Targeting IL-6 trans-signalling by sgp130Fc attenuates severity in SARS-CoV-2 -infected mice and reduces endotheliopathy.

BACKGROUND: SARS-CoV-2 infection is considered as a relapsing inflammatory process with a dysregulation of IL-6 signalling. Classic IL-6 signalling is thought to represent a defence mechanism against pathogens. In contrast, IL-6 trans-signalling has pro-inflammatory effects. In severe COVID-19, therapeutic strategies have focused on global inhibition of IL-6, with controversial results. We hypothesized that specific blockade of IL-6 trans-signalling could inhibit inflammatory response preserving the host defence activity inherent to IL-6 classic signalling. METHODS: To test the role of the specific IL-6 trans-signalling inhibition by sgp130Fc in short- and long-term consequences of COVID-19, we used the established K18-hACE2 transgenic mouse model. Histological as well as immunohistochemical analysis, and pro-inflammatory marker profiling were performed. To investigate IL-6 trans-signalling in human cells we used primary lung microvascular endothelial cells and fibroblasts in the presence/absence of sgp130Fc. FINDINGS: We report that targeting IL-6 trans-signalling by sgp130Fc attenuated SARS-CoV-2-related clinical symptoms and mortality. In surviving mice, the treatment caused a significant decrease in lung damage. In vitro, IL-6 trans-signalling induced strong and persisting JAK1/STAT3 activation in endothelial cells and lung fibroblasts with proinflammatory effects, which were attenuated by sgp130Fc. Our data also suggest that in those cells with scant amounts of IL-6R, the induction of gp130 and IL-6 by IL-6:sIL-6R complex sustains IL-6 trans-signalling. INTERPRETATION: IL-6 trans-signalling fosters progression of COVID-19, and suggests that specific blockade of this signalling mode could offer a promising alternative to mitigate both short- and long-term consequences without affecting the beneficial effects of IL-6 classic signalling. These results have implications for the development of new therapies of lung injury and endotheliopathy in COVID-19. FUNDING: The project was supported by ISCIII, Spain (COV-20/00792 to MB, PI23/01351 to MARH) and the European Commission-Next generation EU (European Union) (Regulation EU 2020/2094), through CSIC's Global Health Platform (PTI Salud Global, SGL2103029 to MB). PID2019-110587RB-I00 (MB) supported by MICIN/AEI/10.13039/501100011033/and PID2022-143034OB-I00 (MB) by MICIN/AEI/10.13039/501100011033/FEDER. MAR-H acknowledges support from ISCIII, Spain and the European Commission-Next generation EU (European Union), through CSIC's Global Health PTI.

2-Deoxy-d-glucose induces deglycosylation of proinflammatory cytokine receptors and strongly reduces immunological responses in mouse models of inflammation.

Anti-proinflammatory cytokine therapies against interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-1 are major advancements in treating inflammatory diseases, especially rheumatoid arthritis. Such therapies are mainly performed by injection of antibodies against cytokines or cytokine receptors. We initially found that the glycolytic inhibitor 2-deoxy-d-glucose (2-DG), a simple monosaccharide, attenuated cellular responses to IL-6 by inhibiting N-linked glycosylation of the IL-6 receptor gp130. Aglycoforms of gp130 did not bind to IL-6 or activate downstream intracellular signals that included Janus kinases. 2-DG completely inhibited dextran sodium sulfate-induced colitis, a mouse model for inflammatory bowel disease, and alleviated laminarin-induced arthritis in the SKG mouse, an experimental model for human rheumatoid arthritis. These diseases have been shown to be partially dependent on IL-6. We also found that 2-DG inhibited signals for other proinflammatory cytokines such as TNF-α, IL-1ß, and interferon -γ, and accordingly, prevented death by another inflammatory disease, lipopolysaccharide (LPS) shock. Furthermore, 2-DG prevented LPS shock, a model for a cytokine storm, and LPS-induced pulmonary inflammation, a model for acute respiratory distress syndrome of coronavirus disease 2019 (COVID-19). These results suggest that targeted therapies that inhibit cytokine receptor glycosylation are effective for treatment of various inflammatory diseases.

