Retrospective analyses of m-RNA gene expression profile from formalin fixed paraffin embedded (FFPE) specimens in colorectal cancer (CRC) and correlation with chemoresponsiveness

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Background: Patients with chemoresponsive tumors are more likely to have a survival advantage, consequently a great interest is being placed on the identification of predictive markers. Currently, the improving in the extraction techniques allow the detection of gene profile at the mRNA level from FFPE materials. The purpose of the study was to analyse the m-RNA level of specific genes from FFPE (Stanta et al, BioTechniques 1998), both primary tumor (T) and locoregional lymphnodes (N) in CRC patients treated with chemotherapy (CT), and to relate it with chemoresponsiveness. Material and Methods: RNA was extract from FFPE tumor specimen both in T and N. RNA was reversing transcribed to cDNA. From the cDNA sample, BRCA1, ERCC1, CES2 and TS gene transcripts were specifically amplified by PCR. ERCC1 and BRCA1 are involved in platinum-compound resistance; TS is involved in responses to 5Fluorouracil (5FU) and CES2 level expression was recently related to Irinotecan pro-drug activation. Eligible patients included metastatic CRC patients treated from March 2000 to December 2003 as first line CT with Oxaliplatin/5FU or Irinotecan/5FU or 5FU alone. Results: Forty-five consecutive patients were retrospectively analysed. 15 of them received Oxaliplatin/5FU, 15 Irinotecan/5FU and the other 15 5FU alone. Median age was 64 (range 46–75). 13 patients (28%) had received adjuvant CT. 32 patients (72%) had metastatic disease at the time of surgery. Global Response Rate was 44%. All 45 patients received 5FU and they were analysed for the level of TS expression. With Multiple Regression Analysis, no statistical significant relation between TS level expression and response to 5FU was observed (P=0.36). A strong relation was observed between ERCC1 and response to Oxaliplatin (P=0.006) and a possible correlation of BRCA1-exon11 level expression and response to Irinotecan (P=0.06). The analyses of CES2 and the relation between gene expression and survival are ongoing. Conclusions: The analyses of mRNA gene expression profile from FFPE could be use to predicting response to CT in CRC patients. To test this hypothesis, a randomized phase II-III prospective study of tailored therapy in metastatic CRC is planned.

No significant financial relationships to disclose.

Transcription factor decoy oligodeoxynucleotides to nuclear factor-kappaB inhibit reverse passive Arthus reaction in rat

In the present study we investigated in the reverse passive Arthus reaction elicited in the rat skin the anti-inflammatory effect of double-stranded oligodeoxynucleotides (ODN) with consensus nuclear factor-kappaB (NF-kappaB) sequence as transcription factor decoys (TFD) to inhibit NF-kappaB binding to native DNA sites. Local administration of wild-type-, but not mutant-decoy ODN, dose-dependently reduced both plasma leakage and neutrophil infiltration in rat skin. Molecular analysis performed on soft tissue obtained from rat skin demonstrated: (1) an inhibition of NF-kappaB/DNA binding activity; (2) a decreased nuclear level of p50 and p65 NF-kappaB subunits; (3) an inhibition of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) protein expression, two inflammatory enzymes transcriptionally controlled by NF-kappaB. Furthermore, SN-50, a cell-permeable peptide capable of inhibiting the nuclear translocation of NF-kappaB complexes, as well as ammonium pyrrolidine dithiocarbamate, an inhibitor of NF-kappaB activation, exhibited a similar profile of activity of decoy ODN. Our results indicate that decoy ODN, acting as an in vivo competitor for the transcription factor's ability to bind to cognate recognition sequence, may represent a novel strategy to modulate immune reactions.

Role of nuclear factor-kappaB in a rat model of vascular injury

In this study we have investigated the relationship between neointima formation and NF-kappaB activation in a model of endothelial denudation of rat carotid artery (balloon angioplasty) using the antioxidant pyrrolidine dithiocarbamate as inhibitor of NF-kappaB activation. Furthermore, we have correlated NF-kappaB activation to the expression of inducible isoforms of both nitric oxide synthase (iNOS) and cyclooxygenase (COX-2) in injured carotids. In control group a significant proliferation of neointima was observed 14 days after balloon angioplasty, which was correlated to an increase of NF-kappaB/DNA binding activity as well as p50/p65 nuclear levels compared to those observed in the carotids from naive or sham-operated rats. Furthermore, NF-kappaB activation was correlated to increased iNOS and COX-2, but not beta-actin, protein expression. Treatment of rats for 14 days with the antioxidant agent pyrrolidine dithiocarbamate (50, 100, 200 mg/kg per os and day) caused a significant inhibition of all the parameters assayed, except beta-actin protein expression. These results indicate that prevention of NF-kappaB activation may lead to the inhibition of neointima formation and suggest that antioxidant agents may have therapeutic relevance for the prevention of human restenosis.

Nitric oxide prevents inducible cyclooxygenase expression by inhibiting nuclear factor-kappa B and nuclear factor-interleukin-6 activation

Stimulation of J774 macrophages with lipopolysaccharide (LPS) leads to the release of large amounts of prostaglandins (PGs) generated by the inducible isoform of cyclooxygenase (COX-2). Nitric oxide (NO), a pleiotropic free radical, has been demonstrated to modulate the release of a broad range of inflammatory mediators, amongst these PGs. In the present study we investigated the molecular mechanism by which NO affects cyclooxygenase pathway. Incubation of J774 cells with LPS caused an increase of prostaglandin E2 production and COX-2 protein expression which was prevented in a concentration-dependent fashion by pre-incubating cells with sodium nitroprusside (SNP) and S-nitroso-glutathione (GSNO), two NO-generating agents. Electrophoretic mobility shift assay indicated that both NO-generating agents blocked LPS-induced activation of nuclear factor-kappaB (NF-kappaB) by increasing IkappaB-alpha protein expression and blocking nuclear translocation of NF-kappaB subunits p50 and p65. SNP and GSNO also inhibited nuclear factor-interleukin-6 (NF-IL6) activation. These results show for the first time that SNP and GSNO down-regulate LPS-induced COX-2 expression by inhibiting NF-kappaB and NF-IL6 activation and suggest a negative feed-back mechanism that may be important for limiting excessive or prolonged PGs production in pathological events.

