The effect of endotoxin on functional parameters of mammary CID-9 cells

Endotoxin Triggers Tumor Initiation Events in Nontumorigenic Breast Epithelial Cells and Enhances Invasion-Related Phenotype in Pretumorigenic and Tumorigenic Breast Epithelial Cells

Inflammation is associated with the development of several cancers, including breast cancer. However, the molecular mechanisms driving breast cancer initiation or enhancement by inflammation are yet to be deciphered. Hence, we opted to investigate the role of inflammation in initiating and enhancing tumor-like phenotypes in nontumorigenic, pretumorigenic, and tumorigenic breast epithelial cells. Noncytotoxic endotoxin (ET) concentrations capable of inducing an inflammatory phenotype were determined for the different cell lines. Results showed that short-term ET exposure upregulated matrix metalloproteinase-9 (MMP-9) activity in nontumorigenic mammary epithelial cells of mouse (SCp2) and human origins (HMT-3522 S1; S1) and upregulated inflammatory mediators including nitric oxide (NO) and interleukin 1-β in tumorigenic human breast cells (MDA-MB-231), all in a dose-dependent manner. Long-term ET treatment, but not short-term, triggered the migration of SCp2 cells, and proliferation and migration of tumorigenic human breast cells MCF-7 and MDA-MB-231. Both short- and long-term ET exposures preferentially enhanced the invasion of pretumorigenic S1-connexin 43 knockout (Cx43-KO S1) cells compared to their nontumorigenic S1 counterparts. Moreover, both ET exposures disrupted lumen formation and apicolateral distribution of β-catenin in 3D cultures of S1 cells. In conclusion, ET treatment at concentrations that elicited inflammatory phenotype triggered tumor initiation events in nontumorigenic and pretumorigenic breast cells, and increased tumorigenicity of breast cancer cells. Our findings highlight the role of inflammation in enhancing migration, invasion, and loss of normal 3D morphology and suggest that such inflammatory insults can "add injury" to pretumorigenic and tumorigenic breast epithelial cells.

Anti-proliferative and anti-inflammatory activities of the sea cucumber Holothuria polii aqueous extract

Objective:

Sea cucumbers are considered among the most important functional foods. Following bioassay guided fractionation, we assessed the anti-proliferative and anti-inflammatory activities of Holothuria polii (H. polii) extracts.

Methods:

Sea cucumber ethanolic extract and the partially purified aqueous fractions were assessed for their anti-proliferative activities. These latter bioactivities were evaluated in the highly invasive MDA-MB-231 human breast cancer cells in two-dimensional and three-dimensional cultures using trypan blue exclusion assay. The tumor-suppressive effects of sea cucumber ethanolic extract and aqueous fractions were assayed by measuring the trans-well invasion of MDA-MB-231 cells and the expression of some epithelial mesenchymal transition markers using quantitative reverse-transcription polymerase chain reaction and western blot analysis. The anti-inflammatory activity of the aqueous fraction was tested by measuring the secreted levels of interleukin-6, nitric oxide, and matrix metalloproteinase 9 in endotoxin-induced mammary epithelial SCp2 cells and interleukin-1β in phorbol-12-myristate-13-acetate-activated human monocytic THP-1 cells.

Results:

Sea cucumber ethanolic extract and the aqueous fraction significantly decreased the proliferation of MDA-MB-231 cells by more than 50% at similar and noncytotoxic concentrations and caused an arrest in the S-phase of the cell cycle of treated cells. In contrast, petroleum ether, chloroform, ethyl acetate, and n-butanol organic fractions did not show any significant activity. Furthermore, sea cucumber ethanolic extract and aqueous fraction reduced the proliferation of MDA-MB-231 cells in three-dimensional cultures by more than 60% at noncytotoxic concentrations. In addition, treatment with these concentrations resulted in the loss of stellate outgrowths in favor of spherical aggregates and a 30% decrease in invasive properties. Both sea cucumber ethanolic extract and aqueous decreased the transcription of vimentin and the protein expression levels of vimentin and N-cadherin in three-dimensional cultures. The aqueous fraction decreased the levels of inflammatory markers interleukin-6, nitric oxide, and matrix metalloproteinase 9 in the mouse mammary SCp2 cells, and the level of interleukin-1β produced by phorbol-12-myristate-13-acetate-activated THP-1 human monocytic cells.

Conclusion:

The data reveal for the first time promising anti-proliferative and anti-inflammatory activities in H. polii water extract in two-dimensional and three-dimensional culture models.