Diffuse large B-cell lymphoma-derived exosomes push macrophage polarization toward M2 phenotype via GP130/STAT3 signaling pathway.

Growing evidence shows that cancer progression links with both heterogeneity of the tumor microenvironment and dysregulated activity of immune cells. Cancer-secreted exosomes are being recognized as indispensable mediators of the exchange cargo between cancer and immune cells. The M2-phenotype tumor-associated macrophages have the function of promoting tumor progression and drug resistance. Diffuse large B-cell lymphoma(DLBCL) is a highly heterogeneous and very common malignant non-Hodgkin's lymphoma. Here, we demonstrate that different subtype DLBCL cell-derived exosomes are internalized by macrophages, which can affect macrophages polarization. The mechanism of DLBCL-derived exosomes on macrophage polarization remains unclear currently. This study showed that DLBCL-secreted exosomes could induce the transformation of macrophages to a protumor M2-like phenotype, and block the drug-induced apoptosis of DLBCL cells in an indirect co-culture system. Different DLBCL-derived exosomes could change the phenotype of macrophages through the STAT3 signaling, which upregulated the expression of oncogenic genes and classical markers of M2-like phenotype macrophages, such as IL-10, CD206, and CD163. The addition of DLBCL-derived exosomes resulted in the activation of the STAT3 signaling pathway of M0/M2 macrophages in an indirect co-culture system. GP130 was highly enriched in DLBCL-derived exosomes, which triggered the activation of STAT3 of macrophages and subsequently induced the downstream targets such as BCL2, SURVIVIN, and BAX. The parallel changes of STAT3 and GP130 in macrophages confirmed that GP130 of DLBCL-derived exosomes promoted macrophage polarization by activating STAT3 signaling. Furthermore, all of these effects could be reversed by the GP130 inhibitor SC144. The data indicated that DLBCL-derived exosomes could trigger macrophages polarization into a pro-survival M2-like phenotype, which was at least partially through the GP130/STAT3 signaling pathway. Collectively, this study showed that DLBCL-derived exosomes could promote macrophages transformation to protumor M2-like phenotype in the tumor microenvironment.

A myeloid-stromal niche and gp130 rescue in NOD2-driven Crohn's disease.

Crohn's disease is a chronic inflammatory intestinal disease that is frequently accompanied by aberrant healing and stricturing complications. Crosstalk between activated myeloid and stromal cells is critical in the pathogenicity of Crohn's disease1,2, and increases in intravasating monocytes are correlated with a lack of response to anti-TNF treatment3. The risk alleles with the highest effect on Crohn's disease are loss-of-function mutations in NOD24,5, which increase the risk of stricturing6. However, the mechanisms that underlie pathogenicity driven by NOD2 mutations and the pathways that might rescue a lack of response to anti-TNF treatment remain largely uncharacterized. Here we use direct ex vivo analyses of patients who carry risk alleles of NOD2 to show that loss of NOD2 leads to dysregulated homeostasis of activated fibroblasts and macrophages. CD14+ peripheral blood mononuclear cells from carriers of NOD2 risk alleles produce cells that express high levels of collagen, and elevation of conserved signatures is observed in nod2-deficient zebrafish models of intestinal injury. The enrichment of STAT3 regulation and gp130 ligands in activated fibroblasts and macrophages suggested that gp130 blockade might rescue the activated program in NOD2-deficient cells. We show that post-treatment induction of the STAT3 pathway is correlated with a lack of response to anti-TNF treatment in patients, and demonstrate in vivo in zebrafish the amelioration of the activated myeloid-stromal niche using the specific gp130 inhibitor bazedoxifene. Our results provide insights into NOD2-driven fibrosis in Crohn's disease, and suggest that gp130 blockade may benefit some patients with Crohn's disease-potentially as a complement to anti-TNF therapy.

Role of Interleukin-6 in Lung Complications in Patients With COVID-19: Therapeutic Implications.

