Effects of Medicinal Fungi-Derived β-Glucan on Tumor Progression

β-Glucans have been studied in animal species, from earthworms to humans. They form a heterogenous group of glucose polymers found in fungi, plants, bacteria, and seaweed. β-Glucans have slowly emerged as an important target for the recognition of pathogens. In the current review, we highlight the major roles of mushroom-derived β-glucans on cancer progression.

Lysosomotropic Features and Autophagy Modulators among Medical Drugs: Evaluation of Their Role in Pathologies

The concept of lysosomotropic agents significantly changed numerous aspects of cellular biochemistry, biochemical pharmacology, and clinical medicine. In the present review, we focused on numerous low-molecular and high-molecular lipophilic basic compounds and on the role of lipophagy and autophagy in experimental and clinical medicine. Attention was primarily focused on the most promising agents acting as autophagy inducers, which offer a new window for treatment and/or prophylaxis of various diseases, including type 2 diabetes mellitus, Parkinson's disease, and atherosclerosis. The present review summarizes current knowledge on the lysosomotropic features of medical drugs, as well as autophagy inducers, and their role in pathological processes.

The Pluripotency Factor Nanog Protects against Neuronal Amyloid β-Induced Toxicity and Oxidative Stress through Insulin Sensitivity Restoration

Amyloid β (Aβ) is a peptide fragment of the amyloid precursor protein that triggers the progression of Alzheimer's Disease (AD). It is believed that Aβ contributes to neurodegeneration in several ways, including mitochondria dysfunction, oxidative stress and brain insulin resistance. Therefore, protecting neurons from Aβ-induced neurotoxicity is an effective strategy for attenuating AD pathogenesis. Recently, applications of stem cell-based therapies have demonstrated the ability to reduce the progression and outcome of neurodegenerative diseases. Particularly, Nanog is recognized as a stem cell-related pluripotency factor that enhances self-renewing capacities and helps reduce the senescent phenotypes of aged neuronal cells. However, whether the upregulation of Nanog can be an effective approach to alleviate Aβ-induced neurotoxicity and senescence is not yet understood. In the present study, we transiently overexpressed Nanog-both in vitro and in vivo-and investigated the protective effects and underlying mechanisms against Aβ. We found that overexpression of Nanog is responsible for attenuating Aβ-triggered neuronal insulin resistance, which restores cell survival through reducing intracellular mitochondrial superoxide accumulation and cellular senescence. In addition, upregulation of Nanog expression appears to increase secretion of neurotrophic factors through activation of the Nrf2 antioxidant defense pathway. Furthermore, improvement of memory and learning were also observed in rat model of Aβ neurotoxicity mediated by upregulation of Nanog in the brain. Taken together, our study suggests a potential role for Nanog in attenuating the neurotoxic effects of Aβ, which in turn, suggests that strategies to enhance Nanog expression may be used as a novel intervention for reducing Aβ neurotoxicity in the AD brain.

Hypolipidemic Effects of β-Glucans, Mannans, and Fucoidans: Mechanism of Action and Their Prospects for Clinical Application

The search for lipid-lowering drugs is important for clinical medicine. This review summarizes our research findings regarding the hypolipidemic activity of polysaccharides. There are several validated agents altering lipid levels which reduce the risk of atherosclerotic cardiovascular events. Nonetheless, for many people, the risk of such an event remains unacceptably high despite treatment with these agents. This situation has prompted the search for new therapies to reduce the residual cardiovascular risk. The lipid-lowering effect of β-glucans consumed with food was demonstrated in patients with atherosclerosis. The mechanism of the protective effect of β-glucans is poorly studied. The effects of β-glucans are mediated by Toll-like receptors, by dectin-1, and possibly by other receptors. Nevertheless, the mechanism of the protective action of β-glucan in lipemic mice has been studied insufficiently. This review will present up-to-date information regarding experimental hypolipidemic polysaccharide compounds that hold promise for medicine. Phagocyte-specific chitotriosidase in humans contributes to innate immune responses against chitin-containing fungi. This enzyme has been first described in patients with Gaucher disease and serves as an important diagnostic biomarker. It has been reported that, in mice, chitin particles of certain size are recognized by macrophages through Toll-like receptors, dectin-1, and to a lesser extent through mannose receptor.

Glucan and Mannan-Two Peas in a Pod

In recent decades, various polysaccharides isolated from algae, mushrooms, yeast, and higher plants have attracted serious attention in the area of nutrition and medicine. The reasons include their low toxicity, rare negative side effects, relatively low price, and broad spectrum of therapeutic actions. The two most and best-studied polysaccharides are mannan and glucan. This review focused on their biological properties.

GLP-1 Analogue Liraglutide Attenuates Mutant Huntingtin-Induced Neurotoxicity by Restoration of Neuronal Insulin Signaling

Huntington’s disease (HD) is a progressive and fatal neurodegenerative disease caused by CAG repeat expansion in the coding region of huntingtin (HTT) protein. The accumulation of mutant HTT (mHTT) contributes to neurotoxicity by causing autophagy defects and oxidative stress that ultimately lead to neuronal death. Interestingly, epidemiologic studies have demonstrated that the prevalence of type-2 diabetes, a metabolic disease mainly caused by defective insulin signaling, is higher in patients with HD than in healthy controls. Although the precise mechanisms of mHTT-mediated toxicity remain unclear, the blockade of brain insulin signaling may initiate or exacerbate mHTT-induced neurodegeneration. In this study, we used an in vitro HD model to investigate whether neuronal insulin signaling is involved in mHTT-mediated neurotoxicity. Our results demonstrated that mHTT overexpression significantly impairs insulin signaling and causes apoptosis in neuronal cells. However, treatment with liraglutide, a GLP-1 analogue, markedly restores insulin sensitivity and enhances cell viability. This neuroprotective effect may be attributed to the contribution of the upregulated expression of genes associated with endogenous antioxidant pathways to oxidative stress reduction. In addition, liraglutide stimulates autophagy through AMPK activation, which attenuates the accumulation of HTT aggregates within neuronal cells. Our findings collectively suggest that liraglutide can rescue impaired insulin signaling caused by mHTT and that GLP-1 may potentially reduce mHTT-induced neurotoxicity in the pathogenesis of HD.