Protective role of nuclear factor kappa B against nitric oxide-induced apoptosis in J774 macrophages

We investigated the role of constitutive transcription factor nuclear factor kappaB (NF-kappaB) in nitric oxide (NO)-mediated apoptosis in J774 macrophages. Our results show that NF-kappaB is present in untreated J774 cells in a form constitutively active. Incubation of cells with sodium nitroprusside (SNP) and S-nitroso-glutathione (GSNO), two NO-generating compounds, caused: (a) inhibition of constitutive NF-kappaB/DNA binding activity; (b) decrease of cell viability; (c) DNA fragmentation; (d) ApopTag positivity. Pyrrolidine dithiocarbamate (PDTC) and N-alpha-para-tosyl-L-lysine chloromethyl ketone (TLCK), two inhibitors of NF-kappaB activation, showed the same effects of both NO-generating compounds. Furthermore, SNP and GSNO as well as PDTC and TLCK significantly increased the cytoplasmic level of IkappaBalpha. All together these results demonstrate that constitutive NF-kappaB protects J774 macrophages from NO-induced apoptosis. Moreover, these findings show, for the first time, that NO-generating compounds may induce apoptosis in J774 macrophages by down-regulating constitutive NF-kappaB/DNA binding activity and suggest a novel mechanism by which NO induces apoptosis.

Local administration of transcription factor decoy oligonucleotides to nuclear factor-kappaB prevents carrageenin-induced inflammation in rat hind paw

The transcription factor nuclear factor-kappaB (NF-kappaB) plays a key role in the expression of several genes involved in the inflammatory process. In the present study we investigated in an acute model of inflammation, the carrageenin-induced hind paw edema, the anti-inflammatory effect of double stranded oligodeoxynucleotides (ODN) with consensus nuclear factor-kappaB (NF-kappaB) sequence as transcription factor decoys (TFD) to inhibit NF-kappaB binding to native DNA sites. Local administration of wild-type, but not mutant-ODN decoy, dose-dependently inhibited edema formation induced by carrageenin in rat paw. Molecular analysis performed on soft tissue obtained from inflamed paw demonstrated: (1) an inhibition of NF-kappaB DNA binding activity; (2) a decreased nuclear level of p50 and p65 NF-kappaB subunits; (3) an inhibition of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) protein expression, two inflammatory enzymes transcriptionally controlled by NF-kappaB. Furthermore, SN-50, a cell-permeable peptide capable of inhibiting the nuclear translocation of NF-kappaB complexes, exhibited a similar profile of activity of ODN decoy. Our results indicate for the first time that ODN decoy, acting as an in vivo competitor for the transcription factor's ability to bind to cognate recognition sequence, may represent a novel strategy to modulate acute inflammation.

Cyclolinteinone, a sesterterpene from sponge Cacospongia linteiformis, prevents inducible nitric oxide synthase and inducible cyclo-oxygenase protein expression by blocking nuclear factor-kappaB activation in J774 macrophages

We investigated the effect of cyclolinteinone, a sesterterpene from Caribbean sponge Cacospongia linteiformis, on inducible NO synthase (iNOS) and cyclo-oxygenase-2 (COX-2) protein expression in lipopolysaccharide (LPS)-stimulated J774 macrophages. Incubation of J774 cells with LPS (1 microgram/ml) caused an increase of both iNOS and COX-2 protein expression, which was prevented in a concentration-dependent fashion by cyclolinteinone (12.5, 25 and 50 microM). Electrophoretic mobility-shift assay indicated that cyclolinteinone blocked the activation of nuclear factor-kappaB (NF-kappaB), a transcription factor necessary for either iNOS or COX-2 induction. Cyclolinteinone also blocked disappearance of I(kappa)B-alpha from cytosolic fraction and nuclear translocation of NF-kappaB subunits p50 and p65. These results show that cyclolinteinone down-regulates iNOS and COX-2 protein expression by inhibiting NF-kappaB activation and suggest that it may represent a novel anti-inflammatory compound capable of controlling the excessive production of prostaglandins and nitric oxide occurring in several inflammatory diseases.

Anti-inflammatory activity of macrolide antibiotics

The effect of four macrolide antibiotics (roxithromycin, clarithromycin, erythromycin, and azithromycin) on the generation of some mediators and cytokines involved in the inflammatory process has been studied both in vivo and in vitro. Rat carrageenin pleurisy was used as a model of acute inflammation, and the macrolides were administered (10, 20, and 40 mg/kg p.o.) 1 h before the carrageenin challenge. Exudate volume and leukocyte accumulation were both dose-dependently reduced by roxithromycin, clarithromycin and erythromycin in either normal or adrenalectomized animals. Furthermore, in normal rats, prostaglandin (PG)E(2), nitrate plus nitrite, and tumor necrosis factor-alpha levels in pleural exudate were significantly reduced by these macrolides. Roxithromycin appeared more effective than erythromycin and clarithromycin, whereas azithromycin only slightly affected the inflammatory reaction. None of the macrolides were able to modify leukotriene B(4) exudate levels. In vitro experiments have shown that the four macrolides (5-80 microM) reduced in a concentration-dependent manner the production of 6-keto-PGF(1alpha), NO(2)(-), tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 by lipopolysaccharide-stimulated J774 macrophages. In J774 cells, the inhibition of 6-keto-PGF(1alpha) and NO(2)(-) production by roxithromycin and erythromycin was not dependent on direct inhibition of cyclooxygenase-2 and inducible nitric oxide synthase activity because it appears to be related to the inhibition of cyclooxygenase-2 and inducible nitric oxide synthase protein expression. In conclusion, the present study shows that macrolide antibiotics have anti-inflammatory activity, which likely depends on their ability to prevent the production of proinflammatory mediators and cytokines, and suggest that these agents, particularly roxithromycin, can exert therapeutic effects independently of their antibacterial activity.

