Identification of Spiro-Fused [3-azabicyclo[3.1.0]hexane]oxindoles as Potential Antitumor Agents: Initial In Vitro Evaluation of Anti-Proliferative Effect and Actin Cytoskeleton Transformation in 3T3 and 3T3-SV40 Fibroblast

Novel heterocyclic compounds containing 3-spiro[3-azabicyclo[3.1.0]hexane]oxindole framework (4a, 4b and 4c) have been studied as potential antitumor agents. The in silico ADMET (adsorption, distribution, metabolism, excretion and toxicity) analysis was performed on 4a-c compounds with promising antiproliferative activity, previously synthetized and screened against human erythroleukemic cell line K562 tumor cell line. Cytotoxicity of 4a-c against murine fibroblast 3T3 and SV-40 transformed murine fibroblast 3T3-SV40 cell lines were evaluated. The 4a and 4c compounds were cytotoxic against 3T3-SV40 cells in comparison with those of 3T3. In agreement with the DNA cytometry studies, the tested compounds have achieved significant cell-cycle perturbation with higher accumulation of cells in G0/G1 phase. Using confocal microscopy, we found that with 4a and 4c treatment of 3T3 cells, actin filaments disappeared, and granular actin was distributed diffusely in the cytoplasm in 82-97% of cells. The number of 3T3-SV40 cells with stress fibers increased to 7-30% against 2% in control. We discovered that transformed 3T3-SV40 cells after treatment with compounds 4a and 4c significantly reduced the number of cells with filopodium-like membrane protrusions (from 86 % in control cells to 6-18% after treatment), which indirectly suggests a decrease in cell motility. We can conclude that the studied compounds 4a and 4c have a cytostatic effect, which can lead to a decrease in the number of filopodium-like membrane protrusions.

Dur3 and nrt2 genes in the bloom-forming dinoflagellate Prorocentrum minimum: Transcriptional responses to available nitrogen sources

The increasing inflow of nitrogen (N) substrates into marine nearshore ecosystems induces proliferation of harmful algal blooms (HABs) of dinoflagellates, such as potentially toxic invasive species Prorocentrum minimum. In this study, we estimated the influence of NO3-, NH4+ and urea on transcription levels and urea transporter dur3 and nitrate transporter nrt2 genes expression in these dinoflagellates. We identified dur3 and nrt2 genes sequences in unannotated transcriptomes of P. minimum and other dinoflagellates presented in MMETSP database. Phylogenetic analysis showed that these genes of dinoflagellates clustered to the distinct clade demonstrating evolutionary relationship with the other known dur3 and nrt2 genes of microalgae. The evaluation of expression levels of dur3 and nrt2 genes by RT-qPCR revealed their sensitivity to input of the studied N sources. Dur3 expression levels were downregulated after the supplementation of additional N sources and were 1.7-2.6-fold lower than in the nitrate-grown culture. Nrt2 expression levels decreased 1.9-fold in the presence of NH4+. We estimated total RNA and DNA synthesis rates by the analysis of incorporation of 3H-thymidine and 3H-uridine in batch and continuous cultures. Addition of N compounds did not affect the DNA synthesis rates. Transcription levels increased up to 12.5-fold after the N supplementation in urea-limited treatments. Investigation of various nitrogen sources as biomarkers of dinoflagellate proliferation due to their differentiated impact on expression of dur3 and nrt2 genes and transcription rates in P. minimum cells allowed concluding about high potential of the studied parameters for future modeling of HABs under global N pollution.

Polychromatic Light (480-3400 nm) Upregulates Sensitivity of Tumor Cells to Lysis by Natural Killers

OBJECTIVE

This study evaluates the participation of immunological mechanisms of downregulation of murine hepatoma cells MH22a after direct exposure to polychromatic polarized light.

BACKGROUND DATA

Previous studies have shown that exposure to a combination of visible (VIS) and infrared (IR) light leads to decreased tumorigenicity of the murine hepatoma cells MH22a, which correlated with an increase in the amount of cells with reorganized cytoskeleton in the submembrane region. The mechanism of tumor inhibition and elimination has not been determined.

MATERIALS AND METHODS

Polychromatic light (480-3400 nm) has been used at doses of 4.8 and 9.6 J/cm(2) to determine the sensitivity of murine MH22a cells and human erythroleukemia cells K562 exposed to this light, to lysis by effector cells of innate immunity (NK cells), and enhancement of the glycocalyx of the studied tumor cells. This was determined using flow cytometry, the H(3)-uridine cytotoxic test followed by spectrophotometry.

