Induced IL-6 Secretion Research Articles

312 Activation of AhR in Langerhans cells by a microbial metabolite of tryptophan maintains skin homeostasis

Skin commensal bacteria play important roles in maintenance of skin homeostasis, and Langerhans cells (LCs) are critical in induction of peripheral tolerance; however, the role of LCs' response to the skin microbiota, specifically the microbial metabolites, in skin homeostasis is not clear. In the present study, LCs that derived from CD34+ hematopoietic stem cells in the cord blood cells were utilized, and we found that a microbial metabolite of tryptophan (Trp), indole-3-aldehyde (IAId), induced the production of indoleamine 2,3-dioxygenase and IL-10 in LCs through activation of aryl hydrocarbon receptor (AhR). Moreover, IAId promoted the expression of receptor activator of NF-κB and receptor activator of NF-κB ligand on LCs and keratinocytes in an AhR-dependent manner respectively, which might result in the activation of NF-κB signaling and production of IL-10. Additionally, despite a mature phenotype of LCs induced by IAId, IAId-activated LCs inhibited CD4+ T cell proliferation and induced IL-10 secretion. Our study revealed a negatively regulatory function of a Trp microbial metabolite on LCs through activation of AhR, and microbial metabolites could be developed as a new strategy for the treatment of inflammatory skin diseases.

The role of osteosarcoma cell-derived exosomes in the promotion of lung metastasis

Abstract Osteosarcoma (OS) is the most common primary tumor of bone and typically occurs in children and young adults. 30–40% of OS patients develop lung metastases after initial diagnosis, with only 20% of these patients surviving 4 years post-relapse. For over 30 years, there have been no improvements in the treatment of OS, and more importantly, no diagnostic tools that help identify those patients at high risk for lung metastases. Recent data has shown that in other tumor types, tumor-secreted extracellular vesicles (EVs) deliver biological cargo to distant sites, resulting in priming of non-malignant host cells for promotion of metastasis. The aim of this project is to understand how OS EVs influence the response of lung fibroblasts (LFs) and alveolar macrophages (AMs), and if their uptake of EVs results in pre-metastatic priming that can be detected via AM transcriptomic changes. Hypothesis LFs are primary targets of OS EVs, which will increase LF IL-6 production and cause paracrine STAT3 activation of AM’s into an M2 tumor-promoting phenotype. Results Flow cytometry and confocal microscopy demonstrated in vitro uptake of OS EVs by LF cells. In vitro ‘education’ of LFs with OS EVs induced significant production of IL-6, IL-8, and CCL2, with the greatest mean difference between EV-educated and naïve LFs observed with IL-6 secretion. Conclusion This data suggest that OS EVs efficiently prime LFs to induce IL-6 secretion, and this response may be associated with promotion of OS lung metastasis. Further data is being collected to determine the role of IL-6 in OS cell survival and lung metastatic colonization. RNA sequencing of AMs will be used to characterize phenotype which could serve as an effective cellular biomarker to predict lung metastasis.

Antileishmanial Drugs Modulate IL-12 Expression and Inflammasome Activation in Primary Human Cells.

Leishmaniases are neglected tropical diseases. The treatment of leishmaniasis relies exclusively on chemotherapy including amphotericin B (AmB), miltefosine (hexadecylphosphocholine), and pentamidine. Besides the fact that these molecules are harmful for patients, little is known about the impact of such antileishmanial drugs on primary human cells in relation to immune function. The present study demonstrates that all antileishmanial drugs inhibit CD4 and CD8 T cell proliferation at the doses that are not related to increased cell death. Our results highlight that antileishmanial drugs have an impact on monocytes by altering the expression of IL-12 induced by LPS, whereas only AmB induced IL-10 secretion; both cytokines are essential in regulating Th1 cell-mediated immunity. Interestingly, IL-12 and anti-IL-10 Abs improved T cell proliferation inhibited by AmB. Furthermore, our results show that in contrast to hexadecylphosphocholine and pentamidine, AmB induced gene expression of the inflammasome pathway. Thus, AmB induced IL-1β and IL-18 secretions, which are reduced by specific inhibitors of caspase activation (Q-VD) and NLRP3 activation (MCC950). Our results reveal previously underestimated effects of antileishmanial drugs on primary human cells.

