Mediated STAT3 Activation Research Articles

Dietary diosgenin transcriptionally down-regulated intestinal NPC1L1 expression to prevent cholesterol gallstone formation in mice

BackgroundCholesterol gallstone disease is a common disease. Reducing cholesterol burden is important to prevent/treat gallstone. In this study, we investigated the application of diosgenin (DG) to prevent the formation of gallstone in mice.MethodsAdult male C57BL/6J mice were fed with the lithogenic diet (LD) only or LD supplemented with DG or ezetimibe for 8 weeks. Incidences of gallstone formation were documented. Intestine and liver tissues were collected to measure the lipid contents and expression of genes in cholesterol metabolism. Caco2 cells were treated with DG to monitor the regulation on cholesterol absorption and the transcriptional regulation of Npc1l1 gene. Changes of gut microbiota by DG was analyzed. Intraperitoneal injection of LPS on mice was performed to verify its effects on STAT3 activation and Npc1l1 expression in the small intestine.ResultsLD led to 100% formation of gallstones in mice. In comparison, dietary DG or ezetimibe supplementary completely prevents gallstones formation. DG inhibited intestinal cholesterol absorption in mice as well as in Caco2 cells by down-regulation of Npc1l1 expression. DG could directly inhibit phosphorylation of STAT3 and its transcriptional regulation of Npc1l1 expression. Furthermore, DG could modulate gut microbiota profiles and LPS mediated STAT3 activation and Npc1l1 expression.ConclusionOur results demonstrated that dietary DG could inhibit intestinal cholesterol absorption through decreasing NPC1L1 expression to prevent cholesterol gallstone formation.

Regulation of STAT3 signaling in IFNγ and IL10 pathways and in their cross-talk.

The pro-inflammatory IFNγ-STAT1 pathway and anti-inflammatory IL10-STAT3 pathway elicit cellular responses primarily utilizing their canonical STATs. However IL10 mediated STAT1 and IFNγ mediated STAT3 activation is also observed, suggesting crosstalk of these functionally opposing signaling pathways can potentially reshape the canonical dynamics both STATs and alter the expression of their target genes. Herein, we measured the dynamics of STATs in response to different doses of IL10 or IFNγ and in their co-stimulation and employed quantitative modeling to understand the regulatory mechanisms controlling signal responses in individual and co-simulation scenarios. Our experiments show, STAT3 in particular, exhibits a bell-shaped dose-response while treated with IFNγ or IL10 and our model quantiatively captured the dose-dependent dynamics of both the STATs in both pathways. The model next predicted and subsequent experiments validated that STAT3 dynamics would robustly remain IL10 specific when subjected to a co-stimulation of both IFNγ and IL10. Genes common to both pathways also exhibited IL10 specific expression during the co-stimulation. The findings thus uncover anovel feature of the IL10-STAT3 signaling axis during pathway crosstalk. Finally, parameter sampling coupled to information theory based analysis showed that bell-shaped signal-response of STAT3 in both pathways is primarily dependent on receptor concentration whereas robustness of IL10-STAT3 signaling axis in co-stimulation results from the negative regulation of the IFNγ pathway.

Recombinant IL-22 promotes protection in a murine model of Aspergillus flavus keratitis and mediates host immune responses in human corneal epithelial cells.

Aspergillus flavus is a leading cause of corneal infections in India and worldwide, resulting in severe visual impairment. We studied the host immune response towards A. flavus in immortalised human corneal epithelial cells (HCEC) and found increased expression of Toll-like receptors, antimicrobial peptides and proinflammatory cytokines like IL-6 and IL-8. Differential expressions of antimicrobial peptides were determined in corneal scrapings from A. flavus keratitis patients with significantly increased expression of LL-37, S100A12 and RNase 7. Increased levels of IL-22 expression were observed both in patients with A. flavus keratitis and in experimental mice model of corneal infections along with IL-17, IL-23 and IL-18. IL-22 is an important mediator of inflammation during microbial infections, and acts primarily on fibroblasts and epithelial cells. We observed constitutive expression of IL-22 receptors in HCEC, and IL-22 mediated activation of NF-κB, MAPK pathways and STAT3, along with increased expression of antimicrobial peptides in these cells. IL-22 also efficiently lessened cell deaths in corneal epithelial cells during A. flavus infection in vitro. Furthermore, recombinant IL-22 reduced fungal burden and corneal opacity in an experimental murine model of A. flavus keratitis.