Hypolipidemic effect of mannans from C. albicans serotypes a and B in acute hyperlipidemia in mice

Mannans, which are biological macromolecules of polysaccharide origin and function as immunomodulators, have been shown to stimulate macrophages in vivo by interaction with the mannose receptor. Thus, they can be used to stimulate macrophages in order to effectively remove circulating atherogenic lipoproteins. Our primary aim was to evaluate the hypolipidemic potential of mannans from C. albicans serotype A (mannan A) and serotype B (mannan B) in a murine model of hyperlipidemia. Mannan A and mannan B were shown to significantly (p<0.05) stimulate both the proliferation (p <0.05) and nitric oxide production of murine peritoneal macrophages in vitro. Pre-treatment of CBA/Lac mice with mannan A prior to induction of hyperlipidemia significantly (p<0.001) reduced serum atherogenic LDL-cholesterol, total cholesterol, and triglycerides. Mannan B exhibited a similar, but more potent, hypolipidemic effect. Electron microscopic analysis of liver revealed a significant (p<0.001) decrease in the volume of lipid droplets when hyperlipidemic mice were pretreated by both mannans. In conclusion, our findings would suggest that both polysaccharide-based biological macromolecules evaluated in the present study, specifically, the natural immunomodulators (mannans A and B), appeared to function as effective lipid-lowering macromolecules, which could potentially serve as adjunct therapy to more conventional hypolipidemic medications such as a statin drug.

Cystatin C as a Marker of Progressing Cardiovascular Events during Coronary Heart Disease

The role of cystatin C, an inhibitor of cysteine proteases, as an alternative and potent predictor of acute cardiovascular events in coronary heart disease (CHD) patients was examined and compared to that of other markers of cardiorenal abnormalities. The patients with CHD demonstrated elevated serum cystatin C, especially in cases with serious risk of cardiovascular complications. In comparison with other indicators of cardiorenal dysfunction, cystatin C can be viewed as an alternative predictor of cardiovascular complications, although its sensitivity is inferior to that of high-sensitivity C-reactive protein and natriuretic peptide.

Effects of Anti-CD206 Antibodies on Macrophage Functions in Male CBF1 Mice with Lipidemia

The effects of anti-CD208 antibodies (mannose receptor) on functional characteristics of peritoneal macrophages were studied in intact mice and mice with lipidemia induced by poloxamer-407. Lipidemia was associated with suppression of phagocytosis and increase in spontaneous proliferative potential and NO production by macrophages. Anti-CD206 antibodies suppressed NO production by macrophages in mice with lipidemia.

Hypolipidemic Effect of Mannan in Mice with Acute Lipemia Induced by Poloxamer 407

We studied biological effects of mannan, a polysaccharide immunomodulator from C. albicans, that interacts with mannose receptor in vivo. It is shown that preliminary administration of mannan (5 times in a dose of 50 mg/kg or 2 times in a dose of 100 mg/kg) to mice with acute lipemia induced by lipase inhibitor poloxamer 407 (300 mg/kg) reduces the serum concentrations of atherogenic LDL, cholesterol, and triglycerides. Administration of mannan to intact mice and animals with acute lipemia reduces triglyceride concentration and causes labilization of lysosomal membranes in the liver. Serum activity of chitotriosidase, a marker of macrophage activation, was elevated in mice with acute lipemia treated with mannan. Thus, mannan from C. albicans is a promising hypolipidemic polysaccharide compound, similar by its activity to β-glycan, a component of LPS.

[A Therapeutic Target for Inhibition of Neurodegeneration: Autophagy]

The role of autophagy in cell survival and suppression of neurodegeneration was considered. We discussed its involvement in Alzheimer's, Parkinson's, and Huntington's diseases connected with accumulation of amy- loid-β, α-synuclein, and huntingtin, respectively. Autophagy is reduced in these diseases and in aging as well to various extent. Elimination of accumulated toxic proteins and structures is performed by autophagy mech- anisms (chaperon-mediated autophagy, macroautophagy, selected autophagy) in an interaction with ubiqui- tin-proteasome system. In many cases activation of mTOR-dependent autophagy and mTOR-independent regulatory pathways lead to the therapeutic effect of inhibition of neurodegeneration in cell cultures and an- imal models. Some autophagy enhancers such as resveratrol, metformin, rilmenidine, lithium, and curcumin are tested now in clinical trials.

Ratio of Active Matrix Metalloproteinases and Proenzymes during Growth and Metastasizing of Mouse Lewis Lung Adenocarcinoma

Ratio between proMMP and active MMP was studied in the dynamics of growth of the Lewis lung adenocarcinoma with lung metastasis. It was shown that tumor growth is associated with an increase in the content of proMMP (day 20; terminal stage), but the level of active MMP in tumor tissue did not signifi cantly change. The development of lung metastasis was accompanied by accumulation of active MMP (days 7, 15, and 20) and a decrease in the content of pro-MMP (days 7, and 20) in comparison with the control. In the spleen of these mice (metastasis-free organ), an increase in the levels of proMMP (day 20) and especially active MMP (days 7, 15, and 20) were found. The results suggest that tumor development shifts the proportion between active MMP and proenzymes in the tumor, lungs with metastasis, and spleen without metastasis.

