Inflammation and cancer: IL-6 and STAT3 complete the link

Intravesicular administration of sodium hyaluronate ameliorates the inflammation and cell proliferation of cystitis cystica et glandularis involving interleukin-6/JAK2/Stat3 signaling pathway

Cystitis cystica et glandularis (CCEG) is a chronic cystitis that causes extreme agony in affected patients. However, there are lack of effective conservative treatments. In this study, it is evident that intravesicular sodium hyaluronate (SH) therapy significantly improved the clinical symptoms of CCEG patients and ameliorated the bladder mucosal inflammation and cell proliferation characteristics of the disease. Immunohistochemical staining showed that the staining intensities of hyaluronidase (HYAL 1/2), CD44, IL-6 and phosphorylated signal transducer and activator of transcription 3 (p-Stat3) in bladder mucosal tissue were significantly increased in CCEG patients compared with control patients and that intravesicular SH treatment suppressed these protein expression. We established a CCEG rat model by treating rats with E. coli intravesicularly, and we found that HYAL 1/2 and CD44 expression levels were significantly increased in the E. coli group compared with the NC group. Activation of the IL-6/JAK2/Stat3 pathway and the expression levels of the downstream pro-apoptotic proteins Mcl-1 and Bcl-xL were also significantly increased in the E. coli group compared with the NC group. The above changes were significantly mitigated by intravesicular SH treatment. Therefore, SH may serve as an effective therapy for CCEG by inhibiting bladder mucosal inflammation and proliferation.

Hedyotis diffusa willd extract suppresses colorectal cancer growth through multiple cellular pathways

The development of colorectal cancer (CRC) is strongly associated with the imbalance of various intracellular signal transduction cascades, including protein kinase B (AKT), mitogen-activated protein kinase 1 (MAPK), signal transducer and activator of transcription 3 (STAT3), as well as crosstalk between these signaling networks. At present, anti-tumor agents are often single-targeted and therefore are not always therapeutically effective. Moreover, long-term use of these anti-tumor agents often generates drug resistance and potential side effects. These problems highlight the urgent need for the development of novel and more effective anti-cancer drugs. Hedyotis diffusa Willd (HDW) has been used as a major component in traditional Chinese medicine for the clinical treatment of colorectal cancer, with a limited number of adverse effects. However, the molecular mechanisms, which underlie its anti-cancer activity, still require further elucidation. In the present study, using xenograft models and various different human CRC cell lines, the efficacy of the ethanol extract of HDW (EEHDW) against tumor growth was evaluated, and its underlying molecular mechanisms of action were investigated. It was demonstrated that EEHDW was able to inhibit cancer growth in vivo and in vitro. Furthermore, EEHDW was able to suppress the activation of several CRC-associated signaling pathways and was able to regulate the expression of various inflammatory and angiogenic factors. This resulted in the induction of apoptosis and inhibition of cellular proliferation, as well as tumor angiogenesis. The present study demonstrated that EEHDW is able to exhibit anti-cancer activity due to its ability to affect multiple intracellular targets, which suggests that it may be a novel multi-potent therapeutic agent for the treatment of colorectal cancer.

Sphingosine Kinase 1 and Sphingosine-1-Phosphate Signaling in Colorectal Cancer

Sphingosine kinase 1 (Sphk1) is a highly conserved lipid kinase that phosphorylates sphingosine to form sphingosine-1-phosphate (S1P). Growing studies have demonstrated that Sphk1 is overexpressed in various types of solid cancers and can be induced by growth factors, cytokines, and carcinogens, leading to the increase of S1P production. Subsequently, the increased Sphk1/S1P facilitates cancer cell proliferation, mobility, angiogenesis, invasion, and metastasis. Therefore, Sphk1/S1P signaling plays oncogenic roles. This review summarizes the features of Sphk1/S1P signaling and their functions in colorectal cancer cell growth, tumorigenesis, and metastasis, as well as the possible underlying mechanisms.

Perspective on the dynamics of cancer

BACKGROUND

The genetic diversity of cancer and the dynamic interactions between heterogeneous tumor cells, the stroma and immune cells present daunting challenges to the development of effective cancer therapies. Although cancer biology is more understood than ever, this has not translated into therapies that overcome drug resistance, cancer recurrence and metastasis. The future development of effective therapies will require more understanding of the dynamics of homeostatic dysregulation that drives cancer growth and progression.

RESULTS

Cancer dynamics are explored using a model involving genes mediating the regulatory interactions between the signaling and metabolic pathways. The exploration is informed by a proposed genetic dysregulation measure of cellular processes. The analysis of the interaction dynamics between cancer cells, cancer associated fibroblasts, and tumor associate macrophages suggests that the mutual dependence of these cells promotes cancer growth and proliferation. In particular, MTOR and AMPK are hypothesized to be concurrently activated in cancer cells by amino acids recycled from the stroma. This leads to a proliferative growth supported by an upregulated glycolysis and a tricarboxylic acid cycle driven by glutamine sourced from the stroma. In other words, while genetic aberrations ignite carcinogenesis and lead to the dysregulation of key cellular processes, it is postulated that the dysregulation of metabolism locks cancer cells in a state of mutual dependence with the tumor microenvironment and deepens the tumor's inflammation and immunosuppressive state which perpetuates as a result the growth and proliferation dynamics of cancer.

CONCLUSIONS

Cancer therapies should aim for a progressive disruption of the dynamics of interactions between cancer cells and the tumor microenvironment by targeting metabolic dysregulation and inflammation to partially restore tissue homeostasis and turn on the immune cancer kill switch. One potentially effective cancer therapeutic strategy is to induce the reduction of lactate and steer the tumor microenvironment to a state of reduced inflammation so as to enable an effective intervention of the immune system. The translation of this therapeutic approach into treatment regimens would however require more understanding of the adaptive complexity of cancer resulting from the interactions of cancer cells with the tumor microenvironment and the immune system.

IL-6 secreted by cancer-associated fibroblasts promotes epithelial-mesenchymal transition and metastasis of gastric cancer via JAK2/STAT3 signaling pathway

Cancer-associated fibroblasts (CAFs), as the activated fibroblasts in tumor stroma, are important modifiers of tumor progression. However, the molecular mechanisms underlying the tumor-promoting properties of CAFs in gastric cancer remain unclear. Here, we show that CAFs isolated from gastric cancer produce significant amounts of interleukin-6 (IL-6). CAFs enhances the migration and EMT of gastric cancer cells through the secretion of IL-6 that activates Janus kinase 2/signal transducers and activators of transcription (JAK2/STAT3) pathway in gastric cancer cells, while deprivation of IL-6 using a neutralizing antibody or inhibition of JAK/STAT3 pathway with specific inhibitor AG490 markedly attenuates these phenotypes in gastric cancer cells induced by CAFs. Moreover, silencing IL-6 expression in CAFs or inhibiting JAK2/STAT3 pathway in gastric cancer cells impairs tumor peritoneal metastasis induced by CAFs in vivo. Taken together, these results suggest that CAFs in the tumor microenvironment promote the progression of gastric cancer through IL-6/JAK2/STAT3 signaling, and IL-6 targeted therapy could be a complementary approach against gastric cancer by exerting their action on stromal fibroblasts.

Microglia in Cancer: For Good or for Bad?

Glioblastoma is a malignant tumor of astrocytic origin that is highly invasive, proliferative and angiogenic. Despite current advances in multimodal therapies, such as surgery, radio- and chemotherapy, the outcome for patients with glioblastoma is nearly always fatal. The glioblastoma microenvironment has a tremendous influence over the tumor growth and spread. Microglia and macrophages are abundant cells in the tumor mass. Increasing evidence indicates that glioblastoma recruits these cell populations and signals in a way that microglia and macrophages are subverted to promote tumor progression. In this chapter, we discuss some aspects of the interaction between microglia and glioblastoma, consequences of this interaction for tumor progression and the possibility of microglial cells being used as therapeutic vectors, which opens up new alternatives for the development of GBM therapies targeting microglia.