CCL16 maintains stem cell-like properties in breast cancer by activating CCR2/GSK3β/β-catenin/OCT4 axis.

Rationale: Considerable evidence suggests that breast cancer metastasis and recurrence occur due to emergence of cancer stem cells (CSCs). In our previous study, we designed a high-throughput siRNA screening platform that identifies inflammation genes involved in the regulation of cancer cell stemness. We reported that CCL16 protein decreases OCT4 expression and reduces the ALDH+ subpopulation. However, the mechanism by which CCL16 maintains stem cell-like properties remains unclear.Methods: Tissue microarrays were used to evaluate CCL16 expression. Cancer stemness assays were performed in CCL16 knockdown and overexpressing cells in vitro and in a xenograft model in vivo. Human phosphokinase array, immunofluorescence and chromatin immunoprecipitation assays were performed to explore the underlying mechanism.Results: We report that CCL16 was overexpressed in breast tumors and significantly correlated with clinical progression. We found that silencing CCL16 in MDA-MB-231 and BT549 cells diminished CSC properties including ALDH+ subpopulation, side population, chemo-resistance, and sphere formation. Furthermore, mice bearing CCL16-silenced MDA-MB-231 xenografts had lower tumorigenic frequency and developed smaller tumors. Exploration of the underlying mechanism found that CCL16 selects CCR2 to activate p-AKT/GSK3β signaling and facilitate β-catenin nuclear translocation. Further, CCL16 binds to the OCT4 promoter and promotes OCT4 expression. In addition, shRNAs targeting CCR2 and XAV939 targeting β-catenin abolished CCL16-mediated cancer stemness. Upstream, IL10 mediates STAT3 activation, which binds to the CCL16 promoter and enhances its expression. The STAT3-targeted inhibitor Stattic suppressed CCL16 expression in vitro and restrained tumor progression in vivo.Conclusions: We identified a potential CSC regulator and suggest a novel mechanism for how CCL16 governs cancer cell stemness. We propose that CCL16 could be an effective target for breast cancer therapy.

Mitochondrial Respiratory Defect Enhances Hepatoma Cell Invasiveness via STAT3/NFE2L1/STX12 Axis.

