Cytogenetic effect of the antineoplastic anthracycline antibiotic 4'-epidoxorubicin

Cytogenetic action of 4'-epidoxorubicin (farmorubicin), an antitumor antibiotic was studied with using rat bone marrow cells. It was shown that after intraperitoneal administration the antibiotic increased the number of the aberrant metaphases when the dose was not lower than that equivalent to 1/30 of the LD50. The number of the aberrant metaphases increased with increasing of the antibiotic dose. The maximum number of the cells with impaired chromosomal apparatus was observed 6 hours after the antibiotic administration. In 72 hours it decreased to the level of spontaneous mutations in myelocariocytes. Cytogenetic activity of 4'-epidoxorubicin was comparable to that of doxorubicin (adriablastin) widely used in medical practice.     

Quantitative determination of anthracycline antibiotic binding with DNA]

A new method of quantitative intravital assessment of anthracyclines accumulation and binding with DNA in alive cells has been developed. For this purpose DNA specific fluorescent dye Hoechst 33258 was used. Extent of fluorescence quenching of bound with DNA dye correlated with binding of daunomycin with cell DNA after mixing solutions of the drug and cells. It allowed us to determine quantity of drug molecules bound with DNA in the cells during the time.     

Kinetics of anthracycline antibiotic free radical formation and reductive glycosidase activity

Adriamycin free radical anion concentrations have been correlated with production of 7-deoxyadriamycin aglycone in a reaction catalyzed by NADPH-cytochrome c reductase. The free radical species is detected by electron spin resonance (ESR) spectroscopy and quantified by double integrations. The 7-deoxyaglycone product is isolated by thin-layer chromatography (TLC) and quantified by fluorometry. As the concentration of adriamycin increases, a concomitant increase in aglycone and free radical levels occurs. These results as well as those with inhibitors Vitamin K₃, Vitamin E, and 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) point to an obligatory free radical intermediate in the metabolism of adriamycin. DMPO inhibits the reaction under aerobic conditions only, and shows no effect under anaerobiosis at the concentrations studied here. Vitamin E and aerobic DMPO act as free radical scavangers, while Vitamin K₃ competes for the reducing power of NADPH in the NADPH-cytochrome c reductase system.     

The antitumor activity of liposomal aclarubicin in vitro and in vivo]

Study on antitumor activity of free and liposomal anthracycline antibiotic aclarubicin in vitro and in vivo showed that liposomal aclarubicin was characterised by activity against ascitic Ehrlich carcinoma comparable to that of free aclarubicin when used in a dose of 25 mg/kg. Liposomal antibiotic had a more pronounced antimetastatic action and showed no toxicity (in a dose of 30 mg/kg). Liposomal aclarubicin had a higher activating capacity with respect to the macrophage tumoricidal properties.     

Comparative study of the cardiotoxicity of the anthracycline antibiotics, carminomycin and adriamycin, in white mice]

The cardiotoxic effect of karminomycin and adriamycin administered intravenously for 5 times in equitoxic doses constituting equal portions of LD50 of the respective antibiotic on its single intravenous administration was studied on albino mice. Histological examination of the heart showed that almost identical damages of the myocardium occured after administration of karminomycin and adriamycin in doses of 0.45 of LD50 (1.5 mg/kg) and 0.3 of LD50 (6.3 mg/kg) respectively. The character of the damages due to the antibiotics was close, the most significant changes were observed when the animals were sacrificed 1 month after the last administration of the drug. The histological method is of value in estimation of the cardiotoxic effect of the drugs, using mice as the model suitable for the investigation. Adriamycin had more pronounced cumulative properties as compared to karminomycin: suppression of the weight gain in the mice and their death rate were higher with the use of adriamycin.     

Inhibitory effect of rat immunization with tularemia vaccine on the in vivo clastogenicity of 4 anthracycline antibiotics

We studied the in vivo effect of rat immunization with tularemia live vaccine (TLV) on chromosomal aberrations (CA) induced in bone marrow cells by 4 anthracycline antibiotics. CA induced by adriamycin (ADR) and 4'-epiadriamycin (EADR) in rat bone marrow cells consisted mainly of chromatid breaks (approximately 90%), whereas lesions induced by aclacur (AC) and aclarubicin (ACR) consisted only of chromatid breaks. Preliminary cutaneous immunization of rats with TLV revealed significant suppression of CA induced by all 4 antibiotics. The present and previous results suggest that TLV may be a potent anticlastogenic factor.     

Depressed T-cell reactivity and suppressor activity of lymphoid cells from cyclophosphamide-treated mice

A study was made of the in vitro proliferative activity of thymus-derived lymphoid cells from cyclophosphamide-treated mice (Cy-mice) and the relationship between this and some in vivo immunological responses. The proliferative response to phytohaemagglutinin (PHA) and allogeneic cells was depressed for up to 3 weeks after drug treatment in spleen and lymph node cells, responsiveness recovering more rapidly in lymph node cells. Cell concentration in culture was shown to be important in such measurements as cells from some Cy-mice were able to inhibit their own proliferation and that of normal lymph node cells. No stable soluble factor responsible for this effect could be isolated. It was shown that in vitro proliferative activity is not a good indicator of in vivo T-cell capability as indicated by the very rapid recovery of ability to reject skin grafts and the fairly rapid recovery of ability to produce cytotoxic cells compared to the slower recovery of in vitro T-cell activities.     