Capsazepine inhibits JAK/STAT3 signaling, tumor growth, and cell survival in prostate cancer

Persistent STAT3 activation is seen in many tumor cells and promotes malignant transformation. Here, we investigated whether capsazepine (Capz), a synthetic analogue of capsaicin, exerts anticancer effects by inhibiting STAT3 activation in prostate cancer cells. Capz inhibited both constitutive and induced STAT3 activation in human prostate carcinoma cells. Capz also inhibited activation of the upstream kinases JAK1/2 and c-Src. The phosphatase inhibitor pervanadate reversed Capz-induced STAT3 inhibition, indicating that the effect of Capz depends on a protein tyrosine phosphatase. Capz treatment increased PTPε protein and mRNA levels. Moreover, siRNA-mediated knockdown of PTPε reversed the Capz-induced induction of PTPε and inhibition of STAT3 activation, indicating that PTPε is crucial for Capz-dependent STAT3 dephosphorylation. Capz also decreased levels of the protein products of various oncogenes, which in turn inhibited proliferation and invasion and induced apoptosis. Finally, intraperitoneal Capz administration decreased tumor growth in a xenograft mouse prostate cancer model and reduced p-STAT3 and Ki-67 expression. These data suggest that Capz is a novel pharmacological inhibitor of STAT3 activation with several anticancer effects in prostate cancer cells.

The landscape of DNA methylation-mediated regulation of long non-coding RNAs in breast cancer

Although systematic studies have identified a host of long non-coding RNAs (lncRNAs) which are involved in breast cancer, the knowledge about the methyla-tion-mediated dysregulation of those lncRNAs remains limited. Here, we integrated multi-omics data to analyze the methylated alteration of lncRNAs in breast invasive carcinoma (BRCA). We found that lncRNAs showed diverse methylation patterns on promoter regions in BRCA. LncRNAs were divided into two categories and four subcategories based on their promoter methylation patterns and expression levels be-tween tumor and normal samples. Through cis-regulatory analysis and gene ontology network, abnormally methylated lncRNAs were identified to be associated with can-cer regulation, proliferation or expression of transcription factors. Competing endog-enous RNA network and functional enrichment analysis of abnormally methylated lncRNAs showed that lncRNAs with different methylation patterns were involved in several hallmarks and KEGG pathways of cancers significantly. Finally, survival analysis based on mRNA modules in networks revealed that lncRNAs silenced by high methylation were associated with prognosis significantly in BRCA. This study enhances the understanding of aberrantly methylated patterns of lncRNAs and pro-vides a novel insight for identifying cancer biomarkers and potential therapeutic tar-gets in breast cancer.

Overexpression of microRNA let-7 correlates with disease progression and poor prognosis in hepatocellular carcinoma

The aim of the study was to explore the clinical significance of let-7 expression in hepatocellular carcinoma (HCC).A PCR array was conducted to screen for let-7 expression in early-stage HCC. Next, the deregulation of let-7 was confirmed by quantitative real-time RT-PCR (qRT-PCR) in another set of liver tissues, including normal control (NC), chronic hepatitis (CH), liver cirrhosis (LC), HCC, and adjacent nontumor (NT) tissues. In addition, as the potential target mRNA of let-7, alpha 2(I) collagen (COL1A2) mRNA was also quantified in the above liver tissues. Finally, an association study comparing let-7 and COL1A2 and their clinical significance in HCC was conducted.PCR array analysis revealed that the expression levels of let-7a/7b/7c were significantly downregulated in early-stage HCC compared to those in NT tissues. As compared to NC samples, qRT-PCR further confirmed that let-7a/7b/7c/7e were significantly upregulated in CH, LC, and NT tissues, while there were no significant differences in expression between the HCC and NC groups. Although COL1A2 may be the target mRNA of let-7, only let-7c expression was inversely correlated with COL1A2 mRNA expression in CH tissues. In HCC tissues, levels of let-7a/7b/7c/7e were positively correlated with that of COL1A2 mRNA. The clinical significance study revealed that elevated let-7a expression was significantly correlated with serosal and vein invasion, while elevated let-7c expression was significantly correlated with vein invasion and advanced TNM stage. Elevated let-7e expression was significantly correlated with vein invasion in HCC. Significantly shorter postoperative overall survival was observed in HCC patients with high let-7c expression.The results suggest that aberrant expression of let-7a/7b/7c/7e occurs in benign liver diseases and HCC. The upregulation of let-7 expression is associated with the progression and poor prognosis of HCC, and further mechanistic studies are warranted.

Shaping functional gut microbiota using dietary bioactives to reduce colon cancer risk

Colon cancer is a multifactorial disease associated with a variety of lifestyle factors. Alterations in the gut microbiota and the intestinal metabolome are noted during colon carcinogenesis, implicating them as critical contributors or results of the disease process. Diet is a known determinant of health, and as a modifier of the gut microbiota and its metabolism, a critical element in maintenance of intestinal health. This review summarizes recent evidence demonstrating the role and responses of the intestinal microbiota during colon tumorigenesis and the ability of dietary bioactive compounds and probiotics to impact colon health from the intestinal lumen to the epithelium and systemically. We first describe changes to the intestinal microbiome, metabolome, and epithelium associated with colon carcinogenesis. This is followed by a discussion of recent evidence indicating how specific classes of dietary bioactives, prebiotics, or probiotics affect colon carcinogenesis. Lastly, we briefly address the prospects of using multiple 'omics' techniques to integrate the effects of diet, host, and microbiota on colon tumorigenesis with the goal of more fully appreciating the interconnectedness of these systems and thus, how these approaches can be used to advance personalized nutrition strategies and nutrition research.

Norcantharidin inhibits IL-6-induced epithelial‑mesenchymal transition via the JAK2/STAT3/TWIST signaling pathway in hepatocellular carcinoma cells

Epithelial-mesenchymal transition (EMT), plays a vital role in hepatocellular carcinoma (HCC) development and metastasis. Norcantharidin (NCTD; 7-oxabicyclo (2.2.1) heptane-2,3-dicarboxylic anhydride) plays anticancer roles in the regulation of tumor cell proliferation, apoptosis and migration. However, the molecular mechanism of HCC EMT and the effects of NCTD in the HCC EMT process have been either poorly elucidated or not studied. In this study, HCC EMT was induced by the treatment of IL-6 and various concentrations of NCTD (0, 30, 60 and 120 µM) were treated with HCC cell lines, HCCLM3 and SMMC-7721. We investigated the effect of NCTD on the invasion of HCC cells by using Transwell assay. Immunofluorescence staining, western blot analysis and quantitative RT-PCR were performed to evaluate the protein and mRNA expression levels of HCC cells. Here, using cell line models, our data demonstrated that interleukin 6 (IL-6) induced EMT through the JAK/STAT3/TWIST pathway in HCC. Moreover, our studies revealed that NCTD markedly inhibited IL-6-induced EMT and cell invasiveness. Signaling studies revealed that NCTD sufficiently suppressed JAK/STAT3/TWIST signaling to reverse the IL-6-promoting effects. Collectively, these data provide evidence for the use of NCTD as a potential anticancer drug in HCC metastatic patients.

