STAT3-dependent Manner Research Articles

Blockade of STAT3 Signaling Contributes to Anticancer Effect of 5-Acetyloxy-6,7,8,4'-Tetra-Methoxyflavone, a Tangeretin Derivative, on Human Glioblastoma Multiforme Cells.

Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor with poor prognosis, largely due to resistance to current radiotherapy and Temozolomide chemotherapy. The constitutive activation of Signal Transducer and Activator of Transcription 3 (STAT3) is evidenced as a pivotal driver of GBM pathogenesis and therapy resistance, and hence, is a promising GBM drug target. 5-acetyloxy-6,7,8,4′-tetramethoxyflavone (5-AcTMF) is an acetylated derivative of Tangeretin which is known to exert anticancer effects on breast, colon, lung, and multiple myeloma; however, its effect on GBM remains elusive. Herein, we reported that 5-AcTMF suppressed the viability and clonogenicity along with inducing apoptosis in multiple human GBM cell lines. Mechanistic analyses further revealed that 5-AcTMF lowered the levels of Tyrosine 705-phosphorylated STAT3 (p-STAT3), a canonical marker of STAT3 activation, but also dampened p-STAT3 upregulation elicited by Interleukin-6. Notably, ectopic expression of dominant-active STAT3 impeded 5-AcTMF-induced suppression of viability and clonogenicity plus apoptosis induction in GBM cells, confirming the prerequisite of STAT3 blockage for the inhibitory action of 5-AcTMF on GBM cell survival and growth. Additionally, 5-AcTMF impaired the activation of STAT3 upstream kinase JAK2 but also downregulated antiapoptotic BCL-2 and BCL-xL in a STAT3-dependent manner. Moreover, the overexpression of either BCL-2 or BCL-xL abrogated 5-AcTMF-mediated viability reduction and apoptosis induction in GBM cells. Collectively, we, for the first time, revealed the anticancer effect of 5-AcTMF on GBM cells, which was executed via thwarting the JAK2-STAT3-BCL-2/BCL-xL signaling axis. Our findings further implicate the therapeutic potential of 5-AcTMF for GBM treatment.

Oncostatin M induces C2C12 myotube atrophy by modulating muscle differentiation and degradation

Oncostatin M (OSM) is a cytokine of the interleukin-6 family and plays a role in various disorders such as cancer and inflammatory diseases, which are often accompanied by skeletal muscle atrophy, or sarcopenia. However, the role of OSM in the regulation of skeletal muscle mass remains to be identified. In this study, we investigated the effect of OSM on C2C12 myotube formation in vitro. C2C12 myoblasts were induced to differentiate into myotubes for 3 days and then treated with OSM for 24 or 48 h. The diameter of differentiated C2C12 myotubes were reduced by 18.7% and 23.3% compared to control cells after treatment with OSM for 24 and 48 h, respectively. The expression levels of MyoD and myogenin were decreased, while those of atrogin-1, CCAAT/enhancer binding protein δ, and OSM receptor were increased in C2C12 myotubes treated with OSM for 24 h compared to control cells. Furthermore, the inhibitory effect of OSM on myotube formation was significantly attenuated by pretreatment with an inhibitor of signal transducer and activator of transcription (STAT) 3 or by knockdown of Stat3. Finally, the OSM-induced changes in the expression levels of MyoD, myogenin, and atrogin-1 were reversed by pretreatment with an inhibitor of STAT3 or by Stat3 knockdown in C2C12 myotubes. In conclusion, OSM induces C2C12 myotube atrophy by inhibiting myogenic differentiation and activating muscle degradation in a STAT3-dependent manner.

Abstract 2025: Nicotine promotes lung metastasis in triple negative breast cancer through paracrine signaling in the tumor microenvironment