Inhibitory effect of zeatin, isolated from Fiatoua villosa, on acetylcholinesterase activity from PC12 cells

Acetylcholinesterase (AChE) inhibitors, which enhance cholinergic transmission by reducing the enzymatic degradation of acetylcholine, are the only source of the compound that is currently approved for the treatment of Alzheimer's disease (AD). The methanol extract from Fiatoua villosa among 100 traditional edible plants that were tested, showed the most potent inhibitory effect (51%) on acetylcholinesterase in vitro. After the sequential solvent fractionation of the methanol extract of Fiatoua villosa, the active fraction was repeatedly subjected to open-column chromatography on silica gel. From the highest inhibitory fraction, the chloroform fraction (75%) on AChE, the single compound, was obtained by the Sep-Pak Cartridge (C18: reverse phase column). This compound was finally purified by HPLC (micro-bondapack C18 reverse phase column: 19 x 300 mm). According to the electron impact mass spectrometry (EI-MS), we confirmed that the molecular mass was 219 m/z. The structure of this compound was identified as zeatin [2-methyl-4-(1H-purine-6-ylamino)-2-buten-1-ol], one of the derivatives of purine adenine. The concentration that was required for 50% enzyme inhibition (IC50 value) was 1.09 x 10(-4) M. This study demonstrated that the zeatin from Fiatoua villosa appeared to be the most potent AChE inhibitor in AD.     

The effect of indomethacin on the activation and effector function of suppressor cells from tumor-bearing mice

Summary The spleens of mice with large M-1 fibrosarcomas contain two populations of suppressor cells with the properties of macrophages and T cells. In this study, we tested the effect of indomethacin on suppressor cell activation and effector function. Neither the activation nor the effector function of the suppressor macrophages was inhibited by indomethacin, and the activity of suppressor macrophages correlated with the tumor size. In contrast, the treatment of tumor-bearing mice with indomethacin from the day of injection of tumor cells completely blocked the in vivo activation of suppressor T cells. Indomethacin did not, however, depress suppressor T cell activity if mice were treated only during the third week of tumor growth. The effector function of the suppressor T cells, as assessed in mixing assays, was partially blocked by indomethacin, while selective suppression by low-molecular-weight factors was completely blocked if indomethacin was present in the cultures. Furthermore, the in vitro activation of suppressor cells by soluble factors secreted by tumor-bearer spleen cells was completely blocked by indomethacin, and this inhibition was reversed by prostaglandin E₁. These data are consistent with the hypothesis that prostaglandins are involved in the activation, but not the effector function, of tumor-activated suppressor T cells.     

The effect of cyclosporin A on the islet cells of mice]

The action of immunosuppressive agent ciclosporin A on the insular apparatus was studied with an original method of cytochemical zinc detection in experiments on mice. The drug was found to lower zinc levels in pancreatic beta-cells. In ciclosporin A pretreatment the sensitivity of mice to zinc-binding diabetogenic agent enhanced.     

Inhibitory activity of four demethoxy fluorinated anthracycline analogs against five human-tumor cell lines

Four anthracycline analogs synthesized in our laboratory were evaluated in comparison with adriamycin (doxorubicin) for their growth-inhibitory effect against five human-tumor cell lines, including lung carcinoma, colon adenocarcinoma, breast adenocarcinoma, melanoma, and glioblastoma. The compounds included 4-demethoxy-7-O-(2,6-dideoxy-2-fluoro--l-talopyranosyl)daunomycinone (2), its 3′,4′-diacetate (1), its 14-bromo derivative 3, and its 14-hydroxy analog, namely 4-demethoxy-7-O-(2,6-dideoxy-2-fluoro-α-l-talopyranosyl)adriamycinone (4). Compounds 1, 2, and 3 showed moderate cytotoxic effect in most of the cell lines, while compound 4 had a strong effect, comparable to or better than that of adriamycin in most of the cell lines.     

Effect of terrilytin on antifungal antibiotic activity]

The antifungal activity of terrilitine, an enzymatic preparation of microbial origin and its effect on the activity of antifungal polyenic antibiotics and griseofulvine were studied in vitro. It was found with the method of serial dilutions in Sabourand's liquid medium that terrilitine was active against C. albicans and certain dermatophytes. In combination with amphotericin B, amphoglucamine, mycoheptine, levorin, nystatin or griseofulvin it increased the activity of these antibiotics 2-16 times.     