Simple SummaryMitochondria are essential organelles responsible for aerobic ATP production in eukaryotes. However, many solid tumor cells harbor an impaired mitochondrial ATP production system: oxidative phosphorylation (OXPHOS). The aim of this study was to elucidate the involvement of the mitochondrial OXPHOS defect in cancer cell activity, especially focusing on hepatoma cell invasiveness. We demonstrated that NADH:Ubiquinone Oxidoreductase Subunit A9 (NDUFA9) depletion was an upstream driver of the OXPHOS defect and nuclear factor-erythroid 2 like 1 (NFE2L1) upregulation in HCC tumors. NFE2L1 is the key transcription factor to enhance hepatoma cell invasiveness via STX12 expression. Our study presents a novel mitochondrial dysfunction-mediated retrograde signaling pathway and the resulting transcriptomic reprogramming in liver cancer progression, providing the NDUFA9/NFE2L1/STX12 axis as a key prognostic marker of aggressive liver cancer with mitochondrial defects.Mitochondrial respiratory defects have been implicated in cancer progression and metastasis, but how they control tumor cell aggressiveness remains unclear. Here, we demonstrate that a mitochondrial respiratory defect induces nuclear factor-erythroid 2 like 1 (NFE2L1) expression at the transcriptional level via reactive oxygen species (ROS)-mediated STAT3 activation. We identified syntaxin 12 (STX12) as an effective downstream target of NFE2L1 by performing cDNA microarray analysis after the overexpression and depletion of NFE2L1 in hepatoma cells. Bioinformatics analysis of The Cancer Genome Atlas Liver Hepatocellular carcinoma (TCGA-LIHC) open database (n = 371) also revealed a significant positive association (r = 0.3, p = 2.49 × 10−9) between NFE2L1 and STX12 expression. We further demonstrated that STX12 is upregulated through the ROS/STAT3/NFE2L1 axis and is a key downstream effector of NFE2L1 in modulating hepatoma cell invasiveness. In addition, gene enrichment analysis of TCGA-LIHC also showed that epithelial–mesenchymal transition (EMT)-related core genes are significantly upregulated in tumors co-expressing NFE2L1 and STX12. The positive association between NFE2L1 and STX12 expression was validated by immunohistochemistry of the hepatocellular carcinoma tissue array. Finally, higher EMT gene enrichment and worse overall survival (p = 0.043) were observed in the NFE2L1 and STX12 co-expression group with mitochondrial defect, as indicated by low NDUFA9 expression. Collectively, our results indicate that NFE2L1 is a key mitochondrial retrograde signaling-mediated primary gene product enhancing hepatoma cell invasiveness via STX12 expression and promoting liver cancer progression.

Berberine functions as a negative regulator in lipopolysaccharide -induced sepsis by suppressing NF-κB and IL-6 mediated STAT3 activation.

Sepsis is a deadly complication raised by bacterial pathogens-induced dysregulated innate inflammatory response. Thus, anti-inflammatory is a potential therapeutic treatment for septic patients. Numerous evidence exhibited that berberine possesses potent anti-inflammatory, anti-apoptotic and anti-oxidative activities. However, the effect of berberine on sepsis is not fully understood. The anti-inflammatory effect of berberine was evaluated using lipopolysaccharide (LPS)-induced macrophages differentiation model in vitro and using LPS/D-galactosamine-challenged septic mice model in vivo. The secreted protein levels were determined by ELISA assay. The multiple targets mRNA and protein levels were measured by quantitative RT-PCR and western blot assay, respectively. Our study demonstrated that administration of berberine significantly attenuated lung tissue injury, and potently increased the survival rate of septic mice by modulating excessive inflammatory response with negligible side-effects. We further found that berberine inhibited the expression of tumor necrosis factor (TNF)-α, interleukin-(IL)-1β and IL-6 via suppressing nuclear factor kappa B subunit 1 (NF-κB) signaling activation. Our study strongly supported the concept that berberine may serve as a single drug or a promising adjuvant that can be used in conjunction with other medications for the treatment of septic patients.

JAK2V617F expressing macrophages stimulate IL-6 production through PKM1 mediated STAT3 activation

Abstract The JAK2V617F mutation is intimately involved in the pathogenesis of myeloproliferative neoplasms (MPNs) including polycythemia vera and essential thrombocytosis. The thrombotic events are serious complications occurring in individuals with MPNs which affect their prognosis. Interestingly, JAK2V617F is detected in some individuals who developed thrombosis without MPNs and thrombotic risk factors. These observations prompted us to hypothesize that JAK2V617F arising in myeloid cells could contribute to cardiovascular disease by promoting the production of proinflammatory cytokines. To test this, we established JAK2V617F expressing murine macrophages (JAK2V617F macrophages) and explored their function. We found that the levels of p-STAT3, one of downstream targets of JAK2, were markedly elevated in JAK2V617F macrophages in associated with an increase in the production of IL-6 at baseline and following stimulation with LPS, as measured by Western blotting and ELISA, respectively. While, inhibition of STAT3 by C188-9 significantly decreased the production of IL-6 in the culture medium harvested from JAK2V617F macrophages. In further experiments, JAK2V617F endowed macrophages with elevated glycolytic phenotype in parallel with aberrant expression of PKM1. Interestingly, silencing of PKM1 inactivated STAT3. On contrary, ectopic expression of PKM1 activated STAT3. Importantly, JAK2V617F contributed to PKM1 protein stabilization via blockade of lysosomal-dependent degradation via chaperone-mediated autophagy (CMA). All of these observations indicated that JAK2V617F could protect PKM1 from CMA-mediated degradation, leading to activation of STAT3, which promoted IL-6 production.

