Induced IL-6 Secretion Research Articles

Biased Signaling by Agonists of Protease Activated Receptor 2.

Protease activated receptor 2 (PAR2) is associated with metabolism, obesity, inflammatory, respiratory and gastrointestinal disorders, pain, cancer, and other diseases. The extracellular N-terminus of PAR2 is a common target for multiple proteases, which cleave it at different sites to generate different N-termini that activate different PAR2-mediated intracellular signaling pathways. There are no synthetic PAR2 ligands that reproduce the same signaling profiles and potencies as proteases. Structure-activity relationships here for 26 compounds spanned a signaling bias over 3 log units, culminating in three small ligands as biased agonist tools for interrogating PAR2 functions. DF253 (2f-LAAAAI-NH2) triggered PAR2-mediated calcium release (EC50 2 μM) but not ERK1/2 phosphorylation (EC50 > 100 μM) in CHO cells transfected with hPAR2. AY77 (Isox-Cha-Chg-NH2) was a more potent calcium-biased agonist (EC50 40 nM, Ca2+; EC50 2 μM, ERK1/2), while its analogue AY254 (Isox-Cha-Chg-A-R-NH2) was an ERK-biased agonist (EC50 2 nM, ERK1/2; EC50 80 nM, Ca2+). Signaling bias led to different functional responses in human colorectal carcinoma cells (HT29). AY254, but not AY77 or DF253, attenuated cytokine-induced caspase 3/8 activation, promoted scratch-wound healing, and induced IL-8 secretion, all via PAR2-ERK1/2 signaling. Different ligand components were responsible for different PAR2 signaling and functions, clues that can potentially lead to drugs that modulate different pathway-selective cellular and physiological responses.

Sulforaphane enhances the anticancer activity of taxanes against triple negative breast cancer by killing cancer stem cells

Triple negative breast cancer (TNBC) typically exhibits rapid progression, high mortality and faster relapse rates relative to other breast cancer subtypes. In this report we examine the combination of taxanes (paclitaxel or docetaxel) with a breast cancer stem cell (CSC)-targeting agent sulforaphane for use against TNBC. We demonstrate that paclitaxel or docetaxel treatment induces IL-6 secretion and results in expansion of CSCs in TNBC cell lines. Conversely, sulforaphane is capable of preferentially eliminating CSCs, by inhibiting NF-κB p65 subunit translocation, downregulating p52 and consequent downstream transcriptional activity. Sulforaphane also reverses taxane-induced aldehyde dehydrogenase-positive (ALDH+) cell enrichment, and dramatically reduces the size and number of primary and secondary mammospheres formed. In vivo in an advanced treatment orthotopic mouse xenograft model together with extreme limiting dilution analysis (ELDA), the combination of docetaxel and sulforaphane exhibits a greater reduction in primary tumor volume and significantly reduces secondary tumor formation relative to either treatment alone. These results suggest that treatment of TNBCs with cytotoxic chemotherapy would be greatly benefited by the addition of sulforaphane to prevent expansion of and eliminate breast CSCs.

EMMPRIN Inhibits bFGF-Induced IL-6 Secretion in an Osteoblastic Cell Line, MC3T3-E1.

Background: Electrolytically-generated acid functional water (FW) is obtained by electrolyzing low concentrations of saline. Although it has been widely used in clinical practice with various purposes, the underlying mechanisms of action involved have not been fully elucidated so far. We used the human cervical cancer-derived fibroblastic cell line (HeLa), to examine the cytokine secretion profile following FW treatment in the present study.Results: FW stimulation significantly induced the secretion of basic fibroblast growth factor (bFGF) and extracellular matrix metalloproteinase inducer (EMMPRIN). The effect of both factors on osteoblast-like MC3T3-E1 cells was further examined by stimulating the cells with the conditioned medium of FW-stimulated HeLa cells. However, the conditioned medium failed to induce IL-6 secretion. The MC3T3-E1 cells were further stimulated with recombinant bFGF or EMMPRIN or a combination of both factors. Intriguingly, bFGF-stimulated IL-6 induction was totally inhibited by EMMPRIN. Pretreatment with the specific inhibitor of nuclear factor-kappa B (NF-κB) drastically inhibited IL-6 secretion indicating that bFGF-induced IL-6 expression was dependent on NF-κB activation. The phosphorylation status of NF-κB p65 subunit was further examined. The results indicated that EMMPRIN inhibited bFGF-induced NF-κB p65 phosphorylation.Conclusions: These findings suggest that bFGF can induce IL-6 secretion in MC3T3-E1 cells through NF-κB activation. As EMMPRIN inhibited bFGF-induced IL-6 secretion by reducing the p65 subunit phosphorylation, it might be concluded that bFGF and EMMPRIN crosstalk in their respective signaling pathways.

