Staurosporine induces rapid homotypic intercellular adhesion of U937 cells via multiple kinase activation

The respiratory syncytial virus fusion protein formulated with a polymer-based adjuvant induces multiple signaling pathways in macrophages

Respiratory syncytial virus (RSV) causes acute respiratory tract infections in infants, the elderly and immunocompromised individuals. No licensed vaccine is available against RSV. We previously reported that intranasal immunization of rodents and lambs with a RSV vaccine candidate (ΔF/TriAdj) induces protective immunity with a good safety profile. ΔF/TriAdj promoted innate immune responses in respiratory mucosal tissues in vivo, by local chemokine and cytokine production, as well as infiltration and activation of immune cells including macrophages. The macrophage is an important cell type in context of both innate and adaptive immune responses against RSV. Therefore, we characterized the effects of ΔF/TriAdj on a murine macrophage cell line, RAW264.7, and bone marrow-derived macrophages (BMMs). A gene expression study of pattern recognition receptors (PRRs) revealed induction of endosomal and cytosolic receptors in RAW264.7 cells and BMMs by ΔF/TriAdj, but no up-regulation by ΔF in PBS. As a secondary response to the PRR gene expression, induction of several chemokines and pro-inflammatory cytokines, as well as up-regulation of MHC-II and co-stimulatory immune markers, was observed. To further investigate the mechanisms involved in ΔF/TriAdj-mediated secondary responses, we used relevant signal transduction pathway inhibitors. Based on inhibition studies at both transcript and protein levels, JNK, ERK1/2, CaMKII, PI3K and JAK pathways were clearly responsible for ΔF/TriAdj-mediated chemokine and pro-inflammatory cytokine responses, while the p38 and NF-κB pathways appeared to be not or minimally involved. ΔF/TriAdj induced IFN-β, which may participate in the JAK-STAT pathway to further amplify CXCL-10 production, which was strongly up-regulated. Blocking this pathway by a JAK inhibitor almost completely abrogated CXCL-10 production and caused a significant reduction in the cell surface expression of MHC-II and co-stimulatory immune markers. These data demonstrate that ΔF/TriAdj induces multiple signaling pathways in macrophages.

Staurosporine enhances ATRA-induced granulocytic differentiation in human leukemia U937 cells via the MEK/ERK signaling pathway

Although all-trans retinoic acid (ATRA) is regarded as a prominent example of differentiation therapy, it is not effective for the treatment of other subtypes of acute myeloid leukemia (AML) beyond acute promyelocytic leukemia (APL). Therefore, new strategies need to be explored to extend the efficacy of ATRA-based therapy to non-APL AML patients. In the present study, staurosporine, a protein kinase C (PKC) pan-inhibitor, exhibited synergism with ATRA to promote granulocytic differentiation in poorly ATRA-sensitive U937 cells but not in ATRA unresponsive K562 and Kasumi cells. Staurosporine or the combined treatment did not affect PKC activity in U937 cells. Moreover, other selective PKC inhibitors, UCN-01, Go6976 or rottlerin failed to enhance ATRA‑induced granulocytic differentiation in U937 cells. Therefore, staurosporine-enhanced ATRA-induced granulocytic differentiation in U937 cells may be independent of PKC. Staurosporine activated mitogen‑activated protein kinase kinase (MEK) and extracellular signal‑regulated kinase (ERK). Meanwhile, staurosporine also enhanced ATRA-promoted upregulation of the protein level of CCAAT/enhancer‑binding protein β (C/EBPβ) and C/EBPε in U937 cells. Furthermore, blockade of MEK activation suppressed staurosporine‑enhanced differentiation as well as the elevated protein level of C/EBPs. Taken together, we concluded that staurosporine enhanced ATRA‑induced granulocytic differentiation in U937 cells via MEK/ERK-mediated modulation of the protein level of C/EBPs.