Abstract Triple-negative breast cancer (TNBC) is responsible for a majority of the mortalities through aggressive metastatic spread, which accounts for a poor 5-year survival. Despite progress in the development of drugs that efficiently target cancer cells, treatments for TNBC are often ineffective. Increasing evidence from epidemiologic studies indicate that cigarette smoking is a major risk factor of TNBC with increased metastatic burden and recurrence. Nicotine, the major addictive component of cigarettes, is not carcinogenic but can promotes cancer progression. However, how nicotine promotes breast cancer lung metastasis is not well understood. To address this question, we orthotopically implanted 4T1 cells (TNBC) into Balb/c mice followed by i.p. injection of nicotine and measured tumor growth and metastatic progression. We found that nicotine increased the growth of primary tumor by 10-fold while it promoted the lung metastasis burden by 100-fold in vivo. Similar results were obtained in experimental metastasis. Immunohistochemical analysis of the primary and lung metastasis tissues showed predominant infiltration of neutrophils in lung metastasis lesions. This observation was further validated by depleting neutrophils using anti-Ly6G antibody, which showed significant decrease in lung metastasis burden in vivo. Intriguingly, infiltrated neutrophils in the lung metastasis tissues selectively overexpressed N2-polarization phenotype. Furthermore, in vitro treatment of primary neutrophils with nicotine induced them into N2 phenotype in a Stat3-dependent manner. To explore further the functional contribution of neutrophils to metastasis, we cultured MDA-MB-231 and MCF10CA (TNBC) cells in primary neutrophils conditioned medium (CM) prior treated with or without nicotine. We found that both MDA-MB-231 and MCF10CA cells displayed epithelial phenotype with loss of mesenchymal markers and gain of epithelial markers in nicotine-induced primary neutrophils CM. These results strongly suggest that nicotine-induced polarization of N2-neutrophils plays a critical role in regulating cancer cell plasticity. We then examined secretory factor(s) from nicotine-treated primary neutrophils using a customized qPCR array system. We found that secretion of LCN2 was significantly augmented in nicotine treated primary neutrophils conditioned medium. In addition, clinical data of stage-II breast cancer patients also showed high LCN2 serum level in smokers than non-smokers. Collectively, our results suggest that nicotine promotes N2 polarization of neutrophils thereby supporting MET transition in a paracrine manner via secreting LCN2 that facilitate metastatic colonization of TNBC cells. Citation Format: Abhishek Tyagi, Sambad Sharma, Kerui Wu, Shih-Ying Wu, Fei Xing, Yin Liu, Dan Zhao, Ravindra Pramod Deshpande, Yin-Yuan MO, Kounosuke Watabe. Nicotine promotes lung metastasis in triple negative breast cancer through paracrine signaling in the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2025.

Enhanced responsiveness of platelets to vicagrel in IL‐10‐deficient mice through STAT3‐dependent up‐regulation of the hydrolase arylacetamide deacetylase in the intestine

Vicagrel is a novel promising antiplatelet drug designed for overcoming clopidogrel resistance. There is limited evidence indicating that exogenous IL-10 suppresses CYP3A4 activity in healthy subjects and that IL-10 knockout (KO) mice exhibit increased clopidogrel bioactivation compared with wild-type (WT) mice. In this study, we sought to determine whether IL-10 could play an important role in the metabolism of and platelet response to vicagrel in mice. IL-10 KO and WT mice were administered vicagrel, then their plasma H4 (active metabolite of vicagrel) concentrations were determined by LC-MS/MS, and inhibition of ADP-induced whole-blood platelet aggregation by vicagrel was assessed with an aggregometer. The mRNA and protein levels of several relevant genes between IL-10 KO and WT mice were measured by qRT-PCR and Western blots, respectively. Intestinal Aadac protein levels were measured in IL-10 WT mice injected i.p. with vehicle control, Stattic, or BAY 11-7082. Compared with WT mice, IL-10 KO mice exhibited significantly increased plasma levels of H4 and enhanced platelet responses to vicagrel, as well as significantly higher mRNA and protein levels of arylacetamide deacetylase (Aadac) in the intestine. In WT mice, STAT3, not NF-κB, mediated Aadac expression in the intestine. IL-10 suppresses metabolic activation of vicagrel through down-regulation of Aadac in mouse intestine in a STAT3-dependent manner and, consequently, attenuates platelet responses to vicagrel, suggesting that the antiplatelet effect of vicagrel may be modulated by changes in plasma IL-10 levels in relevant clinical settings.