Activités immunomodulatrice, anti-inflammatoire, antiprurigineuse et tolérogénique induites par I-modulia®, un extrait issu de culture d’Aquaphilus dolomiae, dans les modèles pharmacologiques de dermatite atopique: Immunomodulatory, anti-inflammatory, anti-pruritus and tolerogenic activities induced by I-modulia®, an Aquaphilus dolomiae culture extract, in atopic dermatitis pharmacology models

Atopic dermatitis (AD) is an inflammatory and pruritic dermatosis of multifactorial origin. Topical steroids are the first line treatment for severe AD however alternatives treatment are increasingly needed. A biological concentrate was elaborated from culture of an Avène aquatic microflora isolate namely Aquaphilus dolomiae. Numerous extracts were evaluated in relevant AD in vitro models with human keratinocytes. Among these extracts, a particular one I-modulia® was found to be remarkable in terms of pharmacological activities: innate immunity modulating by agonizing Toll like receptor (TLR)2, TLR4 and TLR5, induction of anti-microbial peptides, inhibition of cytokines characteristics of T helper (Th)1, Th2 and Th17 responses, inhibition of Protease-activated-receptor (PAR) 2 and Thymic-stromal-lymphopoeitin (TSLP) both being known to be upregulated in pruritus. Additionally, when human dendritic cells (DC) were stimulated in vitro by Staphylococcus aureus secretomes from AD children lesions, I-modulia® was capable to induce IL-10 secretion to activate regular T lymphocytes and rendered DC tolerogenic. I-modulia®, extract of biotech origin incorporated in emollient, displays anti-inflammatory, anti-pruritus activities, restores homeostasis immune and ameliorates AD in young infant.

In vitro effects of the toll-like receptor agonists monophosphoryl lipid A and CpG-rich oligonucleotides on cytokine production by equine cells

Insect bite hypersensitivity (IBH) is an equine allergic dermatitis to Culicoides spp. antigens. Attempts at using allergen-specific immunotherapy (AIT) as a treatment for IBH have so far proven unsuccessful. Toll-like receptor (TLR) agonists can promote a shift in the immune response from the allergy-promoting T helper cell 2 (Th2) response towards a Th1 and/or regulatory response. The aim of this study was to evaluate two immunomodulatory TLR agonists in vitro as potential vaccine adjuvants for a more efficacious AIT in IBH. Peripheral blood mononuclear cells (PBMCs) from healthy and IBH-affected horses were stimulated with the TLR-agonists monophosphoryl lipid A (MPLA) or CpG-rich oligodeoxynucleotides (CpG-ODN) in the presence or absence of Culicoides spp. allergens. Cytokine concentrations of interferon (IFN)-α, IFN-γ, interleukin (IL)-4, IL-10 and IL-17 were quantified in the supernatants of stimulated PBMCs. MPLA induced IL-10 secretion in all horses, regardless of presence and nature of antigens, while suppressing antigen-induced production of IFN-γ, IL-4 and IL-17. CpG-ODN significantly increased IFN-α, IFN-γ and IL-4 production, but had little effect on IL-10 production. In conclusion, MPLA promotes a regulatory immune response and is therefore a promising adjuvant candidate for allergy vaccines in horses. While C-class CpG-ODN is an unsuitable adjuvant for AIT, it induces IFN-γ and IFN-α, and thus may be a useful adjuvant in combination with vaccines for equine infectious or neoplastic diseases.