[Effect of statins on activity of matrix metalloproteases and serum concentration of cystatin C in patients with various risk of development of ischemic heart disease and in patients after coronary artery bypass surgery]

We compared new non-lipid atherosclerosis indexes related to inflammation and macrophage stimulation (serum concentration of cystatin C, matrix metalloproteases and chitotriosidase activity) with common inflammatory (high sensitivity C reactive protein) and lipid markers in elderly persons and patients with atherosclerosis and ischemic heart disease who have undergone coronary bypass surgery.

Fractional composition of blood serum lipoproteins in mice and rats with Triton WR 1339-induced lipemia

We compared fractional composition of blood serum lipoproteins (LP) in female ICR mice and Wistar rats induced by single administration of a nonionic detergent Triton WR 1339 in doses of 300 and 500 mg/kg. Lipemia in animals of both species was characterized by a sharp increase in the concentration of cholesterol and, particularly, of triglycerides in blood serum lipoproteins by the 24th hour after administration of the detergent. We revealed a significant increase in the concentrations of atherogenic VLDL cholesterol (due to VLDL2), intermediate density lipoproteins, and LDL. These changes were more pronounced in rats. The model of lipemia can be used to study the role of fractional composition of lipoproteins and, particularly, of triglycerides in the pathogenesis of atherosclerosis. Moreover, this model holds much promise for evaluation of the efficiency of hypolipidemic drugs (statins and fibrates) in normalizing the increased level of atherogenic cholesterol of VLDL and LDL.

[Effect of macrophage stimulators on development of selective depression of liver macrophage in vivo]

A single administration of zymosan (50 mg/kg) and chito-carboxymethylated glucan (25 mg/kg) to mice was shown to improve the selective liver macrophage depression induced by gadolinium chloride (7.5 mg/kg, intravenous administration). Both beta-1,3-glucans (ChitoCMG and CMG) studied revealed the signs of liver macrophage stimulation: increased number and phagocytic activity of liver macrophages and increased serum chitotriosidase activity. The model of selective liver macrophage depression was characterized by decreased activity of serum chitotriosidase. ChitoCMG as well as zymosan increased the uptake of gadolinium by liver cells during preliminary (before gadolinium chloride) administration of beta-1,3-glucans. It was concluded that the model of selective liver macrophagedepression is useful for studying the protective effects of biological response modifiers such as polysaccharides (beta-1,3-glucans) in vivo.

[The lysosomal cathepsins B, L and D in development of murine experimental leukemias]

Lysosomal proteases are actively involved in pathogenesis of cancer progression. Alterations in proteases and their inhibitors interaction were suggested to be implicated in the processes of tumor invasion and metastasis. Among proteases connected with malignant growth, cysteine cathepsins B and L and aspartic cathepsin D play the main role in the tumor development. The present study was designed to investigate activity of cathepsins B, L and D activity in the development and treatment of murine experimental leukemias and to determine the correlation of these proteases with tumor malignancy and the chemotherapy effect. P-388 leukemia was characterized by a more aggressive development and unfavorable prognosis than L1210/1 leukemia. The activity of cathepsins B, L and D in tumor tissues of mice infected with P-388 leukemia, as well as in liver and spleen and the activity of cathepsins B and L in serum were lower than their activity in mice infected with L1210/1 leukemia. Changes of cathepsin activity in liver and spleen of mice with leukemias have demonstrated a level of aggressiveness of tumor development and invasion of liver and spleen by neoplastic cells. The treatment resulted in the increase of cathepsin B, L and D activities in tumor tissue, liver, spleen and cathepsin B and L activities in serum. The highest activity of proteases was revealed in the groups of mice characterized by the greatest suppression of tumor growth. These data have shown that lysosomal proteases are involved in progression of murine experimental leukemias and elimination of tumor cells in the result of treatment. Determination of the activity of cysteine and aspartic proteases can be used for evaluation of cancer diseases malignancy, their sensitivity for chemotherapy and efficiency of treatment.

[The role of changes in matrix metalloproteases and chitotriosidase in the mechanism of protective effect of atorvastatin in experimental murine lipemia]

The effect of atorvastatin on the activity of chitotriosidase (CTO) and total matrix metalloproteases (MMPs)-new markers of cardiovascular disorder-was studied on the model of murine lipemia induced by single administration of Triton WR 1339 in two doses, 500 mg/kg (mild lipemia) and 850 mg/kg (severe lipemia). A hypolipidemic effect of atorvastatin was observed in mice with mild lipemia, but not in those with severe lipemia. In both mild and severe lipemia cases, the serum CTO activity was increased upon the combined administration of atorvastatin and Triton WR 1339, correlating with cholesterol and triglyceride concentration. The total serum MMP activity decreased only in experiments with atorvastatin administration to intact mice. In mice with experimental lipemia induced by Triton WR 1339, the administration of atorvastatin also increased the ALT and AST activity in the blood serum.

In vivo effect of selective macrophage suppression on the development of intrahepatic cholestasis in mice

We studied the role of selective suppression of liver Kupffer cells (gadolinium chloride, 14 mg/kg intravenously) in the development of intrahepatic cholestasis in CBA/C57B1/6 mice after intraperitoneal injection of alpha-naphthylisothiocyanate in a single dose of 200 mg/kg. Pretreatment with gadolinium chloride increased the severity of cholestasis and signs of liver damage. Gadolinium accumulation in the liver peaked after 24 h and was accompanied by a decrease in activities of cathepsin D and cathepsin B and concentration of matrix metalloprotease-2. Our results confirm the hypothesis that normal function of Kupffer cells and extracellular matrix plays an important role in cholestasis. Administration of gadolinium chloride serves as a convenient model to study the side effects, toxicity, and safety of lanthanides as nanoparticles.

