TGF-beta suppresses tumor progression in colon cancer by inhibition of IL-6 trans-signaling

Bowel Radiation Injury: Complexity of the Pathophysiology and Promises of Cell and Tissue Engineering

Ionizing radiation is effective to treat malignant pelvic cancers, but the toxicity to surrounding healthy tissue remains a substantial limitation. Early and late side effects not only limit the escalation of the radiation dose to the tumor but may also be life-threatening in some patients. Numerous preclinical studies determined specific mechanisms induced after irradiation in different compartments of the intestine. This review outlines the complexity of the pathogenesis, highlighting the roles of the epithelial barrier in the vascular network, and the inflammatory microenvironment, which together lead to chronic fibrosis. Despite the large number of pharmacological molecules available, the studies presented in this review provide encouraging proof of concept regarding the use of mesenchymal stromal cell (MSC) therapy to treat radiation-induced intestinal damage. The therapeutic efficacy of MSCs has been demonstrated in animal models and in patients, but an enormous number of cells and multiple injections are needed due to their poor engraftment capacity. Moreover, it has been observed that although MSCs have pleiotropic effects, some intestinal compartments are less restored after a high dose of irradiation. Future research should seek to optimize the efficacy of the injected cells, particularly with regard to extending their life span in the irradiated tissue. Moreover, improving the host microenvironment, combining MSCs with other specific regenerative cells, or introducing new tissue engineering strategies could be tested as methods to treat the severe side effects of pelvic radiotherapy.

Dissecting Interleukin-6 Classic- and Trans-Signaling in Inflammation and Cancer

Interleukin-6 is a cytokine synthesized by many cells in the human body. IL-6 binds to a membrane bound IL-6R, which is only present on hepatocytes, some epithelial cells and some leukocytes. The complex of IL-6 and IL-6R binds to the ubiquitously expressed receptor subunit gp130, which forms a homodimer and thereby initiates intracellular signaling via the JAK/STAT and the MAPK pathways. IL-6R expressing cells can cleave the receptor protein to generate a soluble IL-6R (sIL-6R), which can still bind IL-6 and can associate with gp130 and induce signaling even on cells, which do not express IL-6R. This paradigm has been called IL-6 trans-signaling whereas signaling via the membrane bound IL-6R is referred to as classic signaling. We have generated several molecular tools to differentiate between IL-6 classic- and trans-signaling and to analyze the consequence of cellular IL-6 signaling in vivo.

Potential therapeutic implications of IL-6/IL-6R/gp130-targeting agents in breast cancer

Interleukin-6 (IL-6) is a pleiotropic cytokine with known multiple functions in immune regulation, inflammation, and oncogenesis. Binding of IL-6 to the IL-6 receptor (IL-6R) induces homodimerization and recruitment of glycoprotein 130 (gp130), which leads to activation of downstream signaling. Emerging evidence suggests that high levels of IL-6 are correlated with poor prognosis in breast cancer patients. IL-6 appears to play a critical role in the growth and metastasis of breast cancer cells, renewal of breast cancer stem cells (BCSCs), and drug resistance of BCSCs, making anti-IL-6/IL-6R/gp130 therapies promising options for the treatment and prevention of breast cancers. However, preclinical and clinical studies of the applications of anti-IL-6/IL-6R/gp130 therapy in breast cancers are limited. In this review, we summarize the structures, preclinical and clinical studies, mechanisms of action of chemical and biological blockers that directly bind to IL-6, IL-6R, or gp130, and the potential clinical applications of these pharmacological agents as breast cancer therapies.

Analgesic, anti-inflammatory and anticancer activities of Combretin A and Combretin B isolated from Combretum fragrans F. HOFFM (Combretaceae) leaves

Previous pharmacological and phytochemical studies showed that, Combretum fragrans F. HOFFM (Combretaceae) is a Cameroonian medicinal plant possessing numerous therapeutic virtues and rich in various active secondary metabolites. In this study, we investigate in vivo anti-nociceptive and anti-inflammatory activity and, in vitro anticancer, anti-TNFα, ROS and NO-inhibitory activities of Combretum A and Combretin B, two triterpenes cycloartane-type isolated from the leaves of Combretum fragrans. The effect on ROS, TNF-α and NO production, anticancer activity and cytotoxicity assay were done using chemiluminescence technique, ELISA kit, colorimetric method, MCF-7 cells and MTT assay, respectively. Antinociceptive and anti-inflammatory activities were estimated using a model of acetic acid, formalin and carrageenan. Combretin A and Combretin B significantly (p < 0.001) inhibited extracellular ROS production. These compounds also significantly (p < 0.001) reduced TNF-α and NO production. Moreover, these compounds decreased cell viability of MCF-7 cell lines. For acetic acid- or formalin-induced pain, as well as carrageenan-induced acute inflammation, Combretin A and Combretin B exhibited significant (p < 0.001) anti-nociceptive and anti-inflammatory activities. Anti-nociceptive, anti-inflammatory and anticancer potential associated with inhibitory effects on ROS, TNFα and NO production in this study show that, Combretin A and Combretin B could be considered as the promising chemotherapeutic agents in breast cancer treatment and inflammatory disease.