COVID-19 is viral respiratory infection with frequently fatal lung complications in the elderly or in people with serious comorbidities. Lung destruction appears to be associated with a cytokine storm related to an increased level of interleukin-6 (IL6). Therapeutic targeting of the interleukin-6 signaling pathway can attenuate such a cytokine storm and can be beneficial for patients with COVID-19 in danger of pulmonary failure. This article demonstrates the importance of IL6 in progression of disease and the possibility of inhibition of IL6 signaling in COVID-19 therapy.

Coinhibition of S1PR1 and GP130 by siRNA-loaded alginate-conjugated trimethyl chitosan nanoparticles robustly blocks development of cancer cells.

There is an interconnected network between S1P/sphingosine-1-phosphate receptor 1 (S1PR1), IL-6/glycoprotein 130 (GP130), and signal transducer and activator of transcription 3 (STAT3) signaling pathways in the tumor microenvironment, which leads to cancer progression. S1P/S1PR1 and IL-6/GP130 signaling pathways phosphorylate and activate STAT3, and it then induces the expression of S1PR1 and interleukin-6 (IL-6) in a positive feedback loop leading to cancer progression. We hypothesized that blockade of this amplification loop can suppress the growth and development of cancer cells. Therefore, we silenced STAT3 upstream molecules including the S1PR1 and GP130 molecules in cancer cells using small interfering RNA (siRNA)-loaded alginate-conjugated trimethyl chitosan (ATMC) nanoparticles (NPs). The generated NPs had competent properties including the appropriate size, zeta potential, polydispersity index, morphology, high uptake of siRNA, high rate of capacity, high stability, and low toxicity. We evaluated the effects of siRNA loaded ATMC NPs on tumor hallmarks of three murine-derived cancer cell lines, including 4T1 (breast cancer), B16-F10 (melanoma), and CT26 (colon cancer). The results confirmed the tumor-suppressive effects of combinational targeting of S1PR1 and GP130. Moreover, combination therapy could potently suppress tumor growth as assessed by the chick chorioallantoic membrane assay. In this study, we targeted this positive feedback loop for the first time and applied this novel combination therapy, which provides a promising approach for cancer treatment. The development of a potent nanocarrier system with ATMC for this combination was also another aspect of this study, which should be further investigated in cancer animal models in further studies.

Discovery of bazedoxifene analogues targeting glycoprotein 130.

Deregulation of GP130 in signal transduction is involved in multiple types of human diseases, especially in cancers, indicating that GP130 is an attractive target for cancer therapy. However, GP130 was conventionally considered as an undruggable target thus the discovery of GP130 PPI inhibitors is extremely challenging. By the aid of structure-based drug design, in this study, two series of bazedoxifene based analogues were designed to target GP130 D1 domain and block the IL-6/GP130/STAT3 signaling pathway for antitumor treatment. Most of these designed compounds displayed potent anti-proliferative activity against cancer cells. The representative compound 10a was demonstrated to directly bind to GP130 protein with an affinity (KD) value of 3.8 µM via both SPR and DARTS methods. Subsequently, molecular docking study predicted that 10a targeted D1 domain of GP130 and co-IP assay demonstrated that 10a did not inhibit IL-6R/GP130 interaction, which meant 10a did not bind to the D2 and D3 domains of GP130. Moreover, 10a selectively inhibited JAK2 and STAT3 phosphorylation as well as IL-6 induced STAT3 phosphorylation. 10a effectively inhibited tumor cell viability, migration and promoted apoptosis. Furthermore, 10a effectively suppressed xenograft model tumor growth in vivo. Taken together, this study described a new class of bazedoxifene derived GP130 inhibitors as antitumor agents.

Combination of gp130-targeting and TNF-targeting small molecules in alleviating arthritis through the down-regulation of Th17 differentiation and osteoclastogenesis.