Nuclear factor-kappaB activation mediates inducible nitric oxide synthase expression in carrageenin-induced rat pleurisy

We studied the involvement of nuclear factor-kappaB (NF-kappaB) in the regulation of inducible nitric oxide synthase expression in carrageenin-induced rat pleurisy. Injection of 0.2 ml of 1% lambda-carrageenin into the pleural cavity of male Wistar rats caused after 6 h: (a) exudate formation and leukocyte migration into the pleural cavity; (b) inducible NO synthase protein expression and accumulation of NO2- plus NO3- in pleural exudate; (c) increase in p50/p65 nuclear level as well as NF-kappaB/DNA binding activity. Treatment of rats with pyrrolidine dithiocarbamate (10, 30, and 100 mg/kg) and N-alpha-p-tosyl-L-lysine chloromethylketone (30 mg/kg), two inhibitors of NF-kappaB activation, given subcutaneously concomitantly with carrageenin, caused a significant inhibition of all the parameters assayed. These results suggest that in carrageenin-induced rat pleurisy the activation of NF-kappaB plays a key role in inducible NO synthase protein expression and in the development of inflammatory response.

Evidence that mast cell degranulation, histamine and tumour necrosis factor alpha release occur in LPS-induced plasma leakage in rat skin

1. In the present study we investigated the role of mast cells during inflammation in rat skin. As the release of several pro-inflammatory mediators, such as histamine and tumour necrosis factor alpha (TNFalpha), occurs following mast cell activation we studied whether mast cell degranulation and the release of both histamine (H) and TNFalpha occurred in a model of lipopolysaccharide (LPS)-induced plasma leakage in rat skin. 2. Plasma leakage in the rat skin was measured over a period of 2 h as the local accumulation of intravenous injection of 125I-human serum albumin (125I-HSA) in response to intradermal injection of LPS. LPS (10 microg site-1) produced an increase of plasma leakage (50.1+/-2.3 microl site-1) as compared to saline (9.0+/-3.2 microl site-1). Histological analysis of rat tissue showed that LPS induced a remarkable mast cell degranulation (59.8+/-2.1%) as compared to saline (13.5+/-2.2%). 3. Ketotifen (10-9 - 10-7 mol site-1), a well-known mast cell-membrane stabilizer, produced a dose-related inhibition of LPS-induced plasma leakage by 36+/-3.5%, 47+/-4.0%, 60+/-3.3% respectively. In addition, ketotifen (10-7 mol site-1) inhibited mast cell degranulation by 59. 2+/-2.7%. 4. Chlorpheniramine maleate (CPM) (10-9 - 10-7 mol site-1), an H1 histamine receptor antagonist only partially inhibited LPS-induced plasma leakage in rat skin (38+/-1.1% at the highest dose). Furthermore, CPM (10-7 mol site-1) did not prevent mast cell degranulation. 5. A polyclonal antibody against TNFalpha (1:500, 1:100, 1:50 v v-1 dilution), locally injected, decreased LPS-induced plasma leakage in the skin by 15+/-2.0%, 24+/-2.1% and 50+/-3.0% respectively. 6. Taken together these results suggest that LPS-induced plasma leakage in rat skin is mediated, at least in part, by mast cell degranulation and by the release of histamine and TNFalpha from these cells.

Activation of nuclear transcription factor kappaB in rat carrageenin-induced pleurisy

In this study we investigated the activation of nuclear factor-kappaB in the carrageenin-induced rat pleurisy. We found that nuclear factor-kappaB DNA binding activity, measured in inflammatory cells which migrated into the pleural cavity, was detectable at 3 and 6 h, markedly increased at 24 h and decreased at 48 h after induction of the inflammation. The increase in nuclear factor-kappaB DNA binding activity paralleled both exudate formation and leukocyte infiltration. Treatment of animals with pyrrolidine dithiocarbamate, an inhibitor of nuclear factor-kappaB activation, inhibited the nuclear factor-kappaB DNA binding activity as well as exudate formation and leukocyte infiltration. These results indicate that nuclear factor-kappaB is activated in the carrageenin-induced pleurisy and suggest that its inhibition may represent a novel strategy for the modulation of inflammatory response.

Inhibition of nuclear factor-kappaB prevents the loss of vascular tone in lipopolysaccharide-treated rats

We studied the role of nuclear factor-kappaB (NF-kappaB) on the tone and on the expression of inducible nitric oxide (NO) synthase, both evaluated in aortas from lipopolysaccharide-treated rats. Thoracic aorta rings from lipopolysaccharide-treated rats (4 mg/kg, i.p.), compared to those from naive animals, showed: (i) reduced contractility to phenylephrine, (ii) progressive loss in tone when contracted with phenylephrine, (iii) increased inducible NO synthase protein expression and NF-kappaB activation. Pyrrolidine dithiocarbamate (10, 30, 100 mg/kg, i.p.), an antioxidant inhibitor of NF-kappaB activation, dose dependently suppressed all these lipopolysaccharide-induced effects. These results demonstrate that in vivo inhibition of NF-kappaB activation prevented the lipopolysaccharide-induced loss of vascular tone, an effect which was correlated to reduced expression of inducible NO synthase protein.