[Chitotriosidase of human macrophages and mammalian chitinases: biological functions and abnormalities in pathology]

Recently discovered human chitotriosidase is a member of chitinase family capable to hydrolyze chitin, a polymer of N-acetylglucosamine. Serum and plasma chitotriosidase activity is usually measured as the first step in diagnosis of Gaucher disease. Monitoring chitotriosidase activity is widely used during treatment of this pathology by enzyme replacement therapy. Its elevated plasma level reflects gradual intralysosomal accumulation in Gaucher cells (lipid-loaded macrophages). Macrophages overloaded by the enzyme accumulated in lysosomal material (lipids) were shown to secrete chitotriosidase; its increased expression was noted in several lysosomal storage diseases and atherosclerosis. We observed enhanced chitotriosidase activity in healthy young and elderly persons probably associated with the development of atherosclerosis and plaque formation. Chitotriosidase is believed to play a role in mechanisms of immunity and protection against chitin-containing pathogens.

[Prognostic significance of lysosomal cysteine proteases in the estimation of the effectiveness of the antitumorigenic therapy]

The influence of the untitumor drugs, cyclophosphamide (CPA) and nitrosomethylurea (NMM) on the activity of lysosomal cysteine proteases cathepsin B and L in the tumor tissue was studied. Regression or reduction in the rate of growth of LS and RLS (drug sensitive and resistant sarcomas, respectively) during injection of CPA or NMM was accompanied by the increase in the activity of cysteine proteases cathepsin B and L in the tumor tissue. The increase of cathepsin B and L activity in the tumor tissue was correlated with the therapeutic effect of the used drugs. Data obtained suggest that cathepsin B and L activity in the tumor tissue have a prognostic significance for the effectiveness of antitumor therapy.

[Cystatins: cysteine proteases regulation and disturbances in tumors and inflammation]

Cystatin C belongs to the group of wide spread extracellular cysteine protease inhibitors. Using ELISA kits it was shown that the highest cystatin C concentration was in human cerebrospinal fluid and low cystatin C concentration was in human urine. In healthy young persons serum cystatin C concentration was lower than in elder patients (50-65 year old). In patients with hemoblastoses (lymphoma, lymphogranulomatosis) increased serum cystatin C concentration was normalized after effective antitumor therapy. According to these data one can conclude that serum cystatin C concentration can be used as one of the prognostic criteria in patients with several kinds of hemoblastoses.

[Cystatins: biological role and changes in pathology]

Cystatins are new recently discovered group of endogenous inhibitors of cysteine proteases. Their biological role is under investigation now. Cystatin C, belonging to type 2 of cystatins superfamily, was found practically all cell types. Cystatin C is the most effective inhibitor of lysosomal cysteine proteases. Intracellular functions of cystatins are associated with cell proliferation, differentiation, ageing and death, antigen presentation. The role of cystatin C as a marker of tumors and atherosclerosis is discussed.

Yeast cell wall polysaccharides as antioxidants and antimutagens: can they fight cancer?

Polysaccharides represent the major part of the yeast cell wall dry weight and build the skeletal carcass defining cell wall stability and cell morphology (beta-D-glucans) or constitute amorphous matrix and cell surface fibrous material (mannans and mannoproteins). It is known that yeast cell wall beta-D-glucans reveal immunomodulating properties, which allows for their application in anti-infective and antitumor therapy. Recent data also suggest that polysaccharides reveal antioxidant activity that can result in their protective function as antioxidants, antimutagens, and antigenotoxic agents. The paper provides a review of our continuing research involving water-soluble derivatives of beta-D-glucan isolated from the baker's yeast Saccharomyces serevisiae and of a glucomannan isolated from the industrial yeast Candida utilis. The results are confronted with the available literature data. The derivatives of beta-D-glucan demonstrated potent inhibitory effect on lipid peroxidation comparable to that of the known antioxidants and exerted DNA protection from oxidative damage. The free radical scavenging activity was confirmed by spin-trap electron paramagnetic resonance. Antimutagenic and antigenotoxic activity of the yeast polysaccharides was demonstrated using yeast, bacterial, and algal models. The derivatives of beta-D-glucan exerted potent enhancement of tumor necrosis factor alpha (TNF-alpha) released from murine macrophages and revealed synergistic effect with cyclophosphamide in the treatment of Lewis lung carcinoma and two types of lymphosarcoma in murine models. The results indicate significant protective antioxidant, antimutagenic, and antigenotoxic activities of the yeast polysaccharides and imply their potential application in anticancer prevention/therapy.

[Cystatin C: a biological role and impaired secretion in viral hepatitis c and hepatic cirrhosis]

Cystatin C is a non-glycated cationic protein with a molecular weight of 13.3 kD, which belongs to the superfamily of cystatins; its basic function is to inhibit and regulate the activity of cysteine proteinase. In apparently healthy individuals, the extracellular concentration of cystatin C is shown to be substantially higher in serum than in urine and bile. The increased serum concentration of cystatin C has been found in the development of chronic viral hepatitis C, and hepatic cirrhosis in particular, which reflects the development of an inflammatory process and, evidently, the higher secretion of cystatin C by stimulated macrophages.