4-Isopropyl-2,6-bis(1-phenylethyl)aniline 1, an Analogue of KTH-13 Isolated from Cordyceps bassiana, Inhibits the NF-κB-Mediated Inflammatory Response

The Cordyceps species has been a good source of compounds with anticancer and anti-inflammatory activities. Recently, we reported a novel compound (4-isopropyl-2,6-bis(1-phenylethyl)phenol, KTH-13) with anticancer activity isolated from Cordyceps bassiana and created several derivatives to increase its pharmacological activity. In this study, we tested one of the KTH-013 derivatives, 4-isopropyl-2,6-bis(1-phenylethyl)aniline 1 (KTH-13-AD1), with regard to anti-inflammatory activity under macrophage-mediated inflammatory conditions. KTH-13-AD1 clearly suppressed the production of nitric oxide (NO) and reactive oxygen species (ROS) in lipopolysaccharide (LPS) and sodium nitroprusside- (SNP-) treated macrophage-like cells (RAW264.7 cells). Similarly, this compound also reduced mRNA expression of inducible NO synthase (iNOS) and tumor necrosis factor-α (TNF-α), as analyzed by RT-PCR and real-time PCR. Interestingly, KTH-13-AD1 strongly diminished NF-κB-mediated luciferase activities and nuclear translocation of NF-κB family proteins. In accordance, KTH-13-AD1 suppressed the upstream signaling pathway of NF-κB activation, including IκBα, IKKα/β, AKT, p85/PI3K, and Src in a time- and dose-dependent manner. The autophosphorylation of Src and NF-κB observed during the overexpression of Src was also suppressed by KTH-13-AD1. These results strongly suggest that KTH-13-AD1 has strong anti-inflammatory features mediated by suppression of the Src/NF-κB regulatory loop.

Complementary PTM Profiling of Drug Response in Human Gastric Carcinoma by Immunoaffinity and IMAC Methods with Total Proteome Analysis

Gaining insight into normal cellular signaling and disease biology is a critical goal of proteomic analyses. The ability to perform these studies successfully to extract the maximum value and discovery of biologically relevant candidate biomarkers is therefore of primary importance. Many successful studies in the past have focused on total proteome analysis (changes at the protein level) combined with phosphorylation analysis by metal affinity enrichment (changes at the PTM level). Here, we use the gastric carcinoma cell line MKN-45 treated with the c-Met inhibitor SU11274 and PKC inhibitor staurosporine to investigate the most efficient and most comprehensive strategies for both total protein and PTM analysis. Under the conditions used, total protein analysis yielded few changes in response to either compound, while analysis of phosphorylation identified thousands of sites that changed differentially between the two treatments. Both metal affinity and antibody-based enrichments were used to assess phosphopeptide changes, and the data generated by the two methods was largely complementary (non-overlapping). Label-free quantitation of peptide peak abundances was used to accurately determine fold-changes between control and treated samples. Protein interaction network analysis allowed the data to be placed in a biologically relevant context, and follow-up validation of selected findings confirmed the accuracy of the proteomic data. Together, this study provides a framework for start-to-finish proteomic analysis of any experimental system under investigation to maximize the value of the proteomic study and yield the best chance for uncovering actionable target candidates.

Carbon monoxide regulates the expression of the wound-inducible gene ipomoelin through antioxidation and MAPK phosphorylation in sweet potato

Carbon monoxide (CO), one of the haem oxygenase (HO) products, plays important roles in plant development and stress adaptation. However, the function of CO involved in wounding responses is seldom studied. A wound-inducible gene, ipomoelin (IPO), of sweet potato (Ipomoea batatas cv. Tainung 57) was used as a target to study the regulation of CO in wounding responses. After wounding for 1h, the endogenous CO content and IbHO expression level were significantly reduced in leaves. IPO expression upon wounding was prohibited by the HO activator hemin, whereas the HO inhibitor zinc protoporphyrin IX elevated IPO expression. The IPO expression induced by wounding, H2O2, or methyl jasmonate was inhibited by CO. CO also affected the activities of ascorbate peroxidase, catalase, and peroxidase, and largely decreased H2O2 content in leaves. CO inhibited the extracellular signal-regulated kinase (ERK) phosphorylation induced by wounding. IbMAPK, the ERK of sweet potato, was identified by immunoblotting, and the interaction with its upstream activator, IbMEK1, was further confirmed by bimolecular fluorescence complementation and co-immunoprecipitation. Conclusively, wounding in leaves repressed IbHO expression and CO production, induced H2O2 generation and ERK phosphorylation, and then stimulated IPO expression.