Prostaglandins prevent inducible nitric oxide synthase protein expression by inhibiting nuclear factor-kappaB activation in J774 macrophages

We investigated the effect of PGE2 and iloprost (a prostacyclin analogue) on inducible nitric oxide synthase (iNOS) protein expression and nuclear factor-kappaB (NF-kappaB) activation in lipopolysaccharide (LPS)-stimulated J774 macrophages. Incubation of J774 cells with LPS (10 microg/ml) caused an increase of iNOS protein expression which was prevented in a concentration-dependent fashion by PGE2 (0.1, 1, 10 microM) and iloprost (0.01, 0.1, 1 microM). Electrophoretic mobility shift assay indicated that both prostanoids blocked the activation of NF-kappaB, a transcription factor necessary for NO synthase induction. PGE2 and iloprost also blocked disappearance of I kappaB-alpha from cytosolic fraction and nuclear translocation of NF-kappaB subunits p50 and p65. These results show for the first time that PGE2 and iloprost down-regulate iNOS protein expression by inhibiting NF-kappaB activation and suggest a negative feed-back mechanism that may be important for limiting excessive or prolonged NO production in pathological events.

Evidence that inducible nitric oxide synthase is involved in LPS-induced plasma leakage in rat skin through the activation of nuclear factor-kappaB

1. Rats challenged with lipopolysaccharide (LPS) produce large amounts of nitric oxide (NO) following the induction of the inducible NO-synthase (iNOS) in several tissues and organs. Recent studies have shown that the expression of iNOS is regulated at the transcriptional level by a transcription nuclear factor-kappaB (NF-kappaB). In this study we investigated the role of NO in a model of LPS-induced plasma-leakage in rat skin and the involvement of NF-kappaB. 2. Plasma leakage in the rat skin was measured over a period of 30 min to 2 h as the local accumulation of intravenous (i.v.) injection of [125I]-human serum albumin ([125I]-HSA) in response to intradermal (i.d.) injection of LPS. LPS (1, 10, 100 microg/site) produced a dose-related increase in plasma extravasation (18.2+/-3.2, 27.2+/-2.9, 40.4+/-9.6 microl/site) as compared to saline control (11.4+/-2.2 microl/site). This increase was maximal after 2 h; therefore this time point and the dose of LPS 10 microg/site was used in all the successive experiments. 3. To investigate the role of NO in LPS-induced plasma leakage in rat skin, the non-selective NOS inhibitor NG-nitro-L-arginine-methyl ester (L-NAME) or the more selective iNOS inhibitor S-methyl-isothiourea (SMT) was injected i.d. with LPS. L-NAME and SMT (0.01, 0.1 and 1 micromol/site) inhibited LPS-induced plasma leakage in a dose-related fashion (L-NAME: 26.0+/-5.5, 20.2+/-1.6, 18.0+/-2.0 microl/site; SMT: 19.5+/-1.5, 17.0+/-1.6, 15.0+/-2.6 microl/site) as compared to LPS alone (27.2+/-2.9 microl/site). At the lowest concentration used (0.01 micromol/site), SMT significantly reduced plasma leakage by 30%+/-0.7 while L-NAME (0.01 micromol/site) was not effective. 4. Treatment with increasing concentrations of pyrrolidinedithyocarbamate (PDTC) (0.01, 0.1, 1 micromol/site), an inhibitor of NF-kappaB activation, injected i.d. 30 min before LPS challenge, inhibited in a concentration-dependent fashion LPS-induced plasma leakage by 9.0+/-0.6, 33+/-4.0, 51+/-2.0% respectively. Moreover, PDTC (0.1, 1 micromol/site) suppressed LPS-induced NF-kappaB DNA-binding. 5. Western blot analysis showed significant levels of iNOS proteins in the skin samples of LPS-treated rats, as compared to basal levels present in saline-injected rat skin. PDTC (0.1, 1.0 micromol/site) dose-dependently decreased the amount of iNOS protein expression induced by LPS. 6. Our results indicate that LPS-induced plasma leakage in rat skin is modulated by NO mainly produced by the inducible isoform of NOS. Furthermore, the suppression of plasma leakage by PDTC, an inhibitor of NF-kappaB activation, is correlated to the inhibition of iNOS protein expression.

Antiproliferative sesterterpenes from the Caribbean sponge Cacospongia cf. linteiformis

Two new sesterterpenes, lintenolides F (6 a, b) and G (7 a, b), were isolated from the Caribbean sponge Cacospongia cf. linteiformis. Their stereostructures were determined using spectroscopic and chemical methods. The new compounds (6 a, b and 7 a, b) and the related compounds lintenolides A-E (1 a, b-5 a, b), previously isolated from the sponge, exhibited antiproliferative activity on four cell lines.

Involvement of NF-kappaB in the regulation of cyclooxygenase-2 protein expression in LPS-stimulated J774 macrophages

We investigated the involvement of NF-kappaB in the regulation of COX-2 protein expression and prostaglandin production in LPS-stimulated J774 macrophages. Incubation of J774 cells with LPS (1 microg/ml) for 24 h caused an increase of COX-2 protein expression and accumulation of both PGE2 and 6-keto-PGF1alpha in the cell culture medium. Ammonium pyrrolidinedithiocarbamate (APDC, 0.1, 1, 10 microM) and N-alpha-p-tosyl-L-lysine chloromethylketone (TLCK, 1, 10, 100 microM), two inhibitors of NF-kappaB activation, suppressed in a concentration-dependent manner both LPS-induced COX-2 protein expression and prostanoid generation. Moreover, APDC and TLCK both inhibited the LPS-induced increase of NF-kappaB DNA binding activity and prevented IkappaB-alpha degradation. Our results show for the first time that NF-kappaB is involved in COX-2 protein expression in LPS-stimulated J774 macrophages and suggest that inhibitors of NF-kappaB activation may represent a useful tool for the pharmacological control of inflammation.