Porphyromonas gingivalis-stimulated macrophage subsets exhibit differential induction and responsiveness to interleukin-10

ObjectivesOral mucosal macrophages (Mϕs) determine immune responses; maintaining tolerance whilst retaining the capacity to activate defences against pathogens. Mϕ responses are determined by two distinct subsets; pro-inflammatory M1- and anti-inflammatory/regulatory M2-Mϕs. Tolerance induction is driven by M2 Mϕs, whereas M1-like Mϕs predominate in inflammation, such as that exhibited in chronic Porphyromonas gingivalis (PG) periodontal infection. Mϕ responses can be suppressed to benefit either the host or the pathogen. Chronic stimulation by pathogen associated molecular patterns (PAMPs), such as LPS, is well established to induce tolerance. The aim of this study was to investigate the P. gingivalis-driven induction of and responsiveness to the suppressive, anti-inflammatory cytokine, IL-10, by Mϕ subsets. MethodsM1- and M2-like Mϕs were generated in vitro from the THP-1 monocyte cell line by differentiation with PMA and Vitamin D3, respectively. Mϕ subsets were stimulated by PG-LPS in the presence or absence of IL-10. ResultsPG-LPS differentially induced IL-10 secretion and endogenous IL-10 activity in M1- and M2-like subsets. In addition, these subsets exhibited differential sensitivity to IL-10-mediated suppression of TNFα, where M2 Mϕs where sensitive to IL-10 and M1 Mϕs were refractory to suppression. In addition, this differential responsiveness to IL-10 was independent of IL-10-binding and expression of the IL-10 receptor signal transducing subunit, IL-10Rβ, but was in fact dependent on activation of STAT-3. ConclusionP.gingivalis selectively tolerises regulatory M2 Mϕs with little effect on pro-inflammatory M1 Mϕs; differential suppression facilitating immunopathology at the expense of immunity.

IκB-Kinase-epsilon (IKKε) over-expression promotes the growth of prostate cancer through the C/EBP-β dependent activation of IL-6 gene expression.

The inflammatory cytokine IL-6 has been shown to induce the nuclear translocation of androgen receptors in prostate cancer cells and to activate the androgen receptors in a ligand-independent manner, suggesting it may contribute to the development of a castrate-resistant phenotype. Elevated IL-6 serum levels have also been associated with metastasis-related morbidity in prostate cancer patients. We have previously established that over-expression of I-kappa-B-kinase-epsilon (IKKε also named IKKi or IκBKε) in hormone-sensitive prostate cancer cell lines induces IL-6 secretion. We have also reported that prostate cancer cell lines lacking androgen receptor expression exhibit high constitutive IKKε expression and IL-6 secretion. In the present study, we validated the impact of IKKε depletion on the in vitro proliferation of castrate-resistant prostate cancer cells, and characterized how IKKε depletion affects tumor growth and IL-6 tumor secretion in vivo through a mouse xenograft-based approach. We observed a significant growth delay in IKKε-silenced PC-3 cells injected in SCID mice fed with a doxycycline-supplemented diet in comparison with mice fed with a normal diet. We also found a decrease in IL-6 secretion levels that strongly correlated with tumor growth inhibition. Finally, using constructs with various IL-6-mutated promoters, we demonstrated that IKKε over-expression induces a NF-κB-independent stimulation of the IL-6 gene promoter through the activation and nuclear accumulation of the transcription factor C/EBP-β. Our study demonstrates the pro-proliferative role of the oncogene IKKε in castrate-resistant prostate cancer cell lines, involving the phosphorylation and nuclear translocation of C/EBP-β that initiates IL-6 gene expression.