Rheumatoid arthritis (RA) is a systemic, chronic inflammatory disease that is characterized by T helper 17 (Th17) cell- and osteoclast-induced joint destruction and inflammation. In RA, several cytokines (interleukin (IL)-1, 6,17, and tumor necrosis factor (TNF)) are involved in almost all aspects of articular inflammation and destruction. This study aimed to evaluate the combinatorial effect of TNF and IL-6 inhibitors on the differentiation and activation of Th17 cells and osteoclasts in the context of RA, and to identify the RA-related mechanisms through IL-6 signaling. Tetrahydropapaverine (THP) showed direct binding to TNF in screening-ELISA, and SPR and TNF-neutralization assays. In a previous study, the therapeutic effect of gp130-targeting LMT-28 was confirmed in RA. Combinatorial treatment with LMT-28 and THP reduced the arthritis index and showed protective effects against bone and cartilage destruction in CIA mice. The secretion levels of TNF, IL-6, and IL-1ß significantly decreased upon combinatorial treatment with LMT-28 and THP. Further, the LMT-28 and THP combination suppressed the differentiation and activation of Th17 cells in mouse splenocytes and human PBMCs. In human RA-FLS, the LMT-28 and THP combination inhibited cell proliferation and downregulated IL-6 and/or TNF-mediated signaling relative to that observed upon independent treatment with LMT-28 or THP. Furthermore, the combination of LMT-28 and THP significantly inhibited the differentiation of mouse bone marrow monocytes (BMMs) into osteoclasts. In conclusion, the LMT-28 and THP combination can attenuate RA through the inhibition of Th17 differentiation and osteoclastogenesis, and suppression of IL-6 or TNF-induced signaling pathways. This combinatorial therapy could be used as a new strategy for the treatment of RA.

Gp130 degradation induced by epirubicin contributes to chemotherapy efficacy.

Two anthracyclines, doxorubicin and epirubicin have been widely used alone or in combination with other antitumor reagents in the chemotherapeutic treatment of various malignancies. Although therapeutic efficacy of anthracyclines has been studied extensively, precise cytotoxic mechanism of these drugs is not been completely elucidated. Here we show that epirubicin-induced degradation of transmembrane protein gp130 contributes to antitumor effect of epirubicin. gp130 is degraded by epirubicin in a proteasome- and autophagy-dependent manner. Epirubicin induces activation of p38-MK2 signaling pathway to phosphorylate gp130 at Ser 782, which results in gp130 internalization and degradation by lysosome. Although mutation of Ser 782 to Ala or Cys in gp130 upregulates global epirubicin-induced autophagy, reduced degradation of gp130 accompanied with enhanced Stat3 phosphorylation at tyrosine 705 is observed. We also show that epirubicin-resistant tumor cells express higher level of gp130. Altogether, our results indicate that degradation of gp130 and subsequent reduction of gp130-Stat3 signaling contributes to epirubicin-induced tumor cell death.

Targeting Interleukin-6 Signaling in Clinic.

Interleukin-6 (IL-6) is a pleiotropic cytokine with roles in immunity, tissue regeneration, and metabolism. Rapid production of IL-6 contributes to host defense during infection and tissue injury, but excessive synthesis of IL-6 and dysregulation of IL-6 receptor signaling is involved in disease pathology. Therapeutic agents targeting the IL-6 axis are effective in rheumatoid arthritis, and applications are being extended to other settings of acute and chronic inflammation. Recent studies reveal that selective blockade of different modes of IL-6 receptor signaling has different outcomes on disease pathology, suggesting novel strategies for therapeutic intervention. However, some inflammatory diseases do not seem to respond to IL-6 blockade. Here, we review the current state of IL-6-targeting approaches in the clinic and discuss how to apply the growing understanding of the immunobiology of IL-6 to clinical decisions.

Bazedoxifene is a novel IL-6/GP130 inhibitor for treating triple-negative breast cancer.