Role of ADAM10 in intestinal crypt homeostasis and tumorigenesis

A disintegrin and metalloproteinases (ADAMs) are a family of mSultidomain, membrane-anchored proteases that regulate diverse cellular functions, including cell adhesion, migration, proteolysis and other cell signaling events. Catalytically-active ADAMs act as ectodomain sheddases that proteolytically cleave type I and type II transmembrane proteins and some GPI-anchored proteins from the cellular surface. ADAMs can also modulate other cellular signaling events through a process known as regulated intramembrane proteolysis (RIP). Through their proteolytic activity, ADAMs can rapidly modulate key cell signaling pathways in response to changes in the extracellular environment (e.g. inflammation) and play a central role in coordinating intercellular communication. Dysregulation of these processes through aberrant expression, or sustained ADAM activity, is linked to chronic inflammation, inflammation-associated cancer and tumorigenesis. ADAM10 was the first disintegrin-metalloproteinase demonstrated to have proteolytic activity and is the prototypic ADAM associated with RIP activity (e.g. sequential Notch receptor processing). ADAM10 is abundantly expressed throughout the gastrointestinal tract and during normal intestinal homeostasis ADAM10 regulates many cellular processes associated with intestinal development, cell fate specification and maintenance of intestinal stem cell/progenitor populations. In addition, several signaling pathways that undergo ectodomain shedding by ADAM10 (e.g. Notch, EGFR/ErbB, IL-6/sIL-6R) help control intestinal injury/regenerative responses and may drive intestinal inflammation and colon cancer initiation and progression. Here, I review some of the proposed functions of ADAM10 associated with intestinal crypt homeostasis and tumorigenesis within the gastrointestinal tract in vivo. This article is part of a Special Issue entitled: Proteolysis as a Regulatory Event in Pathophysiology edited by Stefan Rose-John.

Cibinetide dampens innate immune cell functions thus ameliorating the course of experimental colitis

Two distinct forms of the erythropoietin receptor (EPOR) mediate the cellular responses to erythropoietin (EPO) in different tissues. EPOR homodimers signal to promote the maturation of erythroid progenitor cells. In other cell types, including immune cells, EPOR and the ß-common receptor (CD131) form heteromers (the innate repair receptor; IRR), and exert tissue protective effects. We used dextran sulphate sodium (DSS) to induce colitis in C57BL/6 N mice. Once colitis was established, mice were treated with solvent, EPO or the selective IRR agonist cibinetide. We found that both cibinetide and EPO ameliorated the clinical course of experimental colitis in mice, resulting in improved weight gain and survival. Correspondingly, DSS-exposed mice treated with cibinetide or EPO displayed preserved tissue integrity due to reduced infiltration of myeloid cells and diminished production of pro-inflammatory disease mediators including cytokines, chemokines and nitric oxide synthase-2. Experiments using LPS-activated primary macrophages revealed that the anti-inflammatory effects of cibinetide were dependent on CD131 and JAK2 functionality and were mediated via inhibition of NF-κB subunit p65 activity. Cibinetide activation of the IRR exerts potent anti-inflammatory effects, especially within the myeloid population, reduces disease activity and mortality in mice. Cibinetide thus holds promise as novel disease-modifying therapeutic of inflammatory bowel disease.

Açaí Berries Inhibit Colon Tumorigenesis in Azoxymethane/Dextran Sulfate Sodium-Treated Mice

Background/Aims

The aim of this study was to investigate the protective effect of açaí against azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced colorectal cancer development.

Methods

The effect of açaí on tumorigenesis was assessed by evaluating tumor incidence, multiplicity and invasiveness in the mouse colon. The levels of myeloperoxidase (MPO) and proinflammatory cytokines (tumor necrosis factor α [TNF-α], interleukin [IL]-1β, and IL-6) were measured via enzyme-linked immunosorbent assay. Protein levels of cyclooxygenase 2 (COX-2), proliferating cell nuclear antigen (PCNA), B-cell lymphoma 2 (Bcl-2), Bcl-2-associated death promoter (Bad) and cleaved-caspase-3 were assessed by immunoblotting.

Results

Administration of pellets containing 5% açaí powder reduced the incidences of both colonic adenoma and cancer (adenoma, 23.1% vs 76.9%, respectively, p=0.006; cancer, 15.4% vs 76.9%, respectively, p=0.002). In the açaí-treated mice, the MPO, TNF-α, IL-1β and IL-6 levels in the colon were significantly down-regulated. Açaí inhibited PCNA and Bcl-2 expression and increased Bad and cleaved-caspase-3 expression. In vitro studies demonstrated that açaí treatment reduced lipopolysaccharide-induced expression of TNF-α, IL-1β, IL-6 and COX-2 in murine macrophage RAW 264.7 cells.

Conclusions

Açaí demonstrated protective effects against AOM/DSS-induced colon carcinogenesis, which suggests that the intake of açaí may be beneficial for the prevention of human colon cancer.