Cigarette smoke and electronic cigarettes differentially activate bronchial epithelial cells

BackgroundThe use of electronic cigarettes (ECIGs) is increasing, but the impact of ECIG-vapor on cellular processes like inflammation or host defense are less understood. The aim of the present study was to compare the acute effects of traditional cigarettes (TCIGs) and ECIG-exposure on host defense, inflammation, and cellular activation of cell lines and primary differentiated human airway epithelial cells (pHBE).MethodsWe exposed pHBEs and several cell lines to TCIG-smoke or ECIG-vapor. Epithelial host defense and barrier integrity were determined. The transcriptome of airway epithelial cells was compared by gene expression array analysis. Gene interaction networks were constructed and differential gene expression over all groups analyzed. The expression of several candidate genes was validated by qRT-PCR.ResultsBacterial killing, barrier integrity and the expression of antimicrobial peptides were not affected by ECIG-vapor compared to control samples. In contrast, TCIGs negatively affected host defense and reduced barrier integrity in a significant way. Furthermore ECIG-exposure significantly induced IL-8 secretion from Calu-3 cells but had no effect on NCI-H292 or primary cells. The gene expression based on array analysis distinguished TCIG-exposed cells from ECIG and room air-exposed samples.ConclusionThe transcriptome patterns of host defense and inflammatory genes are significantly distinct between ECIG-exposed and TCIG-treated cells. The overall effects of ECIGs on epithelial cells are less in comparison to TCIG, and ECIG-vapor does not affect host defense. Nevertheless, although acute exposure to ECIG-vapor induces inflammation, and the expression of S100 proteins, long term in vivo data is needed to evaluate the chronic effects of ECIG use.

Histoplasma capsulatum chemotypes I and II induce IL-8 secretion in lung epithelial cells in distinct manners.

The cell wall is one of the most important structures of pathogenic fungi, enabling initial interaction with the host and consequent modulation of immunological responses. Over the years, some researchers have shown that cell wall components of Histoplasma capsulatum vary among fungal isolates, and one of the major differences is the presence or absence of α-(1,3)-glucan, classifying wild-type fungi as chemotypes II or I, respectively. The present work shows that an isolate of H. capsulatum chemotype I induced lower levels of interleukin (IL)-8 secretion by the lung epithelial cell line A549, when compared to chemotype II yeasts. Thus, we expected that the absence of α-glucan in spontaneous variant yeasts, which were isolated from chemotype II cultures, would modify IL-8 secretion by A549 cells, but surprisingly, these fungi promoted similar levels of IL-8 secretion as their wild-type counterpart. Furthermore, when using a specific inhibitor for Syk activation, we observed that this inhibitor reduced IL-8 levels in A549 cell cultures infected with wild type chemotype I fungi. This inhibitor failed to reduce this cytokine levels in A549 cell cultures infected with chemotype II and their spontaneous variant yeasts, which also do not present α-glucan on their surface. The importance of SFKs and PKC δ in this event was also analyzed. Our results show that different isolates of H. capsulatum modulate distinct cell signaling pathways to promote cytokine secretion in host epithelial cells, emphasizing the existence of various mechanisms for Histoplasma pathogenicity.

Gut bacteria characteristic of the infant microbiota down-regulate inflammatory transcriptional responses in HT-29 cells

Immuno-modulatory effects of infant gut bacteria were tested on poly(I:C) stimulated HT-29 intestinal epithelial cells. Blautia producta, Bacteroides vulgatus, Bacteroides fragilis and Bacteroides thetaiotaomicron decreased transcription of poly(I:C)-induced inflammatory genes. Modulation of basal level and poly(I:C)-induced IL-8 secretion varied between bacterial species, and between heat treated and non-heat treated bacterial cells.

