activators.

Adenosine deaminase and 5'-nucleotidase activities as well as chemiluminescence emission were measured in peritoneal macrophages of Syrian hamsters in the growth process of tumours with different grade of malignancy. The adenosine deaminase activity was established to decrease, while the 5'nucleotidase activity--to increase in macrophages after the subcutaneous injection of tumour cells with high level of malignancy as compared with these values in normal cells. This is accompanied by a decrease of the macrophage chemiluminescence during the whole experimental period. At the same time adenosine deaminase and 5'-nucleotidase activities as well as chemiluminescence emission in peritoneal macrophages of hamsters treated with low-malignancy cells do not differ from these values in the control group.

Experiments in vitro were made to study adenosine deaminase (ADA) and 5'-nucleotidase (5-N) activity in NK after their treatment with interferon inductor--Newcastle disease virus (NDV) or with prostaglandin E2 (PGE2). It has been established that treatment of human NK with NDV leads to increasing of their cytotoxic activity (CTA), which is accompanied by rising of ADA activity and reducing of 5-N activity in these cells. Decrease of CTA under the influence of PGE2 occurs together with reduction of ADA activity and increase of 5-N activity in human NK. Changes in NK activity under the influence of various exogenous or endogenous factors may be due to the modification of activity of adenosine metabolism enzymes in these cells.

A correlation between reactions of the sympathoadrenal system and the activity of adenosine transformation enzymes in lymphocytes is demonstrated in the dynamics of metastatic Lewis carcinoma development in C57Bl mice. In the period when metastases arise a decrease in the adenosine deaminase activity in lymphoid cells of the thymus and spleen is accompanied by drop in the content of DOPA, noradrenalin and adrenalin in adrenals. At the late stages of the tumour process a decrease in the amount of these compounds in adrenals is accompanied by the diminution of the adenosine deaminase activity and by an increase in the 5'-nucleotidase activity in the thymus. Contrary changes are observed in spleen lymphocytes. The revealed disturbances may stimulate to a considerable extent the appearance and growth of metastases.

Studies on the action of adenine nucleotides on the Con A-induced blast transformation of rat thymocytes have shown that addition of milimolar concentrations of AMP and ADP to the cultural medium as well as that of adenosine produce an inhibitory effect on the reaction. Addition to the cells of adenosine deaminase almost completely abolishes this effect. Unlike the nucleotides, the suppressant effect of ATP on thymocyte proliferation is less pronounced and is not reversed by addition of adenosine deaminase. cAMP and ATP given in the concentrations sufficient for giving rise to the protein kinase reaction and ammonium ions (1 mM) have no effect on thymocyte blast transformation. The latter is appreciably suppressed by 1 mM pyrophosphate and almost completely by papaverine and curantyl. The nucleotides added to the thymocytes get dephosphorylated, however, extracellular adenosine is not accumulated during 80 minutes, its concentration being of the order of 10(-6) M.

The adenosine deaminase, 5'-nucleotidase, AMP-aminohydrolase and adenylate kinase activities and thymostimulin influence on these indices in vivo were studied in rat thymus and spleen lymphocytes in the latent period of DMBA-induced mammary carcinogenesis. The adenosine deaminase activity was established to increase while 5'-nucleotidase and AMF-aminohydrolase activity to decrease in the thymocytes of intact animals treated with thymostimulin; the adenylae kinase activity of spleen lymphocytes decreased as compared with that in the rats not treated with the preparation. The dynamics of changes in the investigated enzymes in activities in lymphocytes was of wave-like pattern in the latent period. The treatment of animals with thymostimulin in this period normalized adenosine deaminase activity and decreased the activity of the other enzymes in these cells.

Surgical operation of metastatic Lewis carcinoma, carried out in male mice of C57B1 strain, which stimulated distinctly the metastases spreading, was accompanied by phase impairments in activities of adenosine deaminase and 5'-nucleotidase in immunocompetent cells correlating with neurochemical stressory reactions. Thus, excessive stressory alterations in activity of symptoadrenal and hypothalamic mediatory systems appear to be among the factors responsible for inhibition of metabolism in lymphoid cells and for stimulation of metastatic spreading.