Lancemaside A from Codonopsis lanceolata modulates the inflammatory responses mediated by monocytes and macrophages

In this study, we aimed to examine the cellular and molecular mechanisms of lancemaside A from Codonopsis lanceolata (Campanulaceae) in the inflammatory responses of monocytes (U937 cells) and macrophages (RAW264.7 cells). Lancemaside A significantly suppressed the inflammatory functions of lipopolysaccharide- (LPS-) treated RAW264.7 cells by suppressing the production of nitric oxide (NO), the expression of the NO-producing enzyme inducible NO synthase (iNOS), the upregulation of the costimulatory molecule CD80, and the morphological changes induced by LPS exposure. In addition, lancemaside A diminished the phagocytic activity of RAW264.7 cells and boosted the neutralizing capacity of these cells when treated with the radical generator sodium nitroprusside (SNP). Interestingly, lancemaside A strongly blocked the adhesion activity of RAW264.7 cells to plastic culture plates, inhibited the cell-cell and cell-fibronectin (FN) adhesion of U937 cells that was triggered by treatment with an anti-β1-integrin (CD29) antibody and immobilized FN, respectively. By evaluating the activation of various intracellular signaling pathways and the levels of related nuclear transcription factors, lancemaside A was found to block the activation of inhibitor of κB kinase (IKK) and p65/nuclear factor- (NF-) κB. Taken together, our findings strongly suggest that the anti-inflammatory function of lancemaside A is the result of its strong antioxidative and IKK/NF-κB inhibitory activities.

Erythroid and megakaryocytic differentiation of K562 erythroleukemic cells by monochloramine

The induction of leukemic cell differentiation is a hopeful therapeutic modality. We studied the effects of monochloramine (NH2Cl) on erythroleukemic K562 cell differentiation, and compared the effects observed with those of U0126 and staurosporine, which are known inducers of erythroid and megakaryocytic differentiation, respectively. CD235 (glycophorin) expression, a marker of erythroid differentiation, was significantly increased by NH2Cl and U0126, along with an increase in cd235 mRNA levels. Other erythroid markers such as γ-globin and CD71 (transferrin receptor) were also increased by NH2Cl and U0126. In contrast, CD61 (integrin β3) and CD42b (GP1bα) expression, markers of megakaryocytic differentiation, was increased by staurosporine, but did not change significantly by NH2Cl and U0126. NH2Cl retarded cell proliferation without a marked loss of viability. When ERK phosphorylation (T202/Y204) and CD235 expression were compared using various chemicals, a strong negative correlation was observed (r = -0.76). Paradoxically, NH2Cl and staurosporine, but not U0126, induced large cells with multiple or lobulated nuclei, which was characteristic to megakaryocytes. NH2Cl increased the mRNA levels of gata1 and scl, decreased that of gata2, and did not change those of pu.1 and klf1. The changes observed in mRNA expression were different from those of U0126 or staurosporine. These results suggest that NH2Cl induces the bidirectional differentiation of K562. Oxidative stress may be effective in inducing leukemic cell differentiation.

Human breast tumor cells are more resistant to cardiac glycoside toxicity than non-tumorigenic breast cells

Cardiotonic steroids (CTS), specific inhibitors of Na,K-ATPase activity, have been widely used for treating cardiac insufficiency. Recent studies suggest that low levels of endogenous CTS do not inhibit Na,K-ATPase activity but play a role in regulating blood pressure, inducing cellular kinase activity, and promoting cell viability. Higher CTS concentrations inhibit Na,K-ATPase activity and can induce reactive oxygen species, growth arrest, and cell death. CTS are being considered as potential novel therapies in cancer treatment, as they have been shown to limit tumor cell growth. However, there is a lack of information on the relative toxicity of tumor cells and comparable non-tumor cells. We have investigated the effects of CTS compounds, ouabain, digitoxin, and bufalin, on cell growth and survival in cell lines exhibiting the full spectrum of non-cancerous to malignant phenotypes. We show that CTS inhibit membrane Na,K-ATPase activity equally well in all cell lines tested regardless of metastatic potential. In contrast, the cellular responses to the drugs are different in non-tumor and tumor cells. Ouabain causes greater inhibition of proliferation and more extensive apoptosis in non-tumor breast cells compared to malignant or oncogene-transfected cells. In tumor cells, the effects of ouabain are accompanied by activation of anti-apoptotic ERK1/2. However, ERK1/2 or Src inhibition does not sensitize tumor cells to CTS cytotoxicity, suggesting that other mechanisms provide protection to the tumor cells. Reduced CTS-sensitivity in breast tumor cells compared to non-tumor cells indicates that CTS are not good candidates as cancer therapies.