Anti-human CD63 monoclonal antibody COS3A upregulates monocyte-induced IL-10 excretion leading to diminution of CD3-mediated T cell response

Human CD63 has been reported to play a role either as an inhibitor or as a co-stimulator of T- cell responses, although the mechanism of this is unclear. In this study, an anti-human CD63 monoclonal antibody (mAb) COS3A was used to monitor the role of CD63 in T-cell activation. MAb COS3A could inhibit CD3-mediated T-cell proliferation and CD25 expression in peripheral blood mononuclear cells (PBMCs), used as a study model, but the suppressive effect was not observed when purified T-cells were used instead of PBMCs. The inhibitory phenomenon was associated with downregulation of IL-2 and IFN-γ by T-cells, but upregulation of IL-10 by monocytes. Neutralizing IL-10 with anti-IL-10 mAb improved the T-cell response, indicating the role of IL-10 in T-cell suppression. In this study, monocytes were demonstrated to play a role in impeding T-cell activation by the anti-CD63 mAb COS3A. This is the first evidence that anti-CD63 mAb induces IL-10 secretion by monocytes, which later play a role in T-cell hypo-responsiveness.

Kaempferia parviflora Extract Inhibits STAT3 Activation and Interleukin-6 Production in HeLa Cervical Cancer Cells.

Kaempferia parviflora (KP) has been reported to have anti-cancer activities. We previously reported its effects against cervical cancer cells and continued to elucidate the effects of KP on inhibiting the production and secretion of interleukin (IL)-6, as well as its relevant signaling pathways involved in cervical tumorigenesis. We discovered that KP suppressed epidermal growth factor (EGF)-induced IL-6 secretion in HeLa cells, and it was associated with a reduced level of Glycoprotein 130 (GP130), phosphorylated signal transducers and activators of transcription 3 (STAT3), and Mcl-1. Our data clearly showed that KP has no effect on nuclear factor kappa B (NF-κB) localization status. However, we found that KP inhibited EGF-stimulated phosphorylation of tyrosine 1045 and tyrosine 1068 of EGF receptor (EGFR) without affecting its expression level. The inhibition of EGFR activation was verified by the observation that KP significantly suppressed a major downstream MAP kinase, ERK1/2. Consistently, KP reduced the expression of Ki-67 protein, which is a cellular marker for proliferation. Moreover, KP potently inhibited phosphorylation of STAT3, Akt, and the expression of Mcl-1 in response to exogenous IL-6 stimulation. These data suggest that KP suppresses EGF-induced production of IL-6 and inhibits its autocrine IL-6/STAT3 signaling critical for maintaining cancer cell progression. We believe that KP may be a potential alternative anti-cancer agent for suppressing cervical tumorigenesis.

Cancer immunotherapy using the Fusion gene of Sendai virus.

Inactivated Sendai virus particle (or hemagglutinating virus of Japan envelope; HVJ-E) has been previously reported to possess antitumour properties that activate antitumour immunity. Two glycoproteins, fusion (F) and hemagglutinin-neuraminidase (HN), are present on the surface of HVJ-E. HN is necessary for binding to receptors such as acidic gangliosides, and F induces membrane fusion by associating with membrane lipids. We previously reported that liposomes reconstituted with F but not HN showed antitumour activity by inducing IL-6 secretion in dendritic cells (DCs), suggesting that F protein is capable of eliciting antitumour activity. Here, we attempted to deliver F gene into tumour tissue in mice by electroporation and demonstrated that F gene therapy retarded tumour growth, increased CD4+ and CD8+ T-cell infiltration into tumours and induced tumour-specific IFN-γ T-cell response. However, neutralisation of IL-6R signalling did not impact F plasmid-mediated antitumour effect. Instead, we found that F plasmid treatment resulted in a significant increase in the secretion of the chemokine RANTES (regulated upon activation, normal T cell expressed and secreted) by tumour-infiltrating T cells. Neutralising antibody against RANTES abolished the antitumour effect of F plasmid treatment in a dose-dependent manner. Thus, F gene therapy may show promise as a novel therapeutic for single or combined cancer immunotherapy.