RESULTS

VIS-IR light increases the sensitivity of MH-22a cells at a dose 4.8 J/cm(2) and K562 cells at 9.6 J/cm(2). The enhancement of sensitivity of tumor cells to NK lysis changed their ability to absorb alcian blue, reflecting a change in the expression of the glycocalyx.

CONCLUSIONS

Increasing the sensitivity of the murine tumor cells MH22a and human K562 irradiated VIS-IR light correlated with a change in the expression of their glycocalyx. The results of the present study demonstrate that the reduction of tumorigenicity of irradiated tumor cells is due to their sensitivity to lysis by NK cells of the immune system.

[Polychromatic visible and infrared light (480-3400 nm) downregulates the growth of hepatoma MH22a in mice]

We studied the effect of polychromatic visible (380-750 nm) (VIS) and combined with the visible infrared (480-3400 nm) (VIS-IR) radiation on the growth of hepatoma in mice. In the first series of experiments on C3HA mice with subcutaneously transplanted syngeneic hepatoma MH22a it was shown 1.5-4 times inhibition of tumor volume after irradiation of tumor-bearing mice with VIS-infrared light at a dose 4.8 J/ cm2. Mice irradiation at doses of 9.6 J/cm2 and 38.4 J/cm2 had no effect on the rate of tumor growth. Exposition to VIS and IR-light in all doses we used an increase of the surviveness of animals in the 1.5 and 2 times respectively was observed. In a second series of experiments we investigated the effect VIS-IR radiation on tumor cells in vitro with subsequent inoculation to intact mice. After implantation in mice irradiated cells at a dose of 4.8 J/cm2 9.6 J/cm2 inhibition of tumor growth during the first 25 days at 3-12 times as compared to control and increased survival in mice 1.5-2 respectively was observed. The main results of this study consists in the fact that none of the doses used VIS and a IR-radiation has not been shown to stimulate tumor growth both in irradiated mice with tumors, and the irradiation of MH22a hepatoma cells under in vitro conditions prior to transplantation of intact mice. Furthermore it was detected dose range VIS-IR light (4.8-9.6 Joules/cm2) when the rate of growth of hepatoma MH22a decreased and increased surviveness of animals.

Downregulation of tumorogenicity and changes in the actin cytoskeleton of murine hepatoma after irradiation with polychromatic visible and IR light

OBJECTIVE

This study evaluated the function and structural consequences of direct exposure of murine hepatoma MH-22a cells to polychromatic polarized light, to determine potential risk of malignancy following irradiation.

BACKGROUND DATA

Visible (VIS) and infrared (IR) light have been actively used for prevention and treatment of complications developed after conventional tumor therapy. However, the safety associated with this irradiation has not been determined.

MATERIALS AND METHODS

Polychromatic light (480-3400 and 385-750 nm), were used at different doses (4.8-38.4 J/cm(2)) to determine the viability, proliferation, and actin cytoskeleton in vitro by flow cytometry and confocal microscopy. Tumorogenic properties of cells were studied in vivo after transplantation in C3HA mice.

RESULTS

Polychromatic light of a wide range of doses did not change the viability and proliferation of cells. After transplantation of cells irradiated with VIS-IR light (4.8 and 9.6 J/cm(2)) and VIS light (38.4 J/cm(2)) the tumor volume was lower in the treated group than in the control group in vivo. Transplantability of the irradiated cells also decreased, whereas survival of tumor-bearing mice increased. Three cell populations with different cytoskeleton structure were identified. After irradiation, the reorganized part of the actin cytoskeleton changed its localization to the submembranous area.

CONCLUSIONS

A decrease of tumorigenicity in cells irradiated with polychromatic light used in non-damaging doses correlated with an increase in the number of cells with reorganized actin in the submembranous area. The results of the present study argue in favor of the oncological safety of polychromatic VIS-IR light (480-3400 nm).