Inhibition of inducible nitric oxide synthase gene expression by glucocorticoid-induced protein(s) in lipopolysaccharide-stimulated J774 cells

Glucocorticoids inhibit inducible-type NO synthase activity in a variety of cell types. We report here that proteins recovered from the medium of dexamethasone-treated J774 macrophages (1, 10, 100 microg/ml) inhibited lipopolysaccharide-stimulated nitrite generation by 10.0 +/- 3.0%, 32.3 +/- 5.3% and 55.0 +/- 6.0%, respectively, and inducible NO synthase mRNA expression in these cells. Immunoblotting analysis of crude and partially purified glucocorticoid-induced proteins with an anti-lipocortin-1 polyclonal antiserum revealed the presence of lipocortin-1-like immunoreactive species with a molecular mass of 35-37 kDa. Furthermore, inhibition of lipopolysaccharide-induced nitrite production by glucocorticoid-induced proteins in J774 cells was reversed by addition of anti-lipocortin-1 neutralizing polyclonal antibody (1:60 dilution; 4 h before lipopolysaccharide). Comparison of glucocorticoid-induced proteins inhibition of both nitrite production and inducible NO synthase mRNA expression suggests that these effects result mainly from inhibition of lipopolysaccharide-mediated inducible NO synthase gene expression. These results indicate that negative regulation of inducible NO synthase by glucocorticoids is, at least in part, mediated by glucocorticoid-induced proteins that involve also members of the lipocortin-like superfamily.

Porrigenins A and B, novel cytotoxic and antiproliferative sapogenins isolated from Allium porrum

Four new sapogenins, porrigenins A (2a) and B (3a), identified as (25R)-5 alpha-spirostan-2 beta,3 beta,6 beta-triol and (25R)-2-oxo-5 alpha-spirostan-3 beta,6 beta-diol, respectively, and neoporrigenins A (2b) and B (3b) were also isolated from Allium porrum. In addition, the known agigenin (1a) and its 25S epimer, neoagigenin (1b), were also identified. Their structure elucidation was provided by comprehensive spectroscopic analyses. Compounds 1a, 2a, and 3a exhibited cytotoxicity and high antiproliferative activity on four different tumor cell lines in vitro.

Differential effect of L-NAME and S-methyl-isothiourea on leukocyte emigration in carrageenin-soaked sponge implants in rat

1. The role of nitric oxide (NO) in leukocyte (polymorphonuclear cells, monocytes and lymphocytes) emigration was studied in a model of carrageenin-sponge implants in rats. 2. The subcutaneous implantation of 1% (w/v) of lambda-carrageenin-soaked sponges elicited an inflammatory response that was characterized by a time-related increase in leukocyte infiltration in the sponges and increased levels of nitrite in the exudate. Total leukocyte infiltration and nitrite production were maximal at 24 h and decreased after 48 and 96 h. The mononuclear cell influx was maximal at 48 h (21% of the total leukocytes). Therefore, this time point was used in the successive experiments. 3. Polymorphonuclear cell (PMN) and lymphocyte infiltration in the sponges significantly increased when rats were treated with the non-specific NO-synthase (NOS) inhibitor, NG-nitro-L-arginine methylester (L-NAME) (1 mg ml-1) in drinking water ad libitum). Monocyte emigration was not affected by L-NAME treatment. The nitrite levels in the exudate of L-NAME-treated rats were significantly reduced. The concomitant ingestion of L-arginine (30 mg ml-1) resulted in a reversion of the L-NAME effect, while D-arginine (30 mg ml-1) had no effect, indicating the involvement of the L-arginine: NO pathway. 4. Administration of L-NAME resulted also in an increased release of tumour necrosis factor-alpha (TNF-alpha) and prostacyclin (measured as the stable metabolite, 6-keto-PGF 1 alpha). L-NAME had no effect on monocyte chemoattractant protein-1 (MCP-1) release in the exudate. 5. Since L-NAME may have effects on the local blood flow, phenylephrine (0.034 mg ml-2) in drinking water) was used as it has an effect on the local blood flow similar to L-NAME. Phenylephrine had no effect on either leukocyte emigration, or on nitrite, TNF-alpha, prostacyclin or MCP-1 accumulation in the exudate. 6. In contrast, the more selective iNOS inhibitor S-methyl-isothiourea (SMT) (10 micrograms ml-1) in drinking water) significantly reduced PMNs and lymphocyte influx in the sponge having no effect on monocyte influx. Moreover, SMT decreased nitrite production in the exudate to a comparable extent as L-NAME. 7. Administration of SMT significantly reduced MCP-1 release in the exudate, without an effect on TNF-alpha or prostacyclin production. Moreover SMT did not produce any changes in local blood flow. 8. Our results show that a different outcome of the inflammatory process can be obtained depending on the types of NOS inhibitor used.

Nitric oxide inhibits LPS-induced tumor necrosis factor synthesis in vitro and in vivo

The effect of nitric oxide (NO) on LPS-stimulated TNF-alpha synthesis has been studied in vitro and in vivo. The synthesis of TNF-alpha in J774 macrophages stimulated with LPS (0.1 microgram/ml) was increased in concentration-related fashion by NO synthase inhibitor L-NMMA (3-30-300 microM) and reduced by either L-arginine (3-30-300 microM) or the NO donor SIN-1 (1-10-100 microM). The level of TNF-alpha in the serum of LPS-challenged rats (6mg/kg/i.p.) was increased in animals pre-treated s.c. with L-NMMA (10 and 50mg/kg) and reduced in those given L-arginine (100 and 300mg/kg). These results show a negative feedback mechanism exhibited by NO on TNF-alpha synthesis suggesting an important regulatory link between NO and TNF-alpha in pathological processes.