Assessment of adipogenic, antioxidant, and anti-inflammatory properties of whole and whey bovine colostrum

Bovine colostrum (BC) has been used for nutraceutical purposes for animals and humans. Bovine colostrum is a complex heterogeneous product and its antimicrobial activity, antioxidant potential, and growth factors can vary depending on age and species of the cow as well as their environment. Bovine colostrum preparation in skimmed or whey fractions can also alter properties of BC. Our goal was to compare cumulative anti-inflammatory, antioxidant, and adipogenic properties of natural (whole) versus whey BC. We compared properties of whole and whey BC in 3T3-L1 preadipocytes permanently transfected with reporters responding to changes in inflammatory (NfκbRE/green fluorescent protein), anti-inflammatory (Nrf2/YFP), and adipogenic (Fabp4/cyan fluorescent protein) status in cells. Interleukin-6 secretion in these cells was measured by ELISA. Whole and whey BC induce IL-6 secretion from 3T3-L1 fibroblasts; however, whey preparation stimulated less IL-6 secretion. Cumulative inflammatory nuclear factor (NF)κB activation in the presence of lipopolysaccharide was reduced by both whole (-27%) and whey BC (-22%) compared with lipopolysaccharide-treated cells (100%). Treatment with whole BC was more effective in the reduction of NFκB activation compared with whey BC and occurred in a dose-dependent manner. In consonance with decreased NFκB activation, the Nrf2 promoter activity was also reduced in response to whole (-27%) and whey (-13%) treatments compared with nontreated cells (100%). Whole and whey BC suppressed adipogenesis, measured as induction of Fabp4, by -27 and -13%, respectively, compared with nontreated 3T3-L1 fibroblasts (100%). Our results showed distinct differences in properties of whey and whole BC that could be used to attain reduced adipogenic or cumulative inflammatory responses.

Cooperativity between stromal cytokines drives the invasive migration of human breast cancer cells.

The cross-talk between cancer cells and the stromal microenvironment plays a key role in regulating cancer invasion. Here, we employed an ex vivo invasion model system for exploring the regulation of breast cancer cells infiltration into a variety of stromal fibroblast monolayers. Our results revealed considerable variability in the stromal induction of invasiveness, with some lines promoting and others blocking invasion. It was shown that conditioned medium (CM), derived from invasion-promoting fibroblasts, can induce epithelial-mesenchymal transition-like process in the cancer cells, and trigger their infiltration into a monolayer of invasion-blocking fibroblasts. To identify the specific invasion-promoting molecules, we analysed the cytokines in stimulatory CM, screened a library of purified cytokines for invasion-promoting activity and tested the effect of specific inhibitors of selected cytokine receptors on the CM-induced invasion. Taken together, these experiments indicated that the invasiveness of BT-474 is induced by the combined action of IL1 and IL6 and that IL1 can induce IL6 secretion by invasion-blocking fibroblasts, thereby triggering cancer cell invasion into the stroma. This unexpected observation suggests that stromal regulation of cancer invasion may involve not only cross-talk between stromal and cancer cells, but also cooperation between different stromal subpopulations. This article is part of a discussion meeting issue 'Forces in cancer: interdisciplinary approaches in tumour mechanobiology'.

IL-1\u03b2, IL-23, and TGF-\u03b2 drive plasticity of human ILC2s towards IL-17-producing ILCs in nasal inflammation

Innate lymphoid cells (ILCs) are crucial for the immune surveillance at mucosal sites. ILCs coordinate early eradication of pathogens and contribute to tissue healing and remodeling, features that are dysfunctional in patients with cystic fibrosis (CF). The mechanisms by which ILCs contribute to CF-immunopathology are ill-defined. Here, we show that group 2 ILCs (ILC2s) transdifferentiated into IL-17-secreting cells in the presence of the epithelial-derived cytokines IL-1β, IL-23 and TGF-β. This conversion is abrogated by IL-4 or vitamin D3. IL-17 producing ILC2s induce IL-8 secretion by epithelial cells and their presence in nasal polyps of CF patients is associated with neutrophilia. Our data suggest that ILC2s undergo transdifferentiation in CF nasal polyps in response to local cytokines, which are induced by infectious agents.