Abstract 4316: Targeting LIFR overcomes HDAC inhibitor resistance in ovarian cancer

Abstract Ovarian cancer (OCa) is the deadliest of all gynecologic cancers in the United States and a critical need exists for the development of novel therapies for the treatment of OCa. Leukemia inhibitory factor receptor (LIFR) and its ligand LIF play a critical role in cancer progression, metastasis, stem cell maintenance, and therapy resistance. Recent clinical studies showed that cancer cells elucidate feedback activation of LIFR that limits response to histone deacetylase (HDAC) inhibitors. Recently, we developed a first-in-class inhibitor of LIFR, EC359 that directly interacts with LIFR and effectively blocks LIF-LIFR interactions. Here, we examined whether LIFR inhibitor EC359 abrogate the side effects of histone deacetylase inhibitor SAHA (Vorinostat) for the treatment of OCa. Methods: The effect of EC359 and SAHA as a combination therapy on OCa cell viability was examined by MTT assays. The efficacy of combination therapy on cell survival and apoptosis was determined using clonogenic assays and caspase3/7 assays respectively. The efficacy of combination therapy on OCa stem cells was determined using extreme limiting dilution assays. Mechanistic studies were performed using western blotting, qRT-PCR and Mass Spectrometry analyses. The effect of combination therapy on STAT3 signaling was examined using reporter gene assays. The in vivo efficacy of combination therapy on tumors was examined using ex vivopatient derived explants and mouse xenograft models. Results: EC359 significantly enhanced the efficacy of SAHA in reducing cell viability, colony formation ability, and apoptosis compared to monotherapy of SAHA in multiple established and primary OCa cells. Further, EC359 enhanced SAHA ability to reduce self-renewal of OCa stem cells. As expected in STAT3 reporter assays, SAHA treatment activated STAT3 reporter and EC359 addition abrogated SAHA mediated STAT3 activation. Mechanistic studies using multiple OCa models and western blot analysis confirmed activation of LIFR signaling pathway upon SAHA treatment and its blockage by EC359 treatment. Treatment of human primary OCa tumor explants with EC359 enhanced ability of SAHA to decrease the proliferation (Ki-67 positivity) compared to monotherapy treated tumors. DIA based Mass Spectrometry analyses identified unique pathways modulated by combination therapy. Treatment of OCa xenografts with EC359 enhanced the ability of SAHA to reduce in vivotumor growth compared to monotherapy treated tumors. Conclusions: Our results suggest that EC359 has therapeutic utility in overcoming the limitation of feedback activation of LIFR observed in the treatment of HDAC inhibitors in treating OCa. Citation Format: Mengxing Li, Suryavathi Viswanadhapalli, Gangadhara Reddy Sareddy, Bindu Santhamma, Hui Yan, Zhenming Xu, Edward Kost, Rajeshwar Rao Tekmal, Hareesh B. Nair, Klaus J. Nickisch, Ratna K. Vadlamudi. Targeting LIFR overcomes HDAC inhibitor resistance in ovarian cancer [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 4316.

IL-6 mediated JAK/STAT3 signaling pathway in cancer patients with cachexia.