E-105 Mesenchymal stromal cells: Mediators of inflammation in cancer

Cancer-associated fibroblasts (CAF) have been identified in the tumor microenvironment (TME) of many cancers. CAF represent a heterogeneous population of cells that can have pro-tumorigenic and anti-tumorigenic functions. We have isolated from primary human neuroblastoma tumors, a population of CAF that share phenotypic and functional characteristics of bone marrow-derived mesenchymal stromal cells (MSC). These cells are CD73+, CD90+, CD105+, CD34−, CD45−, CD14−, CD19−, CD31−, and VEGFR2−, and retain the ability to differentiate into osteoblasts, chondrocytes and adipocytes, a feature of MSC. However, we show that these cells also express fibroblast activation protein alpha (FAP/DPPIV), fibroblast specific protein 1 (FSP1/S1004A) and alpha smooth muscle actin (SMA), markers of cancer-associated fibroblasts. When in the presence of tumor cells, these MSC/CAF stimulate the production of multiple pro-tumorigenic cytokines and chemokines including interleukin (IL)-6, IL-8, CCL2/monocyte chemoattractant protein 1, CXCL-12/stromal-derived factor 1 (SDF1), CXCL1, vascular endothelial growth factor (VEGF-A), plasminogen activator inhibitor 1 (PAI-1) and transforming growth factor (TGF) β. The production of these cytokines/chemokines by MSC/CAF is stimulated by the production of soluble factors by tumor cells including galectin-3 binding protein and extracellular vesicles. In addition to stimulating angiogenesis, the recruitment and M2 polarization of macrophages, and to suppress immune cells, MSC/CAF have a direct effect on tumor cells by stimulating tumor cell growth, survival and resistance to chemotherapy in an ERK1/2 and STAT3-dependent manner. We then show that targeting ERK1/2 and STAT3 or targeting MSC in combination with chemotherapy or immunotherapy in mice orthotopically implanted with human neuroblastoma tumors, inhibits tumor growth and extends survival. In contrast, targeting a single cytokine like IL-6 has no significant effect. These data thus identify a new type of CAF sharing characteristics of bone marrow-derived MSCs that contribute to a pro-tumorigenic inflammatory reaction in the TME and provide preclinical evidence that targeting these cells or the pathways they activated in tumor cells is a valuable therapeutic approach.

Long noncoding RNA DANCR promotes nasopharyngeal carcinoma progression by interacting with STAT3, enhancing IL-6/JAK1/STAT3 signaling

Nasopharyngeal carcinoma (NPC) is the most common type of malignancy of the neck and head in Southeast Asia and North Africa. Long noncoding RNA (LncRNA) Differentiation antagonizing nonprotein coding RNA (DANCR) has been reported to exert oncogenic functions in various malignant tumors. However, whether DANCR is involved in NPC tumorgenesis and its underlying mechanisms are still unknown. In the current study, we investigated the expression and biological functions of DANCR in NPC cells and found that DANCR is highly expressed in NPC cells and IL-6 stimulation upregulates DANCR expression through an STAT3-dependent manner. Besides, DANCR knockdown attenuates IL-6-induced proliferation and invasion of NPC cells. Furthermore, DANCR specifically interacts with STAT3 to promote STAT3 activation in NPC cells. Moreover, DANCR knockdown evidently decreases IL-6 induced the association between STAT3 and JAK1 in NPC cells. In addition, we also found that DANCR also indirectly binds to JAK1 through interacting with STAT3 under IL-6 stimulation in NPC cells. Taken together, the present study for the first time demonstrates that DANCR, acting as an oncogene in NPC, promotes NPC progression by interacting with STAT3 and enhancing JAK1 binding to STAT3 to strengthen IL-6/JAK1/STAT3 signaling, suggesting that it may be a potential target to be used as a novel strategy to develop NPC therapeutics.

E2F is required for STAT3-mediated upregulation of cyclin B1 and Cdc2 expressions and contributes to G2-M phase transition.

Activation of transcription factor STAT3 is involved in cell proliferation, differentiation, and cell survival. Constitutive activation of STAT3 pathway has been associated with the oncogenesis of various types of cancers. It has been reported that STAT3 plays a key role in the G1 to S phase cell cycle transition induced by the cytokine receptor subunit gp130, through the upregulation of cyclins D1, D2, D3, A, and Cdc25A and the concomitant downregulation of p21 and p27. However, its role in mediating G2-M phase transition has not been studied. The cyclin B1/Cdc2 complex is widely accepted as the trigger of mitosis in all organisms and is believed to be necessary for progression through S phase and keep active during the G2-M transition and progression. In the present study, we found that activation of STAT3 stimulates cyclin B1 and Cdc2 expressions. Deletion and site-directed mutations on cyclin B1 and Cdc2 promoters indicated that E2F element mediates the upregulation of these two promoters in a STAT3-dependent manner. The findings reported here demonstrated that STAT3 participates in modulating G2-M phase checkpoint by regulating gene expressions of cyclin B1 and Cdc2 via E2F.