Effects of extracellular Hsp70 and cigarette smoke on differentiated THP-1 cells and human monocyte-derived macrophages

Extracellular Hsp70 (eHsp70) can act as pro-inflammatory mediator and is elevated in blood of chronic obstructive pulmonary disease (COPD) patients. Most of those patients are smokers, and it was suggested previously that cigarette smoke might induce Hsp70 secretion from the circulating cells. Therefore, we aimed to explore inflammation-associated effects of cigarette smoke extract (CSE) and its combinations with eHsp70 in monocyte-derived macrophages (MDMs) and THP-1 cell line, used as systemic component models of COPD. We hypothesized that eHsp70 induces inflammation, but that it can also modulate cigarette smoke extract (CSE)-stimulated inflammatory responses.We assessed IL-8 secretion, TLR2, TLR4 and Hsp70 expressions, MAPKs and NF-κB activation, and cytotoxicity after treating the cells with CSE (2.5 and 5%) and its combinations with low-endotoxin recombinant human (rh) Hsp70, used to mimic eHsp70 effects.CSE induced IL-8 secretion from both cell types, but its combinations with rhHsp70 increased IL-8 release compared to CSE alone only from MDMs. In THP-1, combinations of rhHsp70 with 2.5% CSE induced TLR2 and TLR4 mRNA, while 5% CSE decreased TLR2 expression. In MDMs, CSE alone attenuated TLR2, while rhHsp70 increased TLR2 and lowered TLR4 gene expression. Hsp70 mRNA expression was suppressed in THP-1 with rhHsp70 and CSE; however, the same treatments increased its level in MDMs. CSE had cytotoxic effect only on MDMs, but cytotoxicity was reduced in co-treatments with rhHsp70, which also triggered apoptosis. CSE and rhHsp70 activated p38 and JNK, while ERK was activated only by rhHsp70 in MDMs. In THP-1, 2.5% CSE activated ERK, and 5% CSE activated p38. Inhibition of NF-κB and JNK in MDMs, and ERK and JNK in THP-1 cells, attenuated IL-8 release after rhHsp70 treatment.In conclusion, rhHsp70 provoked pro-inflammatory effects and could also modulate inflammatory response to CSE on protein and gene expression levels in THP-1 cells and MDMs, which suggests that eHsp70 might be implicated in systemic inflammation induced by cigarette smoke.

ERK-dependent IL-6 positive feedback loop mediates resistance against a combined treatment using danusertib and BKM120 in Burkitt lymphoma cell lines

This study was conducted to define the synergistic effect of the PI3K inhibitor BKM120 with the pan-Aurora kinase inhibitor danusertib and the potential mechanism of resistance to the combined inhibitor treatment in Burkitt lymphoma cell lines. The combination of danusertib and BKM120 showed a synergistic effect on Namalwa cells but not on BJAB cells. The combined treatment led to ERK hyperactivation and induced IL-6 secretion in BJAB cells but not in Namalwa cells. A blockade of ERK signaling with trametinib suppressed the combination treatment-induced ERK activation, reduced IL-6 mRNA expression, and downregulated IL-6R mRNA expression, resulting in an improvement in the antitumor effect. We stepwise treated Namalwa cells with both inhibitors using on-and-off treatment cycles and found that Namalwa cells gained chemoresistance by activating the ERK/IL-6 feedback loop, suggesting that the ERK-dependent IL-6 positive feedback loop can compensate for AKT inactivation and is closely associated with adaptive resistance and relapse.

Induction of human regulatory innate lymphoid cells from group 2 innate lymphoid cells by retinoic acid