[CELLS FORM AND THEIR SENSITIVITY TO LYTIC ACTIVITY OF NATURAL KILLER CELLS UNDER THE ANTIOXIDANT ACTION]

The present paper is an attempt to estimate the influence of cell surface morphology changes to functional activity under the effect of antioxidant, N-acetylcysteine (NAC), and alpha-lipoic asid (ALA). Two experimental parameters were used to characterize transformed fibroblasts 3T3-SV40 status. The functional one was the cell sensitivity to lysis by natural killer (NK) mouse splenocytes, and morphology index (cell form index) was a cell area. We showed that addition of NAC or ALA to the cell medium caused fast decrease of cell area and changes of cell form. On the other hand, their sensitivity to lysis NK cells gradually and significantly decreased. Then we compared NAC or ALA effect with the effects of other substances, which were non-antioxidants but caused cell responses which concurred with of antioxidants, at least partly. They were: latrunculin B, desorganizing actin filaments (as both antioxidants), OTZ reducing ROS level in the cell (as NAC), BSO (inhibitor of glutathione synthesis), increasing ROS level in the cell (as ALA), antibodies to gelatinases, MMP-2 and MMP-9 inactivating their activities (as both antioxidants). The results obtained showed a correlation between changes of morphology index and functional activity, sensitivity to lysis by NK cells. We suppose that geometry of cell surface might be a functional indicator of cell reaction to the antioxidant.

[Effect of polychromatic visible light combined with infrared radiation on tumorigenicity of murine hepatoma cells and their sensitivity to lytic activity of natural killers]

Tumorigenicity of murine hepatoma cells (MH22a) and their sensitivity to lysis by natural killers (NKs) have been studied after exposure to polychromatic visible and infrared light (VIS-IR, 480-3400 nm, 40 mW/cm2), similar to the terrestrial solar spectrum without its minor UV component, in order to elucidate the involvement of this important environmental and physiotherapeutic factor in regulation of the anti-tumor defense system. The MH22 cells were in vitro exposed to VIS-IR light and their sensitivity to lytic activity of NKs was evaluated. We found that sensitivity of MH22a cells to lysis by NKs after exposure to VIS-IR light at a dose of 4.8 J/cm2 increased 1.5-2 times, while it did not change after exposure to a dose of 9.6 J/cm2 at all ratios (1 : 5-1 : 50) of the number of NKs (effectors) to that of hepatoma cells (targets). The increase in the sensitivity of hepatoma cells to NKs was accompanied by structural changes of cell surface: the capability of supramembraneous glycoproteins (glycocalix) to sorb the vital dye alcian blue (AB) was significantly lower as compared with the unexposed cells of control group. However, no changes in AB sorption was revealed in hepatoma cells exposed to the light at a dose 9.6 J/cm2. Tumorigenicity of photo-irradiated MH22a cells has been studied in the in vivo experiments. Light-exposed (4.8 and 9.6 J/cm2) and intact hepatoma cells were transplanted into syngenic mice C3HA. Tumor volumes 25 days after transplantation proved to be smaller after exposure to the light at both doses than in the control group (4-4.5 times and 2.5-4 times, respectively), which correlated with the increase in the sensitivity to lisys by NKs and decrease in the AB sorption only after light exposure at dose 4.8 J/cm2. Using the flow cytometry method we could show that VIS-IR light at the applied doses did not interfere with the distribution of hepatoma cells over the cycle phases and thus deceleration of the tumor growth was not associated with cytostatic effect of VIS-IR light. To evaluate effect of polychromatic light on the growth of the preformed tumors, the 5-day course of daily light exposures of tumor bearing mice C3HA was carried out in 10 days after subcutaneous transplantation of 2 x 10(5) cells of syngene hepatoma when the tumors had developed in 100% animals. Like in the case of transplantation of the light-exposed cells, irradiation of the tumor bearing mice at doses 4.8-9.6 J/cm2 resulted in deceleration of tumor growth (2.1-2.9 and 2.2 times respectively) for 4 weeks as compared with non-irradiated mice.