20S-dihydroprotopanaxadiol, a ginsenoside derivative, boosts innate immune responses of monocytes and macrophages

20S-dihydroprotopanaxadiol (2H-PPD) is a derivative of protopanaxadiol, a glycone of ginsenosides prepared from Panax ginseng. Although ginsenosides and acidic polysaccharides are known to be major active ingredients in ginseng, the immunopharmacological activities of their metabolites and derivatives have not been fully explored. In this study, we aimed to elucidate the regulatory action of 2H-PPD on the function of monocytes and macrophages in innate immune responses. 2H-PPD was able to boost the phagocytic uptake of fluorescein isothiocyanate-dextran in macrophages and enhance the generation of radicals (reactive oxygen species) in sodium nitroprusside-treated RAW264.7 cells. The surface levels of the costimulatory molecules such as CD80 and CD86 were also increased during 2H-PPD treatment. In addition, this compound boosted U937 cellcell aggregation induced by CD29 and CD43 antibodies, but not by cell-extracellular matrix (fibronectin) adhesion. Similarly, the surface levels of CD29 and CD43 were increased by 2H-PPD exposure. Therefore, our results strongly suggest that 2H-PPD has the pharmacological capability to upregulate the functional role of macrophages/monocytes in innate immunity.

20S-dihydroprotopanaxatriol modulates functional activation of monocytes and macrophages

20S-dihydroprotopanaxatriol (2H-PPT) is a derivative of protopanaxatrol from ginseng. Unlike other components from Panax ginseng, the pharmacological activity of this compound has not been fully elucidated. In this study, we investigated the modulatory activity of 2H-PPT on the cellular responses of monocytes and macrophages to understand its immunoregulatory actions. 2H-PPT strongly upregulated the release of radicals in sodium nitroprusside-treated RAW264.7 cells and the surface levels of costimulatory molecule CD86. More importantly, this compound remarkably suppressed nitric oxide production, morphological changes, phagocytic uptake, cell-cell aggregation, and cell-matrix adhesion in RAW264.7 and U937 cells in the presence or absence of lipopolysaccharide, anti-CD43 antibody, fibronectin, and phorbal 12-myristate 13-acetate. Therefore, our results suggest that 2H-PPT can be applied as a novel functional immunoregulator of macrophages and monocytes.

Extracellular signal-regulated kinase is a direct target of the anti-inflammatory compound amentoflavone derived from Torreya nucifera

Amentoflavone is a biflavonoid compound with antioxidant, anticancer, antibacterial, antiviral, anti-inflammatory, and UV-blocking activities that can be isolated from Torreya nucifera, Biophytum sensitivum, and Selaginella tamariscina. In this study, the molecular mechanism underlying amentoflavone's anti-inflammatory activity was investigated. Amentoflavone dose dependently suppressed the production of nitric oxide (NO) and prostaglandin E₂ (PGE₂) in RAW264.7 cells stimulated with the TLR4 ligand lipopolysaccharide (LPS; derived from Gram-negative bacteria). Amentoflavone suppressed the nuclear translocation of c-Fos, a subunit of activator protein (AP)-1, at 60 min after LPS stimulation and inhibited the activity of purified and immunoprecipitated extracellular signal-regulated kinase (ERK), which mediates c-Fos translocation. In agreement with these results, amentoflavone also suppressed the formation of a molecular complex including ERK and c-Fos. Therefore, our data strongly suggest that amentoflavone's immunopharmacological activities are due to its direct effect on ERK.

Predicting new indications for approved drugs using a proteochemometric method

The most effective way to move from target identification to the clinic is to identify already approved drugs with the potential for activating or inhibiting unintended targets (repurposing or repositioning). This is usually achieved by high throughput chemical screening, transcriptome matching, or simple in silico ligand docking. We now describe a novel rapid computational proteochemometric method called "train, match, fit, streamline" (TMFS) to map new drug-target interaction space and predict new uses. The TMFS method combines shape, topology, and chemical signatures, including docking score and functional contact points of the ligand, to predict potential drug-target interactions with remarkable accuracy. Using the TMFS method, we performed extensive molecular fit computations on 3671 FDA approved drugs across 2335 human protein crystal structures. The TMFS method predicts drug-target associations with 91% accuracy for the majority of drugs. Over 58% of the known best ligands for each target were correctly predicted as top ranked, followed by 66%, 76%, 84%, and 91% for agents ranked in the top 10, 20, 30, and 40, respectively, out of all 3671 drugs. Drugs ranked in the top 1-40 that have not been experimentally validated for a particular target now become candidates for repositioning. Furthermore, we used the TMFS method to discover that mebendazole, an antiparasitic with recently discovered and unexpected anticancer properties, has the structural potential to inhibit VEGFR2. We confirmed experimentally that mebendazole inhibits VEGFR2 kinase activity and angiogenesis at doses comparable with its known effects on hookworm. TMFS also predicted, and was confirmed with surface plasmon resonance, that dimethyl celecoxib and the anti-inflammatory agent celecoxib can bind cadherin-11, an adhesion molecule important in rheumatoid arthritis and poor prognosis malignancies for which no targeted therapies exist. We anticipate that expanding our TMFS method to the >27 000 clinically active agents available worldwide across all targets will be most useful in the repositioning of existing drugs for new therapeutic targets.