Group 2 innate lymphoid cells (ILC2s) play critical roles in induction and exacerbation of allergic airway inflammation. Thus clarification of the mechanisms that underlie regulation of ILC2 activation has received significant attention. Although innate lymphoid cells are divided into 3 major subsets that mirror helper effector T-cell subsets, counterpart subsets of regulatory T cells have not been well characterized. We sought to determine the factors that induce regulatory innate lymphoid cells (ILCregs). IL-10+ ILCregs induced from ILC2s by using retinoic acid (RA) were analyzed with RNA-sequencing and flow cytometry. ILCregs were evaluated in human nasal tissue from healthy subjects and patients with chronic rhinosinusitis with nasal polyps and lung tissue from house dust mite- or saline-treated mice. RA induced IL-10 secretion by human ILC2s but not type 2 cytokines. IL-10+ ILCregs, which were converted from ILC2s by means of RA stimulation, expressed a regulatory Tcell-like signature with expression of IL-10, cytotoxic Tlymphocyte-associated protein 4, and CD25, with downregulated effector type 2-related markers, such as chemoattractant receptor-homologous molecule on TH2 cells and ST2, and suppressed activation of CD4+ T cells and ILC2s. ILCregs were rarely detected in human nasal tissue from healthy subjects or lung tissue from saline-treated mice, but numbers were increased in nasal tissue from patients with chronic rhinosinusitis with nasal polyps and in lung tissue from house dust mite-treated mice. Enzymes for RA synthesis were upregulated in airway epithelial cells during type 2 inflammation invivo and by IL-13 invitro. We have identified a unique immune regulatory and anti-inflammatory pathway by which RA converts ILC2s to ILCregs. Interactions between airway epithelial cells and ILC2s play an important roles in the generation of ILCregs.

IL-1β-induced ICAM-1 and IL-8 expression/secretion of dental pulp cells is differentially regulated by IRAK and p38

Interleukin 1 beta (IL-1β) is a pro-inflammatory cytokine involved in the acute and chronic inflammatory processes of dental pulp. Intercellular adhesion molecule-1 (ICAM-1) and IL-8 are two major inflammatory mediators. However, the role of interleukin-1 receptor-associated kinases (IRAKs) signaling pathways in responsible for the inflammatory effects of IL-1β on dental pulp cells is not clear. Cultured human dental pulp cells were exposed to IL-1β with/without pretreatment and co-incubation with IRAK1/4 inhibitor or SB203580 (p38 inhibitor). IRAK-1 phosphorylation was evaluated by immunno fluorescent staining. The protein expression of ICAM-1 and IL-8 were tested by western blotting. The secretion of soluble ICAM-1 (sICAM-1) and IL-8 was measured by enzyme-linked immunosorbant assay (ELISA). IL-1β stimulated IRAK-1 phosphorylation of pulp cells within 120min of exposure. IRAK1/4 inhibitor attenuated the IL-1β-induced ICAM-1, but not IL-8 protein expression. IRAK1/4 inhibitor also prevented the IL-1β-induced sICAM-1, but not IL-8 secretion. SB203580 showed little effect on IL-1β-induced sICAM-1 secretion, but effectively inhibited its induction of IL-8 secretion in pulp cells. The Results reveal the important role of IL-1β in pulpal inflammatory responses via stimulation of IL-8 and ICAM-1 expression and secretion. Moreover, IL-1β-induced effects on IL-8 and ICAM-1 are differentially regulated by IRAK1/4 and p38 signaling in dental pulp cells. Blocking of IRAKs and p38 signaling may have potential to control inflammation of dental pulp in the future.

Human αS1-casein induces IL-8 secretion by binding to the ecto-domain of the TLR4/MD2 receptor complex

BackgroundThe milk protein αS1-casein was recently reported to induce secretion of proinflammatory cytokines via Toll-like receptor 4 (TLR4). In this study, αS1-casein was identified as binder of theTLR4 ecto domain. MethodsIL-8 secretion after stimulation of TLR4/MD2 (myeloid differentiation factor 2)/CD14 (cluster of differentiation 14)-transfected HEK293 cells (TLR4+) and Mono Mac 6 cells (MM6) with recombinant αS1-casein, or LPS as control was monitored. Binding of αS1-casein to TLR4 was quantified by microscale thermophoresis (MST). ResultsαS1-casein induced secretion of IL-8 in TLR4+ cells and in MM6 cells with a six-times higher final IL-8 concentration in supernatants. IL-8 secretion was inhibited by intracellular TLR4-domain antagonist TAK-242 with an IC50-value of 259.6 nM, by ecto-domain TLR4 antagonistic mianserin with 10–51 μM and by anti-CD14-IgA. The binding constants (KD) of αS1-casein to the TLR4, MD2, and CD14 were 2.8 μM, 0.3 μM and 2.7 μM, respectively. Finally, αS1-casein showed a higher affinity to TLR4/MD2 (KD: 2.2 μM) compared to LPS (KD: 8.2 μM). ConclusionHuman αS1-casein induced proinflammatory effects are dependent upon binding to the TLR4 ectodomain and the presence of CD14. αS1-casein displayed stronger TLR4 agonistic activity than LPS via a different mode of action. General significanceBreast milk protein αS1-casein is a proinflammatory cytokine.

