Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

12-O-Tetradecanoylphorbol-13-acetate, a potent promoter of carcinogenesis in mouse skin, enhanced differentiation of cultured mouse myeloid leukemia cells (M1) induced by human urinary protein or by lipopolysaccharide from Salmonella typhosa. 12-O-Tetradecanoylphorbol-13-acetate enhanced differentiation of all the markers tested, such as phagocytosis, Fc rosette formation, lysozyme activity, and morphological change. Other potent tumor-promoting macrocyclic plant diterpenes also enhanced the induction of differentiation, but no-tumor-promoting diterpenes did not. These findings were in marked contrast with generally accepted findings on the inhibitory effect of 12-O-tetradecanoylphorbol-13-acetate on terminal differentiation observed in other cell culture systems but consistent with the observations with some kinds of leukemia cells.
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PMID:Enhancing effect of phorbol esters on induction of differentiation of mouse myeloid leukemia cells by human urinary protein and lipopolysaccharide. 29 79

The cytosol fraction of J774-1 murine macrophages activated with lipopolysaccharide (LPS) + interferon-gamma (IFN-gamma) was found to nitrosate a wide range of secondary and tertiary amines. The reaction was dependent on L-arginine and NADPH. The optimal pH for nitrosation was 7.2-7.3. Nitrosation was inhibited by arginine derivatives such as NG-monomethyl-L-arginine and NG-nitro-L-arginine, well-known inhibitors of nitric oxide (NO) synthase. These results indicate that nitrosation is mediated by NO synthase, which catalyzes formation of NO and L-citrulline from L-arginine. Nitrosamine formation also required oxygen and was inversely correlated with the basicity of nitrosatable amines. The nitrosation was inhibited by oxyhemoglobin, an NO trapping agent, and enhanced by superoxide dismutase, which stabilizes NO. LPS + IFN-gamma induced approximately 500-600 times greater nitrosation activity than that of non-activated macrophages. Macrophages treated with LPS alone exhibited 3-4 times greater nitrosation activity than untreated macrophages, whereas macrophages treated with IFN-gamma alone did not show enhanced nitrosation activity. A combination of the cytosols from macrophages treated with LPS alone and IFN-gamma alone did not nitrosate morpholine as rapidly as the cytosol of macrophages treated with both compounds together. The activity for forming L-citrulline and nitrite/nitrate from L-arginine was markedly induced by treatment with either LPS alone or LPS + IFN-gamma but not with IFN-gamma. Those results suggest that some other factor(s) in addition to NO synthase is involved for efficient nitrosation by the macrophage cytosol. This factor(s) was not induced in macrophages by either LPS- or IFN-gamma alone, but was induced only in the presence of the two compounds.
Carcinogenesis 1991 Jul
PMID:L-arginine-dependent formation of N-nitrosamines by the cytosol of macrophages activated with lipopolysaccharide and interferon-gamma. 171 76

The endogenous formation of nitrate in the rat, mouse and human occurs through cellular processes involving the oxidation of the guanido group of arginine. These processes proceed from arginine to nitric oxide with subsequent conversion to electrophilic nitrosating agents capable of forming carcinogenic nitrosamines. We have now demonstrated that endogenous nitrosamine formation can occur via cells stimulated in vivo by bacterial lipopolysaccharide (LPS). The nitrosation of morpholine given to rats by i.p. injection yields N-nitrosomorpholine (NMOR) which is subsequently oxidized in the liver. A major metabolite of NMOR, N-nitroso-(2-hydroxyethyl)glycine, was previously shown by other investigators to be excreted into urine. Treatment of rats with LPS, arginine and morpholine creates a large increase in NMOR urinary metabolites over a 24-h period. This process is not influenced by simultaneous dosage with large amounts of NaNO3. Therefore the endogenous LPS-induced formation of NMOR proceeds directly from nitric oxide prior to incorporation into the nitrate body pool. The proportion of endogenously synthesized nitric oxide incorporated into NMOR is approximately 3 x 10(-6).
Carcinogenesis 1991 Mar
PMID:Endogenous incorporation of nitric oxide from L-arginine into N-nitrosomorpholine stimulated by Escherichia coli lipopolysaccharide in the rat. 184 54

Marked formation of N-nitrosothioproline (N-nitrosothiazolidine-4-carboxylic acid) by stimulation with Escherichia coli lipopolysaccharide (LPS) was demonstrated in ascorbic acid-deficient mutant rats (osteogenic disorder syndrome rats; ODS rats) unable to synthesize ascorbic acid. The amounts of urinary nitrate and N-nitrosothioproline excretion after thioproline administration was measured in ODS rats with and without ascorbic acid supplement before and after the injection of LPS. LPS caused marked increase of urinary nitrate excretion in both groups. Urinary N-nitrosothioproline excretion increased 6-fold after LPS injection in ODS rats not supplied with ascorbic acid, but supplement with ascorbic acid markedly decreased the excretion of N-nitrosothioproline.
Carcinogenesis 1990 Oct
PMID:Marked nitrosation by stimulation with lipopolysaccharide in ascorbic acid-deficient rats. 220 2