Anti-Inflammatory and Cytostatic Activities of a Parthenolide-Like Sesquiterpene Lactone from Cota palaestina subsp. syriaca

A sesquiterpene lactone 1-β,10-Epoxy-6-hydroxy-1,10H-inunolide (K100) was isolated through "bioassay-guided fractionation" from Cota palaestina subsp. syriaca, an Eastern Mediterranean endemic plant. K100 inhibited endotoxin- (ET-) induced proinflammatory markers: IL-6, MMP-9, and NO in normal mouse mammary SCp2 Cells. Molecular docking in silico suggested that K100, having highly analogous structure as parthenolide (PTL), an anticancer compound, could bind PTL target proteins at similar positions and with comparable binding affinities. Both compounds, K100 and PTL, inhibited the proliferation and prolonged the S-phase of the cell cycle of breast adenocarcinoma MDA-MB-231 cells grown in 2D cultures. Noncytotoxic concentrations of K100 and PTL decreased the proliferation rate of MDA-MB-231 and shifted their morphology from stellate to spherical colonies in 3D cultures. This was accompanied with a significant increase in the amount of small colonies and a decrease in the amount of large colonies. Moreover, K100 and PTL decreased cellular motility and invasiveness of MDA-MB-231 cells. In summary, these results suggest that K100 exhibits PTL-analogous anti-inflammatory, cytostatic, and antimetastatic effects.

Differential response of bovine mammary epithelial cells to Staphylococcus aureus or Escherichia coli agonists of the innate immune system

Mastitis caused by Escherichia coli and Staphylococcus aureus is a major pathology of dairy cows. To better understand the differential response of the mammary gland to these two pathogens, we stimulated bovine mammary epithelial cells (bMEC) with either E. coli crude lipopolysaccharide (LPS) or with S. aureus culture supernatant (SaS) to compare the transcriptomic profiles of the initial bMEC response. By using HEK 293 reporter cells for pattern recognition receptors, the LPS preparation was found to stimulate TLR2 and TLR4 but not TLR5, Nod1 or Nod2, whereas SaS stimulated TLR2. Biochemical analysis revealed that lipoteichoic acid, protein A and α-hemolysin were all present in SaS, and bMEC were found to be responsive to each of these molecules. Transcriptome profiling revealed a core innate immune response partly shared by LPS and SaS. However, LPS induced expression of a significant higher number of genes and the fold changes were of greater magnitude than those induced by SaS. Microarray data analysis suggests that the activation pathways and the early chemokine and cytokine production preceded the defense and stress responses. A major differential response was the activation of the type I IFN pathway by LPS but not by SaS. The higher upregulation of chemokines (Cxcl10, Ccl2, Ccl5 and Ccl20) that target mononuclear leucocytes by LPS than by SaS is likely to be related to the differential activation of the type I IFN pathway, and could induce a different profile of the initial recruitment of leucocytes. The MEC responses to the two stimuli were different, as LPS was associated with NF-κB and Fas signaling pathways, whereas SaS was associated with AP-1 and IL-17A signaling pathways. It is noteworthy that at the protein level secretion of TNF-α and IL-1β was not induced by either stimulus. These results suggest that the response of MEC to diffusible stimuli from E. coli and S. aureus contributes to the onset of the response with differential leucocyte recruitment and distinct inflammatory and innate immune reactions of the mammary gland to infection.

Prenylated Flavonoids from Morus alba L. Cause Inhibition of G1/S Transition in THP-1 Human Leukemia Cells and Prevent the Lipopolysaccharide-Induced Inflammatory Response

Morus alba L. (MA) is a natural source of many compounds with different biological effects. It has been described to possess anti-inflammatory, antioxidant, and hepatoprotective activities. The aim of this study was to evaluate cytotoxicity of three flavonoids isolated from MA (kuwanon E, cudraflavone B, and 4′-O-methylkuwanon E) and to determine their effects on proliferation of THP-1 cells, and on cell cycle progression of cancer cells. Anti-inflammatory effects were also determined for all three given flavonoids. Methods used in the study included quantification of cells by hemocytometer and WST-1 assays, flow cytometry, western blotting, ELISA, and zymography. From the three compounds tested, cudraflavone B showed the strongest effects on cell cycle progression and viability of tumor and/or immortalized cells and also on inflammatory response of macrophage-like cells. Kuwanon E and 4′-O-methylkuwanon E exerted more sophisticated rather than direct toxic effect on used cell types. Our data indicate that mechanisms different from stress-related or apoptotic signaling pathways are involved in the action of these compounds. Although further studies are required to precisely define the mechanisms of MA flavonoid action in human cancer and macrophage-like cells, here we demonstrate their effects combining antiproliferative and anti-inflammatory activities, respectively.