PURPOSE: Triple-negative breast cancer (TNBC) has been ranked as one of the devastating malignancy worldwide. Its disease progression and treatment obstacle is associated with the negligible expression of estrogen receptors (ER-), progesterone receptors (PR-), and HER2 (HER2-). Due to a lack of growth hormone receptors, TNBC is desperately demanding effective therapeutic regimens. A growing body of evidence indicated that glycoprotein 130 kDa (GP130), the pivotal mediator involved in interleukin 6 (IL-6) and signal transducer and activator of transcription 3 (STAT3) signaling pathways, is strongly correlated with tumor progression. Therefore, GP130 could become a novel target for treating TNBC. In our earlier studies, we demonstrated bazedoxifene as being a novel GP130 inhibitor. METHODS: In the current report, anti-tumor effect of bazedoxifene on TNBC was further evaluated in TNBC cell lines SUM159, MDA-MB-231, and MDA-MB-468. We assessed anti-TNBC potency of bazedoxifene by carrying out various analysis encompassing western blot, cell proliferation, cell migration, colony formation, and growth of tumors in the xenograft mice. RESULTS: Our findings demonstrated that bazedoxifene not only decreased the expression of P-STAT3, IL-6/GP130-mediated downstream target genes P-AKT and P-ERK, but also blocked mitogen effects stimulated by IL-6, including cell viability, and overall cell survive, proliferation as well as cell migration. Likewise in laboratory animal model, tumor growth in mice was remarkably suppressed by bazedoxifene via an oral administration route. Combinational treatment of bazedoxifene plus the conventional chemotherapeutic agent, paclitaxel, synergistically impeded cell viability, colony formation, and cell migration far more significantly than the one from single-drug alone. CONCLUSIONS: Taken together, our data suggest that bazedoxifene may be developed as a promising small molecular therapeutic agent for eradicating TNBC intrinsically associated with constitutively active IL-6/GP130/STAT3 signaling cascade.

Blocking IL-6/GP130 Signaling Inhibits Cell Viability/Proliferation, Glycolysis, and Colony Forming Activity in Human Pancreatic Cancer Cells.

BACKGROUND: Elevated production of the pro-inflammatory cytokine interleukin-6 (IL-6) and dysfunction of IL-6 signaling promotes tumorigenesis and are associated with poor survival outcomes in multiple cancer types. Recent studies showed that the IL-6/GP130/STAT3 signaling pathway plays a pivotal role in pancreatic cancer development and maintenance. OBJECTIVE: We aim to develop effective treatments through inhibition of IL-6/GP130 signaling in pancreatic cancer. METHODS: The effects on cell viability and cell proliferation were measured by MTT and BrdU assays, respectively. The effects on glycolysis was determined by cell-based assays to measure lactate levels. Protein expression changes were evaluated by western blotting and immunoprecipitation. siRNA transfection was used to knock down estrogen receptor α gene expression. Colony forming ability was determined by colony forming cell assay. RESULTS: We demonstrated that IL-6 can induce pancreatic cancer cell viability/proliferation and glycolysis. We also showed that a repurposing FDA-approved drug bazedoxifene could inhibit the IL-6/IL-6R/GP130 complexes. Bazedoxifene also inhibited JAK1 binding to IL-6/IL-6R/GP130 complexes and STAT3 phosphorylation. In addition, bazedoxifene impeded IL-6 mediated cell viability/ proliferation and glycolysis in pancreatic cancer cells. Consistently, other IL-6/GP130 inhibitors SC144 and evista showed similar inhibition of IL-6 stimulated cell viability, cell proliferation and glycolysis. Furthermore, all three IL-6/GP130 inhibitors reduced the colony forming ability in pancreatic cancer cells. CONCLUSION: Our findings demonstrated that IL-6 stimulates pancreatic cancer cell proliferation, survival and glycolysis, and supported persistent IL-6 signaling is a viable therapeutic target for pancreatic cancer using IL-6/GP130 inhibitors.

IL-6 and CXCL8 mediate osteosarcoma-lung interactions critical to metastasis.

Osteosarcoma (OS), a malignant tumor of bone, kills through aggressive metastatic spread almost exclusively to the lung. Mechanisms driving this tropism for lung tissue remain unknown, though likely invoke specific interactions between tumor cells and other cells within the lung metastatic niche. Aberrant overexpression of ΔNp63 in OS cells directly drives production of IL-6 and CXCL8. All these factors were expressed at higher levels in OS lung metastases than in matched primary tumors from the same patients. Expression in cell lines correlated strongly with lung colonization efficiency in murine xenograft models. Lentivirus-mediated expression endowed poorly metastatic OS cells with increased metastatic capacity. Disruption of IL-6 and CXCL8 signaling using genetic or pharmaceutical inhibitors had minimal effects on tumor cell proliferation in vitro or in vivo, but combination treatment inhibited metastasis across multiple models of metastatic OS. Strong interactions occurred between OS cells and both primary bronchial epithelial cells and bronchial smooth muscle cells that drove feed-forward amplification of IL-6 and CXCL8 production. These results identify IL-6 and CXCL8 as primary mediators of OS lung tropism and suggest pleiotropic, redundant mechanisms by which they might effect metastasis. Combination therapy studies demonstrate proof of concept for targeting these tumor-lung interactions to affect metastatic disease.