It has been established that N-acetylglucosaminyl-N-acetylmuramyl-L-alanyl-D-isoglutamine (GMDP), a new synthetic analog of muramyl dipeptide, while incubated in vitro with macrophages essentially inhibits 5'-nucleotidase (5-N) activity without any influence on the activity of adenosine deaminase in these cells. The maximal effect was recorded 24 h after co-incubation. As 0.01 = 1 microgram/ml concentration of GMDP was added, the enzyme activity gradually decreased to minimum. L-D-isomer of GMDP was shown to affect 5-N activity whereas the effect of its analog with a double peptide chain GM (DP)2 was found to be less. Inhibition of 5-N activity may be one of the mechanisms by which macrophages are activated under the influence of GMDP.

The influence of a new, liposome-encapsulated muramyldipeptide analog--GMDP--on Lewis lung carcinoma spreading was studied in mice in which primary tumor had been removed. The drug was found to significantly decrease the extent and number of lung metastases, as compared to mice which had not received GMDP. This was matched by recovery of alveolar and splenic macrophages functional activity, as assessed by adenosine deaminase and 5'-nucleotidase levels in these cells.

The antimetastatic action of bacterial endotoxins (BET), E. coli 0111:B4, B in particular, as well as their influence on the adenosine deaminase and 5'-nucleotidase activity were studied in peritoneal macrophages of mice bearing lung Lewis carcinoma. BET inhibition of lung metastasis growth was found to be due to such changes in macrophage adenosine metabolism, that testifies to the rise of their functional activity. The change in the level of macrophage purine metabolism can be considered as an important evidence of the effectiveness of the drugs capable to inhibit the metastasis growth.

Liposomes of different composition and N-acetylglucosaminyl-N-acetylmuramyl-L-alanyl-D-isoglutamine (GMPD) encapsulated in them are studied for their effect on the functional activity of macrophages by means of determining the 5'-nucleotidase and adenosine deaminase activity in the in vivo experiments. It is shown that both liposomes and GMDP encapsulated in them increase the activity of adenoside deaminase and decrease that of 5'-nucleotidase. This evidences for a change in the adenosine metabolism in the alveolar and peritoneal macrophages and an increase in the functional activity of cells which resulted from that rise. The manifestation of the process depends both on the lipid composition of liposomes and their charge. The observed increase in the functional activity of the alveolar macrophages under the effect of liposomes and GMDP encapsulated in them correlates with inhibition of the lung metastases development in mice.

Adenosine deaminase (ADA) and 5'-nucleotidase (5'-N) activity and cytotoxic activity (CTA) of natural killer cells (NK-cells) isolated from human peripheral blood were studied. These cells were affected by culture medium obtained after the contact of tumour cells with NK-cells, the degree of malignancy in these cells being different. It has been established that pretreatment of NK-cells with culture medium from highly malignant cells and containing PGE, causes a sharp inhibition of their CTA, which is accompanied by an essential decrease of the ADA activity and an increase of the 5'-N activity in these cells as compared with the control.

The procedure for obtaining the CL-C5 suspension cell line from the transplantable rat leukemia (erythromyelosis) is described. Cytochemical and biochemical features of CL-C5 blast cells are established to be typical of T-cells at the differentiation stage, corresponding to thymocytes. The results obtained permit considering CL-C5 cell line as that having phenotypical indications of lymphocytes and retrovirus production lost due to the selection in the cell population.

N-acetylglucosaminyl-N-acetylmuramyl-L-alanyl-D-isoglutamine (GMDP), a new liposome-encapsulated muramyl dipeptide analog, was studied for its effect on the Lewis lung carcinoma metastatic spreading as well as on the adenosine deaminase (ADA) and 5'-nucleotidase (5-N) activity in the alveolar and peritoneal mice macrophages. The drug administration was found to cause a sharp dose-dependent decrease in the lung metastases volume and number as compared to those in mice not treated with GMDP. The antimetastatic effect of GMDP is accompanied by an increase in the functional macrophage activity determined by ADA and 5-N level in these cells.