TGF-β and IL-6 family signalling crosstalk: an integrated model

Mathematical models for TGF-β and IL-6 signalling have been linked, providing a platform for analyzing the crosstalk between the systems. An integrated IL-6:TGF-β model was developed via a reduced set of reaction equations which incorporate both feedback loops and appropriate time-delays for transcription and translation processes. The model simulates stable, robust and realistic responses to both ligands. Pulsatile (multiple pulses) inputs for both TGF-β and IL-6 have been simulated to investigate the effects of each ligand on the sensitivity, equilibrium and dynamic responses of the integrated signalling system. In our simulations the crosstalk between constant IL-6 and TGF-β signalling via SMAD7 does not appear to be sufficient to render the cells resistant to TGF-β inhibition. However, the simulations predict that pulsatile IL-6 stimulation would increase SMAD7 levels substantially and consequentially, lead to resistance to TGF-β. The model also allows the prediction of the integrated signalling pathway responses to the mutation of key components, e.g. Gp130 ^F/F.

Sphingomyelin synthase 2 deficiency inhibits the induction of murine colitis-associated colon cancer

Sphingomyelin synthase 2 (SMS2) is the synthetic enzyme of sphingomyelin (SM), which regulates membrane fluidity and microdomain structure. SMS2 plays a role in LPS-induced lung injury and inflammation; however, its role in inflammation-mediated tumorigenesis is unclear. We investigated the effect of SMS2 deficiency on dextran sodium sulfate (DSS)-induced murine colitis and found inhibition of DSS-induced inflammation in SMS2-deficient (SMS2^-/-) mice. DSS treatment induced a significant increase in ceramide levels, with a decrease of SM levels in SMS2^-/- colon tissue, and demonstrated attenuation of the elevation of both inflammation-related gene expression and proinflammatory cytokines and chemokines, leukocyte infiltration, and MAPK and signal transducer and activator of transcription 3 activation. After undergoing transplantation of wild-type bone marrow, SMS2^-/- mice also exhibited inhibition of DSS-induced inflammation in the colon, which suggested that SMS2 deficiency in bone marrow-derived immune cells was not involved in the inhibition of colitis. Finally, in an azoxymethane/DSS-induced cancer model, SMS2 deficiency significantly decreased tumor incidence in the colon. Our results demonstrate that SMS2 deficiency inhibits DSS-induced colitis and subsequent colitis-associated colon cancer via inhibition of colon epithelial cell-mediated inflammation; therefore, inhibition of SMS2 may be a potential therapeutic target for human colitis and colorectal cancer.-Ohnishi, T., Hashizume, C., Taniguchi, M., Furumoto, H., Han, J., Gao, R., Kinami, S., Kosaka, T., Okazaki, T. Sphingomyelin synthase 2 deficiency inhibits the induction of murine colitis-associated colon cancer.

Inflammatory state exists in familial amyloid polyneuropathy that may be triggered by mutated transthyretin

The relationship between familial amyloid polyneuropathy (FAP), which is caused by mutated transthyretin (TTR), and inflammation has only recently been noted. To determine whether inflammation is present in FAP carriers and patients, serum interleukin (IL)−6 concentration in 57 healthy donors (HD), 21 FAP carriers, and 66 FAP patients was examined, with the relationship between IL-6 and TTR assessed in each group by multiple regression analysis and structural equation models (SEM). Compared with HD, IL-6 concentration was elevated in FAP carriers (p = 0.001, 95% CI 0.398–1.571) and patients (p = 0.002, 95% CI 0.362–1.521). Further, SEM indicated a positive relationship between IL-6 and TTR in FAP carriers (p = 0.010, 95% CI 0.019–0.140), but not in HD and FAP patients. In addition, we determined whether TTR induces production of pro-inflammatory cytokines ex vivo. HD-derived CD14 + monocytes and induced pluripotent stem cell-derived myeloid lineage cells from a HD and FAP patient dose-dependently produced IL-6 under mutated and aggregated TTR conditions, compared with wild-type TTR. In conclusion, FAP carriers and patients are in an inflammatory state, with the presence of mutated TTR being a trigger of inflammation, especially in FAP carriers.

Regulatory miRNAs in Colorectal Carcinogenesis and Metastasis

Colorectal cancer is one of the most common malignancies and is the second-leading cause of cancer-related death world-wide, which is linked to genetic mutations, epigenetic alterations, and oncogenic signaling activation. MicroRNAs, one of the categories of epigenetics, have been demonstrated significant roles in carcinogenesis and progression through regulating of oncogenic signaling pathways, stem cells, epithelial-mesenchymal transition, and metastasis. This review summarizes the roles of microRNAs in the regulating of Wnt, Ras, TGF-β, and inflammatory signaling pathways, stemness, and epithelial-mesenchymal transition, for carcinogenesis and metastasis in colorectal cancer. Improving our understanding of the mechanisms of regulatory interactions of microRNAs with signaling pathways in colorectal cancer formation and progression will aid in determining the genes responsible for colorectal cancer initiation, progression, metastasis, and recurrence and, finally, in developing personalized approaches for cancer prevention and therapy.

Rosmarinic acid suppresses colonic inflammation in dextran sulphate sodium (DSS)-induced mice via dual inhibition of NF-κB and STAT3 activation

Ulcerative colitis (UC), a type of inflammatory bowel disease (IBD), is a chronic inflammatory disorder of the colon. Although UC is generally treated with anti-inflammatory drugs or immunosuppressants, most of these treatments often prove to be inadequate. Rosmarinic acid (RA) is a phenolic ester included in various medicinal herbs such as Salvia miltiorrhiz and Perilla frutescens. Although RA has many biological and pharmacological activities, the anti-inflammatory effect of RA in colonic tissue remains unclear. In this study, we investigated the anti-inflammatory effects and underlying molecular mechanism of RA in mice with dextran sulphate sodium (DSS)-induced colitis. In the DSS-induced colitis model, RA significantly reduced the severity of colitis, as assessed by disease activity index (DAI) scores, colonic damage, and colon length. In addition, RA resulted in the reduction of the inflammatory-related cytokines, such as IL-6, IL-1β, and IL-22, and protein levels of COX-2 and iNOS in mice with DSS-induced colitis. Furthermore, RA effectively and pleiotropically inhibited nuclear factor-kappa B and signal transducer and activator of transcription 3 activation, and subsequently reduced the activity of pro-survival genes that depend on these transcription factors. These results demonstrate that RA has an ameliorative effect on colonic inflammation and thus a potential therapeutic role in colitis.

Sphingosine-1-Phosphate Metabolism and Its Role in the Development of Inflammatory Bowel Disease

Beyond their role as structural molecules, sphingolipids are involved in many important cellular processes including cell proliferation, apoptosis, inflammation, and migration. Altered sphingolipid metabolism is observed in many pathological conditions including gastrointestinal diseases. Inflammatory bowel disease (IBD) represents a state of complex, unpredictable, and destructive inflammation of unknown origin within the gastrointestinal tract. The mechanisms explaining the pathophysiology of IBD involve signal transduction pathways regulating gastro-intestinal system’s immunity. Progressive intestinal tissue destruction observed in chronic inflammation may be associated with an increased risk of colon cancer. Sphingosine-1-phosphate (S1P), a sphingolipid metabolite, functions as a cofactor in inflammatory signaling and becomes a target in the treatment of IBD, which might prevent its conversion to cancer. This paper summarizes new findings indicating the impact of (S1P) on IBD development and IBD-associated carcinogenesis.

Tumor Microenvironment as a New Target for Tumor Immunotherapy of Polysaccharides

Many researches show that polysaccharides derived from fungi and plants have strong pharmacological activities such as enhancing the organism immune and anti-tumor function, and have few toxic and side effects. So the polysaccharides show a wide application prospect in the prevention and therapy of tumor. The tumor microenvironment consists of tumor cells and tumor cells' surrounding environment. The tumor microenvironment not only plays a key role in the development of tumor, but also is a potential treasure for searching new ways to treat tumor. In this review, we summarized polysaccharides' regulation effects on tumor microenvironment progression and tried to give a new theoretical basis for the exploitation of polysaccharides with anti-tumor activity.