We investigated the changes in the IL-6 and STAT3 expression levels in cachectic and non-cachectic patients with gastric, lung and breast cancer and evaluated the association between IL-6 and STAT3 levels and cancer types in terms of cachexia condition. Cancer-associated cachexia, observed in nearly 50‒80 % of cancer patients, has drawn attention in advanced patients. IL-6/JAK/STAT pathway plays an essential role in the progression of cancer cachexia through the regulation of the inflammatory response. This study consisted of 48 gastric, breast and lung cancer patients (18 cachectic and 30 non-cachectic) and healthy individuals. Total RNA isolation and cDNA synthesis was performed after the collection of blood samples. IL-6 and STAT3 expression levels were analyzed by RT- PCR analysis. Our findings demonstrated that IL-6 mRNA levels considerably increased 19.89±8.25, 5.18±2.81 and 15.33±9.54-fold in gastric, lung and breast cancer patients with cachexia, respectively. Additionally, a 16.67±7.13, 14.21±11.72 and 8.85±3.89-fold increase in the STAT3 expression level was detected in cachectic gastric, lung and breast cancer patients, respectively (p<0.01). STAT3 may be considered as a therapeutic target for cachectic patients with gastric, lung and breast cancer. Furthermore, IL-6 mediates STAT3 activation in cachectic gastric and breast cancer patients (Tab. 5, Fig. 2, Ref. 62).

Leukemia inhibitory factor functions in parallel with interleukin-6 to promote ovarian cancer growth.

Ovarian carcinoma-associated mesenchymal stem cells (CA-MSC) produce not only high levels of IL6 but also the related cytokine leukemia inhibitory factor (LIF). Interleukin 6 (IL6) mediated activation of STAT3 is implicated as a critical therapeutic target for cancer therapy. Less is known about the role of LIF, which can similarly activate STAT3, in ovarian cancer. We therefore sought to evaluate the tumorigenic effects of CA-MSC paracrine LIF signaling and the redundancy of IL6 and LIF in activating ovarian cancer STAT3 mediated cancer growth. As expected, we found that both IL6 and LIF induce STAT3 phosphorylation in tumor cells. In addition, both IL6 and LIF increased the percentage of ALDH+ ovarian cancer stem-like cells (CSC). Supporting redundancy of function by the two cytokines, CA-MSC induced STAT3 phosphorylation and increased cancer cell ‘stemness’. This effect was not inhibited by LIF or IL6 blocking antibodies alone, but was prevented by dual IL6/LIF blockade or JAK2 inhibition. Similarly, small hairpin RNA (shRNA)-mediated reduction of IL6 or LIF in CA-MSC partially decreased but could not completely abrograte the ability of CA-MSC to induce STAT3 phosphorylation and stemness. Importantly, the in vivo pro-tumorigenic effect of CA-MSC is abrogated by dual blockade with the JAK2 inhibitor ruxolitinib to a much greater extent than treatment with anti-IL6 or anti-LIF antibody alone. Ruxolitinib treatment also improves survival in the immunocompetent ovarian cancer mouse model system with ID8 tumor cells plus MSC. Ruxolitinib-treated tumors in both the immunocompromised and immunocompetent animal models demonstrate decreased phospho-STAT3, indicating on-target activity. In conclusion, CA-MSC activate ovarian cancer cell STAT3 signaling via IL6 and LIF and increase tumorigenesis cancer stemness. This functional redundancy suggests that therapeutic targeting of a single cytokine may be less effective than strategies such as dual inhibitor therapy or targeting shared downstream factors of the JAK/STAT pathway.

TRIM27 mediates STAT3 activation at retromer-positive structures to promote colitis and colitis-associated carcinogenesis

STAT3 is a transcription factor that plays central roles in various physiological processes and its deregulation results in serious diseases including cancer. The mechanisms on how STAT3 activity is regulated remains enigmatic. Here we identify TRIM27 as a positive regulator of II-6-induced STAT3 activation and downstream gene expression. TRIM27 localizes to retromer-positive punctate structures and serves as a critical link for recruiting gp130, JAK1, and STAT3 to and subsequent phosphorylation of STAT3 at the retromer-positive structures. Overexpression of TRIM27 promotes cancer cell growth in vitro and tumor growth in nude mice, whereas knockdown of TRIM27 has opposite effects. Deficiency of TRIM27 significantly impairs dextran sulfate sodium (DSS)-induced STAT3 activation, inflammatory cytokine expression and colitis as well as azoxymethane (AOM)/DSS-induced colitis-associated cancer in mice. These findings reveal a retromer-dependent mechanism for regulation of STAT3 activation, inflammation, and inflammation-associated cancer development.