Interleukin 4 Induces Macrophage-Mediated Phagocytosis of Leukemia Cells

Acute myeloid leukemia (AML) is an aggressive disease associated with poor prognosis, hence, new therapeutic strategies are needed. The AML cells reside in the bone marrow niche and depend on external signals such as cytokines for their growth and survival. In contrast to providing a supporting role, cytokines can act as negative regulators of AML cells. We previously identified that interleukin 4 (IL-4) induces apoptosis of AML cells in a Stat6-dependent manner and demonstrated strong anti-leukemic activity of IL-4 in a murine AML model driven by MLL-AF9 (Peña-Martínez et al., Leukemia 2017). Ectopic expression of IL-4 in AML cells resulted in prolonged survival in C57BL/6 mice, with mice almost devoid of leukemia cells in bone marrow and spleen upon the time of sacrifice. However, the IL-4-induced apoptosis of AML cells did not fully explain the strong antileukemic activity of IL-4 in vivo.To investigate whether the anti-leukemic effect of ectopic IL-4 expression in vivo was microenvironment dependent, we used IL-2 receptor gamma(-/-) immunodeficient mice, which lack a functional IL-4 receptor type I complex, as recipients for transplantation of murine MLL-AF9 AML cells. Notably, there was no antileukemic activity of IL-4 in these mice, suggesting that the in vivo anti-leukemic effect of IL-4 was predominantly microenvironment-dependent. To identify the cell population that was responsible for the antileukemic effect of IL-4 stimulation, we performed flow cytometry analysis of bone marrow and spleen cells in mice exposed to high IL-4 levels. We found that the anti-leukemic activity of IL-4 was associated with a significant expansion of F4/80+ macrophages in both the bone marrow and spleen, which was confirmed by immunohistochemistry.To determine whether macrophages were responsible for the anti-leukemic effect of IL-4, we depleted macrophages with clodronate liposomes in mice receiving IL-4-secreting AML cells. Depletion of macrophages partially rescued the anti-leukemic effect of IL-4, indicating that macrophages stimulated with IL-4 were responsible for the antileukemic activity. Consistent with these findings, in macrophage differentiation assays with either murine or human monocytes, IL-4 enhanced the phagocytosis of leukemia cells.To characterize the IL-4-induced macrophages, we performed RNA sequencing of F4/80+ macrophages from animals exposed to high IL-4 levels. Gene expression analysis revealed IL-4-induced M2 polarization of the macrophages, as key markers of M2 activation such as Arg1, Retnla and Chil3 were upregulated. Moreover, consistent with the in vitro findings, gene set enrichment analysis revealed an enrichment of phagocytosis signatures in the macrophages stimulated with IL-4.Strikingly, we found that exposure of AML cells to IL-4 resulted in strong upregulation of CD47, a ‘don't eat me signal’, which protects cells from macrophage-mediated phagocytosis. By CRISPR/Cas9-mediated disruption of Stat6 in IL-4 treated AML cells, we found that the CD47 upregulation was Stat6 dependent, recognizing a previously unknown link between IL-4 signalling and CD47 upregulation. Consistent with this finding, combined antibody blockade of CD47 on leukemia cells and IL-4 stimulation of macrophages resulted in enhanced phagocytosis of AML cells.Taken together, this study shows that IL-4 has anti-leukemic activity by activating macrophages, findings that might translate into new immunotherapeutic opportunities in AML and possibly other malignancies. DisclosuresNo relevant conflicts of interest to declare.

Differential Influence on Regulatory B Cells by TH2 Cytokines Affects Protection in Allergic Airway Disease.