Inflammatory responses in epithelia: endotoxin-induced IL-6 secretion and iNOS/NO production are differentially regulated in mouse mammary epithelial cells

Background

IL-6 is a pro-inflammatory cytokine that signals via binding to a soluble or membrane bound receptor, while nitric oxide (NO), an oxidative stress molecule, diffuses through the cell membrane without a receptor. Both mediators signal through different mechanisms, yet they are dependent on NFκB. We proposed that both mediators are co-induced and co-regulated in inflamed mammary epithelial cells.

Methods

SCp2 mammary epithelial cells were treated with bacterial endotoxin (ET) for different time periods and analyzed for induction of IL-6 secretion and NO production by ELISA and Griess reaction, respectively. The expression of IL-6 and induced NO synthase (iNOS) was assayed by real time PCR and/or western immunoblots, and the activation of NFκB was assayed by immunobinding assay. To investigate the role of mammary cell microenvironment (cell-substratum or interaction of mammary epithelial cell types; critical to mammary development, function, and disease) in modulation of the inflammatory response, SCp2 cells were cultured with or without extracellular matrix (EHS) or in coculture with their myoepithelial counterpart (SCg6), and assayed for ET-induced IL-6 and NO.

Results

Endotoxin induced NFκB activation at 1 h after ET application. IL-6 secretion and NO production were induced, but with unexpected delay in expression of mRNA for iNOS compared to IL-6. NFκB/p65 activation was transient but NFκB/p50 activation persisted longer. Selective inhibition of NFκB activation by Wedelolactone reduced ET-induced expression of IL-6 mRNA and protein but not iNOS mRNA or NO production, suggesting differences in IL-6 and iNOS regulation via NFκB. SCp2 cells in coculture with SCg6 but not in presence of EHS dramatically induced IL-6 secretion even in the absence of ET. ET-induced NO production was blunted in SCp2/SCg6 cocultures compared to that in SCp2 alone.

Conclusions

The differential regulation of IL-6 and iNOS together with the differential activation of different NFκB dimers suggest that IL-6 and iNOS are regulated by different NFκB dimers, and differentially regulated by the microenvironment of epithelial cells. The understanding of innate immune responses and inflammation in epithelia and linkage thereof is crucial for understanding the link between chronic inflammation and cancer in epithelial tissues such as the mammary gland.

Activation of nuclear factor kappa B in mammary epithelium promotes milk loss during mammary development and infection

We investigated whether nuclear factor kappa B (NF-kappaB), which exhibits a regulated pattern of activity during murine mammary gland development, plays an important role during lactation and involution, when milk production ceases and the gland undergoes apoptosis and re-modeling. We generated a doxycycline inducible transgenic mouse model to activate NF-kappaB specifically in the mammary epithelium through expression of a constitutively active form of IKK2, the upstream kinase in the classical NF-kappaB signaling cascade. We found that activation of NF-kappaB during involution resulted in a more rapid reduction in milk levels and increased cleavage of caspase-3, an indicator of apoptosis. We also found that activation of NF-kappaB during lactation with no additional involution signals had a similar effect. The observation that NF-kappaB is a key regulator of milk production led us to investigate the role of NF-kappaB during mastitis, an infection of the mammary gland in which milk loss is observed. Mammary gland injection of E. coli LPS resulted in activation of NF-kappaB and milk loss during lactation. This milk loss was decreased by selective inhibition of NF-kappaB in mammary epithelium. Together, our data reveal that activation of NF-kappaB leads to milk clearance in the lactating mammary gland. Therefore, targeting of NF-kappaB signaling may prove therapeutic during mastitis in humans and could be beneficial for the dairy industry, where such infections have a major economic impact.

Interleukin-6 and Cyclooxygenase-2 downregulation by fatty-acid fractions of Ranunculus constantinopolitanus

Background

Medicinal plants represent alternative means for the treatment of several chronic diseases, including inflammation. The genus Ranunculus, a representative of the Ranunculaceae family, has been reported to possess anti-inflammatory, analgesic, antiviral, antibacterial, antiparasitic and antifungal activities, possibly due to the presence of anemonin and other. Different studies have shown the occurrence of unusual fatty acids (FAs) in Ranunculaceae; however, their therapeutic role has not been investigated. The purpose of this study is to characterize potential anti-inflammatory bioactivities in Ranunculus constantinopolitanus D'Urv., traditionally used in Eastern Mediterranean folk medicine.