Abstract 3278: Dopamine inhibits growth of multiple myeloma

Abstract Introduction: Multiple myeloma (MM), progressive plasma cell tumor leading to overproduction of monoclonal immunoglobulins, osteolytic bone lesions, renal disease and immunodeficiency, is the second most prevalent hematologic malignancy in the United States. Vascular endothelial growth factor-A (VEGF-A) is a critical cytokine responsible for the induction of angiogenesis in several solid and hematological malignancies like MM. It is likely that VEGF-A induced bone marrow (BM) angiogenesis promotes the survival, growth and proliferation of MM .Therefore targeting BM angiogenesis in MM may be effective for the treatment of MM patients Objective/Hypothesis: Bone marrow stromal cells (BMSC) are believed to play a central role in progression of MM pathogenesis. Along with other factors, these cells overproduce IL-6 that in turn stimulates growth, survival and progression of MM cells. Since it has been shown that VEGF-A can stimulate IL-6 secretion by these cells and because we have demonstrated that neurotransmitter dopamine (DA) can inhibit VEGF-A functions by acting through its D2 receptors (D2R) and BMSC express DAD2R, we therefore hypothesize that DA or D2R agonists have a role in inhibiting VEGF-A mediated IL-6 secretion by BMSC and thereby, MM progression. Results: Our results indicate that VEGF-A can significantly increase the secretion of IL6 by isolated BMSC cells in vitro. Addition of DA or D2R agonist, quinpirole, to VEGF-A treated BM cells results in suppression of IL-6 production. However treatment with D2R antagonist, eticlopride, prior to treatment with DA results in abrogation of the effect of DA. Similar effects of DA on VEGF-A induced IL-6 secretion was also observed in HS-5 human BM stromal cells. Our results further indicate that VEGF-A induced VEGFR1 phosphorylation is suppressed in HS-5 cells on treatment with D2R agonist. Furthermore, DA also inhibits the proliferation of MM1.S human MM cells in vitro. Conclusion: DA may be a new and an effective approach to retard the progression of MM. Since anti-angiogenic monotherapy cannot eradicate the disease completely, strategies using DA with more traditional modalities to eradicate the disease at the time of initial treatment might be beneficial. Finally, DA or its D2R agonists are being used in the clinics for several years for the treatment of other disorders, therefore these inexpensive drugs (in comparison to presently available drugs for the treatment of MM) with known and manageable side effects can be used in the clinics in near future for the treatment of both early and late stage MM. Citation Format: Chandrani Sarkar, Debanjan Chakroborty, Sujit Basu. Dopamine inhibits growth of multiple myeloma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3278.

Chronic myelogenous leukaemia exosomes modulate bone marrow microenvironment through activation of epidermal growth factor receptor.

Chronic myelogenous leukaemia (CML) is a clonal myeloproliferative disorder. Recent evidence indicates that altered crosstalk between CML and mesenchymal stromal cells may affect leukaemia survival; moreover, vesicles released by both tumour and non‐tumour cells into the microenvironment provide a suitable niche for cancer cell growth and survival. We previously demonstrated that leukaemic and stromal cells establish an exosome‐mediated bidirectional crosstalk leading to the production of IL8 in stromal cells, thus sustaining the survival of CML cells. Human cell lines used are LAMA84 (CML cells), HS5 (stromal cells) and bone marrow primary stromal cells; gene expression and protein analysis were performed by real‐time PCR and Western blot. IL8 and MMP9 secretions were evaluated by ELISA. Exosomes were isolated from CML cells and blood samples of CML patients. Here, we show that LAMA84 and CML patients’ exosomes contain amphiregulin (AREG), thus activating epidermal growth factor receptor (EGFR) signalling in stromal cells. EGFR signalling increases the expression of SNAIL and its targets, MMP9 and IL8. We also demonstrated that pre‐treatment of HS5 with LAMA84 exosomes increases the expression of annexin A2 that promotes the adhesion of leukaemic cells to the stromal monolayer, finally supporting the growth and invasiveness of leukaemic cells. Leukaemic and stromal cells establish a bidirectional crosstalk: exosomes promote proliferation and survival of leukaemic cells, both in vitro and in vivo, by inducing IL8 secretion from stromal cells. We propose that this mechanism is activated by a ligand–receptor interaction between AREG, found in CML exosomes, and EGFR in bone marrow stromal cells.

Resveratrol Interferes with IL1-β-Induced Pro-Inflammatory Paracrine Interaction between Primary Chondrocytes and Macrophages.