The role of regulatory B cells (Bregs) in modulating immune responses and maintaining tolerance are well established. However, how cytokines present during immune responses affect Breg growth and function are not as well defined. Previously, our laboratory reported IL-5- and mCD40L-expressing fibroblast (mCD40L-Fb) stimulation induced IL-10 production from murine B cells. The current study investigated the phenotype and functional relevance of IL-10- producing B cells from this culture. We found IL-5/mCD40L-Fb stimulation induced IL-10 production exclusively from CD5+ splenic B cells of naive mice. After stimulation, the resulting IL-10+ B cells displayed markers of multiple reported Breg phenotypes. Interestingly, when investigating effects of IL-4 (a critical TH2 cytokine) on IL-5/mCD40L-Fb-induced IL-10 production, we found IL-4 inhibited IL-10 production in a STAT6-dependent manner. Upon adoptive transfer, CD5+ B cells previously stimulated with IL-5/mCD40L-Fb were able to reduce development of OVA-induced allergic airway disease in mice. Using B cells from IL-10 mutant mice differentiated by IL-5/mCD40L-Fb, we found protection from allergic airway disease development was dependent on the IL-10 production from the transferred B cells. Bregs have been shown to play crucial roles in the immune tolerance network, and understanding stimuli that modulate their growth and function may be key in development of future treatments for diseases of immune dysregulation.

Targeting the adiponectin expression in ADSCs by a small molecule and its beneficial therapeutic effect on the type 2 diabetes mouse model

Obesity is characterised by hyperleptinaemia and hypoadiponectinaemia and these metabolic abnormalities may contribute to the progression of several obesity-associated cancers including oesophageal adenocarcinoma (OAC). We have examined the effects of leptin and adiponectin on OE33 OAC cells. Leptin stimulated proliferation, invasion and migration and inhibited apoptosis in a STAT3-dependant manner. Leptin-stimulated MMP-2 secretion in a partly STAT3-dependent manner and MMP-9 secretion via a STAT3-independent pathway. Adiponectin inhibited leptin-induced proliferation, migration, invasion, MMP secretion and reduced the anti-apoptotic effects: these effects of adiponectin were ameliorated by both a non-specific tyrosine phosphatase inhibitor and a specific PTP1B inhibitor. Adiponectin reduced leptin-stimulated JAK2 activation and STAT3 transcriptional activity in a PTP1B-sensitive manner and adiponectin increased both PTP1B protein and activity. We conclude that adiponectin restrains leptin-induced signalling and pro-carcinogenic behaviour by inhibiting the early events in leptin-induced signal transduction by activating PTP1B. Relative adiponectin deficiency in obesity may contribute to the promotion of OAC.

Liver Cancer Initiation Requires p53 Inhibition by CD44-Enhanced Growth Factor Signaling

How fully differentiated cells that experience carcinogenic insults become proliferative cancer progenitors that acquire multiple initiating mutations is not clear. This question is of particular relevance to hepatocellular carcinoma (HCC), which arises from differentiated hepatocytes. Here we show that one solution to this problem is provided by CD44, a hyaluronic acid receptor whose expression is rapidly induced in carcinogen-exposed hepatocytes in a STAT3-dependent manner. Once expressed, CD44 potentiates AKT activation to induce the phosphorylation and nuclear translocation of Mdm2, which terminates the p53 genomic surveillance response. This allows DNA-damaged hepatocytes to escape p53-induced death and senescence andrespond to proliferative signals that promote fixation of mutations and their transmission to daughter cells that go on to become HCC progenitors.

Clinical Utility of a STAT3-Regulated miRNA-200 Family Signature with Prognostic Potential in Early Gastric Cancer.

Purpose: The majority of gastric cancer patients are diagnosed with late-stage disease, for which distinct molecular subtypes have been identified that are potentially amenable to targeted therapies. However, there exists no molecular classification system with prognostic power for early-stage gastric cancer (EGC) because the molecular events promoting gastric cancer initiation remain ill-defined.Experimental Design: miRNA microarrays were performed on gastric tissue from the gp130F/F preclinical EGC mouse model, prior to tumor initiation. Computation prediction algorithms were performed on multiple data sets and independent gastric cancer patient cohorts. Quantitative real-time PCR expression profiling was undertaken in gp130F/F-based mouse strains and human gastric cancer cells genetically engineered for suppressed activation of the oncogenic latent transcription factor STAT3. Human gastric cancer cells with modulated expression of the miR-200 family member miR-429 were also assessed for their proliferative response.Results: Increased expression of miR-200 family members is associated with both tumor initiation in a STAT3-dependent manner in gp130F/F mice and EGC (i.e., stage IA) in patient cohorts. Overexpression of miR-429 also elicited contrasting pro- and antiproliferative responses in human gastric cancer cells depending on their cellular histologic subtype. We also identified a miR-200 family-regulated 15-gene signature that integrates multiple key current indicators of EGC, namely tumor invasion depth, differentiation, histology, and stage, and provides superior predictive power for overall survival compared with each EGC indicator alone.Conclusions: Collectively, our discovery of a STAT3-regulated, miR-200 family-associated gene signature specific for EGC, with predictive power, provides a molecular rationale to classify and stratify EGC patients for endoscopic treatment. Clin Cancer Res; 24(6); 1459-72. ©2018 AACR.