Cytopathic effects of chum salmon reovirus to salmonid epithelial, fibroblast and macrophage cell lines

The cytopathic effect (CPE) of chum salmon reovirus (CSV), an aquareovirus, was studied in three salmonid cell lines: epithelial-like CHSE-214 from Chinook salmon embryo, fibroblast-like RTG-2, and monocyte/macrophage-like RTS11, both from rainbow trout. CHSE-214 and RTG-2 supported syncytia formation with more dramatic syncytia being observed in CHSE-214 cultures, while CSV induced homotypic aggregation (HA) in RTS11. Syncytia and HA formation were blocked by cycloheximide and ribavirin but not actinomycin D, suggesting that expression of CSV genes were required for both phenomena. Cultures with syncytia underwent a decline in cell viability, which appeared to be via apoptosis, as determined by intranucleosomal fragmentation and caspase dependence assays using the pan-caspase inhibitor, zVAD-fmk. In the presence of zVAD-fmk, CHSE-214 cultures continued to form syncytia and show diminished energy metabolism, but DNA fragmentation, the loss of membrane integrity, and the release of infectious CSV were considerably blocked. These results suggest that the formation of syncytia triggers apoptosis and a leaky plasma membrane, which enhances viral release. By contrast, RTS11 cultures undergoing HA showed no loss of cell viability. The significance of HA is unclear, but the response suggests that macrophage behaviour in rainbow trout potentially could be modulated by CSV.

Staurosporine induces tyrosine phosphorylation in Dictyostelium discoideum proteins

The treatment of cells with staurosporine results in inhibition and less frequently activation of protein kinases, in a cell-type specific manner. In the social amoeba Dictyostelium discoideum, staurosporine induces marked changes in cell morphology affecting growth and development. Here we describe that incubation of D. discoideum growing or starved cells with staurosporine results in a rapid and unexpected tyrosine phosphorylation on two polypeptides of approximately 64 and approximately 62 kDa. These proteins emerge as novel substrates for tyrosine phosphorylation opening up new perspectives for the study of cell signalling in D. discoideum.

Amyloid precursor protein is involved in staurosporine induced glial differentiation of neural progenitor cells

Staurosporine (STS) has been reported as not only a pro-apoptotic agent, but also a terminal differentiation inducer in several neuroblastoma cell lines. Here, we report involvement of amyloid precursor protein (APP) in a STS induced astrocytic differentiation of human neural progenitor cells (NT-2/D1). We found that STS-treated NT-2/D1 cells expressed astrocyte-specific glial fibrillary acidic protein (GFAP), aspartate transporter, and glutamate transporter-1 with a distinctive astrocytic morphology. STS treatment increased GFAP promoter activity and increased expression and secretion of APP in NT-2/D1 cell culture. Overexpressed APP enhanced GFAP promoter activity and expression of GFAP, while gene silencing of APP by RNA interference decreased GFAP expression. These results indicate involvement of APP in STS induced astrocytic differentiation of NT-2/D1 cells. Furthermore, suppression of ERK1/2 phosphorylation, which is known to regulate APP expression by a MEK1 inhibitor, PD098059, reduced both APP and GFAP expression in STS treated NT-2/D1 cells. Thus, STS may induce astrocytic differentiation of NT-2/D1 by increasing APP levels associate with activation of ERK pathway.