State of the art. Osteoarthritis (OA) is a chronic articular disease characterized by cartilage degradation and osteophyte formation. OA physiopathology is multifactorial and involves mechanical and hereditary factors. So far, there is neither preventive medicine to delay cartilage breakdown nor curative treatment. Objectives. To investigate pro-inflammatory paracrine interactions between human primary chondrocytes and macrophages following interleukin-1-β (IL-1β) treatment; to evaluate the molecular mechanism responsible for the inhibitory effect of resveratrol. Results. The activation of NF-κB in chondrocytes by IL-1β induced IL-6 secretion. The latter will then activate STAT3 protein in macrophages. Moreover, STAT3 was able to positively regulate IL-6 secretion, as confirmed by the doubling level of IL-6 in the coculture compared to macrophage monoculture. These experiments confirm the usefulness of the coculture model in the inflammatory arthritis-linked process as a closer biological situation to the synovial joint than separated chondrocytes and macrophages. Il also demonstrated the presence of an inflammatory amplification loop induced by IL-1β. Resveratrol showed a strong inhibitory effect on the pro-inflammatory marker secretion. The decrease of IL-6 secretion is dependent on the NFκB inhibition in the chondrocytes. Such reduction of the IL-6 level can limit STAT3 activation in the macrophages, leading to the interruption of the inflammatory amplification loop. Conclusion. These results increase our understanding of the anti-inflammatory actions of resveratrol and open new potential approaches to prevent and treat osteoarthritis.

645. T-Cell Activating Mesenchymal Stem Cells as a Biotherapeutic for HCC

Background: The outcome for advanced stage hepatocellular carcinoma (HCC) remains poor, highlighting the need for novel therapies. Mesenchymal stem cells (MSCs) are actively being explored as cancer therapeutics due to their inherent ability to migrate to tumor sites and to deliver ‘toxic payloads’. We have recently shown that cells can be genetically engineered to secrete bispecific T-cell engagers (ENG), which activate T cells in an antigen-dependent fashion. The goal of this project was now to determine if it is feasible to genetically modify MSCs to secrete ENG molecules that are specific for the HCC-associated tumor antigen Glypican-3 (GPC3), and to evaluate their ability to redirect T cells to HCC. Methods: Bone-marrow derived MSCs were genetically modified with lentiviral vectors encoding GPC3-ENG or an irrelevant ENG (EGFRvIII-ENG) and GFP. We performed coculture assays with GPC3-ENG-secreting MSCs (GPC3-ENG.MSCs, +/- freshly isolated T cells, and GPC3+ (HUH7 and G401) or GPC3- (A549) tumor cells. MSCs expressing an irrelevant ENG (EGFRvIII-ENG) served as control. We used standard immunological techniques for measuring cytokine production, proliferation, and cytolytic activity of T cells. Results: Transduction of MSCs resulted in a median transduction efficiency of 95% (range 90-97%) as judged by GFP expression. GPC3-ENG. MSCs activated T cells only in the presence of GPC3+ targets as judged by IFNγ production, and their ability to T-cell proliferation and killing of GPC3+ targets. EGFRvIII-ENG.MSCs did not activate T cells, confirming specificity. However, GPC3-ENG.MSCs did not induce IL2 secretion by T cells indicating lack of costimulation. To evaluate if provision of costimulation could overcome this obstacle, ENG.MSCs were further genetically modified to express CD80, 41BBL, or both. GPC3-ENG.MSCs expressing CD80 and 41BBL induced robust IL2 production in the presence of GPC3+ tumor cells in contrast to GPC3-ENG.MSCs expressing only CD80 or 41BBL. Conclusions: We have successfully generated MSCs that secrete GPC3-ENG and express costimulatory molecules on their cell surface. These MSCs induced potent anti-HCC T-cell responses in vitro, warranting further exploration of our MSC-based cell therapy approach for HCC.

Necrotic cells influence migration and invasion of glioblastoma via NF-κB/AP-1-mediated IL-8 regulation.

Glioblastoma multiforme (GBM) is the most common primary intracranial tumor in adults and has poor prognosis. Diffuse infiltration into normal brain parenchyma, rapid growth, and the presence of necrosis are remarkable hallmarks of GBM. However, the effect of necrotic cells on GBM growth and metastasis is poorly understood at present. In this study, we examined the biological significance of necrotic tissues by exploring the molecular mechanisms underlying the signaling network between necrotic tissues and GBM cells. The migration and invasion of the GBM cell line CRT-MG was significantly enhanced by treatment with necrotic cells, as shown by assays for scratch wound healing and spheroid invasion. Incubation with necrotic cells induced IL-8 secretion in CRT-MG cells in a dose-dependent manner. In human GBM tissues, IL-8 positive cells were mainly distributed in the perinecrotic region, as seen in immunohistochemistry and immunofluorescence analysis. Necrotic cells induced NF-κB and AP-1 activation and their binding to the IL-8 promoter, leading to enhanced IL-8 production and secretion in GBM cells. Our data demonstrate that when GBM cells are exposed to and stimulated by necrotic cells, the migration and invasion of GBM cells are enhanced and facilitated via NF-κB/AP-1 mediated IL-8 upregulation.