Inhibitory effect of memantine, an NMDA-receptor antagonist, on electroporation-induced inward currents in pituitary GH3 cells

Experimental and clinical data support the notion that peroxisome proliferator-activated receptor γ (PPARγ) activation is associated with anti-atherosclerosis as well as anti-diabetic effect. Telmisartan, an angiotensin receptor blocker (ARB), acts as a partial PPARγ agonist. We hypothesized that telmisartan protects against diabetic vascular complications, through PPARγ activation. We compared the effects of telmisartan, telmisartan combined with GW9662 (a PPARγ antagonist), and losartan with no PPARγ activity on vascular injury in obese type 2 diabetic db/db mice. Compared to losartan, telmisartan significantly ameliorated vascular endothelial dysfunction, downregulation of phospho-eNOS, and coronary arterial remodeling in db/db mice. More vascular protective effects of telmisartan than losartan were associated with greater anti-inflammatory effects of telmisartan, as shown by attenuation of vascular nuclear factor kappa B (NFκB) activation and tumor necrosis factor α. Coadministration of GW9662 with telmisartan abolished the above mentioned greater protective effects of telmisartan against vascular injury than losartan in db/db mice. Thus, PPARγ activity appears to be involved in the vascular protective effects of telmisartan in db/db mice. Moreover, telmisartan, but not losartan, prevented the downregulation of vascular PPARγ in db/db mice and this effect of telmisartan was cancelled by the coadministration of GW9662. Our data provided the first evidence indicating that PPARγ activity of telmisartan contributed to the protective effects of telmisartan against diabetic vascular complication. PPARγ activity of telmisartan was involved in the normalization of vascular PPARγ downregulation in diabetic mice. Thus, telmisartan seems to exert vascular protective effects in hypertensive patients with diabetes.     

Subsets of myeloid-derived suppressor cells in tumor-bearing mice

Myeloid-derived suppressor cells (MDSC) are a heterogeneous group of cells that play a critical role in tumor associated immune suppression. In an attempt to identify a specific subset of MDSC primarily responsible for immunosuppressive features of these cells, 10 different tumor models were investigated. All models showed variable but significant increase in the population of MDSC. Variability of MDSC expansion in vivo matched closely the effect of tumor cell condition medium in vitro. MDSC consists of two major subsets of Ly6G(+)Ly6C(low) granulocytic and Ly6G(-)Ly6C(high) monocytic cells. Granulocytic MDSC have increased level of reactive oxygen species and undetectable level of NO whereas monocytic MDSC had increased level of NO but undetectable levels of reactive oxygen species. However, their suppressive activity per cell basis was comparable. Almost all tumor models demonstrated a preferential expansion of granulocytic subset of MDSC. We performed a phenotypical and functional analysis of several surface molecules previously suggested to be involved in MDSC-mediated suppression of T cells: CD115, CD124, CD80, PD-L1, and PD-L2. Although substantial proportion of MDSC expressed those molecules no differences in the level of their expression or the proportion, positive cells were found between MDSC and cells from tumor-free mice that lack immune suppressive activity. The level of MDSC-mediated T cell suppression did not depend on the expression of these molecules. These data indicate that suppressive features of MDSC is caused not by expansion of a specific subset but more likely represent a functional state of these cells.     

芹菜多糖抑制小鼠肺癌的作用研究*

目的:探讨芹菜多糖抗肺癌的作用及机制。方法:提取纯化芹菜多糖,通过红外光谱和凝胶渗透色谱法对其进行鉴定;每只小鼠腹股沟皮下注射2×10⁷个Lewis肺癌细胞,建立肺癌C57BL/6小鼠模型,随机分为5组,每组10只。两天后,分别0、25、50、75、100 mg/kg芹菜多糖灌胃荷瘤小鼠10 d,流式和qPCR法分析小鼠外周血CD4⁺、CD8⁺淋巴细胞和脾淋巴细胞因子IL-2、IFN-γ与IL-4,并取肿瘤组织拍照和称重。结果:本实验所提取的芹菜多糖纯度为82%,鉴定为不均一的多糖,分子量为1.17×10³ kD;芹菜多糖灌胃小鼠可显著抑制肺癌的生长(P＜0.01),75 mg / kg治疗10 d后,可提高小鼠外周血CD4⁺和CD8⁺淋巴细胞的百分比(P ＜0.01),并明显增加50 mg / kg以上治疗组的脾淋巴细胞IL-2、IFN-γ和IL-4的转录水平(P ＜0.01)。结论:芹菜多糖可通过增强机体免疫,尤其是细胞免疫而发挥抗肺癌的作用。     

Inhibitory effect of carboxymethylpachymaran on cyclophosphamide-induced oxidative stress in mice

The aim of the present study was to investigate the immunomodulatory effect and antioxidant activity of carboxymethylpachymaran on cyclophosphamide-induced immunosuppression in mice in vivo. The results showed that carboxymethylpachymaran could be used to overcome the cyclophosphamide-induced immunosuppression in mice. Moreover, it significantly increased the thymus and spleen indices, lysozyme, catalase and superoxidase dismutase activities, and total antioxidant capacity. In contrast, it decreased xanthine oxidase activity and malondialdehyde levels. The results indicated that carboxymethylpachymaran might play an important role in the prevention of oxidative damage in the immunological system.