The addition of sodium nitrite (NaNO2; 5-20 mM) for 72 h to mouse BALB/c3T3 cells resulted in the induction of transformed foci (type III foci) in a dose-dependent manner. The cells isolated from the NaNO2-induced transformed foci produced progressively growing tumors when inoculated into nude mice subcutaneously at an inoculum size of 1 X 10(6) cells per site. In contrast, the original untreated cells did not take even at an inoculum size of 1 X 10(7) cells per site. The possibility that NaNO2 might react with cellular or medium components to make carcinogenic N-nitrosamines and that these might induce cell transformation was examined and almost excluded. Thus, nitrite itself seems to have a cell transforming activity. Recent evidence suggests that NO2- is produced by the activated macrophages of mammals. We also detected NO2- production in culture media in the mouse macrophage-like cell line J774-A1 after lipopolysaccharide (LPS) treatment, and also in the human promyeloleukemia cell line HL60 after differentiation into macrophage-like cells by 12-O-tetradecanoyl phorbol-13-acetate and further activation by LPS.
Carcinogenesis 1990 Apr
PMID:Malignant transformation of mouse BALB/c3T3 cells induced by NaNO2. 232 1

L-Arginine, the primary nitrogen source for nitric oxide synthesized by many cell types in culture and for biosynthesized nitrate in humans, is also a nitrogen source for biosynthesized nitrate in rats and ferrets. After administration of [15N2]L-arginine to rats and ferrets, [15N]NO3- was detected in urine. Escherichia coli lipopolysaccharide induced more than a 10-fold increase in urinary nitrate in rats and a parallel increase in incorporation of 15N from [15N2]L-arginine into NO3-. Bradykinin, a vasodilator which induces nitric oxide production by endothelial cells in vitro, lacked detectable effect on urinary nitrate or on incorporation of L-arginine nitrogen into nitrate in rats. A prolonged period of vasodilation brought on by an extended period of exercise increased urinary nitrate 2-fold in human subjects. In the rat, recoveries in 24 h post-dose urine collections of [15N]NO3- given i.v. and i.p. were 75 and 64% respectively, while in the ferret, recoveries of i.v. and per os [15N]NO3- doses were 49 and 34% respectively. Thus, nitrate synthesized by mammalian cells in vivo would undergo losses similar to those for exogenous nitrate.
Carcinogenesis 1990 May
PMID:Nitrate biosynthesis in rats, ferrets and humans. Precursor studies with L-arginine. 233 12

We investigated whether treatment with the interferon inducer polyinosinic-polycytidylic acid and other cytokines (interleukin-1, tumor necrosis factor) or the cytokine inducer lipopolysaccharide modified O6-alkylguanine-DNA alkyltransferase (AT) in rat liver. AT levels were determined in liver extracts using N-[3H]methyl-N-nitrosourea alkylated calf thymus DNA as substrate and an HPLC procedure to measure O6-methylguanine. Doses as low as 0.1 mg/kg i.p. of polyinosinic-polycytidylic acid caused a highly significant increase (P less than 0.01) in AT levels in the liver, evident either 24 or 48 h after treatment. Lipopolysaccharide at the dose of 80 micrograms/kg i.p. also induced AT whereas interleukin-1 (60 micrograms/kg) or tumor necrosis factor (60 micrograms/kg) were inactive. Treatment with human recombinant interferon alpha A/D caused a highly significant increase in AT levels, thus confirming the hypothesis that interferon was probably responsible for the observed effect. These results suggest a link between the immune response and DNA repair mechanisms.
Carcinogenesis 1990 Jan
PMID:Interferon inducers increase O6-alkylguanine-DNA alkyltransferase in the rat liver. 240 58

Rats and mice treated in vivo with Escherichia coli lipopolysaccharide (LPS) synthesize and excrete large quantities of nitrate. Murine peritoneal macrophages, elicited in vivo with thioglycolate and stimulated in vitro with LPS and/or gamma-interferon (IFN), produce copious amounts of nitrate and nitrite. We report here experiments showing N-nitrosamine formation by macrophages immunostimulated in vitro. Macrophage cell lines J774.1, PU5-1.8, WEHI-3 and RAW 264 and freshly isolated macrophages from C3H/He mice were used. Macrophages were cultured in Dulbecco's modified Eagle's medium (pH 7.5) supplemented with calf serum (10%). Supernatant NO2- and NO3- were measured. N-Nitrosamines were extracted with dichloromethane and the extracts analyzed by a gas chromatography--thermal energy analyzer. Cells (1.5 X 10(6)/ml) were incubated with LPS (10 micrograms/ml) and morpholine (15 mM) for 72 h at 37 degrees C. Under these conditions, all of the cell types listed above produced nitrite (40-70 microM) and N-nitrosomorpholine (NMOR; 114-940 nM). LPS was required for both processes, and this effect was enhanced by IFN. Nitrite (150 microM) incubated with morpholine in cell-free medium did not form NMOR nor did cells plus morpholine and NO2-. The rate of NMOR formation in the J774.1 cell line was highest in the middle incubation period (24-36 h) although [NO2-] was highest in the final incubation period (48-72 h). Thus, the cells do not catalyze nitrosamine formation per se, rather the amine traps out a reactive nitrosating species prior to the formation of NO2- and NO3-. These results suggest that immunostimulated macrophages may be capable of nitrosamine formation under physiological conditions.
Carcinogenesis 1987 Jul
PMID:Nitrosation of amines by stimulated macrophages. 243 25