Effector T Cell Resistance to Suppression and STAT3 Signaling during the Development of Human Type 1 Diabetes

Dysregulation of regulatory T cell (Treg)-mediated suppression and, in particular, resistance of CD4+ effector T cells (Teffs) to suppression have been implicated in the pathogenesis of human type 1 diabetes (T1D). However, the mechanistic basis behind this resistance and the time frame during which it develops in relation to the onset of clinical T1D remain unclear. In this study, we analyzed the capacity of peripheral blood Teffs isolated both from patients with T1D and from prediabetic at-risk subjects positive for multiple diabetes-associated autoantibodies (AAb+) to be suppressed by Tregs. Because STAT3 activation through IL-6 has previously been implicated in mediating Teff resistance, we also investigated the surface expression of IL-6R as well as IL-6- and TCR-mediated phosphorylation of STAT3 in T cells from our study subjects. Teff resistance to suppression was observed both in patients with newly diagnosed and long-standing T1D but not in AAb+ subjects and was shown to be STAT3 dependent. No alterations in IL-6R expression or IL-6-mediated STAT3 activation were observed in T cells from patients with T1D or AAb+ subjects. However, faster STAT3 activation after TCR stimulation without concomitant increase in IL-6 expression was observed in T cells from patients with T1D. These experiments suggest that Teff resistance in T1D patients is STAT3 dependent but not directly linked with the capacity of Teffs to produce or respond to IL-6. In conclusion, Teff resistance to Treg-mediated suppression is likely a feature of disease progression in human T1D and can potentially be targeted by immune therapies that block STAT3 activation.

Abstract 4423: MiR551b-mediated Oncostatin M signaling in breast cancer

Abstract We have previously demonstrated that an oncogenic microRNA miR551b-3p (also known as miR551b) regulates STAT3 transcription thereby enhancing tumor growth and metastasis in ovarian cancer. Herein, we have identified that Oncostatin M (OSM) is upregulated through STAT3-driven transcription, which plays an important role in promoting migration and invasion of breast cancer cells. The purpose of this study was to evaluate the role of miR551b mediated STAT3 activation and the precise mechanism that regulates OSM-Receptor (OSMR) signaling for breast cancer growth and metastasis. MDA-MB231 cells were either overexpressed or silenced with miR551b and anti-miR551b respectively and the effects on proliferation, migration/invasion (Matrigel transwell assay), wound healing and expression of OSMR and its downstream targets (Western blotting, Quantitative RT-PCR) were assessed. Our data demonstrate that miR551b promoted survival, proliferation, invasion and migration and epithelial to mesenchymal transition (EMT) and spheroid formation of breast cancer cells. Our results also show that miR551b-mediated STAT3 activation upregulated the components of OSMR signaling through elevated expression of OSMR, Interleukin 31 receptor-alpha (IL31RA) and their ligands Oncostatin (OSM) and IL31 thereby inducing phosphorylation of STAT3 for tumor cell proliferation, migration and invasion. Conversely, anti-miR551b reduced the expression of OSMR, IL31R and their ligands OSM and IL31 as well as the phosphorylation of STAT3. Briefly, our results provide the first report indicating that miR551b regulates OSMR expression by activating STAT3 and thereby promoting tumor cell growth and metastasis in breast cancer cells through autocrine feed-forward signaling loop. A.G, D.P., contributed equally. Citation Format: Anjali Geethadevi, Deepak Parashar, Miriam Ragle-Aure, Bindu Nair, Yiling Lu, Vessela N. Kristensen, Ming You, Anil K. Sood, Gordon B. Mills, Sunila Pradeep, Pradeep Chaluvally Raghavan. MiR551b-mediated Oncostatin M signaling in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4423.