IL-6 mediates platinum-induced enrichment of ovarian cancer stem cells.

In high-grade serous ovarian cancer (OC), chemotherapy eliminates the majority of tumor cells, leaving behind residual tumors enriched in OC stem cells (OCSC). OCSC, defined as aldehyde dehydrogenase-positive (ALDH+), persist and contribute to tumor relapse. Inflammatory cytokine IL-6 is elevated in residual tumors after platinum treatment, and we hypothesized that IL-6 plays a critical role in platinum-induced OCSC enrichment. We demonstrate that IL-6 regulates stemness features of OCSC driven by ALDH1A1 expression and activity. We show that platinum induces IL-6 secretion by cancer-associated fibroblasts in the tumor microenvironment, promoting OCSC enrichment in residual tumors after chemotherapy. By activating STAT3 and upregulating ALDH1A1 expression, IL-6 treatment converted non-OCSC to OCSC. Having previously shown altered DNA methylation in OCSC, we show here that IL-6 induces DNA methyltransferase 1 (DNMT1) expression and the hypomethylating agent (HMA) guadecitabine induced differentiation of OCSC and reduced - but did not completely eradicate - OCSC. IL-6 neutralizing antibody (IL-6-Nab) combined with HMA fully eradicated OCSC, and the combination blocked IL-6/IL6-R/pSTAT3-mediated ALDH1A1 expression and eliminated OCSC in residual tumors that persisted in vivo after chemotherapy. We conclude that IL-6 signaling blockade combined with an HMA can eliminate OCSC after platinum treatment, supporting this strategy to prevent tumor recurrence after standard chemotherapy.

Inulin Induces IL-10 Secretion and Increased FOXP3 Gene Expression in Human Peripheral Blood Mononuclear Cells

Inulin Induces IL-10 Secretion and Increased FOXP3 Gene Expression in Human Peripheral Blood Mononuclear Cells

Abstract B68: Targeted inhibition of Tgfβr2 reduces IL-6 production from cancer-associated fibroblasts, suppresses Stat3 activation in pancreatic cancer cells and reverses immunosuppression

Abstract Pancreatic cancer is characterized by dense stroma consisting of myofibroblasts, abundant extracellular matrix (ECM) and inflammatory/immune cells. Elevated levels of transforming growth factor β (TGFβ), a prominent driver of stromal accumulation, is a negative prognostic indicator for pancreatic cancer patients. However, inhibition of TGFβ has been challenging due to the context-dependent tumor suppressor function of TGFβ in pancreatic cancer. We reported previously that neutralizing the activity of murine TGFβ receptor 2 (Tgfβr2) using a monoclonal antibody (2G8), has potent antitumor activity in orthotopic human pancreatic tumor xenografts. The findings in xenografts highlight that TGFβ induction of stromal cell function is critical for its impact on tumor cell behavior and PDA progression and supports that inhibition of TGFβ-dependent effector functions on stromal cells has potential efficacy in PDA. Herein we demonstrate that inhibition of murine Tgfβr2 reduces IL-6 production from cancer-associated fibroblasts (CAFs), resulting in a reduction of Stat3 activation in tumor cells and reversion of the immunosuppressive landscape of murine models of PDA. Moreover, the reduction of stromal IL-6 results in activation of NK cells. In summary, we found TGFβ induced IL-6 secretion from CAFs in PDA contributes to tumorigenesis and immunosuppression and can be abrogated by inhibition of stromal Tgfβr2. Citation Format: Huocong Huang, Moriah Hagopian, Wenting Du, Yuqing Zhang, Kyla E. Driscoll, Rolf A. Brekken. Targeted inhibition of Tgfβr2 reduces IL-6 production from cancer-associated fibroblasts, suppresses Stat3 activation in pancreatic cancer cells and reverses immunosuppression [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr B68.