[Proliferation and tumorigenity of the murine hepatoma cells irradiated with polychromatic visible and infrared light]

In experiments in vitro, the effect of the polychromatic visible (VIS) light combined with polychromatic infrared light (VIS-IR, 480-3400 nm) and the effect of the entire spectrum of VIS radiation (385-750 nm) on the viability and proliferative activity of the murine hepatoma cells MH22a. In experiments in vivo, changes of tumorigenic properties of cells MH22a have been studied after the same kinds of light exposure. It was shown that irradiation of the hepatoma cells with two kinds of polychromatic light at a wide range of doses (4.8-38.4 J/cm2) did not lead to an increase in the number of dead cells for 24-72 h of cultivation and did not cause retardation of the hepatoma cell proliferation. Moreover, VIS-IR light at a dose of 4.8 J/cm2 and VIS light at a dose 38.4 J/cm2 stimulated cell proliferation in 24 h. Proliferation index increased by 1.6 and 1.4 times, respective, and the time of the cell number doubling decreased as compared with control. Studying the tumorigenic properties of irradiated tumor cells showed that, for 30 days after transplantation, of hepatoma cells in 24 h after their irradiation with VIS-IR light at a dose of 4.8 J/cm2 to syngenic mice C3HA, the tumor volume reduced significantly (2.6-4 times) of all stages of observation. The incidence of tumor formation decreased, whereas the survival of the tumor-bearing mice did not change. Transplantation of cells irradiated with the same light at a dose of 9.6 J/cm2 did not lead to significant changes of the tumor volume, the tumor formation incidence, and animal survival. The main contribution to the antitumor effect of the VIS-IR light seems to be made by the VIS component, as transplantation of cells irradiated with VIS alone light at a dose of 38.4 J/cm2 also stimulating proliferation of hepatoma cells in vitro into mice resulted in a reduction of their tumorigenic properties. However, the IR component in the combined VIS-IR radiation enhanced the antitumor effect of the VIS light; as a result, this effect was manifested after use of doses 8 times lower (4.8 J/cm2) than in the case of the VIS light alone (38.4 J/cm2). Mechanisms of the decrease of tumorigenic properties of hepatoma cells after irradiation with polychromatic light ad doses stimulating their proliferation in vitro are studied.

[Decrease in tumorigenic activity of murine hepatoma cells after treatment with antioxidants and melatonin]

We studied the effect of antioxidants such as N-acetylcysteine (NAC, 10 mM) and alpha-lipoic acid (ALA, 1.25 mM) and of the hormone melatonin (1 microM) on the ability of murine hepatoma cells MH22a to develop tumors in syngenic mice (C3HA) after subsutaneous injection. Tumor formation and development slowed down and mouse mortality decreased when the injected cells were pretreated by NAC, ALA or melatonin during 20 h. Melatonin had the most marked effect. Tumors appeared in 100 % cases after 10 days in control mice when untreated cells had been injected; injection of cells pretreated by NAC or ALA resulted in tumor formation only in 40 and 53 % of mice, respectively. When cells were pretreated with melatonin the tumors appeared only in 18-20 days after injection. Until the end of the observation (36 days) 67 % of control mice died, but when the cells were pretreated by NAC or ALA mouse death-rate was 20 and 53 %, respectively. In the case of melatonin we did not observed any dead mice at all. We showed that treatment by antioxidants delayed (NAC) or completely inhibited (ALA) cell cycle of hepatoma cells. Cell cycle was restored after removal of the antioxidants. Melatonin did not change cell cycle phase distribution. We conclude that there is no direct correlation between loss of tumorigenic properties and changing of proliferative activity of hepatoma cells. Different mechanisms of antioxidants and melatonin action resulting in transient tumor phenotype normalization are discussed.

[Effect of melatonin on the functional properties of transformed cells]

In vitro, we studied the effect of melatonin (1mkM) on the sensitivity of murine transformed fibroblasts 3T3-SV40 and murine hepatoma cells MN22a to the lysis by natural killer cells. In vivo, we examined changes in tumorigenic properties of MN22a cells treated with melatonin. It was shown that the sensitivities of both cell types to lysis by killer cells fell sharply fourfold after 24-hour treatment with melatonin; their cytotoxic index value approximated to that of intact cells, insensitive to natural killer cells. After MN22a cells were pre-treated with melatonin for 24 h before injection into syngenic mice, tumorigenesis and development slowed down and mortality rates decreased. Both effects were reversible. All cellular parameters were similar to control ones 24 hrs after evacuation of melatonin. Thus melatonin failed to change cell cycle progression which pointed to an unaltered rate of cell proliferation. Different hypotheses are discussed on the mechanisms of melatonin action which result in transient reversion of transformed phenotype.