Basic Transcription Factor 3 Is Required for Proliferation and Epithelial-Mesenchymal Transition via Regulation of FOXM1 and JAK2/STAT3 Signaling in Gastric Cancer

Gastric cancer (GC) is the most common epithelial malignancy worldwide. Basic transcription factor 3 (BTF3) plays a crucial role in the regulation of various biological processes. We designed experiments to investigate the molecular mechanism underlying the role of BTF3 in GC cell proliferation and metastasis. We confirmed that BTF3 expression was decreased in GC tissues and several GC cell lines. Lentivirus-mediated downregulation of BTF3 reduced cell proliferation, induced S and G₂/M cell cycle arrest, and increased apoptosis. Knockdown of BTF3 significantly reduced the expression of Forkhead box M1 (FOXM1). Upregulation of FOXM1 significantly inhibited the decrease in cell proliferation due to BTF3 silencing, S and G₂/M cell cycle arrest, and increase in apoptosis. Knockdown of BTF3 decreased Ki-67 and PCNA expression, whereas it increased p27 expression, which was inhibited by upregulation of FOXM1. Knockdown of BTF3 significantly decreased the ability to invade and migrate. Moreover, knockdown of BTF3 increased E-cadherin expression, whereas it decreased N-cadherin and ZEB2 expression, indicating a decrease in epithelial–mesenchymal transition (EMT). Phosphorylation of Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) was significantly inhibited by knockdown of BTF3. IL-6-stimulated phosphorylation of STAT3 and JAK2 markedly suppressed inhibition of EMT due to BTF3 silencing. Silencing of BTF3 decreased tumor volume and weight and reduced peritoneal nodules in implanted tumors. Our findings provide a novel understanding of the mechanism of GC and highlight the important role of BTF3/FOXM1 in tumor growth and BTF3/JAK2/STAT3 in EMT and metastasis.

IL-6 and PD-L1 blockade combination inhibits hepatocellular carcinoma cancer development in mouse model

Limited efficacy of immune checkpoint inhibitors in hepatocellular carcinoma (HCC) was observed in clinical trials, thus prompting investigation into combination therapy. Interleukin-6 (IL-6) has important roles in modeling immune responses in cancers. Here, we hypothesized that IL-6 blockade would enhance antitumor immunity of HCC and synergize with anti-programmed death-1-ligand 1 (PD-L1) checkpoint inhibitor in treating HCC. The sources and immune modulating effects of IL-6 were investigated in HCC models. Combination of anti-IL-6 and anti-PD-L1 was tested in HCC bearing mice. We found that IL-6 is mainly secreted by cancer associated fibroblast (CAFs), but not tumor cells in HCC. High IL-6 expression CAFs could induce strong immunosuppression in HCC microenvironment by recruiting immunosuppressive cells, such as myeloid derived suppressive cells. In addition, high IL-6 expression CAFs also impaired tumor infiltrating T-cell function via upregulating inhibitory immune checkpoints. Using IL-6 blockade could reverse anti-PD-L1 resistance in HCC tumor model. In conclusion, our study indicates that targeted inhibition of IL-6 may enhance the efficacy of anti-PD-L1 in HCC, providing a potential strategy to overcoming anti-PD-L1 resistance in HCC.

Reciprocal androgen receptor/interleukin-6 crosstalk drives oesophageal carcinoma progression and contributes to patient prognosis

Oesophageal squamous cell carcinoma (ESCC), a leading lethal malignancy of the digestive tract, is characterized by marked gender disparity. Clarifying the roles of the function and regulatory pathway of the androgen receptor (AR) will improve our understanding of oesophageal cancer progression, thereby facilitating the personalized management of ESCC. Here we report evidence to show that AR is a key mediator of inflammatory signals in ESCC cancer progression. High AR expression was associated with poor overall survival in tobacco-using ESCC patients but not in ESCC patients not using tobacco. A gain and loss of AR function enhanced and repressed ESCC cell growth, respectively, by altering cell cycle progression. In mice bearing human ESCC xenografts, silencing AR expression attenuated tumour growth, whereas AR overexpression promoted tumour growth in mice of different androgen statuses (male, female, and castrated male). Array assays revealed that the inflammatory cytokine interleukin-6 (IL6) is a prominent AR target gene in ESCC. By directly binding to the IL6 promoter, AR enhances IL6 transcription, and IL6 can in turn activate AR expression, thus forming a reciprocal regulatory circuit to sustain STAT3 oncogenic signalling in ESCC. Moreover, high expression levels of both AR and IL6 in human ESCC predict poor clinical outcome in tobacco users. Together, these data establish that AR promotes ESCC growth and is associated with poor patient prognosis. The discovery of a positive feedback loop between IL6 and AR bridges the knowledge gaps among lifestyle factor-associated inflammation, gender disparity, and oesophageal carcinoma. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Helicteric Acid, Oleanic Acid, and Betulinic Acid, Three Triterpenes from Helicteres angustifolia L., Inhibit Proliferation and Induce Apoptosis in HT-29 Colorectal Cancer Cells via Suppressing NF-κB and STAT3 Signaling

Colorectal cancer (CRC) is one of the most common malignancies and most frequent cause of cancer death worldwide. The activation of both NF-κB and STAT3 signaling and the crosstalk between them play an important role in colorectal tumor. Helicteres angustifolia L. is a type of commonly used Chinese medicinal herb and possesses a wide variety of biological activities. In the present study, we investigate the effects of three triterpenes from H. angustifolia (HT) such as helicteric acid (HA), oleanic acid (OA), and betulinic acid (BA), on inhibiting CRC progression. Our results showed that HT extracts could decrease proliferation and induce apoptosis in HT-29 colorectal cancer cells. Moreover, HT extracts could suppress LPS-triggered phosphorylation of IKK, IκB, and NF-κB, attenuate IL-6-induced phosphorylation of JAK2 and STAT3, and suppress the expression of c-Myc, cyclin-D1, and BCL-xL, the downstream gene targets of NF-κB and STAT3. Therefore, HT extracts showed potent therapeutic and antitumor effects on CRC via inhibiting NF-κB and STAT3 signaling.

Chronic inflammation confers to the metabolic reprogramming associated with tumorigenesis of colorectal cancer

It's well known that microenvironment inflammatory signals could promote cancer development and progression. In colorectal cancer (CRC), chronic inflammation is a major driving mechanism for the development of CRC in patients having long-standing inflammatory bowel disease (IBD). Though it has been addressed that cancer cells ferment much of their glucose supply into lactate regardless of the presence of oxygen, it is unclear whether cell metabolism has been reprogramed during the process from IBD to CRC. Herein, with dextran sulfate sodium (DSS)-induced mouse colitis model, we found that inflammation upregulated key glycolytic enzymes expression via activation of STAT3/c-Myc signaling pathway. Interestingly, during the whole phase of chronic inflammation, the key metabolic enzymes demonstrated increased expression constantly, indicating the metabolic reprogramming was induced by long-term inflammatory signal. Moreover, either the inhibition of STAT3 signaling or c-Myc activity could block the glycolytic enzymes expression induced by interleukin 6 (IL-6). Thus, we presented the view that inflammation could induce the metabolic reprogramming and promote the progression from chronic colitis to colorectal cancer.

The C-reactive protein/albumin ratio predicts long-term outcomes of patients with operable non-small cell lung cancer

PURPOSE

To investigate the association between C-reactive protein/albumin ratio (CAR), an inflammation-based prognostic score, and clinicopathological factors, as well as its association with long-term outcomes in patients with operable non-small cell lung cancer (NSCLC).

METHODS

A total of 617 operable NSCLC patients were retrospectively evaluated and the data of preoperative serum CRP and serum albumin was collected. The correlation between the CAR and clinicopathological factors was analyzed using the chi-square test. A Cox proportional hazards regression model was performed to evaluate the association between the CAR and outcome.