Intralysosomal accumulation of gadolinium and lysosomal damage during selective depression of liver macrophages in vivo

Kinetics of gadolinium accumulation was studied by inductively coupled plasma-emission spectroscopy after intravenous injection of this agent (7.5 mg/kg) to CBA mice. Gadolinium exhibits lysosomotropic properties (long-term selective accumulation in lysosomes in vivo). Gadolinium uptake by hepatic cells attained maximum 1 h after its intravenous injection and remained at this level during the next day. Accumulation of gadolinium in hepatocytic lysosomes disturbed their osmotic properties (as was seen from the increase in free acid phosphatase activity, which persisted for 19 days). Serum activities of beta-D-galactosidase and beta-D-glucuronidase also increased (24-72 h and day 19). Selective depression of liver macrophages (24-48 h) was accompanied by a decrease in serum chitotriosidase activity. We conclude that accumulation of gadolinium in lysosomes of liver macrophages leads to their damage and elimination of a certain population of macrophages (primarily large cells). Changes in activity of serum lysosomal enzymes also reflect repopulation of liver macrophages.

Antitumor and antimetastatic activity of fucoidan, a sulfated polysaccharide isolated from the Okhotsk Sea Fucus evanescens brown alga

Antitumor and antimetastatic activities of fucoidan, a sulfated polysaccharide isolated from Fucus evanescens (brown alga in Okhotsk sea), was studied in C57Bl/6 mice with transplanted Lewis lung adenocarcinoma. Fucoidan after single and repeated administration in a dose of 10 mg/kg produced moderate antitumor and antimetastatic effects and potentiated the antimetastatic, but not antitumor activities of cyclophosphamide. Fucoidan in a dose of 25 mg/kg potentiated the toxic effect of cyclophosphamide.

Influence of opiate addiction on liver cell damage of patients with viral hepatitis C

Liver functional tests, cholestasis development and serum acute phase proteins, including a-1-proteinase inhibitor (PI) and albumin level (negative reactant of acute phase proteins), C-reactive protein (CRP) have been studied in the patients with viral hepatitis C (HCV) and/or drug addictive disorders (crude home-made opiates). Narcotic drugs were shown to be responsible for aggravation of cholestasis development in HCV patients with opiate addiction. Decreased albumin concentration in serum was registered in all groups with drug addictive disorders, as a result of modified acute phase reaction.

Enhancing effect of new biological response modifier sulfoethylated (1-->3)-beta-D-glucan on antitumor activity of cyclophosphamide in the treatment of experimental murine leukoses

AIM

One of the advanced methodologies of the tumor therapy is the application of the so-called biological response modifiers used for activation of the endogenous antitumor mechanisms and combined with classical cytotoxic agents. The aim of this work was the investigation of the effect of sulfoethylated (1-->3)-beta-D-glucan (SEG) in the treatment of experimental murine leukoses in combination with cyclophosphamide (CPA) and its ability to modulate the activity of lysosomal enzymes in tumor tissues.

MATERIALS AND METHODS

The solid forms of inoculated murine leukoses P388 and L1210/1 were transplantated to male DBA/2 mice. The therapy was performed by treating animals with CPA (Biokhimik, Saransk, Russia) alone or in combination with SEG (Institute of Chemistry, Slovak Academy of Sciences, Slovakia). CPA was administered in saline as a single intraperitoneal (ip) injection on the 10th day after tumor transplantation; SEG was administered to mice ip 3 days after tumor transplantation with the intervals in 3 days. The therapy effect was estimated by measuring of solid tumor volume. Activity of the cysteine proteases--cathepsins B and L--was measured fluorometrically using fluorescent substrates Z-Arg-Arg-MCA and Z-Phe-Arg-MCA (Sigma, USA), respectively. The apoptosis was estimated evaluating the number of cells with fragmented nuclei using optical microscope.

RESULTS

It has been demonstrated that application SEG leads to inhibition of tumor growth and potentiates therapeutic action of CPA, especially at repeated administrations during the whole treatment/observation At addition of SEG, therapeutic effect of a one-half reduced dose of CPA is equal or higher than that of the full dose. Therapeutic action of CPA and SEG on the studied tumors is realized predominantly through induction of apoptosis and is accompanied by a substantial increase of the activity of cysteine proteases cathepsins B and L in tumor tissues. The highest cathepsin B and cathepsin L activity in tumor tissue accompanied with the strongest inhibition of tumor growth. It is suggested that this phenomenon is due to the infiltration of the macrophages rich in the named enzymes into the tumor, where they phagocytize the apoptotic cells and tissue debris.

CONCLUSION

Utilization of this polysaccharide BRM, sulfoethylated (1-->3)-beta-D-glucan, might potentially enhance efficiency of antitumor therapy with standard cytostatics without a need of substantial increase of their dosage and hence avoiding their toxic side-effects.

[Effect of biological response modifier sulfoethylated (1 --> 3)-beta-D-glycan on the experimental leukemia in mice]

Sulfoethylated (1 --> 3)-beta-D-glycan (SE-glycan) is a well-known biological response modifier, which activates the immune system via the influence on macrophages and lymphocytes. In these experiments, SE-glycan suppressed the growth of solid transplants of leukemias P-388 and L1210/1 in mice and, when combined with cyclophosphamide, significantly potentiated its action. The administration of SE-glycan allowed the cyclophosphamide dose to be reduced by half without negatively influencing the curative effect. The proposed treatment also led to an increase in the activity of lysosomal proteases (cathepsins B, L and D) in tumor tissues. The extent of changes was in direct relation to the therapeutic effect.