[Sensitivity to lysis by natural killers depends on the integrity of lipid rafts in plasma membrane of transformed cells]

The present work focused on the role of cholesterol-rich membrane microdomains (rafts) in cellular mechanisms of innate immunity and anticancer defence. The lytic effect of natural killers (NK) was examined in dependence on cholesterol content in transformed target cells. In the current study, K562 human erythroleukaemia cells were the targets. K562 cells were treated with methyl-beta-cyclodextrin (MbCD) to deplete membrane cholesterol that was verified by enzymatic method. With the use of 3H-uridine test, NK (mouse splenocytes) cytotoxity was estimated under various conditions, specifically, after incubation of K562 cells with MbCD or inactive analog alpha-cyclodextrin. The data obtained show that cholesterol-depleting treatment (2.5 or 5 mM MbCD) of target cells results in full loss of their sensitivity to NK lysis. The effect is likely to be due to disintegrity of lipid rafts that is critically dependent on the level of membrane cholesterol. Visualization of cell surface changes by fluorescent labeling of ganglioside GM1 confirmed our conclusions.

[N-acetylcysteine-induced reduction in susceptibility of transformed and embryonic cells to lytic activity of natural killer cells]

We studied N-acetylcysteine (NAC) ability to change the phenotype properties of several transformed and embryonic cells. We examined human epidermoid carcinoma A431 cells, murine hepatoma MH22a cells, and murine embryonic fibroblasts (MEFs) in terms of the sensitivity to natural killer (NK) recognition and abolishment. We have demonstrated that treatment with NAC (10 mM) results in a loss of susceptibility to NK cell activity by transformed A431 and MH22a cells similar to 3T3-SV40 transformed cells whose partial reversion caused by NAC was revealed by us before. We have shown that MEFs are also sensitive to NK activity and abolished by NK cells as well as transformed cells. MEFs pretreated with 10 mM NAC as well as transformed cells lose their susceptibility to NK cell activity. The loss of cell sensitivity to NK cytolytic activity was accompanied by a reorganization of the actin cytoskeleton and the appearance of well-pronounced stress-fibers.

[Morphological and functional heterogeneity of rat ascitic hepatoma Zajdela cells]

This work is devoted to the study of molecular and cellular mechanisms of disdifferentiation during neoplastic transformation of cells by investigating the malignant tumor cell heterogeneity. We have revealed two cell fractions of hepatoma Zajdela which differ in patterns of growth in primary culture. The cells of one fraction were attached to the culture plastic and grew in a monolayer (S-fraction), whereas cells of another fraction floated in the culture medium (F-fraction). Using method of lifetime supervision of primary culture cells (1-2 passages) at the limit of the resolving power of DIC-microscopy it has been revealed, that both fractions contain cells of several types. Some of them were specific for one of the fractions, and others were found in both fractions, but their frequencies differed. It has been shown by the same method, that long separate cultivation of these fractions in vitro (more than 50 passage) change both cellular structure and the initial ratio of different types of cells in both fractions. According to DNA flow cytometry, the cells of both fractions were hypotetraploid and had insignificant differences in DNA contents. After adaptation to in vitro conditions, S-fraction cells raised their proliferative activity in comparison with the F-fraction cells, and after long cultivation showed 2.3 times higher DNA content. Greater amount of cell surface laminin, a hepatocellular carcinoma marker, was observed on F-fraction cells than on S-fraction cells. Interfractional distinctions were confirmed also by immunologic assessment of hepatoma cells resistance to natural killer lyses: the sensitivity of S-fraction cells in primary culture was 2.4 times higher than F-fraction cells sensitivity, and, after long cultivation, F-fraction cells became practically resistant to cytotoxic action of natural killers. Based on the data obtained, the most probable paths of cell disdifferentiation during hepatoma Zajdela formation and during long cultivation of this tumor cells in vitro are discussed.

[Effect of alpha-lipoic acid on the sensitivity of transformed fibroblasts to lysis by natural killer cells. Comparison with NAC action]

The purpose of this study was to compare the effects of two antioxidants, alpha-lipoic acid (ALA) and N-acetylcysteine (NAC) on the sensitivity of 3T3-SV40 fibroblasts to lytic activity of natural killer (NK) cells. ALA (1.25 mM) reduced significantly the fibroblast sensitivity in several hours, whereas NAC (10 mM) did not change it. Subsequent removal of the antioxidants from the cultivation medium resulted in gradual recovery of the sensitivity in the case of ALA and in complete loss of it in the case of NAC. Inactivation of gelatinase MMP-2 (matrix metalloproteinase) using pretreatment of the cells with the inhibitor of MMP, G6001, or specific antibodies to MMP-2 or MMP-9 resulted in decrease of 3T3-SV40 sensitivity to NK cells activity. This effect was similar to that of ALA, not to the NAC one. Pretreatment of NK cells with G6001 did not influence their lytic activity. The results obtained demonstrate that the direct antioxidant, NAC (having reduced thiol groups), and the indirect one, ALA (reducing thiol groups and acting as a direct antioxidant only inside the cell) activate principally different intracellular signal pathways. However, both NAC and ALA pathway includes inactivation of MMP-2.