IL-10 Paradoxically Promotes Autoimmune Neuropathy through S1PR1-Dependent CD4+ T Cell Migration.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a debilitating condition caused by autoimmune demyelination of peripheral nerves. CIDP is associated with increased IL-10, a cytokine with well-described anti-inflammatory effects. However, the role of IL-10 in CIDP is unclear. In this study, we demonstrate that IL-10 paradoxically exacerbates autoimmunity against peripheral nerves. In IL-10-deficient mice, protection from neuropathy was associated with an accrual of highly activated CD4+ T cells in draining lymph nodes and absence of infiltrating immune cells in peripheral nerves. Accumulated CD4+ T cells in draining lymph nodes of IL-10-deficient mice expressed lower sphingosine-1-phosphate receptor 1 (S1pr1), a protein important in lymphocyte egress. Additionally, IL-10 stimulation in vitro induced S1pr1 expression in lymph node cells in a STAT3-dependent manner. Together, these results delineate a novel mechanism in which IL-10-induced STAT3 increases S1pr1 expression and CD4+ T cell migration to accelerate T cell-mediated destruction of peripheral nerves.

Interleukin-6 potentiates FcεRI-induced PGD2 biosynthesis and induces VEGF from human in situ-matured skin mast cells

BackgroundInterleukin-6 is a gp130 utilizing cytokine that is consistently associated with allergic diseases like asthma and urticaria in humans where mast cells are known to play a critical role. However, the role of IL-6 in allergic disease in not known. IL-6 was reported to enhance degranulation of in vitro-derived mast cells, but the effect of IL-6 on mediator release from human in situ-matured tissue-isolated mast cells had not been reported. MethodsHuman mature mast cells were isolated and purified from normal skin tissue from different donors. The expression of surface-expressed IL-6 receptors was demonstrated by flow cytometry. The effect of IL-6 on FcεRI-induced degranulation, PGD2 biosynthesis, and cytokine production was determined with β‑hexosaminidase release assay, Western blotting, quantitative real-time PCR, and ELISA. The small molecule inhibitor of STAT-3, C188-9, was used to demonstrate STAT3 dependency.Results: IL-6 significantly potentiated FcεRI-induced PGD2 biosynthesis, but had no effect on degranulation. IL-6 also induced VEGF gene expression and protein secretion, and enhanced FcεRI-induced IL-8 production. Mechanistically, IL-6 enhanced FcεRI-induced COX‑2 expression, PGD2 biosynthesis, and VEGF production in a STAT3 dependent manner. ConclusionHere, we demonstrate that IL-6 is a potentiator of FcεRI-induced PGD2 biosynthesis, and can induce or enhance production of pro-angiogenesis factors VEGF and IL-8 from human in situ-matured skin mast cells. General significanceThese findings from this study indicate that IL-6 contributes to human allergic disease by enhancing the production of inflammatory PGD2 from tissue-resident mast cells. Moreover, the data suggest a novel role for IL-6 in mast cell-mediated angiogenesis.

Liver-heart crosstalk controls IL-22 activity in cardiac protection after myocardial infarction.

Interleukin (IL)-22 regulates tissue inflammation and repair. Here we report participation of the liver in IL-22-mediated cardiac repair after acute myocardial infarction (MI).Methods: We induced experimental MI in mice by ligation of the left ascending artery and evaluated the effect of IL-22 on post-MI cardiac function and ventricular remodeling.Results: Daily subcutaneous injection of 100 µg/kg mouse recombinant IL-22 for seven days attenuated adverse ventricular remodeling and improved cardiac function in mice at 28 days after left anterior descending coronary artery ligation-induced MI. Pharmacological inhibition of signal transducer and activator of transcription (STAT3) muted these IL-22 activities. While cardiomyocyte-selective depletion of STAT3 did not affect IL-22 activities in protecting post-MI cardiac injury, hepatocyte-specific depletion of STAT3 fully muted these IL-22 cardioprotective activities. Hepatocyte-derived fibroblast growth factor (FGF21) was markedly increased in a STAT3-dependent manner following IL-22 administration and accounted for the cardioprotective benefit of IL-22. Microarray analyses revealed that FGF21 controlled the expression of cardiomyocyte genes that are involved in cholesterol homeostasis, DNA repair, peroxisome, oxidative phosphorylation, glycolysis, apoptosis, and steroid responses, all of which are responsible for cardiomyocyte survival.Conclusions: Supplementation of IL-22 in the first week after acute MI effectively prevented left ventricular dysfunction and heart failure. This activity of IL-22 involved crosstalk between the liver and heart after demonstrating a role of the hepatic STAT3-FGF21 axis in IL-22-induced post-MI cardiac protection.