RESULTS

The CAR was significantly related to sex, smoking status, BMI, histology type and clinical stage (p ≤ 0.05). The patients with characteristic of male, smoker, BMI under 18.5, squamous cell carcinoma or clinical stage III had a high level of CAR. Additionally, elevated CAR indicated a worse outcome, and the patients with higher CAR had 2.02-fold risk for disease progression (95% CI 1.48-2.74, p < 0.001) and 2.61-fold risk for death (95 % CI 2.02-3.37, p < 0.001). Multivariate analyses showed the similar results after adjusted by clinicopathological factors and another four inflammation-based prognostic scores.

CONCLUSIONS

The CAR is a potential independent predictor for disease progression and death in patients with operable NSCLC.

Phosphodiesterase-5 inhibition suppresses colonic inflammation-induced tumorigenesis via blocking the recruitment of MDSC

Phosphodiesterase 5 (PDE-5) is a major isoform of cGMP phosphodiesterase in diverse tissues and plays a critical role in regulating intracellular cGMP concentrations. However, the distribution and expression of PDE-5 in colitis-related colon cancer was still unclear, not even the function and mechanism. Western blotting and ELISA were performed to detect colonic PDE-5 expression in AOM/DSS-induced tumorigenesis model. Sildenafil, a specific PDE-5 inhibitor, was used to treat AOM/DSS-induced and AOM-induced colonic tumorigenesis model and DSS-induced colitis model. The leukocyte infiltration in colonic tissue was examined by flow cytometry and immunofluorescence staining. Further matrigel-based invasion assay was employed to determine the effects of Sildenafil on myeloid-derived suppressor cell (MDSC) in vitro. We first demonstrated the upregulation of colonic PDE-5 expression and the prevention role of PDE-5 inhibition in AOM/DSS-induced tumorigenesis model. More importantly, PDE-5 inhibitor Sildenafil inhibited colonic tumorigenesis dependent on inflammation and suppressed DSS-induced colitis. Molecular mechanism investigation indicated that Sildenafil regulated inflammation microenvironment via directly inhibiting MDSC infiltration in colonic tissue. The study provides solid evidence for the use of PDE-5 inhibitor in preventing and treating colonic inflammation-related tumorigenesis.

A cell-autonomous tumour suppressor role of RAF1 in hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is a leading cause of cancer deaths, but its molecular heterogeneity hampers the design of targeted therapies. Currently, the only therapeutic option for advanced HCC is Sorafenib, an inhibitor whose targets include RAF. Unexpectedly, RAF1 expression is reduced in human HCC samples. Modelling RAF1 downregulation by RNAi increases the proliferation of human HCC lines in xenografts and in culture; furthermore, RAF1 ablation promotes chemical hepatocarcinogenesis and the proliferation of cultured (pre)malignant mouse hepatocytes. The phenotypes depend on increased YAP1 expression and STAT3 activation, observed in cultured RAF1-deficient cells, in HCC xenografts, and in autochthonous liver tumours. Thus RAF1, although essential for the development of skin and lung tumours, is a negative regulator of hepatocarcinogenesis. This unexpected finding highlights the contribution of the cellular/tissue environment in determining the function of a protein, and underscores the importance of understanding the molecular context of a disease to inform therapy design.

The kinase RAF1 usually exerts pro-tumorigenic functions promoting proliferation in RAS-driven cancers. Here, the authors using a mouse model of HCC and clinical data describe an unexpected oncosuppressor role of RAF1 in hepatocarcinoma development linked to a gp130-dependent Stat3 activation and YAP1 regulation.

Effect of targeted silencing of IL-8 on in vitro migration and invasion of SKOV3 ovarian cancer cells

The aim of the study was to determine whether interleukin-8 (IL-8) affects human SKOV3 ovarian cancer cell migration and invasion by targeting silencing of IL-8 expression. Silencing small-interfering RNA (siRNA) targeting IL-8 gene was constructed to infect SKOV3 cells by lentiviral vector. The expression of IL-8 and p-nuclear factor (NF)-κB protein was detected by western blot analysis. The wound scratch and Transwell tests were used to assay the cell migration and invasiveness of SKOV3 cells infected with lentiviral vector targeting IL-8 gene siRNA. The levels of IL-8 protein expressed by SKOV3 cells infected by lentiviral vector targeting IL-8 gene siRNA decreased by 72.3%. IL-8 (50 ng/ml) increased the ability of SKOV3 cells to suppress cell migration (p<0.01). Cisplatin and silencing of IL-8 achieved the ability to inhibit SKOV3 cell invasion (p<0.01), and 100 ng/ml concentration of IL-8 enhanced the ability of SKOV3 invasion (p<0.01). Silencing of IL-8 to a certain extent reduced the expression of p-NF-κB proteins, but it was not statistically significant. In conclusion, silencing of IL-8 may inhibit the migration and invasion of SKOV3 cells, which may be independent of the p-NF-κB protein.

Cancer and inflammation

The relationship between inflammation and cancer has been recognized since the 17^th century,¹ and we now know much about the cells, cytokines and physiological processes that are central to both inflammation and cancer.^2-9 Chronic inflammation can induce certain cancers,^10-17 and solid tumors, in turn, can initiate and perpetuate local inflammatory processes that foster tumor growth and dissemination.⁵ ,^18-20 Consequently, inflammatory pathways have been targeted in attempts to control cancer.^21-23 Inflammation is a central aspect of the innate immune system's response to tissue damage or infection, and also facilitates the recruitment of circulating cells and antibodies of the adaptive immune response to the tissue. Components of the innate immune response carry out a robust, but sometimes overly-conservative response, sacrificing specificity for the sake of preservation. Thus, when innate immunity goes awry, it can have profound implications. How the innate and adaptive immune systems cooperate to neutralize pathogens and repair damaged tissues is still an area of intense investigation. Further, how these systems can respond to cancer, which arises from normal 'self' cells that undergo an oncogenic transformation, has profound implications for cancer therapy. Recently, immunotherapies that activate adaptive immunity have shown unprecedented promise in the clinic, producing durable responses and dramatic increases in survival rate in patients with advanced stage melanoma.^24-26 Consequently, the relationship between cancer and inflammation has now returned to the forefront of clinical oncology. WIREs Syst Biol Med 2017, 9:e1370. doi: 10.1002/wsbm.1370 For further resources related to this article, please visit the WIREs website.

Longer warm ischemia can accelerate tumor growth through the induction of HIF-1α and the IL-6-JAK-STAT3 signaling pathway in a rat hepatocellular carcinoma model

BACKGROUND

The present study aimed to investigate the impact of the duration of hepatic pedicle clamping (HPC) on tumor growth after major hepatectomy in a rat model.

METHODS

Rats were divided into four groups according to the length of HPC during 70% partial hepatectomy followed by N1S1 tumor cell implantation: group 1, without HPC; group 2, with 5-min HPC; group 3, 10-min HPC; and group 4, 15-min HPC. At three weeks after tumor cell implantation, liver tumor growth and its possible mechanisms were investigated.

RESULTS

The number and largest diameter of liver tumor were significantly greater in group 4. At 6 h after reperfusion, serum levels of inflammatory cytokines including interleukin (IL)-6 were significantly higher in group 4 compared with the other groups. In the tumor tissues, the expression of hypoxia inducible factor (HIF)-1α (P < 0.001 versus group 2, P < 0.001 versus group 3) and that of phospho-signal transducer and activator of transcription 3 (STAT3) (P < 0.001 versus group 2, P = 0.026 versus group 3) were significantly upregulated in group 4.

CONCLUSIONS

Longer HPC followed by reperfusion accelerated hepatocellular carcinoma growth through the induction of HIF-1α and the activation of the IL-6-JAK-STAT3 signaling pathway.