[Reorganization of actin cytoskeleton in 3T3-SV40 cells and their sensitivity to lysis by natural killer cells]

The present work was aimed to examine whether the actin reorganization of 3T3-SV40 cells influences their sensitivity to natural killer (NK) cells activity. The effects of N-acetylcystein (NAC) and latrunculin B, actin depolimerizator, on both cellular parameters were studied. Experiments with NAC demonstrated that 3T3-SV40 sensitivity to NK cells activity remained unchanged under the disordered microfilaments but decreased upon the appearance of structured stress-fibres. The data on latrunculin B action resulted in the opposite conclusion: the more microfilaments disorganization in the presence of latrunculin B the lesser 3T3-SV40 sensitivity to lysis by NK cells. These facts suggest that relations between microfilament integrity in 3T3-SV40 cells and their sensitivity to NK cells are rather independent. The latter confirms our previous conclusion (Gamaley et al., 2006). Decrease in 3T3-SV40 sensitivity to NK cells activity accompanied by actin reorganization resulted from both latrunculin B and NAC action suggests changes in cellular surface, which ultimately lead to inactivation (or loss) of the molecules being activating signals to NK cells.

[Recognition and lysis by natural killers of tumor cells with participation of laminin]

According to the data obtained in the present work, the receptor complex of mouse natural killers (NK) includes laminin, antibody to which blocks EK-activity (NKA regardless of the presence of complement. Preincubation of mouse splenocytes with anti-laminin serum led to a decrease in their NKA towards tumor cells-targets (CT), the NKA activity decreasing 2 times with respect to cultivated cells of rat hepatoma HTC, while 10 times - to cultivated cells of human erythroblastosis K562. Pretreatment of aplenocytes with noraml nonimmune serum did not lead to a change of NKA. Quite different was the pattern after the tumor cell preincubation with anti-laminin serum: pretreatment of CT K562 led to a twofold decrease in sensitivity of these cells to NK-lysis, whereas the pretreatment of CT K562, on the contrary, made them twice sensitive to NK-lysis. Electrophoretic separation of protein of CT plasma membranes with subsequent immunoblotting with anti-laminin immune serum revealed the presence oflaminin on HTC cell plasma membrane, which was identified as laminin 8/9 by the mass-spectrometry method, while no laminin was detected on K562 cells. Preincubation of splenocytes with laminin did nor affect NKA with respect to CT K562 and HTC. Pretreatment of CT K562 and HTC with laminin decreased the NKA to zero. The obtained data allow suggesting a doubtless participation of laminin and its receptors in CT cytolysis by NK.

[N-acetylcysteine reduces transformed 3T3-SV40 fibroblast sensitivity to lysis by natural killer cells]

We have shown that 18-20 h cultivation of transformed mouse fibroblasts 3T3-SV40 in the presence of antioxidant, N-acetylcysteine (NAC, 10 mM), did not change their sensitivity to lysis by natural killer (NK) mouse splenocytes. However, in 18-20 h after NAC removal 3T3-SV40 cells demonstrated resistance to NK cell activity. The cytotoxicity index (CI) was reduced up to 4.6 +/- 2.4 % (in comparison with the control value 31.8 +/- 2.4 %) approximating to the value in non-transformed 3T3 mouse fibroblasts. Normal 3T3 cells were resistant to NK action in all experimental conditions (CI varied within 0.7-5.3 %). These results show that NAC can induce partial reversion of transformed phenotype. We suggest that this effect may be due to the NAC-induced modifications of the cell surface and extracellular matrix proteins.