Breast Cancer-Derived Exosomes Alter Macrophage Polarization via gp130/STAT3 Signaling.

Tumor-derived exosomes are being recognized as essential mediators of intercellular communication between cancer and immune cells. It is well established that bone marrow-derived macrophages (BMDMs) take up tumor-derived exosomes. However, the functional impact of these exosomes on macrophage phenotypes is controversial and not well studied. Here, we show that breast cancer-derived exosomes alter the phenotype of macrophages through the interleukin-6 (IL-6) receptor beta (glycoprotein 130, gp130)-STAT3 signaling pathway. Addition of breast cancer-derived exosomes to macrophages results in the activation of the IL-6 response pathway, including phosphorylation of the key downstream transcription factor STAT3. Exosomal gp130, which is highly enriched in cancer exosomes, triggers the secretion of IL-6 from BMDMs. Moreover, the exposure of BMDMs to cancer-derived exosomes triggers changes from a conventional toward a polarized phenotype often observed in tumor-associated macrophages. All of these effects can be inhibited through the addition of a gp130 inhibitor to cancer-derived exosomes or by blocking BMDMs exosome uptake. Collectively, this work demonstrates that breast cancer-derived exosomes are capable of inducing IL-6 secretion and a pro-survival phenotype in macrophages, partially via gp130/STAT3 signaling.

Down-regulating IL-6/GP130 targets improved the anti-tumor effects of 5-fluorouracil in colon cancer.

Recent studies have confirmed that IL-6/GP130 targets are closely associated with tumor growth, metastasis and drug resistance. 5-Fluorouracil (5-FU) is the most common chemotherapeutic agent for colon cancer but is limited due to chemoresistance and high cytotoxicity. Bazedoxifene (BZA), a third-generation selective estrogen receptor modulator, was discovered by multiple ligand simultaneous docking and drug repositioning approaches to have a novel function as an IL-6/GP130 target inhibitor. Thus, we speculated that in colon cancer, the anti-tumor efficacy of 5-FU might be increased in combination with IL-6/GP130 inhibitors. CCK8 assay and colony formation assay were used to detect the cell proliferation and colony formation. We measured the IC50 value of 5-FU alone and in combination with BZA by cell viability inhibition. Cell migration and invasion ability were tested by scratch migration assays and transwell invasion assays. Flow cytometric analysis for cell apoptosis and cell cycle. Quantitative real-time PCR was used to detect Bad, Bcl-2 and Ki-67 mRNA expression and western blotting (WB) assay analyzed protein expression of Bad/Bcl-2 signaling pathway. Further mechanism study, WB analysis detected the key proteins level in IL-6/GP130 targets and JAK/STAT3, Ras/Raf/MEK/ERK, and PI3K/AKT/mTOR signaling pathway. A colon cancer xenograft model was used to further confirm the efficacy of 5-FU and BZA in vivo. The GP130, P-STAT3, P-AKT, and P-ERK expression levels were detected by immunohistochemistry in the xenograft tumor. BZA markedly potentiates the anti-tumor function of 5-FU in vitro and in vivo. Conversely, 5-FU activation is reduced following exogenous IL-6 treatment in cells. Further mechanistic studies determined that BZA treatment enhanced 5-FU anti-tumor activation by inhibiting the IL-6/GP130 signaling pathway and the phosphorylation status of the downstream effectors AKT, ERK and STAT3. In contrast, IL-6 can attenuate 5-FU function via activating IL-6R/GP130 signaling and the P-AKT, P-ERK and P-STAT3 levels. This study firstly verifies that targeting IL-6/GP130 signaling can increase the anti-tumor function of 5-FU; in addition, this strategy can sensitize cancer cell drug sensitivity, implying that blocking IL-6/GP130 targets can reverse chemoresistance. Therefore, combining 5-FU and IL-6/GP130 target inhibitors may be a promising approach for cancer treatment.