A Novel Inflammation-Based Stage (I Stage) Predicts Overall Survival of Patients with Nasopharyngeal Carcinoma

Recent studies have indicated that inflammation-based prognostic scores, such as the Glasgow Prognostic Score (GPS), modified GPS (mGPS) and C-reactive protein/Albumin (CRP/Alb) ratio, platelet-lymphocyte ratio (PLR), and neutrophil-lymphocyte ratio (NLR), have been reported to have prognostic value in patients with many types of cancer, including nasopharyngeal carcinoma (NPC). In this study, we proposed a novel inflammation-based stage, named I stage, for patients with NPC. A retrospective study of 409 newly-diagnosed cases of NPC was conducted. The prognostic factors (GPS, mGPS, CRP/Alb ratios, PLR, and NLR) were evaluated using univariate and multivariate analyses. Then, according to the results of the multivariate analyses, we proposed a I stage combination of independent risk factors (CRP/Alb ratio and PLR). The I stage was calculated as follows: patients with high levels of CRP/Alb ratio (>0.03) and PLR (>146.2) were defined as I2; patients with one or no abnormal values were defined as I1 or I0, respectively. The relationships between the I stage and clinicopathological variables and overall survival (OS) were evaluated. In addition, the discriminatory ability of the I stage with other inflammation-based prognostic scores was assessed using the AUCs (areas under the curves) analyzed by receiver operating characteristics (ROC) curves. The p value of <0.05 was considered to be significant. A total of 409 patients with NPC were enrolled in this study. Multivariate analyses revealed that only the CRP/Alb ratio (Hazard ratio (HR) = 2.093; 95% Confidence interval (CI): 1.222-3.587; p = 0.007) and PLR (HR: 2.003; 95% CI: 1.177-3.410; p = 0.010) were independent prognostic factors in patients with NPC. The five-year overall survival rates for patients with I0, I1, and I2 were 92.1% ± 2.9%, 83.3% ± 2.6%, and 63.1% ± 4.6%, respectively (p < 0.001). The I stage had a higher area under the curve value (0.670) compared with other systemic inflammation-based prognostic scores (p < 0.001). The I stage is a novel and useful predictive factor for OS in patients with NPC.

From obesity to cancer: a review on proposed mechanisms

Nowadays, obesity is considered as a serious and growing global health problem. It is documented that the overweight and obesity are major risk factors for a series of noncommunicable diseases, and in recent years, the obesity-cancer link has received much attention. Numerous epidemiological studies have shown that obesity is associated with increased risk of several cancer types, including colon, breast, endometrium, liver, kidney, esophagus, gastric, pancreatic, gallbladder, and leukemia, and can also lead to poorer treatment. We review here the epidemiological and experimental evidences for the association between obesity and cancer. Specifically, we discuss potential mechanisms focusing how dysfunctional angiogenesis, chronic inflammation, interaction of proinflammatory cytokines, endocrine hormones, and adipokines including leptin, adiponectin insulin, growth factors, estrogen, and progesterone and strikingly, cell metabolism alteration in obesity participate in tumor development and progression, resistance to chemotherapy, and targeted therapies such as antiangiogenic and immune therapies.

Dysregulated JAK2 expression by TrkC promotes metastasis potential, and EMT program of metastatic breast cancer

Metastatic breast cancers are aggressive tumors associated with high levels of epithelial-mesenchymal transition (EMT) markers, activation of IL6/JAK2/STAT3 and PI3K/AKT pathways for cell growth, mobility, invasion, metastasis, and CSC status. We identified a new molecular and functional network present in metastasis that regulates and coordinates with TrkC. Inhibition of SOCS3-mediated JAK2 degradation by TrkC increases total JAK2/STAT3 expression, and then leads to upregulation of Twist-1 through activation of JAK2/STAT3 cascade. Also, TrkC increases secretion and expression of IL-6, suggesting that this autocrine loop generated by TrkC maintains the mesenchymal state by continued activation of the JAK2/STAT3 cascade and upregulation of Twist expression. Moreover, TrkC interacts with the c-Src/Jak2 complex, which increases Twist-1 and Twist-2 levels via regulation of JAK2/STAT3 activation and JAK2/STAT3 expression. Furthermore, TrkC enhances metastatic potential of breast cancer via induction of EMT by upregulating Twist-1 and Twist-2. Additionally, TrkC significantly enhances the ability of breast cancer cells to form pulmonary metastases and primary tumor formation. Unexpectedly, we found that TrkC expression and clinical breast tumor pathological phenotypes show significant correlation. These findings suggest that TrkC plays a central role in tumorigenicity, metastasis, and self-renewal traits of metastatic breast cancer.

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

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

Deletion of interleukin-6 in monocytes/macrophages suppresses the initiation of hepatocellular carcinoma in mice

BACKGROUND

Hepatocellular carcinoma (HCC) is associated with inflammation, and roughly 30 % of the global population shows serological evidence of current or past infection with hepatitis B or hepatitis C virus. Resident hepatic macrophages, known as Kupffer cells (KCs), are considered as the specific tumor-associated macrophages (TAMs) of HCC, and can produce various cytokines-most importantly interleukin (IL)-6-to promote tumorigenesis of HCC. However, the roles of KCs and IL-6 in carcinogenesis in the liver are still unclear.

METHODS

We analyzed leukocyte-related peripheral blood data of 192 patients and constructed a mouse model in which the bone marrow was cleared out by irradiation and reconstructed using bone marrow donated from IL-6-deficient mice to further elucidate the hepatic pathological changes in response to toxic challenge and oncogenic gene mutation.

RESULTS

Peripheral monocyte counts and serum IL-6 levels were significantly higher in patients with HCC than in those without HCC. In addition, there was a significant difference in the levels of IL-6 among individuals with different histopathological grades. In mice with selective IL-6 ablation in monocytes/KCs, we observed decreased toxic liver injury, inflammatory infiltration, and systemic inflammation. In Mdr2-deficient mice, which spontaneously developed HCC, the loss of IL-6 in monocytes/KCs resulted in inhibition of IL-6/signal transducer and activator of transcription 3 signaling, decreased serum IL-6 levels, and delayed tumorigenesis.

CONCLUSIONS

Our findings demonstrate that increased TAM-derived IL-6 had an amplifying effect on the inflammation response, thereby promoting the occurrence and development of HCC.

Chromosome 8p tumor suppressor genes SH2D4A and SORBS3 cooperate to inhibit interleukin-6 signaling in hepatocellular carcinoma

Several chronic inflammatory liver diseases, e.g., chronic hepatitis B or C viral infection and steatohepatitis, have been shown to predispose to the development of hepatocellular carcinoma (HCC). In patients with chronic liver disease, interleukin-6 (IL-6) serum levels are elevated and increase even more when HCC develops. However, the impact and regulatory mechanisms of IL-6 signaling during hepatocarcinogenesis are still poorly defined. Here, we show that gene expression profiles of patients with chromosome 8p loss correlate with increased IL-6 signaling. In addition, the chromosome 8p tumor suppressor genes Src homology 2 domain containing 4A (SH2D4A) and Sorbin and Src homology 3 domain containing 3 (SORBS3) together exerted greater inhibition of cell growth and clonogenicity compared to a single gene. Overexpression of SH2D4A and SORBS3 in HCC cells led to decreased IL-6 target gene expression and reduced signal transducer and activator of transcription 3 (STAT3) signaling. In situ and in vitro coimmunoprecipitation assays revealed that SH2D4A directly interacts with STAT3, thereby retaining STAT3 in the cytoplasm and inhibiting STAT3 transcriptional activity. On the other hand, SORBS3 coactivated estrogen receptor α signaling, leading indirectly to repression of STAT3 signaling. In human HCC tissues, SH2D4A was positively associated with infiltrating regulatory and cytotoxic T-cell populations, suggesting distinct immunophenotypes in HCC subgroups with chromosome 8p loss. Thus, the genetically linked tumor suppressors SH2D4A and SORBS3 functionally cooperate to inhibit STAT3 signaling in HCC.