Cytotoxic activity of blowfly Calliphora vicina hemocytes

The cytotoxic activity of hemocytes isolated from larvae of the blowfly Calliphora vicina was tested using human myelogenous leukemia K562 cells as target. Both single cell and cytotoxicity assays demonstrated that the hemocytes recognize the K562 cells as nonself, firmly attach to their surface and induce target destruction in a manner resembling the effect of mammalian cytotoxic lymphocytes. The cytotoxic activity increased dramatically in the course of larval metamorphosis and was considerably higher shortly before the onset of pupariation, compared to the activity of human peripheral blood or mouse spleen lymphocytes. In insects, the cytotoxic hemocytes may take part in defense against eukaryotic parasites and in the elimination of aberrant self cells, as well as in developmental processes such as metamorphosis.

Antiviral and antitumor peptides from insects

Insects can rapidly clear microbial infections by producing a variety of immune-induced molecules including antibacterial and/or antifungal peptides/polypeptides. In this report, we present the isolation, structural characterization, and biological properties of two variants of a group of bioactive, slightly cationic peptides, referred to as alloferons. Two peptides were isolated from the blood of an experimentally infected insect, the blow fly Calliphora vicina (Diptera), with the following amino acid sequences: HGVSGHGQHGVHG (alloferon 1) and GVSGHGQHGVHG (alloferon 2). Although these peptides have no clear homologies with known immune response modifiers, protein database searches established some structural similarities with proteins containing amino acid stretches similar to alloferon. In vitro experiments reveal that the synthetic version of alloferon has stimulatory activities on natural killer lymphocytes, whereas in vivo trials indicate induction of IFN production in mice after treatments with synthetic alloferon. Additional in vivo experiments in mice indicate that alloferon has antiviral and antitumoral capabilities. Taken together, these results suggest that this peptide, which has immunomodulatory properties, may have therapeutic capacities. The fact that insects may produce cytokine-like materials modulating basic mechanisms for human immunity suggests a source of anti-infection and antitumoral biopharmaceuticals.

[A comparative evaluation of modern antibacterial preparations in the treatment of a severe degree of periodontitis at a stage of exacerbation]

Sensitivities of peptostreptococci, streptococci, Actinomyces, bacteroid, and fusobacterial strains pathogenic for the periodontium to wide-spectrum penicillines, cephalosporines, lincomycin, macrolides, metronidasole, and nitasole are compared. New macrolide antibiotics rulide. Macropene, gramicidin C, levomycetin, and rifampicin are highly effective. Some narrow-spectrum drugs, e.g. augmentin, cephalexin, and vancomycin (towards actinomycetes) were highly effective, too.

[The immunomodulating and immunoprotective activity of small ribonucleoprotein complexes (alpha RNPs) from the LRec-1sf cell line]

Effect of nuclear and released into culture medium alpha RNPs (N- and R-alpha-RNPs, resp.) produced by transformed rat embryo fibroblasts of serum-free cell line LRec-1sf on the nonsensibilized mouse splenocyte cytotoxicity (NK-mediated cell lysis) was studied. A preliminary treatment with N-alpha-RNPs resulted in decreasing K562 cell sensitivity to splenocyte cytotoxicity, whereas pretreatment of the splenocytes themselves exerted no cytotoxic effect. The target cell preincubation with R-alpha-RNPs had no influence on K562 cell resistance to NK cell cytotoxicity. The identical splenocyte preincubation was without action on their cytotoxic effect to LRec-1sf cells, however, resulted in an increase of the K562 cell lysis. The addition of R-alpha-RNPs into splenocyte/target cell mixtures had no influence on NK-mediated lysis, when K562 cells were used as a target cell line, but suppressed the NK-mediated lysis of LRec-1sf cells. The results of the present experiments suggest that alpha RNPs produced by LRec-1sf cell line exhibit the capacity for modulating both mouse NK cytotoxicity, and the transformed cell sensitivity to NK-mediated lysis.

[A trial of the use of rulid, sumamed and makropen in the combined treatment of generalized periodontitis at a stage of exacerbation]

In vitro study of the antibacterial activity of macrolide antibiotics azitromycin (sumamed), midicamycin (macropen), roxitromycin (rulide), and erythromycin demonstrated their high activity towards clinical strains of bacteroids, fusobacteria, peptostreptococci, streptococci, and corynebacteria. These antibiotics were effective in the treatment of 62 adult patients with severe and moderate generalized periodontitis. Rulide and sumamed were the most effective, macropen and erythromycin were inferior to them.