MiR-7-5p functions as a tumor suppressor by targeting SOX18 in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies. Recently, many kinds of microRNAs (miRNAs) have been found to play a significant role in development of PDAC. However, there is no investigation about expression and function of miR-7-5p in PDAC. In this study, we found that miR-7-5p was down-regulated in PDAC tissues and its low expression level indicated a poor survival rate for PDAC patients. By bioinformatic analysis, we found that miR-7-5p targeted SOX18, and there was a negative correlation between them in PDAC tissues. Then luciferase reporter and western blot assays were used to verify the binding of miR-7-5p on SOX18 3'UTR. Cell function assays demonstrated that miR-7-5p inhibited proliferation, migration and invasion of PANC-1 cells by targeting SOX18. The nude mouse tumorigenicity assay further proved that miR-7-5p targeted SOX18 to inhibit pancreatic cancer growth in vivo. In order to further understand the mechanism, we applied a transcription factor prediction tool to explore the underlying targets that transcripted by SOX18, and the result indicated that SOX18 was a transcription factor for gp130 (a subunit of IL-6 receptor), and ChIP assays was performed to prove this prediction. Furthermore, we detected the suppression of gp130/JAK2/STAT3 signaling pathway after silencing SOX18 in PANC-1 cells, which demonstrated the transcriptional activation role of SOX18 on gp130. Thus, our present study revealed that miR-7-5p targeted SOX18 to inhibit gp130/JAK2/STAT3 signaling pathway to exert its suppressing role in PDAC.

Oncostatin M: Potential Implications for Malignancy and Metabolism.

BACKGROUND: The gp130 cytokine, oncostatin M (OSM), serves several physiological and pathological functions. At the molecular level, OSM can directly or indirectly participate in tumorigenesis and insulin resistance development. Although OSM was initially found to be anti-proliferative in tumors, numerous tumorigenic roles for OSM have been reported in a variety of cancers. In metabolic diseases, OSM signaling may be required for homeostasis in both the liver and the adipose tissue, since abrogation of OSM signaling causes obesity, hepatic steatosis, and insulin resistance. This review aims to: 1) examine the current literature regarding the role of OSM in the development of cancers and insulin resistance; and 2) propose a possible link between cancerassociated OSM and the development of the insulin resistance observed with cancer cachexia. CONCLUSION: In light of the potential links between cancer-associated OSM and cachexia-related insulin resistance, additional research is needed, especially given the possible link between these disease states. When considering OSM as a pharmaceutical target, its tumorigenic effects and role in tissue homeostasis must be carefully considered.

Tetraspanin CD9 stabilizes gp130 by preventing its ubiquitin-dependent lysosomal degradation to promote STAT3 activation in glioma stem cells.

Glioblastoma (GBM) is the most malignant and lethal brain tumor harboring glioma stem cells (GSCs) that promote tumor propagation and therapeutic resistance. GSCs preferentially express several critical cell surface molecules that regulate the pro-survival signaling for maintaining the stem cell-like phenotype. Tetraspanin CD9 has recently been reported as a GSC biomarker that is relevant to the GSC maintenance. However, the underlying molecular mechanisms of CD9 in maintaining GSC property remain elusive. Herein, we report that CD9 stabilizes the IL-6 receptor glycoprotein 130 (gp130) by preventing its ubiquitin-dependent lysosomal degradation to facilitate the STAT3 activation in GSCs. CD9 is preferentially expressed in GSCs of human GBM tumors. Mass spectrometry analysis identified gp130 as an interacting protein of CD9 in GSCs, which was confirmed by immunoprecipitation and immunofluorescent analyses. Disrupting CD9 or gp130 by shRNA significantly inhibited the self-renewal and promoted the differentiation of GSCs. Moreover, CD9 disruption markedly reduced gp130 protein levels and STAT3 activating phosphorylation in GSCs. CD9 stabilized gp130 by preventing its ubiquitin-dependent lysosomal degradation to promote the BMX-STAT3 signaling in GSCs. Importantly, targeting CD9 potently inhibited GSC tumor growth in vivo, while ectopic expression of the constitutively activated STAT3 (STAT3-C) restored the tumor growth impaired by CD9 disruption. Collectively, we uncovered a critical regulatory mechanism mediated by tetraspanin CD9 to maintain the stem cell-like property and tumorigenic potential of GSCs.