5,6-Dihydroxyindole-2-carboxylic acid, a diffusible melanin precursor, is a potent stimulator of lipopolysaccharide-induced production of nitric oxide by J774 macrophages

Pre-incubation of J774 murine macrophages with 5,6-dihydroxyindole-2-carboxylic acid (DHICA), a diffusible intermediate in the biosynthesis of eumelanins, leads to a marked increase in the levels of nitric oxide (NO) produced by lipopolysaccharide (LPS)-induced NO-synthase (iNOS). The effect varies with DHICA concentration being maximum at a concentration of 1 x 10(-6)M, and is suppressed by the NOS inhibitor NG-monomethyl-L-arginine (L-NMMA). No stimulation is observed when macrophages are exposed to DHICA after activation with LPS, indicating that the indole does not affect the catalytic activity of iNOS. These results point to a hitherto unrecognized role of DHICA as a chemical messenger mediating interaction between active melanocytes and macrophages in epidermal inflammatory and immune responses.

New cytotoxic steroids from the marine sponge Dysidea fragilis coming from the lagoon of Venice

The sterol composition of the sponge Dysidea fragilis, coming from the lagoon of Venice, has been investigated; our results confirmed the variability of D. fragilis biochemistry. The sponge elaborates, in addition to eight usual 3 beta-hydroxy sterols, thirteen polyhydroxysterols, eight of them (6-13) were novel compounds. Their structures were established by spectroscopic data. New compounds 3 beta,5 alpha,6 beta,7 alpha-tetrahydroxy-cholest-8(9)-en-11-one (8), 3 beta,5 alpha,6 alpha-trihydroxy-9,11-secocholest-7-en-9-one (9) and 3 beta,5 alpha,6 alpha,9 alpha-tetrahydroxy-cholest-7-ene-6-sulfate (11) were proved to be cytotoxic on two different tumor cell lines in vitro.

Mesotheliomas following exposure to asbestos used in railroads: 130 Italian cases

The available knowledge on the oncogenic risks of asbestos, the data on the uses of asbestos in railroads, with particular regard to the Italian State Railroads (Ferrovie dello Stato = FS), and the groups at risk due to the exposure to asbestos used in railroads were briefly reviewed. The available data on the pathological effects of such exposure, and particularly on the onset of mesotheliomas among machinists and other railroad workers, were also summarized. One hundred and thirty cases of mesothelioma (122 pleural, 1 pericardial, 6 peritoneal and 1 pleuro-peritoneal), related to the exposure to asbestos used in railroads, observed in various Italian regions, were reported. Fifty-three of these cases (among which 49 reported in the Emilia Romagna Region) were submitted to a detailed study at the Bologna Institute of Oncology. Seventy-seven cases of mesothelioma occurred among occupationally exposed FS workers, in particular machinists; 45 cases occurred among rolling-stock machinists and workers engaged in the repair and demolition of the rails of workshops not belonging to the FS; 3 cases occurred among travelling workers of rolling-stock, not belonging to the FS; and 5 cases were found in family members (1 daughter, 3 wives and 1 sister) of railroad workers. This series of cases, together with similar data from the literature, proves the existence of an actual health risk due to asbestos used in railroads, and indicates its gravity. On the basis of the available data, the following steps are considered necessary: the promotion of systematic epidemiological investigations, the adoption of preventive measures, the performance of medical oncological surveillance, and the automatic compensation for tumours following the exposure to the asbestos used in railroads.

Mesotheliomas following exposure to asbestos used in sugar refineries: report of 12 Italian cases

Twelve Italian cases of mesothelioma (all the cases but one from the Emilia Romagna Region), following exposure to asbestos used in sugar refinery plants, are reported. Eleven cases arose in workers occupationally exposed, and one in the daughter of an exposed worker, following family contact. Eleven of the cases were pleural and one peritoneal. In the 11 cases following occupational exposure the average latency time was 36.0 (range 23-48) years, and the average age at onset was 63.4 years. In the case which followed family contact, the latency time and the age of the onset were 37 years. This represents the largest series of cases of mesothelioma due to the asbestos present in sugar refinery plants reported to date in the scientific literature. While these cases demonstrate the risk of asbestos mesothelioma in the sugar refinery industry, they in no way give the dimension of the pathological effects of asbestos (and man-made mineral fibres) used in this industry. To assess this risk further research is suggested.

Opioids inhibit the induction of nitric oxide synthase in J774 macrophages

The effect of opioids on NO production by LPS-stimulated murine macrophages J774 has been investigated. Morphine (mu and k opioid receptor agonist), DAGO (selective mu receptor agonist) and U50-488H (selective k receptor agonist), added (10(-10)-10(-6) M) to the cells 0.5 h before activation with LPS, significantly inhibited NO production. This effect was reverted by naloxone (10(-12)-10(-8) M), an opioid specific antagonist. In contrast, DPDPE and deltorphin II respectively delta 1 and delta 2 receptor agonists (10(-10)-10(-6) M) did not affect NO generation. Morphine was not able to inhibit NO production when added after LPS challenge. The results of the present study indicate that opioids are able to inhibit NO formation in LPS-activated macrophages through the involvement of specific opioid receptors. Moreover, the ability of morphine to inhibit NO production only when given before LPS challenge suggests that the opiate inhibits the induction but not the activity of the inducible NO synthase.