[The choice of antibacterial preparations for the combined treatment of periodontitis in the exacerbation stage]

Antibiotic sensitivities of peptostreptococci, streptococci, Actinomyces, bacteroid, and fusobacterial strains pathogenic for the periodontium are analyzed. The sensitivities of these bacteria to broad-spectrum penicillins, cephalosporines, lincomycin, and macrolides, and to metronidasole and nitasole are assessed. New macrolide drugs macropen and rulide and gramicidine C, levomycetine, and rifampicin are highly active towards the above microflora. Microbiological indications for oral and local use of these antibiotics are validated. Some narrow-spectrum antibiotics, such as augmentine, cephalexin, and vancomicin are highly active, too; the latter drug is specifically active towards Actinomyces.

[The growth-stimulating and immunomodulating activity of culture media conditioned by transformed fibroblasts from serum-free lines]

Five cell lines of transformed rodent fibroblasts capable of unlimited growth without exogenous proteins were studied. It has been demonstrated that the media conditioned by these cells (CMs), the protein preparations obtained from CMs, or the feeder cell cultures of the serum-free cell lines are mitogenic to mouse hybridoma cells as well as to primary cell cultures of the rat bone marrow. The addition of CMs proteins into mixtures of mouse splenocytes and transformed target cells resulted in stimulation or suppression of the splenocyte cytotoxicity when YAC-1 [correction of JAC-1] or K562 cell targets were used. A 18-20 h splenocyte preincubation with proteins, released by transformed rat fibroblasts of the serum-free cell line LRec-1sf, resulted in a 1.5-4-fold increase in K562 cell lysis by murine natural killer cells. By contrast, the target cell preincubation with the same proteins resulted in a 1.5-2-fold decrease in K562 cell sensitivity to cytotoxic effect of natural killer cells. Taken together our data show that the transformed rodent fibroblasts, growing without exogenous proteins, produce and release into the culture medium some growth stimulating, immunomodulating and immunoprotective factors.

[The comparative characteristics of stimulators of reparative osteogenesis in the treatment of periodontal diseases]

The authors compare the efficacy of ultra highly dispersed hydroxyapatite (brand OSTIM-100) and demineralized bone matrix implanted to 395 patients for repair of bone defects. OSTIM-100 was found not inferior to bone transplant, but devoid of its shortcomings. Complications occurred in 1.5% cases and never involved the site of osteoplasty, whereas in the group transplanted bone matrix 3.6% patients developed complications, which were frequently associated with the graft rejection. OSTIM-100 was particularly effective in the treatment of periodontitis at the stage of abscesses. It is convenient and recommended, in combination with membranes of directed regeneration of tissues (GORE-TEX), for surgical treatment of patients with periodontal diseases.

[The effect of anti-T sera on the natural killer activity of the splenocytes in C3HA mice at different times after the transplantation of hepatoma 22a cells]

Suspension of splenocytes of control C3HA mice and mice examined early after transplantation of mouse hepatoma 22a cells were fractionated by treatment with anti-T-sera (anti-thymocytes, antibrain and anti-suppressor-T-cells). This treatment leads to various changes in NK-activity due to elimination of different subpopulations of T-lymphocytes. This variability may be associated with the presence of two or more types of suppressor cells able to influence the NK-cells directly or by means of other immunocompetent cells.

[Amine oxidase activity and blood serotonin levels in cancer of the gastro-intestinal tract and lung]

Activity of amine oxidase less than using serotonin as a substrate greater than and content of serotonin were studied in blood of healthy persons and in patients with carcinoma of stomach, intestine and lung at the III-IV steps of the disease. In the patients with carcinoma of gastrointestinal tract the amine oxidase activity was decreased 2-fold and in the patients with carcinoma of lung it was decreased 4-fold as compared with controls. At the same time, content of serotonin was increased both in blood plasma and in blood platelets of the patients. The increase in content of serotonin depends on localization of the tumors.

[Sympathico-adrenal system in lung cancer]

The functional state of sympatho-adrenal system in pulmonary cancer patients, healthy subjects and cases of pneumonia and tuberculosis is compared. It was established that the tone of sympatho-adrenal system in pulmonary cancer patients is abnormally low. This is apparent at the early stages of malignant disease. Administration of substances which stimulate redox processes in tissues and the activity of vegetative centers leads to normalization of the functional state of sympatho-adrenal system in pulmonary cancer patients.