64 - TFF1 Suppresses IL-6 Mediated STAT3 Activation through Interfering with IL6Rα/GP130 Complex Formation

64 - TFF1 Suppresses IL-6 Mediated STAT3 Activation through Interfering with IL6Rα/GP130 Complex Formation

Adiponectin receptor agonists inhibit leptin induced pSTAT3 and in vivo pancreatic tumor growth.

Obesity is a significant risk factor for pancreatic cancer, harboring a chronic inflammatory condition characterized by dysregulation of the adipokines, leptin and adiponectin, that in turn alter oncogenic signaling pathways. We and others have shown that leptin promotes the proliferation and an invasive potential of pancreatic cancer cells through STAT3 mediated signaling. However, the role of adiponectin on the tumorigenicity of pancreatic cancer has not been elucidated. Adiponectin represents an important negative regulator of cytokines, which acts through two receptors, ADIPOR1 and ADIPOR2, to elicit pro-apoptotic, anti-inflammatory, and anti-angiogenic responses. We show that the level and expression of both adiponectin receptors are decreased in pancreatic tumors relative to normal pancreatic tissue. In vitro stimulation with adiponectin or a small molecule adiponectin receptor agonist, AdipoRon, increases apoptosis while inhibiting pancreatic cancer cell proliferation, colony formation, and anchorage independent growth. In addition, adiponectin receptor agonism inhibits leptin mediated STAT3 activation. In vivo, treatment of mice with AdipoRon inhibits orthotopic pancreatic tumor growth. These results demonstrate that adiponectin receptor activation is a key regulator of pancreatic cancer growth and AdipoRon provides a rational agent for the development of novel therapeutic strategies for pancreatic cancer.

Mo1029 - Bile Acid-Induced APE-1 Mediates Stat3 Activation in Barrett's and Esophageal Adenocarcinoma Cells

Mo1029 - Bile Acid-Induced APE-1 Mediates Stat3 Activation in Barrett's and Esophageal Adenocarcinoma Cells

Increased STAT3 phosphorylation on CD27+ B-cells from common variable immunodeficiency disease patients

Maturation and differentiation of B-cells are driven by T-cells' help through IL-21/STAT3 axis in GC centers or through extrafollicular pathways, in a T-independent manner. B-cell differentiation is defective in common variable immunodeficiency disease (CVID) patients. We investigated if IL-21/STAT3 axis alterations could influence B-cell fate. We activated purified CVID B-cells with surrogate T-dependent (anti-CD40), T-independent (TLR-9 ligand) stimuli or through B-cell receptor engagement (anti-IgM) with or without IL-21. IL-21 mediated STAT3 activation was greater on CD27− than CD27+ B-cells depending on the stimulus. IL-21 alone induced STAT3 phosphorylation (pSTAT3) only on CD27− B-cells and IL-21 induced higher pSTAT3 levels on CD27− than CD27+ B-cells after anti-IgM or anti-CD40 activation. CVID CD27+ B-cells showed selective STAT3 hyperphosphorylation after activation with anti-IgM or anti-CD40 alone and anti-IgM, anti-CD40 or ODN combined with IL-21. Increased STAT3 activation during immune responses could result in B-cell differentiation defects in CVID.

Abstract 3060: The role of miR-135b in clinical outcome and metastasis in colorectal cancer