Modulation of granuloma formation by endogenous nitric oxide

We have studied the possible involvement of nitric oxide (NO) in granuloma formation induced by subcutaneous implantation in rats of carrageenin-soaked polyether sponges. Modulation of the L-arginine: NO pathway in rats was achieved by treating rats with the NO synthase inhibitor, NG-nitro-L-arginine methyl ester, as well as with L- or D-arginine. Granulomatous tissue formation, cell infiltration and NO2- production were reduced, in a dose-dependent manner, by NG-nitro-L-arginine methyl ester and increased by L-arginine but not by D-arginine. These results suggest that endogenous NO plays a modulating role in granuloma formation.

Characterization of vasocortin-like proteins induced by dexamethasone in endothelial cells

In this study we have shown that dexamethasone induces vasocortin-like proteins in bovine endothelial cells as well as in the bovine aortic endothelial cell line, GM 7373. Vasocortin-like proteins have been characterized by their ability to mimic the glucocorticoid inhibition of rat dextran oedema and histamine release induced by concanavalin-A in rat mast cells. Following partial purification of these proteins by gel filtration, vasocortin activity was found to be associated to proteins with molecular weight between 20-35 kD. This study showed that dexamethasone induces vasocortin-like proteins in endothelial cells and suggests that endothelial cells are target cells of glucocorticoid activity in vascular tissue.

Cloricromene inhibits the induction of nitric oxide synthase

The effect of cloricromene, a coumarin derivative, was investigated on the lipopolysaccharide-stimulated nitric oxide (NO) synthase induction in intact aortas from endotoxin shocked rats and in the murine macrophage cell line J774. Rings of thoracic aortas from lipopolysaccharide (4 mg/kg, i.v.)-shocked rats, contracted with phenylephrine, showed a progressive decrease in tone, that was of a greater magnitude than that of aortas from naive rats. Moreover, a decreased response to the constrictor effect of phenylephrine was observed in aortas from shocked rats. In vivo treatment with cloricromene (2 mg/kg, i.v.) 30 min before lipopolysaccharide administration partially prevented the loss in tone of aortic rings and improved their reactivity to phenylephrine. Murine J774 macrophages activated with lipopolysaccharide (100 ng/ml) produced significant amounts of nitrites (NO2-; 28.2 +/- 3.5 nmol/10(6) cells per 24 h). Cloricromene (2, 20 or 200 microM) added to the cells concomitantly with lipopolysaccharide inhibited NO2- production in a concentration-dependent manner. Maximum inhibition (84.0 +/- 8.0%) was observed when cloricromene (200 microM) was added to the cells 6 h before lipopolysaccharide, whereas it was ineffective when given 6 h after endotoxin. These results demonstrate that cloricromene inhibits the expression but not the activity of the inducible NO synthase.

The inhibition of platelet aggregation by activated macrophages is blocked by dexamethasone

The effect of dexamethasone on the ability of activated J774 macrophages to inhibit platelet aggregation was investigated. After 24h incubation with lipopolysaccharide and gamma-interferon, J774 cells generated large amounts of nitric oxide and inhibited platelet aggregation. Incubation of the cells with dexamethasone (0.01-10 microM) caused a concentration-dependent inhibition of both the NO2- production and the anti-aggregating activity of the cells. The inhibitory effect of dexamethasone was blocked by the glucocorticoid antagonist RU 38486. These data suggested that the protective effect of glucocorticoids in endotoxin-induced hypotension and their immunosuppressive action may both depend, at least in part, on the inhibition by these steroids of the induction of the nitric oxide synthase.

Lipocortin and vasocortin: Two species of anti-inflammatory proteins mimicking the effects of glucocorticoids

The anti-inflammatory effect of glucocorticoids depends, at least in part, on the induction of two regulatory proteins, lipocortin and vasocortin, both preventing the release of inflammatory mediators. Lipocortin inhibits phospholipase A2 (PLA2) and therefore reduces arachidonic acid metabolites formation. Vasocortin inhibits histamine release from mast cells. Lipocortin and vasocortin may be regarded as the first two identified members of the (perhaps greater) family of glucocorticoid-induced proteins.

Glucocorticoids inhibit the induction of nitric oxide synthase in macrophages

The effect of glucocorticoids on the production of NO2- and NO by the macrophage cell line J774 was investigated. Stimulation of the cells with lipopolysaccharide (LPS) resulted in a time-dependent accumulation of NO2- in the medium, reaching a plateau after 48h. Concomitant incubation of the cells for 24h with dexamethasone (0.001-1.0 microM) or hydrocortisone (0.01-10.0 microM) caused a concentration-dependent inhibition of NO2- formation. The cytosol of J774 cells stimulated with LPS and IFN-gamma produced a time-dependent increase in the release of NO. This was blocked in a concentration-dependent manner by dexamethasone and hydrocortisone, but not progesterone, administered concomitantly with the immunological stimulus. None of these compounds had any effect on the release of NO once the enzyme had been induced. The inhibitory effect of hydrocortisone on NO formation was blocked by cortexolone. These data suggest that part of the anti-inflammatory and immunosuppressive actions of glucocorticoids is due to their inhibition of the induction of the NO synthase.

Selective inhibition by vasocortin of histamine release induced by dextran and concanavalin-A from rat peritoneal cells

Vasocortin, a glucocorticoid-induced anti-inflammatory protein, has been purified from the peritoneal lavage fluid of dexamethasone-treated rats. Vasocortin inhibited the release of histamine from rat peritoneal cells stimulated by dextran or concanavalin A but did not alter the release induced by calcium ionophore A23187 or compound 48/80. This selective effect exhibited by vasocortin mimics the glucocorticoid inhibition of histamine release from rat mast cells.

Vasocortin-like proteins induced by glucocorticoids in vascular tissue

Rat and bovine aorta rings incubated with 10(-5) M dexamethasone release proteins which inhibit rat dextran oedema. These proteins seem to be related to vasocortin, derived from the peritoneal fluid of dexamethasone-treated rats, and may contribute to the control that glucocorticoids exert on vascular tonus and permeability.