Development of Erasin: a chromone-based STAT3 inhibitor which induces apoptosis in Erlotinib-resistant lung cancer cells

Inhibition of protein-protein interactions by small molecules offers tremendous opportunities for basic research and drug development. One of the fundamental challenges of this research field is the broad lack of available lead structures from nature. Here, we demonstrate that modifications of a chromone-based inhibitor of the Src homology 2 (SH2) domain of the transcription factor STAT5 confer inhibitory activity against STAT3. The binding mode of the most potent STAT3 inhibitor Erasin was analyzed by the investigation of structure-activity relationships, which was facilitated by chemical synthesis and biochemical activity analysis, in combination with molecular docking studies. Erasin inhibits tyrosine phosphorylation of STAT3 with selectivity over STAT5 and STAT1 in cell-based assays, and increases the apoptotic rate of cultured NSCLC cells in a STAT3-dependent manner. This ability of Erasin also extends to HCC-827 cells with acquired resistance against Erlotinib, a clinically used inhibitor of the EGF receptor. Our work validates chromone-based acylhydrazones as privileged structures for antagonizing STAT SH2 domains, and demonstrates that apoptosis can be induced in NSCLC cells with acquired Erlotinib resistance by direct inhibition of STAT3.

ADAM12 Is a Novel Regulator of Tumor Angiogenesis via STAT3 Signaling.

ADAM12, (ADisintegrin and metalloproteinase domain-containing protein 12), is upregulated in epithelial cancers and contributes to increased tumor proliferation, metastasis, and endocrine resistance. However, its role in tumor angiogenesis is unknown. Here, we report that ADAM12 is upregulated in the vessels of aggressive breast tumors and exerts key regulatory functions. ADAM12 significantly increases bFGF-mediated angiogenesis in vivo and ADAM12 levels are upregulated in tumors that have undergone a switch to the angiogenic phenotype. Importantly, ADAM12-overexpressing breast tumors display a higher microvessel density (MVD). Our goal was to identify the mechanisms by which tumor-associated ADAM12 promotes angiogenesis. ADAM12 expression in breast tumor cells correlated with a significant upregulation of proangiogenic factors such as VEGF and MMP-9 and downregulation of antiangiogenic factors such as Thrombospondin-1 (THBS1/TSP1) and Tissue Inhibitor of Metalloproteinases-2 (TIMP-2). Co-culture with ADAM12-expressing tumor cells promoted endothelial cell (EC) recruitment and capillary tube formation. Conversely, downregulation of endogenous ADAM12 in breast cancer cell lines resulted in reduction of pro-angiogenic factors and EC recruitment. These ADAM12-mediated effects are driven by the activation of EGFR, STAT3 and Akt signaling. Blockade of EGFR/STAT3 or silencing of ADAM12 reversed the proangiogenic tumor phenotype, significantly downregulated pro-angiogenic mitogens and reduced EC recruitment. In human breast cancer tissues, ADAM12 expression was significantly positively correlated with pro-angiogenic factors including VEGF and MMP-9 but negatively associated with TSP1.Implications: These novel findings suggest that ADAM12 regulates EC function and facilitates a proangiogenic microenvironment in a STAT3-dependent manner. A combined approach of targeting ADAM12 and STAT3 signaling in breast cancer may represent a promising strategy to inhibit tumor neovascularization. Mol Cancer Res; 15(11); 1608-22. ©2017 AACR.

TCR-independent functions of Th17 cells mediated by the synergistic actions of cytokines of the IL-12 and IL-1 families.