Due to interleukin-6 type cytokine redundancy only glycoprotein 130 receptor blockade efficiently inhibits myeloma growth.

Interleukin-6 has an important role in the pathophysiology of multiple myeloma where it supports the growth and survival of the malignant plasma cells in the bone marrow. It belongs to a family of cytokines which use the glycoprotein 130 chain for signal transduction, such as oncostatin M or leukemia inhibitory factor. Targeting interleukin-6 in plasma cell diseases is currently evaluated in clinical trials with monoclonal antibodies. Here, efforts were made to elucidate the contribution of interleukin-6 and glycoprotein 130 signaling in malignant plasma cell growth in vivo In the xenograft severe combined immune deficiency model employing our interleukin-6-dependent plasma cell line INA-6, the lack of human interleukin-6 induced autocrine interleukin-6 production and a proliferative response to other cytokines of the glycoprotein 130 family. Herein, mice were treated with monoclonal antibodies against human interleukin-6 (elsilimomab/B-E8), the interleukin-6 receptor (B-R6), and with an antibody blocking glycoprotein 130 (B-R3). While treatment of mice with interleukin-6 and interleukin-6 receptor antibodies resulted in a modest delay in tumor growth, the development of plasmacytomas was completely prevented with the anti-glycoprotein 130 antibody. Importantly, complete inhibition was also achieved using F(ab')2-fragments of monoclonal antibody B-R3. Tumors harbor activated signal transducer and activator of transcription 3, and in vitro, the antibody inhibited leukemia inhibitory factor stimulated signal transducer and activator of transcription 3 phosphorylation and cell growth, while being less effective against interleukin-6. In conclusion, the growth of INA-6 plasmacytomas in vivo under interleukin-6 withdrawal remains strictly dependent on glycoprotein 130, and other glycoprotein 130 cytokines may substitute for interleukin-6. Antibodies against glycoprotein 130 are able to overcome this redundancy and should be explored for a possible therapeutic window.

Bazedoxifene as a Novel GP130 Inhibitor for Pancreatic Cancer Therapy.

The IL6/GP130/STAT3 pathway is crucial for tumorigenesis in multiple cancer types, including pancreatic cancer, and presents as a viable target for cancer therapy. We reported Bazedoxifene, which is approved as a selective estrogen modulator by FDA, as a novel inhibitor of IL6/GP130 protein-protein interactions using multiple ligand simultaneous docking and drug repositioning approaches. STAT3 is one of the major downstream effectors of IL6/GP130. Here, we observed Bazedoxifene inhibited STAT3 phosphorylation and STAT3 DNA binding, induced apoptosis, and suppressed tumor growth in pancreatic cancer cells with persistent IL6/GP130/STAT3 signaling in vitro and in vivo In addition, IL6, but not INFγ, rescued Bazedoxifene-mediated reduction of cell viability. Bazedoxifene also inhibited STAT3 phosphorylation induced by IL6 and IL11, but not by OSM or STAT1 phosphorylation induced by INFγ in pancreatic cancer cells, suggesting that Bazedoxifene inhibits the GP130/STAT3 pathway mediated by IL6 and IL11. Furthermore, Bazedoxifene combined with paclitaxel or gemcitabine synergistically inhibited cell viability and cell migration in pancreatic cancer cells. These results indicate that Bazedoxifene is a potential agent and can generate synergism when combined with conventional chemotherapy in human pancreatic cancer cells and tumor xenograft in mice. Therefore, our results support that Bazedoxifene as a novel inhibitor of GP130 signaling and may be a potential and safe therapeutic agent for human pancreatic cancer therapy. Mol Cancer Ther; 15(11); 2609-19. ©2016 AACR.