Model systems to study the effects of chemicals of environmental concern on bacterial and parasitic diseases as well as the immunosurveillance and destruction of transplantable tumor cells were described and evaluated. Studies were conducted in female B6C3F1 mice following adult or pre/postnatal exposure to several prototype chemicals. The prototype chemicals employed included the synthetic estrogen diethylstilbestrol (DES), the polycyclic aromatic hydrocarbon benzo(a)pyrene (B[a]P), and the carcinogenesis promoting agent 12-0-tetradecanoyl-phorbol-13-0-acetate (TPA). The host resistance models employed depend primarily on functional thymus-dependent immunity, although humoral immunity is suggested to have a role in the parasite model as well. These models include: subcutaneous challenge with a dose of PYB6 tumor cell causing a 10-20% incidence (TD(10-20)) of tumor; intravenous challenge with B16 melanoma cells; challenge with a dose of Listeria monocytogenes causing a 10-20% incidence of mortality (LD(10-20)); challenge with a dose of E. coli lipopolysaccharide endotoxin causing a 10-20% incidence of lethality (LD(10-20)); and challenge with larvae of Trichinella spiralis for parasite expulsion kinetic studies. Increased mortality was observed following Listeria monocytogenes challenge in DES-exposed mice. B(a)P and TPA exposure did not alter host resistance to this organism. The increased mortality observed following DES was associated with a significant increase in the number of viable Listeria in the spleens and livers at 4 days, a time when T-cell immunity is thought to be expressed, but bacterial counts were similar to control mice at day 1, a time when MPhi are thought to exert their greatest effect. These data suggest that the increased Listeria susceptibility found following DES exposure may result from a T-cell defect, although the intracellular killing capacity of DES-treated Mvarphi's has not been well examined. Tumor susceptibility studies following challenge with 5 x 10(3) viable syngeneic PYB6 tumor cells revealed that nontreated adult B6C3F1 mice resisted tumor formation, with only a 10-20% incidence of tumor formation. In contrast, mice exposed to DES or TPA as adults had a tumor frequency of from 70-100% following TPA and up to 90% following DES exposure. In all cases the tumors were progressive and resulted in death. B(a)P did not alter the frequency of tumor incidence from controls in this model. Preliminary data, using the B16 melanoma intravenous challenge model and (125)IUdR to quantitate tumor mass revealed this model was sensitive to non-specifically activated macrophage kill. DES treated mice with activated macrophages did not demonstrate increased tumor mass, while mice exposed to TPA or the potent immunosuppressive agent cyclophosphamide had a significantly increased tumor mass in their lungs. Expulsion of Trichinella spiralis adults from the gut also apparently required functional T-cells and possibly some element of humoral immunity. Mice exposed to DES and B(a)P exhibited increased numbers of adult worms in the gut at day 14. Sensitivity to gram-negative endotoxin (LPS) was apparently increased following exposure to DES or B(a)P. These data suggest that the detoxification of LPS is related to an intact Mvarphi population. The data presented here demonstrate the sensitivity of the host resistance assay panel proposed for detecting immune alteration. Alteration of T-cell function appeared to correlate with increased susceptibility to bacterial and tumor cell challenge.
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PMID:Application of tumor, bacterial and parasite susceptibility assays to study immune alterations induced by environmental chemicals. 706 May 48

L-Arginine-derived nitric oxide (NO) and its derivatives, such as peroxynitrite and nitrogen dioxide, play a role in inflammation and also possibly in the multistage process of carcinogenesis. We investigated the effect of various non-steroidal anti-inflammatory agents and related compounds on the induction of NO synthase (NOS) in RAW 264.7 macrophages activated with lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma). Low concentrations of curcumin, a potent anti-tumour agent having anti-inflammatory and anti-oxidant properties, inhibited NO production, as measured by the amount of nitrite released into the culture medium in 24 h (IC50 = 6 microM). NOS activity in soluble extracts of macrophages activated for 6-24 h in the presence of curcumin (10 microM) was significantly lower than that of macrophages activated without curcumin. Northern-blot and immunoblotting analyses demonstrated that significantly reduced levels of the mRNA and 130-kDa protein of inducible NOS were expressed in macrophages activated with curcumin, compared to those without curcumin. Inhibition of NOS induction was maximal when curcumin was added together with LPS and IFN-gamma and decreased progressively as the interval between curcumin and LPS/IFN-gamma was increased to 18 h.
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PMID:Curcumin, an anti-tumour promoter and anti-inflammatory agent, inhibits induction of nitric oxide synthase in activated macrophages. 753 2


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