Stimulation of macrophages increases, while suppression of these cells inhibits metastatic dissemination of two transplantable mouse tumors in the liver and lungs

Stimulation of mouse tissue macrophages with carboxymethylated beta-(1-->43)-D-glycan 1 day before intravenous injection of tumor cells increased the number and weight of implants (experimental metastases) of mouse hepatocarcinoma and adenocarcinoma in the liver and lungs, respectively. Suppression of liver macrophages with gadolinium chloride or sequestration of cells during intraperitoneal administration of macrophage attractants inhibited metastatic dissemination of hepatocarcinoma and adenocarcinoma in the liver and lungs, respectively. In the latter case animal lifespan increased. Our results indicate that at certain stages of metastatic dissemination, activation of mononuclear phagocytes can stimulate the formation and growth of metastases.

Effect of Cysteine Protease Inhibitor Ep-475 on TNF-α-Independent Cyclophosphamide-Induced Apoptosis in Mouse Lymphosarcoma LS Cells

Cyclophosphamide 1.5-2.0-fold increased activity of cathepsins B and L in tumor tissue of mouse lymphosarcoma LS and caused tumor regression. The effect was most pronounced on day 5 after treatment. Twofold treatment with a selective cathepsin inhibitor Ep-475 slightly stimulated tumor growth in control mice and significantly reduced the antitumor effect of cyclophosphamide. Lysosomal cysteine proteases cathepsins B and L are involved, but do not play a key role in TNF-alpha-independent apoptosis in LS cells induced by cyclophosphamide.

Cystein proteinase inhibitor stefin A as an indicator of efficiency of tumor treatment in mice

The concentration of stefin A (cystatin A in mice) was measured in animals with experimental tumors (LS lymphosarcoma, HA-1-hepatoma, and Lewis lung carcinoma) during effective antitumor therapy. In mice with these tumors serum concentrations of stefin A increased, while the concentration of cystatin C (extracellular cystein proteinase inhibitor) decreased. The concentration of stefin A in tumor tissue in Lewis lung carcinoma was higher than in LS lymphosarcoma and HA-1-hepatoma ascitic cells, which can be explained by the degree of their malignancy. The content of stefin A in tumor tissue was similar to that in the liver and spleen of tumor-bearing animals, while its concentration in the liver and spleen of tumor-bearing animals was lower than in intact mice. The level of stefin A is an important marker of malignancy and an indicator of the efficiency of antitumor therapy.

Effect of liver macrophage depression on the development of liver metastases of HA-1 tumor in mice

Gadolinium chloride (5 mg/kg) administered to mice 24 h before intravenous transplantation of HA-1 hepatoma cells decreased the volume density of tumor implants in the liver, reduced the intensity of degenerative and necrotic changes developing under the effect of growing tumor metastases, and prolonged the life span of tumor-bearing mice. Development of metastases was not associated with changes in cathepsin B activity in the liver, while activity of cathepsin L decreased only during the early period (4 days) after injection of gadolinium chloride. Injection of gadolinium chloride led to labilization of liver cell lysosomes because of overload with gadolinium chloride particles. The positive effect of gadolinium chloride was probably associated with depression of liver macrophages at the stage of tumor cell invasion and with subsequent migration of monocytes/macrophages preventing the growth of formed metastatic nodes in the liver.

Effect of polysaccharides and human plasma lipoproteins on the secretion of cystatin C by peritoneal macrophages from normal and tumor bearing mice

Intact peritoneal macrophages in vitro secreted the cysteine proteinase inhibitor cystatin C. Polysaccharides stimulated cystatin C secretion: lipopolysaccharide < carboxymethylated beta-D-glucan < sulfoethylated beta-D-glucan. Human plasma low-density- (LDL) and high-density lipoproteins (HDL) are still more potent inducers of cystatin C secretion by macrophages. Peritoneal macrophages from mice with experimental HA-1 hepatoma compared to those from intact mice secreted more cystatin C with maximum polysaccharide-stimulated secretion after 30 min of incubation. LDL and HDL induced cystatin C secretion by tumor macrophages also.

[Cysteine proteinases and their inhibitors in the development of mouse HA-1 hepatoma and antineoplastic therapy]

Development of murine HA-1 hepatoma was accompanied by increased activity of cathepsin B (in ascitic cells), cathepsin D (in ascitic fluid) and increased activity of procathepsin B. There were some changes of cysteine proteinases in liver and spleen, not involved directly into tumor growth. The most prominent changes included the decreased level of cysteine proteinase inhibitors cystatin C and stefin A in ascitic cells (and to a lesser degree in liver tissue). During tumor development serum cystatin C concentration decreased by 3-times compared to intact mice. Treatment by antitumor drug Ukraine increased life span of mice with HA-1 hepatoma (transplanted intravenously), decreased the increment of tumor weight. In ascite such treatment caused a decrease of number of tumor cells and an increase of number of macrophages. Ukraie (administered once or 5-times in a dose of 0.5 mg per mice) increased cystatin C level, revealing protective mechanism of action.

Mouse lymphosarcomas sensitive and resistant to cyclophosphamide therapy: activity of cathepsins B, L, and D during various schemes of treatment with cyclophosphamide and SE-glycan

We measured activities of cysteine (cathepsins B and L) and aspartyl proteinases (cathepsin D) in tumor tissue of mice with sensitive and resistant lymphosarcomas. In cyclophosphamide-resistant lymphosarcoma tissue activities of cathepsins B, L, and D were lower than in cyclophosphamide-sensitive lymphosarcoma. After treatment with cyclophosphamide in high doses enzyme activities in mice with cyclophosphamide-resistant lymphosarcoma increased more significantly than in animals with cyclophosphamide-sensitive lymphosarcoma. Sulfoethylated beta-1,3-D-glycan potentiated the effect of cyclophosphamide in mice with both forms of lymphosarcoma. This drug in the lowest dose (10 mg/kg) was most effective.