In vitro anti-inflammatory and anti-oxidative effects of Cinnamomum camphora extracts

Cinnamomum camphora Sieb (Lauraceae) has long been prescribed in traditional medicine for the treatment of inflammation-related diseases such as rheumatism, sprains, bronchitis and muscle pains. In this study, therefore, we aimed to investigate the inhibitory effects of Cinnamomum camphora on various inflammatory phenomena to explore its potential anti-inflammatory mechanisms under non-cytotoxic (less than 100 microg/ml) conditions. The total crude extract (100 microg/ml) prepared with 80% methanol (MeOH extract) and its fractions (100 microg/ml) obtained by solvent partition with hexane and ethyl acetate (EtOAc) significantly blocked the production of interleukin (IL)-1 beta, IL-6 and the tumor necrosis factor (TNF)-alpha from RAW264.7 cells stimulated by lipopolysaccharide (LPS) up to 20-70%. The hexane and EtOAc extracts (100 microg/ml) also inhibited nitric oxide (NO) production in LPS/interferon (IFN)-gamma-activated macrophages by 65%. The MeOH extract (100 microg/ml) as well as two fractions (100 microg/ml) prepared by solvent partition with n-butanol (BuOH) and EtOAc strongly suppressed the prostaglandin E(2) (PGE(2)) production in LPS/IFN-gamma-activated macrophages up to 70%. It is interesting to note that hexane, BuOH and EtOAc extracts (100 microg/ml) also inhibited the functional activation of beta1-integrins (CD29) assessed by U937 homotypic aggregation up to 70-80%. Furthermore, EtOAc and BuOH extracts displayed strong anti-oxidative activity with IC(50) values of 14 and 15 microM, respectively, when tested by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and xanthine oxide (XO) assays. Taken together, these data suggest that the anti-inflammatory actions of Cinnamomum camphora may be due to the modulation of cytokine, NO and PGE(2) production and oxidative stress, and of the subfractions tested, the EtOAc extract may be further studied to isolate the active anti-inflammatory principles.

Cynaropicrin, a sesquiterpene lactone, as a new strong regulator of CD29 and CD98 functions

Cynaropicrin is a sesquiterpene lactone displaying immunomodulatory effects on the production of cytokine and nitric oxide from macrophages/monocytes. In this study we have examined inhibitory effect of cynaropicrin on activation of major adhesion molecules [CD29 (beta1 integrins), CD43, and CD98] on the cells assessed by U937 (promonocytic cells) homotypic aggregation. Cynaropicrin potently blocked CD29 (beta1 integrins)- and CD98-induced homotypic aggregation with IC(50) values of 3.46 and 2.98 microM, respectively, without displaying cytotoxicity. Similarly, flow cytometric analysis exhibited that cynaropicrin down-regulated strikingly surface level of CD29 and CD147, a functional regulator of CD98, but not CD43. More importantly, cynaropicrin inhibition was linked to blockade of extracellular signal-related kinase (ERK) activation and distinct from other enzyme inhibitors including rottlerin, propranolol, forskolin, and chloroquine, but not cytochalasin B. Therefore, our finding is the first demonstration that cynaropicrin may be a potent functional regulator of CD29 and CD98 via interrupting ERK activation which may be linked to cytoskeleton rearrangement, suggesting further application to CD29- and CD98-mediated diseases such as virus-induced chronic inflammation, and invasion, migration, and metastasis of leukocyte cancer cells.

In vitro anti-inflammatory and pro-aggregative effects of a lipid compound, petrocortyne A, from marine sponges

(3 S,14 S)-Petrocortyne A, a lipid compound (a C(46) polyacetylenic alcohol), from marine sponges ( Petrosia sp.) is potently cytotoxic against several solid tumour cells. In this study, we investigated in vitro anti-inflammatory and pro-aggregative effects of petrocortyne A at non-cytotoxic concentrations on various cellular inflammatory phenomena using the macrophage and monocytic cell lines RAW264.7 and U937. Petrocortyne A blocked tumour necrosis factor-alpha (TNF-alpha) production strongly and concentration-dependently in lipopolysaccharide (LPS)-activated RAW264.7 cells and phorbol 12-myristate 13-acetate (PMA)/LPS-treated U937 cells. It also blocked NO production concentration-dependently in LPS- or interferon (IFN)-gamma-treated RAW264.7 cells. Among the migration factors tested, the compound selectively blocked the expression of hepatocyte growth factor/scatter factor (HGF/SF). On the other hand, as assessed by a cell-cell adhesion assay, petrocortyne A did not block the activation of adhesion molecules induced by aggregative antibodies to adhesion molecules, but suppressed PMA-induced cell-cell adhesion significantly. Intriguingly, petrocortyne A induced U937 homotypic aggregation following long exposure (2 and 3 days), accompanied by weak induction of pro-aggregative signals such as tyrosine phosphorylation of p132 and phosphorylation of extracellular signal-related kinase 1 and 2 (ERK 1/2). Petrocortyne A may thus inhibit cellular inflammatory processes and immune cell migration to inflamed tissue.