AGEs and HMGB1 Increase Inflammatory Cytokine Production from Human Placental Cells, Resulting in an Enhancement of Monocyte Migration.

Advanced glycation end products (AGEs) and high-mobility group box-1 (HMGB1) are considered contributing to placental inflammation. We examined the effect of AGEs and HMGB1 on cytokines from Sw.71 human trophoblast cell lines and the interactions between Sw.71 cells and THP-1-monocytes. Sw.71 cells were cultured with/without AGEs or HMGB1. We examined the role of AGEs or HMGB1 on THP1 migration and effect of AGEs on IL-6 from Sw.71 cells using co-cultures or conditioned medium from THP-1 cells. AGEs and HMGB1 increased interleukin (IL)-6, IL-8, and chemokine C-C motif ligand 2 (CCL2) secretion from Sw.71 cells. The secretion of IL-6 was dependent on reactive oxygen species (ROS) and NF-κB. AGEs stimulated IL-6 secretion through receptor RAGE and TLR4, whereas HMGB1 stimulated it through TLR4. AGEs, but not HMGB1, increased monocyte migration via IL-8 and CCL2 from Sw.71 cells. THP-1 monocytes induced IL-6 secretion from Sw.71 cells, and AGEs further stimulated it. AGEs and HMGB1 may promote sterile placental inflammation cooperating with monocytes/macrophages.

Abstract P2-06-11: Wild type N-Ras, overexpressed in basal-like breast cancer, promotes tumor formation by inducing IL8 secretion via JAK2 activation

Abstract "Basal-like" breast cancer (BLBC) is a very aggressive subtype of breast cancer. BLBC has very poor prognosis — median time to distant recurrence is just 2.6 years vs. 5 years overall, and survival time from diagnosis of distant metastatic disease is 9 months vs. 22 months. BLBC tumors usually do not express ER, Her2, or progesterone receptor. As such, they cannot be treated by the current targeted therapies, which target these molecules. What drive the formation and progression of BLBCs is largely unclear. Ras GTPases are best known for mediating growth factor signaling. Oncogenic mutations in the RAS genes, K-RAS in particular, are found in more than 30% of human tumors. Surprisingly, oncogenic RAS mutations are rare in breast cancer. However, we found that wild-type N-RAS is overexpressed in BLBCs, possibly partly via promoter demethylation, but not in other breast cancer subtypes. Repressing N-RAS inhibits transformation and tumor growth, while overexpressing it enhances these processes even in preinvasive BLBC cells. In contrast, in breast cancer cells of other subtypes, repressing N-RAS expression does not affect growth and transforming activities. We identified N-Ras-responsive genes, most of which encode chemokines and cytokines, e.g., IL8. High expression levels of these N-Ras-responsive genes as well as of N-RAS itself in tumors correlate with poor patient outcome. N-Ras, but not K-Ras, induces IL8 by binding and activating the cytoplasmic pool of JAK2; IL8 then acts on both the cancer cells and stromal fibroblasts. In conclusion, N-Ras drives BLBC by promoting transformation in epithelial cells, which may in turn remodel the tumor microenvironment to create a proinvasive state. Although oncogenic mutations affecting RAS are common in many other human cancers, tumorigenesis in an important subset of breast cancers is driven instead by increasing activity of wild-type N-Ras. Thus, to fully assess the impact of Ras on tumorigenesis, the role of wild-type as well as mutant Ras proteins must be carefully examined. Citation Format: Zheng Z-Y, Bu W, Tian L, Fan C, Gao X, Zhang X, Yu C, Wang H, Liao Y-H, Li Y, Lewis MT, Edwards D, Zwaka TP, Hilsenbeck SG, Medina D, Perou CM, Creighton CJ, Zhang XH, Chang EC. Wild type N-Ras, overexpressed in basal-like breast cancer, promotes tumor formation by inducing IL8 secretion via JAK2 activation. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-06-11.