Vasocortin: a novel glucocorticoid-induced anti-inflammatory protein

The preliminary characterization of ;vasocortin' a novel glucocorticoid-induced anti-inflammatory protein, is described. Vasocortin is released into the rat peritoneal cavity following systemic dexamethasone administration, has an apparent mol. wt. of 100 kD and inhibits rat dextran oedema. Vasocortin is distinct from lipocortin and is likely to be associated with the anti-inflammatory effect of glucocorticoids.

Glucocorticoid induction of angiotensin converting enzyme

Angiotensin converting enzyme (ACE) converts angiotensin I (Angio I) to angiotensin II (Angio II) and inactivates bradykinin (BK). Glucocorticoids in the physiological range increase ACE in rabbit alveolar macrophages and bovine endothelial cells in culture. Since Angio I and BK are cleaved by ACE catalysis during passage through the pulmonary vasculature we have studied the steroid modulation of ACE in the rat lung. The conversion of Angio I to Angio II by isolated lungs from normal or adrenalectomized male Wistar rats has been evaluated. The initial conversion of Angio I to Angio II in lungs from normal rats was about 60%. In contrast the initial converting activity in lungs from adrenalectomized rats was about 30%. In both groups the converting activity progressively decreased. After 3 h it was about 30% in normal lungs and virtually undetectable in lungs from adrenalectomized rats. Dexamethasone infusion (1 microgram/ml) prevented the decrease in ACE activity observed in normal lungs and induced a gradual enhancement of converting activity in lungs from adrenalectomized animals up to the control level. The effect of dexamethasone was abolished by simultaneous infusion of cycloheximide (1 microgram/ml). These results demonstrate that glucocorticoids induce ACE synthesis in the rat lung. By this induction glucocorticoids promote the increase of both Angio II formation and BK degradation. Thus ACE induction may represent a possible mechanism whereby glucocorticoids might control vascular tone and permeability according to the general mode of action of steroid hormones.

The anti-inflammatory effect of glucocorticoid-induced phospholipase inhibitory proteins

The anti-inflammatory effect of glucocorticoids has been investigated in two standard models of experimental inflammation, i.e. rat paw oedema induced by carrageenin or dextran. Both types of oedema are suppressed by dexamethasone while indomethacin and BW755C only suppress carrageenin oedema. Dexamethasone inhibits dextran oedema according to the accepted mode of action of steroid hormones since the inhibition occurs after a 2-3 h time lag and is abolished by pretreating animals with actinomycin D. Dextran oedema and carrageenin oedema are also controlled by endogenous corticoids since adrenalectomy potentiates the paw oedema formation induced by low concentrations of phlogogenic agents. It has been shown that glucocorticoids induce both in vitro and in vivo the formation and release of antiphospholipase proteins which are anti-inflammatory in that they greatly suppress carrageenin oedema. However, these proteins have no effect on dextran oedema. We conclude that the inhibition of dextran oedema by glucocorticoids depends on the formation of another type of anti-inflammatory protein.

Glucocorticoids induce the formation and release of anti-inflammatory and anti-phospholipase proteins into the peritoneal cavity of the rat

1 Dexamethasone and hydrocortisone induced the release of anti-phospholipase proteins into the peritoneal cavities of rats. 2 Adrenocorticotrophic hormone (ACTH) also releases these proteins in normal but not in adrenalectomized rats. 3 Peritoneal lavage proteins were separated by ion-exchange and size exclusion chromatography. The anti-phospholipase activity occurred in four separate fractions with the major component having an apparent mol. wt. of 40 k. 4 Column fractions containing these anti-phospholipase proteins had anti-inflammatory effects in the rat carrageenin pleurisy model whereas other fractions were inactive. 5 The proteins appear to be identical to macrocortin and lipomodulin, the 'second messengers' of glucocorticoid hormone action on the arachidonate system.

The inhibition by hydrocortisone of prostaglandin biosynthesis in rat peritoneal leucocytes is correlated with intracellular macrocortin levels

Hydrocortisone inhibits prostaglandin generation by rat peritoneal leucocytes by releasing the polypeptide phospholipase inhibitor, macrocortin. The susceptibility of these cells to hydrocortisone is directly correlated with their intracellular macrocortin content. Cells depleted of the peptide by prior incubation with steroid cannot respond to the steroid, until a fresh intracellular store has been synthesized. In vitro, this process requires 4-5 h. Cells remain sensitive to the inhibitory action of the peptide at all times.

Macrocortin: a polypeptide causing the anti-phospholipase effect of glucocorticoids

Anti-inflammatory glucocorticoids inhibit prostaglandin (PG) biosynthesis by preventing arachidonic acid release from phospholipids rather than inhibiting the cyclooxygenase. As in other cells, this steroid action depends on receptor occupation and de novo protein/RNA biosynthesis. We have previously shown in guinea pig perfused lungs and rat peritoneal leukocytes that the effect of steroids in PG generation is mediated by an uncharacterized 'second messenger'. Now, we report that this factor (which we have named 'macrocortin') is an intracellular polypeptide whose release and synthesis are stimulated by steroids. Macrocortin derived from rat peritoneal leukocytes is very similar to that released from guinea pig lungs.

Hydrocortisone-induced inhibitor of prostaglandin biosynthesis in rat leucocytes

Rat peritoneal luecocytes incubated with hydrocortisone (10 micrograms/ml) release a factor which inhibits prostaglandin generation. The steroid-induced inhibitor, which mediates the anti-phospholipase effect of antiinflammatory steroids, may be a protein or a polypeptide since its formation is blocked by cycloheximide, a known inhibitor of protein synthesis.