CONCLUSION

The chromosome 8p tumor suppressor genes SORBS3 and SH2D4A are physically and functionally linked and provide a molecular mechanism of inhibiting STAT3-mediated IL-6 signaling in HCC cells. (Hepatology 2016;64:828-842).

Runt-related Transcription Factor 1 (RUNX1) Binds to p50 in Macrophages and Enhances TLR4-triggered Inflammation and Septic Shock

An appropriate inflammatory response plays critical roles in eliminating pathogens, whereas an excessive inflammatory response can cause tissue damage. Runt-related transcription factor 1 (RUNX1), a master regulator of hematopoiesis, plays critical roles in T cells; however, its roles in Toll-like receptor 4 (TLR4)-mediated inflammation in macrophages are unclear. Here, we demonstrated that upon TLR4 ligand stimulation by lipopolysaccharide (LPS), macrophages reduced the expression levels of RUNX1 Silencing of Runx1 attenuated the LPS-induced IL-1β and IL-6 production levels, but the TNF-α levels were not affected. Overexpression of RUNX1 promoted IL-1β and IL-6 production in response to LPS stimulation. Moreover, RUNX1 interacted with the NF-κB subunit p50, and coexpression of RUNX1 with p50 further enhanced the NF-κB luciferase activity. Importantly, treatment with the RUNX1 inhibitor, Ro 5-3335, protected mice from LPS-induced endotoxic shock and substantially reduced the IL-6 levels. These findings suggest that RUNX1 may be a new potential target for resolving TLR4-associated uncontrolled inflammation and preventing sepsis.

STAT3-induced WDR1 overexpression promotes breast cancer cell migration

WD repeat domain 1 (WDR1), a protein that assists cofilin-mediated actin filament disassembly, is overexpressed in the invading front of invasive ductal carcinoma (IDC), but its implication of overexpression and how to be regulated have not been studied. In our study, we demonstrated that STAT3 bound to the 5' upstream sequence (-1971 to -1964), a putative promoter region, of WDR1 gene, and its activation induced WDR1 overexpression in breast cancer cells. The exogenous overexpression of WDR1 increased the migration of MDA-MB-231, which was attenuated by WDR1 knockdown. In the analysis of breast cancer patients, WDR1 overexpression was associated with a shorter distant metastasis-free survival (DMFS), more specifically in basal-like tumors.

Suppression of colitis-associated carcinogenesis through modulation of IL-6/STAT3 pathway by balsalazide and VSL#3

BACKGROUND AND AIM

Recent studies suggest that the anti-inflammatory agent balsalazide (BSZ) and probiotic agent VSL#3 have potential therapeutic benefits for the treatment of patients with inflammatory bowel disease. However, their effectiveness in preventing colitis-associated carcinogenesis (CAC) remains uncertain. The aim of the present study was to determine the chemopreventive effects of BSZ and VSL#3 in the murine azoxymethane (AOM)/dextran sodium sulfate (DSS) model.

METHODS

C57B/L6J mice were randomly divided into four groups: CAC group, BSZ group, VSL#3 group, and BSZ + VSL#3 group. After 2 weeks, the AOM/DSS model was induced by AOM injection followed by two cycles of 2% DSS.

RESULTS

During first and second cycles of DSS, the number of F4/80-positive macrophages was significantly lower in the drug-treated groups compared with the CAC group (P < 0.05). At the endpoint, the total numbers of tumors in the drug-treated groups were significantly low compared with the CAC group (P < 0.05), and the drug-treated groups had significantly lower F4/80-positive macrophages in the tumor stroma (P < 0.01). The protein production of macrophage inflammatory protein 1 beta, monocyte chemoattractant protein-1, interleukin (IL)-6, and IL-10 in the colon tissues decreased in concordance with the plasma concentrations of the cytokines (P < 0.05). The drug-treated groups revealed lower expression of p-STAT3 compared with the CAC group. In addition, BCL2 decreased, and BAX increased markedly in the BSZ + VSL#3 group.

CONCLUSIONS

These results revealed that BSZ and VSL#3 have chemopreventive effects against CAC through IL-6/STAT3 suppression. BSZ and VSL#3 could be suitable options for chemoprevention of colorectal cancer.

Batf-dependent Th17 cells critically regulate IL-23 driven colitis-associated colon cancer

OBJECTIVES

IBDs have an increased risk for development of colorectal cancer (CRC). Here, we aimed at the characterisation of the functional role of Th17-associated transcription factors in sporadic and colitis-associated colon cancer in vivo.

DESIGN

We used mice deficient or transgenic for the activating protein 1 family member basic leucine zipper transcription factor ATF-like (Batf) to evaluate the role of Th17 cells during sporadic and inflammation-induced colon carcinogenesis. We also studied the expression of Batf and RORγt in patients with IBD and CRC.

RESULTS

Batf but not retinoic acid-related orphan receptor γt(RORγt) expression was significantly increased together with interleukin (IL) 23 expression in UC but not in Crohn's disease (CD) tissue samples. In CRC also Batf but not RORγt expression was increased and its expression correlated with the IL-23 and IL-23 receptor (IL-23R) expression. Finally, Batf but not RORγt was coexpressed with IL-17a, IL-23R and IL-6 within CRC-infiltrating CD4(+) T cells. Functional studies in mice revealed that Batf-dependent T cells are crucial regulators of sporadic and inflammation-induced CRC. Colitis-associated Batf(-/-) tumours lacked IL-17a(+)IL-23R(+)IL-6(+)CD4(+) T cells, hence displaying characteristics reminiscent of human CRC-infiltrating CD4(+) T cells. Strikingly, Batf(-/-) tumours contained low IL-23 but high IL-17a expression levels. Tumour formation and intratumoral IL-23 expression could be restored by administration of Hyper-IL-6 consisting of IL-6 and soluble IL-6 receptor.

CONCLUSIONS

Batf-dependent IL-23R(+)IL-6(+)CD4(+) Th17 cells critically control IL-23 driven colitis-associated tumour formation and the progression of sporadic colon tumours. Batf-dependent IL-23R(+) T cells represent a potential future therapeutic target limiting CRC progression.

Avoiding hepatic metastasis naturally: Lessons from the cotton top tamarin (Saguinus oedipus)

Much has been written about hepatic metastasis and animal models abound. In terms of the human experience, progress in treating this final common pathway, a terminal event of many human malignancies has been relatively slow. The current thinking is that primary prevention is best served by early detection of cancer and eradication of early stage cancers by screening. Some cancers spread early in their course and the role of screening may be limited. Until relatively recently there has not been a pathfinder model that makes the evasion of this unfortunate event a reality. This review discusses such an animal model and attempts to relate it to human disease in terms of intervention. Concrete proposals are also offered on how scientists may be able to intervene to prevent this deadly progression of the cancer process.

DNA Damage and Pulmonary Hypertension

Pulmonary hypertension (PH) is defined by a mean pulmonary arterial pressure over 25 mmHg at rest and is diagnosed by right heart catheterization. Among the different groups of PH, pulmonary arterial hypertension (PAH) is characterized by a progressive obstruction of distal pulmonary arteries, related to endothelial cell dysfunction and vascular cell proliferation, which leads to an increased pulmonary vascular resistance, right ventricular hypertrophy, and right heart failure. Although the primary trigger of PAH remains unknown, oxidative stress and inflammation have been shown to play a key role in the development and progression of vascular remodeling. These factors are known to increase DNA damage that might favor the emergence of the proliferative and apoptosis-resistant phenotype observed in PAH vascular cells. High levels of DNA damage were reported to occur in PAH lungs and remodeled arteries as well as in animal models of PH. Moreover, recent studies have demonstrated that impaired DNA-response mechanisms may lead to an increased mutagen sensitivity in PAH patients. Finally, PAH was linked with decreased breast cancer 1 protein (BRCA1) and DNA topoisomerase 2-binding protein 1 (TopBP1) expression, both involved in maintaining genome integrity. This review aims to provide an overview of recent evidence of DNA damage and DNA repair deficiency and their implication in PAH pathogenesis.