Transcriptome profiling unveils the role of cholesterol in IL-17A signaling in psoriasis.

Psoriasis is a chronic inflammatory skin disease characterized by altered proliferation and differentiation of keratinocytes as well as infiltration of immune cells. Increased expression of Th17 cells and cytokines secreted by them provides evidence for its central role in the pathogenesis of psoriasis. IL-17A, signature cytokine of Th17 cells was found to be highly differentially expressed in psoriatic lesional skin. However, cellular and molecular mechanism by which IL-17A exerts its function on keratinocyte is incompletely understood. To understand IL-17A mediated signal transduction pathways, gene expression profiling was done and differentially expressed genes were analysed by IPA software. Here, we demonstrate that during IL-17A signaling total cholesterol levels were elevated, which in turn resulted in the suppression of genes of cholesterol and fatty acid biosynthesis. We found that accumulation of cholesterol was essential for IL-17A signaling as reduced total cholesterol levels by methyl β cyclodextrin (MBCD), significantly decreased IL-17A induced secretion of CCL20, IL-8 and S100A7 from the keratinocytes. To our knowledge this study for the first time unveils that high level of intracellular cholesterol plays a crucial role in IL-17A signaling in keratinocytes and may explain the strong association between psoriasis and dyslipidemia.

Effect of 1,25-(OH)2D3 and lipopolysaccharide on mononuclear cell inflammation in type 2 diabetes mellitus and diabetic nephropathy uremia

The prevention and treatment of type-2 diabetes mellitus (T2DM) and diabetic nephropathy (DN), which are disorders with high incidence rates, is of primary importance. In this study, we analyzed the effect of 1,25-(OH)2D3 and lipopolysaccharide (LPS) in combination with interleukin (IL)-15 on the inflammatory immune response and expression of vitamin D receptor (VDR) in mononuclear cells of T2DM and DN uremia (DNU) patients. The human acute monocytic leukemia cell line THP-1 was treated with peripheral blood serum isolated from 30 healthy controls and T2DM and DNU patients each, cultured in the presence or absence of 1,25-(OH)2D3, and subsequently treated with LPS and IL-15. The VDR mRNA and protein expression in THP-1 cells was detected by real-time polymerase chain reaction and western blot (and immunofluorescence assay), respectively, and IL-6 and IL-10 concentrations in the culture supernatant were detected by enzyme-linked immunosorbent assay. LPS treatment induced a significant decrease in VDR mRNA expression in T2DM and DNU serum-treated THP-1 cells compared to the control cells (P < 0.05). The VDR protein expression in DNU serum-treated THP-1 cells was also significantly down-regulated (P < 0.05). LPS treatment induced IL-6 secretion in serum-treated THP-1 cells (P < 0.05), while 1,25-(OH)2D3 treatment inhibited IL-6 secretion to some extent. These findings suggested that LPS down-regulates the expression of VDR in mononuclear cells of T2DM and DNU patients and induces an imbalance in the pro-inflammatory and anti-inflammatory cytokine response, while 1,25-(OH)2D3 partially reversed the effect of LPS and protected patients with T2DM and DNU.

Presence of commensal house dust mite allergen in human gastrointestinal tract: a potential contributor to intestinal barrier dysfunction

BackgroundAbnormal gut barrier function is the basis of gut inflammatory disease. It is known that house dust mite (HDM) aero-allergens induce inflammation in respiratory mucosa. We have recently reported allergen...

TLR2/MyD88/NF-κB signalling pathway regulates IL-8 production in porcine alveolar macrophages infected with porcine circovirus 2.

Porcine circovirus 2 (PCV2) is the primary cause of post-weaning multisystemic wasting syndrome, in which it stimulates a strong IL-8 response that is associated with chronic inflammation as well as lesions in the lymphoid organs. However, the mechanism underlying PCV2-induced IL-8 production is still unclear. In the present study, we demonstrated that increased IL-8 expression during PCV2 infection depends on Toll-like receptor (TLR2), but not TLR4 or TLR9 signalling pathways in porcine alveolar macrophages. Moreover, we found that impairment of the MyD88/NF-κB signalling pathway by MyD88 knockdown or NF-κB inhibitors markedly decreased PCV2-induced IL-8 secretion. These results suggest that PCV2 induces IL-8 secretion via the TLR2/MyD88/NF-κB signalling pathway. Therefore, it is important to elucidate the molecular mechanisms of the PCV2-induced inflammatory response.