[Immunoenzyme technique for analysis of cystatin C in serum of patients with hemoblastosis]

Cystatin C is a low-molecular endogenous inhibitor of cysteic proteinases. Sets for immune-enzyme assay of cystatin C in human blood serum (KRKK, Slovenia) were made used of in the case study. The concentration of cystatin C (CCC) in blood serum was found to be higher in cases of certain hemoblastoses (Non-Hodgkin's disease, lymphogranulomatosis and multiple myeloma), with the highest concentration of the inhibitor being observed in patients with resistance to the conducted polychemotherapy and a poor prognostication. The treatment of Non-Hodgkin's disease and of lymphogranulomatosis brought about a normalized CCC in blood serum. It was suggested that CCC in blood serum reflects a nature of tumor growth and, obviously, it can be a criterion in assessing the therapy efficiency. The concentration of alpha 1-proteinases inhibitor remained unchanged before and after treatment.

[Comparative characteristic of serpin--alpha-1 proteinase inhibitor in human and mice serum]

Serpin alpha-1-proteinase inhibitor have been studied in human subjects and in mice of different lines as acute phase reactant and during tumor development. In humans, there was no difference of serpin activity between men and women. Increased activity was noted in men with acute trauma (acute phase reaction). Comparatively to male, in female mice of different lines decreased activity of serum alpha-1-proteinase inhibitor, was shown. There was no increase of alpha-1-proteinase inhibitor activity during inflammation induced by zymosan administration in mice. alpha-1-proteinase inhibitor belongs to acute phase reactants in humans but not in mice; for mice alpha-2-macroglobulin is a more typical acute phase reactant as compared to alpha-1-proteinase inhibitor. Murine tumor development (hepatoma HA-1, lymphosarcoma LS, Lewis lung adenocarcinoma) was followed by a decreased activity of serum alpha-1-proteinase inhibitor both in successfully treated and untreated groups. According to data of literature, similar dated were obtained in humans with tumors. It was suggested that changes of expressiln of alpha-1-proteinase inhibitor by tumors and its secretion were involved in decreased activity of alpha-1-proteinase inhibitor.

[Effect of stimulation and depression of macrophages on development of paracetamol-induced acute toxic hepatitis in rats]

The role of macrophage (Kupffer cell) stimulation and suppression in the development of a toxic liver damage was studied in rats with acute hepatitis induced by paracetamol (acetaminophen, 1000 mg/kg). Pretreatment with carboxymethylated (1-->3)-beta-D-glucan (25 mg/kg, i.p., 48 h before paracetamol) for the macrophage stimulation or with gadolinium chloride (GdCl3, 7.5 mg/kg, i.v., 24 h before paracetamol) for the macrophage suppression has a protective effect manifested by normalization of the liver function test parameters and by a decrease in the degree of morphological changes in the liver cells. A relation between these positive effects and the TNF-alpha secretion by macrophages is discussed.

Cystatin C and cysteine proteinases during the development and therapy of Lewis lung adenocarcinoma in mice

We measured plasma cystatin C concentration and activity of cathepsins B and L in tumor tissue as possible markers for the efficiency of antitumor therapy and prognostic criteria for Lewis lung adenocarcinoma in mice. Plasma cystatin C concentration markedly decreased in mice with tumors. During successive therapy the increase in plasma cystatin C concentration correlated with the degree of inhibition of tumor growth. Activities of cathepsins B and L in the liver increased in animals with tumors. In mice receiving successive antitumor therapy activities of cathepsins B and L increased in tumor tissue, but decreased in the liver (compared to untreated animals).

Activity and concentration of cathepsin B as prognostic criteria for the development of mouse LS lymphosarcoma and Lewis lung adenocarcinoma

We measured activity and content of cathepsin B in tumor tissues, liver, and spleen in mice with Lewis adenocarcinoma and LS-lymphosarcoma. Cathepsin B activity in Lewis adenocarcinoma cells was lower than in LS-lymphosarcoma cells, which was probably related to differences in their metastatic properties. Antitumor therapy increased activity and content of cathepsin B in tumor tissues. Changes in the content and activity of cathepsin B in tumor tissues can serve as a prognostic criterion for tumor regression during therapy. Cathepsin B is probably involved in apoptosis of tumor cells during chemotherapy of lymphosarcoma-LS with cyclophosphamide.

Chitotriosidase as a new marker of macrophage stimulation in a tumor model treated with cyclophosphamide and Ukrain

Ukrain has previously been demonstrated to exert a malignotoxic effect in vivo. This antitumor drug has been effective in the treatment of some malignancies in experimental animals as a result of immunostimulation (macrophage stimulation). In the present study, serum chitotriosidase activity was measured as a biochemical marker of macrophage stimulation in several murine and rat models of macrophage stimulation. It was shown that zymosan, carboxymethylated glucan and Triton WR 1339 administration to CBA mice or Wistar rats was followed by a considerable increase in serum chitotriosidase activity. Murine LS lymphosarcoma development decreased serum chitotriosidase activity. Antitumor treatment by Ukrain or cyclophosphamide did not restore this index to the normal value.