The development of Th17 cells is accompanied by the acquisition of responsiveness to both IL-12 and IL-23, cytokines with established roles in the development and/or function of Th1 and Th17 cells, respectively. IL-12 signaling promotes antigen-dependent Th1 differentiation but, in combination with IL-18, allows the antigen-independent perpetuation of Th1 responses. On the other hand, while IL-23 is dispensable for initial commitment to the Th17 lineage, it promotes the pathogenic function of the Th17 cells. In this study, we have examined the overlap between Th1 and Th17 cells in their responsiveness to common pro-inflammatory cytokines and how this affects the antigen-independent cytokine responses of Th17 cells. We found that in addition to the IL-1 receptor, developing Th17 cells also up-regulate the IL-18 receptor. Consequently, in the presence of IL-1β or IL-18, and in the absence of TCR activation, Th17 cells produce Th17 lineage cytokines in a STAT3-dependent manner when stimulated with IL-23, and IFN© via a STAT4-dependent mechanism when stimulated with IL-12. Thus, building on previous findings of antigen-induced plasticity of Th17 cells, our results indicate that this potential of Th17 cells extends to their cytokine-dependent antigen-independent responses. Collectively, our data suggest a model whereby signaling via either IL-1β or IL-18 allows for bystander responses of Th17 cells to pathogens or pathogen products that differentially activate innate cell production of IL-12 or IL-23.

(+)-Borneol improves the efficacy of edaravone against DSS-induced colitis by promoting M2 macrophages polarization via JAK2-STAT3 signaling pathway

Compound edaravone injection (C.EDA), a compound preparation composed of edaravone (EDA) and (+)-Borneol with the mass ratio of 4: 1, displays a better anti-inflammatory activity than EDA. However, its precise mechanism remains to be further studied. In this work, we investigated whether (+)-Borneol could improve the efficacy of EDA against DSS-induced colitis. We found that C.EDA at 7.5 and 15mg/kg could significantly relieve the disease activity index (DAI) and reduce the loss of body weight and colon length in a dose-dependent manner, while EDA or (+)-Borneol alone only had moderate effects even at the highest dose. Additionally, ELISA revealed that C.EDA could more dramatically decrease the protein levels of inflammatory cytokines and increase the levels of anti-inflammatory cytokine than EDA or (+)-Borneol alone both in colon tissues and serum. H&E staining and IHC assay also indicated that C.EDA exhibited more prominent effects on increasing the population of M2 macrophages, decreasing M1 macrophages infiltration and protecting intestinal barrier integrity. Furthermore, in vitro studied demonstrated that C.EDA, EDA or (+)-Borneol failed in inhibiting M1 macrophages activation but could specifically induce the activation of M2 macrophages in a STAT3-dependent manner. Knockdown the expression of STAT3 successfully abolished the effect of C.EDA and EDA on promoting M2 macrophages activation. Consistent with in vivo study, C.EDA exhibited a more efficient ability of inducing M2 macrophages polarization and STAT3 activation than EDA or (+)-Borneol alone in vitro. In conclusion, we confirmed that (+)-Borneol improved the efficacy of EDA against DSS-induced colitis by promoting M2 macrophages polarization via JAK2-STAT3 signaling pathway.

DOCK8 regulates fitness and function of regulatory T cells through modulation of IL-2 signaling.

Foxp3+ Tregs possess potent immunosuppressive activity, which is critical for maintaining immune homeostasis and self-tolerance. Defects in Treg development or function result in inadvertent immune activation and autoimmunity. Despite recent advances in Treg biology, we still do not completely understand the molecular and cellular mechanisms governing the development and suppressive function of these cells. Here, we have demonstrated an essential role of the dedicator of cytokinesis 8 (DOCK8), guanine nucleotide exchange factors required for cytoskeleton rearrangement, cell migration, and immune cell survival in controlling Treg fitness and their function. Treg-specific DOCK8 deletion led to spontaneous multiorgan inflammation in mice due to uncontrolled T cell activation and production of proinflammatory cytokines. In addition, we show that DOCK8-deficient Tregs are defective in competitive fitness and in vivo suppressive function. Furthermore, DOCK8 controls IL-2 signaling, crucial for maintenance and competitive fitness of Tregs, via a STAT5-dependent manner. Our study provides potentially novel insights into the essential function of DOCK8 in Tregs and immune regulation, and it explains the autoimmune manifestations associated with DOCK8 deficiency.