Methods

The aerial part of R. constantinopolitanus was subjected to methanol (MeOH) extraction and solvent fractionation. The bioactive fraction (I.2) was further fractionated using column chromatography, and the biologically active subfraction (Y₂₊₃) was identified using infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS). The effects of I.2 and Y₂₊₃ on cell viability were studied in mouse mammary epithelial SCp2 cells using trypan blue exclusion method. To study the anti-inflammatory activities of I.2 and Y₂₊₃, their ability to reduce interleukin (IL)-6 levels was assessed in endotoxin (ET)-stimulated SCp2 cells using enzyme-linked immunosorbent assay (ELISA). In addition, the ability of Y₂₊₃ to reduce cyclooxygenase (COX)-2 expression was studied in IL-1-treated mouse intestinal epithelial Mode-K cells via western blotting. Data were analyzed by one-way analysis of variance (ANOVA), Student-Newman-Keuls (SNK), Tukey HSD, two-sample t-test and Dunnett t-tests for multiple comparisons.

Results

The chloroform fraction (I.2) derived from crude MeOH extract of the plant, in addition to Y₂₊₃, a FA mix isolated from this fraction and containing palmitic acid, C18:2 and C18:1 isomers and stearic acid (1:5:8:1 ratio), reduced ET-induced IL-6 levels in SCp2 cells without affecting cell viability or morphology. When compared to fish oil, conjugated linoleic acid (CLA) and to individual FAs as palmitic, linoleic, oleic and stearic acid or to a mix of these FAs (1:5:8:1 ratio), Y₂₊₃ exhibited higher potency in reducing ET-induced IL-6 levels within a shorter period of time. Y₂₊₃ also reduced COX-2 expression in IL-1-treated Mode-K cells.

Conclusion

Our studies demonstrate the existence of potential anti-inflammatory bioactivities in R. constantinopolitanus and attribute them to a FA mix in this plant.

Metallothioneins are multipurpose neuroprotectants during brain pathology

Metallothioneins (MTs) constitute a family of cysteine-rich metalloproteins involved in cytoprotection during pathology. In mammals there are four isoforms (MT-I - IV), of which MT-I and -II (MT-I + II) are the best characterized MT proteins in the brain. Accumulating studies have demonstrated MT-I + II as multipurpose factors important for host defense responses, immunoregulation, cell survival and brain repair. This review will focus on expression and roles of MT-I + II in the disordered brain. Initially, studies of genetically modified mice with MT-I + II deficiency or endogenous MT-I overexpression demonstrated the importance of MT-I + II for coping with brain pathology. In addition, exogenous MT-I or MT-II injected intraperitoneally is able to promote similar effects as those of endogenous MT-I + II, which indicates that MT-I + II have both extra- and intracellular actions. In injured brain, MT-I + II inhibit macrophages, T lymphocytes and their formation of interleukins, tumor necrosis factor-alpha, matrix metalloproteinases, and reactive oxygen species. In addition, MT-I + II enhance cell cycle progression, mitosis and cell survival, while neuronal apoptosis is inhibited. The precise mechanisms downstream of MT-I + II have not been fully established, but convincing data show that MT-I + II are essential for coping with neuropathology and for brain recovery. As MT-I and/or MT-II compounds are well tolerated, they may provide a potential therapy for a range of brain disorders.

Bacterial cell shape-dependent inflammatory response in mammary epithelial cells

An in vitro co-culture model of SCp2 mammary epithelial cells and Escherichia coli strains was established in bacterial non-CO(2) incubators. Co-culturing SCp2 cells with either the rod-shaped W3110 or spherical-shaped GC7378Tn10 strains of Escherichia coli led to an increase in interleukin-6 (IL-6) levels by SCp2 cells after 9 h. At a ratio of 1:100 (epithelial:bacterial), the rod-shaped W3110 strain induced almost double the amount of IL-6 induced by the spherical-shaped GC7378Tn10 strain. The effect of Escherichia coli morphology (rod versus spherical) on IL-6 production by SCp2 cells was further investigated by shifting GC7378Tn10 morphology to rod through introducing the pbpA gene by transduction and transformation. In both approaches, the generated rod strains elicited higher IL-6 levels in SCp2 cells compared to the spherical ones at 1:50 and 1:100 ratios (epithelial:bacterial). Our findings demonstrate the significance of cell shape in bacterial-host interactions with potential implications in bacterial pathogenesis in general.