Cysteine proteinase inhibitor level in tumor and normal tissues in control and cured mice

Cystatin C is the best known extracellular endogenous cysteine proteinase inhibitor and has been studied as a possible index of tumor growth and as a marker of the effectiveness of antitumor therapy. The aim of this study was to evaluate cystatin C concentrations in murine tumor tissues (compared with other organs not directly involved with tumor development, such as the liver and spleen) during treatment with several antitumor drugs (Ukrain and/or cyclophosphane). Cystatin C concentrations in murine tissues and biological fluids was determined by enzyme-linked immunosorbent (ELISA) assay. The cystatin C ELISA test is a sandwich immunoassay, which uses immobilized rabbit antihuman cystatin C Pab and mouse antihuman cystatin C Mab-HRP (monoclonal antibodies, conjugated with horseradish peroxidase). We observed decreased serum cystatin C concentrations compared with controls in all nontreated tumor models: HA-1 hepatoma (solid and ascitic forms), lung adenocarcinoma (solid and ascitic forms) and LS lymphosarcoma. In the ascitic fluid of mice with HA-1 hepatoma the cystatin C concentration was much lower than in the serum of the same mice (about 20-fold lower). In the HA-1 model of hepatoma cells cystatin C concentration decreased about 2-3-fold compared with the control (intact liver) and Ukrain significantly increased the cystatin C concentration. Cyclophosphane treatment of LS lymphosarcoma significantly increased the cystatin C concentration in serum. Cyclophosphane treatment (50 mg/kg, single injection) increased cystatin C by up to 8-fold more in tumor issue. Ukrain treatment of LS lymphosarcoma was also followed by increased levels of cystatin C in tumor tissue (4-fold); cyclophosphane plus Ukrain had a similar positive effect. In the group with LS lymphosarcoma Ukrain or cyclophosphane plus Ukrain treatment induced a significant increase in cystatin C concentration in liver. Liver cystatin C concentration decreased in the HA-1 hepatoma group and treatment with Ukrain or carboxymethylated beta-1, 3-glucan (CMG) increased this index in both groups. Spleen cystatin C concentrations decreased about 5-fold in LS lymphosarcoma compared with controls and combined treatment with cyclophosphane plus Ukrain restored the index to the normal value. We can conclude that both murine tumors studied were characterized by low cystatin C concentrations in tumor tissues and decreased cystatin C concentrations (to a lesser degree) were also observed in liver and spleen as a result of the "toxic" effect of tumor bearing. Effective treatment in all cases (especially with Ukrain or a combination of cyclophosphane plus Ukrain) induced a significant increase in cystatin C. Obviously, the decrease in cystatin C concentration predominantly in tumor tissue was connected with tumor development and restoration of cystatin C level may be used as a marker of efficacy of antitumor therapy.

Cystatin C in LS lymphosarcoma and HA-1 hepatoma treated with Ukrain and cyclophosphamide and involvement of apoptosis

The concentration of cystatin C, a cysteine proteinase inhibitor, was measured during the treatment of murine LS lymphosarcoma with cyclophosphamide and HA-1 murine hepatoma with the antitumor drug Ukrain. It was shown that concentrations of cystatin C were very low in both the tumor tissues studied (HA-1 hepatoma cells and LS lymphosarcoma); increased cystatin C concentrations were found only in Ukrain-treated murine hepatoma, suggesting the mechanism of antitumor effect of this drug. Cyclophosphamide treatment in LS lymphosarcoma did not influence the concentration of cystatin C in tumor cells. At the same time, a marked increase in cathepsin B and cathepsin L activity in LS lymphosarcoma was found, indicating the involvement of apoptosis in the mechanism of antitumor action of cyclophosphamide. While the DNA from untreated LS lymphosarcoma was very homogenous and its molecular weight was high, the DNA from tumors of treated mice broke down, giving rise to the ladder figure characteristically produced by cells dying from apoptosis. Evidence was obtained that cyclophosphamide-induced tumor regression was effected by apoptosis.

Influence of Ukrain and cyclophosphamide administration on HA-1 murine hepatoma and LS lymphoma on aspartic proteinase cathepsin D

Cathepsin D, the major lysosomal aspartyl proteinase and a mediator of interferon-gamma and tumor necrosis factor-alpha-induced apoptosis, was studied in murine models of LS lymphosarcoma treated by cyclophosphamide (possible apoptosis induction), and HA-1 hepatoma treated by Ukrain (positive antitumor effect). It was found that cyclophosphamide, as well as cyclophosphamide plus Ukrain, increased cathepsin D specific activity in mice with LS lymphosarcoma. Ukrain alone had no effect on cathepsin D activity in LS lymphosarcoma. In HA-1 hepatoma cells cathepsin D activity was not changed compared with intact normal murine liver (day 10) and activity decreased during tumor development (on day 12). Ukrain significantly increased cathepsin D activity in ascitic fluid (day 10) and had a tendency to increase cathepsin D activity in ascitic cells but not to the normal value.

Macrophage Stimulator beta-(1-->3)-D-carboxymethylglucan improves the efficiency of chemotherapy of Lewis lung carcinoma

We studied the effect of macrophage stimulator water-soluble beta-(1-->3)-D-carboxymethylglucan on the efficiency of cyclophosphamide chemotherapy in Lewis lung carcinoma. Cyclophosphamide inhibited the growth of primary tumor nodes by 57%. The preparation possessed pronounced antimetastatic activity: metastases were found in 40.9% animals. Combination therapy with cyclophosphamide and (1-->3)-beta;-D-glucan inhibited the growth of intramuscular tumors by 75-89% and reduced the incidence of metastases into the lungs by 92-94%. The therapeutic effect was most pronounced after simultaneous administration of these preparations: tumor growth was suppressed by 89.3% and metastases were found in only 7.5% animals (vs. 100% in the control). The potentiating effect of beta-(1-->3)-D-carboxymethylglucan is related to accumulation of cysteine proteinase inhibitors in the tumor tissue and plasma, but not to changes in blood cell composition.