SUMOylation and SENP3 regulate STAT3 activation in head and neck cancer

Hyperphosphorylation of signal transducer and activator of transcription 3 (STAT3) has been found in various types of human cancers, including head and neck cancer (HNC). Although smoking is critical in the development and progression of HNC, how tobacco components activate STAT3 is unclear. We demonstrated that exposure of HNC cell lines to a tobacco extract induced a rapid Y705 phosphorylation of STAT3 and a rapid increase in the SUMO protease SENP3 that depended on a simultaneous increase in reactive oxygen species. We identified that SUMOylation at the lysine 451 site facilitated STAT3 binding to the phosphatase TC45 through an SUMO-interacting motif of TC45. SENP3 could thus enhance STAT3 phosphorylation by de-conjugating the SUMO2/3 modification of STAT3. Knocking-down of SENP3 greatly impaired basal and induced STAT3 phosphorylation by tobacco extract or interleukin 6. A correlation between SENP3 protein levels and STAT3 Y705 phosphorylation levels in human laryngeal carcinoma specimens was found, which was more significant in the specimens derived from the smoker patients and with poor clinicopathological parameters. Our data identified SUMOylation as a previously undescribed post-translational modification of STAT3 and SENP3 as a critical positive modulator of tobacco- or cytokine-induced STAT3 activation. These findings provide novel insights into the hyperphosphorylation of STAT3 in development of HNC.

4-Hydroxy-2,3-Dimethyl-2-Nonen-4-Olide Has an Inhibitory Effect on Pro-Inflammatory Cytokine Production in CpG-Stimulated Bone Marrow-Derived Dendritic Cells

This study was intended to assess the anti-inflammatory properties of 4-hydroxy-2,3-dimethyl-2-nonen-4-olide (Comp) isolated from Ulva pertusa Kjellman on production of pro-inflammatory cytokines. Comp revealed remarkable inhibitory effects on production of pro-inflammatory cytokines in bone marrow-derived dendritic cells (BMDCs). Comp pre-treatment in the CpG DNA-stimulated BMDCs exhibited strong inhibition of interleukin (IL)-12 p40 and IL-6 production with IC₅₀ values ranging from 7.57 ± 0.2 to 10.83 ± 0.3, respectively. It revealed an inhibitory effect on the phosphorylation of ERK1/2, JNK1/2, and p38, and on activator protein (AP)-1 reporter activity. Comp displayed noteworthy inhibitory effects on phosphorylation and degradation of IκBα, and on NF-κB reporter activity. In summary, these data propose that Comp has substantial anti-inflammatory properties and warrants further study concerning its potential use as a therapeutic agent for inflammation-associated maladies.

Transient expression of Fc-fused human glycoprotein 130 in Expi293F suspension cells

Human glycoprotein 130 (gp130) is a signal-transducing receptor for interleukin 6 (IL-6), whose signaling plays a critical role in chronic inflammation and cancer. The soluble form of gp130 specifically inhibits IL-6 trans-signaling. However, achieving high-level expression of a large glycoprotein such as gp130 is difficult. Here, we designed and constructed one Fc-gp130-pcDNA mammalian expression vector, with the mouse IgG2a Fc fragment added to the N-terminus of human gp130, which greatly increased the secretion of recombinant gp130 protein from Expi293F suspension cells. Recombinant fusion Fc-gp130 was easily and efficiently purified from the supernatant of transfected cells by one-step affinity chromatography. Moreover, Fc-gp130 could automatically form dimers by the disulfide bond. Fc-gp130 was confirmed as a more efficient IL-6 trans-signaling blocker by its higher biological activity against signal transducer and activator of transcription 3 (STAT3). This purified active Fc-gp130 could be used to develop valuable therapeutic agents against inflammatory diseases and cancers.

Oleanolic acid inhibits colorectal cancer angiogenesis in vivo and in vitro via suppression of STAT3 and Hedgehog pathways

Angiogenesis is an essential process of cancer progression and is regulated by multiple intracellular signaling pathways, including signal transducer and activator of transcription 3 (STAT3) and sonic hedgehog (SHH). Thus, these pathways have become a promising target for anti‑cancer therapeutic strategies. Oleanolic acid (OA) is an active compound present in various herbal medicines, which have been used historically for the clinical treatment of various types of human malignancies, including colorectal cancer (CRC). The present study used a CRC mouse xenograft model and human umbilical vein endothelial cells (HUVECs) to evaluate the effect of OA on tumor angiogenesis and on the activation of the STAT3 and SHH signaling pathways. It was determined that OA treatment significantly inhibited tumor growth and reduced intratumoral microvessel density (MVD) in CRC mice. In addition, OA treatment inhibited the proliferation, migration and tube formation in HUVECs, in a dose and time-dependent manner. Furthermore, OA markedly suppressed the activation of the STAT3 and SHH signaling pathways and inhibited the expression of the pro‑angiogenic vascular endothelial growth factor A and basic fibroblast growth factor, two important target genes of the aforementioned signaling pathways. Therefore it is suggested that inhibition of tumor angiogenesis via the suppression of multiple signaling pathways may be one of the underlying mechanisms by which OA exerts its anti-cancer effect.

AIM2 inflammasome mediates Arsenic-induced secretion of IL-1 β and IL-18

Chronic sterile inflammation has been implicated in the pathogenesis of many cancers, including skin cancer. Chronic arsenic exposure is closely associated with the development of skin cancer. However, there is a lack of understanding how arsenic induces chronic inflammation in the skin. Interleukin-1 family cytokines play a central role in regulating immune and inflammatory response. IL-1α, IL-1β and IL-18 are three pro-inflammatory cytokines in IL-1 family. Their secretion, especially the secretion of IL-1β and IL-18, is regulated by inflammasomes which are multi-protein complexes containing sensor proteins, adaptor protein and caspase-1. The data from current study show sub-chronic arsenic exposure activates AIM2 inflammasome which in turn activates caspase-1 and enhances the secretion of IL-1β and IL-18 in HaCaT cells and the skin of BALB/c mice. In addition, arsenic-promoted activation of AIM2 inflammasome and increase of IL-1β/IL-18 production are inhibited by PKR inhibitor in HaCaT cells or in the skin of PKR mutant mice, indicating a potential role of PKR in arsenic-induced sterile inflammation.

Icaritin suppresses multiple myeloma, by inhibiting IL-6/JAK2/STAT3

Icaritin is an active prenylflavonoid derived from Epimedium genus, a traditional Chinese medicine. Icaritin has a wide range of pharmacological and biological activities, including cardiovascular function improvement, hormone regulation and antitumor activity. Here, we investigated the effect of icaritin on multiple myeloma (MM) in vitro and in vivo. Icaritin inhibited cell growth of MM cell line and primary MM cells. In contrast, icaritin had low or no cytotoxic effect on normal hematopoiesis. We also demonstrated that in MM xenograft mouse models, icaritin suppressed tumor growth and decreased serum IL-6 and IgE levels, but did not show adverse reactions such as body weight loss. The anti-MM activity of icaritin was mainly mediated by inhibiting IL-6/JAK2/STAT3 signaling. We suggest that icaritin can be further tested in clinical trials in MM.