Identification of Acanthamoeba Membrane Protein That is Recognized by TLR4 on Corneal Epithelial Cells

We have shown that Acanthamoeba spp. activate TLR4 on corneal epithelial cells and induce secretion of chemokines. However, the components of Acanthamoeba trophozoites that induce chemokines production remain unknown. We sought to identify the trophozoite molecules that interact with TLR4 on human corneal epithelial (HCE) cells and trigger IL-8 production. Acanthamoeba membrane protein (AcMP) was isolated by homogenization of trophozoites. The supernatants were collected, solubilized, and membrane fractions were separated by centrifugation using Mem-PER TM plus kit. To examine functional activity of AcMP, HCE and TLR4-expressing HEK293 cells were incubated with or without A. castellanii (1×10 5 cells/ml) and AcMP (10, 25, and 50 µg/ml) for 24 hours. AcMP was chromatographed by fast protein liquid chromatography (FPLC) and fractions were pooled into four peaks (AcMP-P1 - AcMP-P4). TLR4-ligand in AcMP-P1 - AcMP-P4 was determined by Western blotting. HEK293 and HCE cells were incubated with or without A. castellanii , lipopolysaccharide (LPS, 10 µg/ml), and AcMP-P1 - AcMP-P4 (20 µg/ml) for 24 hours. qRT-PCR and ELISA were used to examine the ability of AcMP-P1 - AcMP-P4 to stimulate IL-8 production in HEK293 and HCE cells. Inhibition of TLR4 involved preincubating HEK293 and HCE cells for 1 hour with neutralizing TLR4-antibody (10 µg/ml) or with the control antibody (10 µg/ml, goat serum) followed by incubation with or without A. castellanii , LPS, and AcMP-P2 for 24 hours. AcMP induced significant IL-8 production at doses of 10, 25, and 50 µg/ml in HEK293 cells while IL-8 mRNA expression and IL-8 secretion were significantly increased in HCE cells at the dose of 50 µg/ml. Treatments of HEK293 with FPLC chromatographed trophozoites’ proteins, AcMP-P1 - AcMP-P4; only AcMP-P2 upregulated significant IL-8 production and mRNA expression. Western blotting of AcMP-P1 - AcMP-P4 showed TLR4-antigen in AcMP-P2 and was recognized an approximate 15-kDa protein band. Anti-TLR4 antibody attenuated IL-8 secretion that is stimulated by AcMP-P2 from HEK293 and HCE cells. These results suggest that A. castellanii trophozoites recognize TLR4 on HCE and HEK293 cells by an approximate 15-kDa molecular mass protein of AcMP and induce IL-8 secretion.

Induction of metastatic potential by TrkB via activation of IL6/JAK2/STAT3 and PI3K/AKT signaling in breast cancer

In metastatic breast cancers, the acquisition of metastatic ability, which leads to clinically incurable disease and poor survival, has been associated with acquisition of epithelial-mesenchymal transition (EMT) program and self-renewing trait (CSCs) via activation of PI3K/AKT and IL6/JAK2/STAT3 signaling pathways. We found that TrkB is a key regulator of PI3K/AKT and JAK/STAT signal pathway-mediated tumor metastasis and EMT program. Here, we demonstrated that TrkB activates AKT by directly binding to c-Src, leading to increased proliferation. Also, TrkB increases Twist-1 and Twist-2 expression through activation of JAK2/STAT3 by inducing c-Src-JAK2 complex formation. Furthermore, TrkB in the absence of c-Src binds directly to JAK2 and inhibits SOCS3-mediated JAK2 degradation, resulting in increased total JAK2 and STAT3 levels, which subsequently leads to JAK2/STAT3 activation and Twist-1 upregulation. Additionally, activation of the JAK2/STAT3 pathway via induction of IL-6 secretion by TrkB enables induction of activation of the EMT program via induction of STAT3 nuclear translocation. These observations suggest that TrkB is a promising target for future intervention strategies to prevent tumor metastasis, EMT program and self-renewing trait in breast cancer.