Abstract Colorectal cancer (CRC) is one of the leading causes of cancer death in both the Western world and Taiwan. Age, gender, and genes are important risk factors for colorectal cancer. Activation of Wnt signaling pathway is an important step involved in the pathogenesis of colorectal cancer. Approximately 70-80% of sporadic colorectal carcinomas have somatic mutations that inactivate APC. But, only 30% CRC patients in Taiwan have APC gene mutation that was significantly lower than the other countries. Thus, the other mechanism involved in APC gene inactivation may contributed to CRC progression in Taiwan. Here, we focus on the Wnt signaling associate microRNAs. Four wnt signaling-associated microRNAs were selected in this study, including miR-21, miR-200a, miR-135a and miR-135b. A total of 156 colorectal cancer patients were enrolled in this study. The expression of miR-21, miR-200a, miR-135a, miR-135b and wnt signaling association genes were analyzed by quantitative RT-PCR and immunohistochemistry. The expression levels of miR-21, miR-200a and miR-135a were not correlated with clinical parameters of CRC patients. The expression of miR-135b were positive correlated with gender, tumor stage, and lymph node metastasis. No any significantly correlation were found between miR-135b, Wnt, β-catenin and APC. But the expression levels of miR-135b were positive correlated with the upstream gene STAT3, β-catenin and C-Myc. Thus, we suggested that upregulation of miR-135b may through β-catenin mediated STAT3 activation. Citation Format: Wei-Ran Wang, Yawen Cheng, Nan-Yung Hsu Hsu. The role of miR-135b in clinical outcome and metastasis in colorectal cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3060. doi:10.1158/1538-7445.AM2015-3060

STATs profiling reveals predominantly-activated STAT3 in cholangiocarcinoma genesis and progression.

We investigated the aberrant expression of the STAT family in humans and liver fluke (Opisthorchis viverrini, Ov)-induced hamster cholangiocarcinoma (CCA) tissues. The expression and phosphorylation of STAT1, STAT2, STAT3, STAT4, STAT5a, STAT5b and STAT6 in human hamster CCA tissues were immunohistochemistry-profiled. Localizations of STAT5 in macrophages and lipopolysaccharide (LPS)-induced macrophage-conditioned media mediated STAT3 activation in CCA cells were demonstrated. The expressions of STAT 1-4 and 6 were detected in the cytoplasm of hyperplastic bile ducts and tumor cells, whereas STAT5a and STAT5b were observed in macrophages and connective tissues surrounding tumor, respectively. The expressions of STAT3 and STAT5b were significantly observed in tumors with a poorer histological differentiation. STAT3 expression was significantly associated with shorter survival of CCA patients and was predominately activated in CCA cell lines. In the CCA-hamsters, STATs expression was gradually increased along the carcinogenesis, especially at 30 days post-infection in which the inflammatory response was markedly observed, showing the correlation between the inflammation and STATs activation. Moreover, LPS-induced macrophage-conditioned media could mediate STAT3 activation in CCA cells. STAT3 is the major STAT, which plays roles in the inflammation that contributes to CCA carcinogenesis and progression and may serve as a marker for a poor prognosis of CCA.

Pharmacological and genetic depletion of fibrinogen protects from kidney fibrosis.

Fibrinogen (Fg) has been implicated in the pathogenesis of several fibrotic disorders by acting as a profibrotic ligand for a variety of cellular surface receptors and by modulating the provisional fibrin matrix formed after injury. We demonstrated increased renal Fg expression after unilateral ureteral obstruction and folic acid (FA) nephropathy in mice, respectively. Urinary Fg excretion was also increased in FA nephropathy. Using in vitro and in vivo approaches, our results suggested that IL-6 mediates STAT3 activation in kidney fibrosis and that phosphorylated (p)STAT3 binds to Fgα, Fgβ, and Fgγ promoters in the kidney to regulate their transcription. Genetically modified Fg heterozygous mice (∼75% of normal plasma Fg levels) exhibited only 3% kidney interstitial fibrosis and tubular atrophy after FA nephropathy compared with 24% for wild-type mice. Fibrinogenolysis through Ancrod administration after FA reduced interstitial fibrosis more than threefold compared with vehicle-treated control mice. Mechanistically, we show that Fg acts synergistically with transforming growth factor (TGF)-β1 to induce fibroblast proliferation and activates TGF-β1/pSMAD2 signaling. This study offers increased understanding of Fg expression and molecular interactions with TGF-β1 in the progression to kidney fibrosis and, importantly, indicates that fibrinogenolytics like Ancrod present a treatment opportunity for a yet intractable disease.