Takinib, a Selective TAK1 Inhibitor, Broadens the Therapeutic Efficacy of TNF-α Inhibition for Cancer and Autoimmune Disease

Tumor necrosis factor alpha (TNF-α) has both positive and negative roles in human disease. In certain cancers, TNF-α is infused locally to promote tumor regression, but dose-limiting inflammatory effects limit broader utility. In autoimmune disease, anti-TNF-α antibodies control inflammation in most patients, but these benefits are offset during chronic treatment. TAK1 acts as a key mediator between survival and cell death in TNF-α-mediated signaling. Here, we describe Takinib, a potent and selective TAK1 inhibitor that induces apoptosis following TNF-α stimulation in cell models of rheumatoid arthritis and metastatic breast cancer. We demonstrate that Takinib is an inhibitor of autophosphorylated and non-phosphorylated TAK1 that binds within the ATP-binding pocket and inhibits by slowing down the rate-limiting step of TAK1 activation. Overall, Takinib is an attractive starting point for the development of inhibitors that sensitize cells to TNF-α-induced cell death, with general implications for cancer and autoimmune disease treatment.

Suppression of inflammation and tissue damage by a hookworm recombinant protein in experimental colitis

Gastrointestinal parasites, hookworms in particular, have evolved to cause minimal harm to their hosts when present in small numbers, allowing them to establish chronic infections for decades. They do so by creating an immunoregulatory environment that promotes their own survival, but paradoxically also benefits the host by protecting against the onset of many inflammatory diseases. To harness the therapeutic value of hookworms without using live parasites, we have examined the protective properties of the recombinant protein anti-inflammatory protein (AIP)-1, secreted in abundance by hookworms within the intestinal mucosa, in experimental colitis. Colitic inflammation assessed by weight loss, colon atrophy, oedema, ulceration and necrosis, as well as abdominal adhesion was significantly suppressed in mice treated with a single intraperitoneal dose of AIP-1 at 1 mg kg⁻¹. Local infiltration of inflammatory cells was also significantly reduced, with minimal goblet cell loss and preserved mucosal architecture. Treatment with AIP-1 promoted the production of colon interleukin (IL)-10, transforming growth factor (TGF)-β and thymic stromal lymphopoietin (TSLP), resulting in the suppression of tumour necrosis factor (TNF)-α, IL-13 and IL-17 A cytokines and granulocyte macrophage colony-stimulating factor (GM-CSF), CX motif chemokine (CXCL)-11 and cyclooxygenase synthase (COX)-2 mRNA transcripts. AIP-1 promoted the accumulation of regulatory T cells in the colon likely allowing rapid healing of the colon mucosa. Hookworm recombinant AIP-1 is a novel therapeutic candidate for the treatment of inflammatory bowel diseases that can be explored for the prevention of acute inflammatory relapses, an important cause of colorectal cancer.

Microbiome, inflammation and colorectal cancer

Chronic inflammation is linked to the development of multiple cancers, including those of the colon. Inflammation in the gut induces carcinogenic mutagenesis and promotes colorectal cancer initiation. Additionally, myeloid and lymphoid cells infiltrate established tumors and propagate so called "tumor-elicited inflammation", which in turn favors cancer development by supporting the survival and proliferation of cancer cells. In addition to the interaction between cancer cells and tumor infiltrating immune cells, the gut also hosts trillions of bacteria and other microbes, whose roles in colorectal inflammation and cancer have only been appreciated in the past decade or so. Commensal and pathobiotic bacteria promote colorectal cancer development by exploiting tumor surface barrier defects following cancer initiation, by invading normal colonic tissue and inducing local inflammation, and by generating genotoxicity against colonic epithelial cells to accelerate their oncogenic transformation. On the other hand, a balanced population of microbiota is important for the prevention of colorectal cancer due to their roles in providing certain bacterial metabolites and inhibiting intestinal inflammation. In this review we summarize our current knowledge regarding the link between microbiota, inflammation, and colorectal cancer, and aim to delineate the mechanisms by which gut microbiome and inflammatory cytokines regulate colorectal tumorigenesis.

Identification of molecular mechanisms of glutamine in pancreatic cancer

The aim of the present study was to explore the critical genes and molecular mechanisms in pancreatic cancer (PC) cells with glutamine. By analyzing microarray data GSE17632 from the Gene Expression Omnibus database, the DEGs between PC cells treated with glutamine and without glutamine were evaluated. Additionally, function enrichment analyses and protein-protein interaction (PPI) network construction of DEGs were performed. Network module and literature mining analyses were performed to analyze the critical DEGs in PC cells. In total, 495 genes were selected as DEGs between control and glutamine cells in PC. These DEGs were mainly enriched in several Gene Ontology (GO) terms in biological process, cellular components and molecular function. Additionally, they were also enriched in certain pathways, including metabolic pathways and the Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway. MYC, heat shock 70kDa protein 5 (HSPA5), interleukin 8 (IL8), and chemokine (C-X-C motif) receptor 4 (CXCR4) were hub genes in the PPI network. Furthermore, two sub-network modules of PPI network and two co-occurrence networks were obtained. The DEGs of MYC, HSPA5, IL18 and CXCR4 may exert important roles in molecular mechanisms of PC cells with glutamine.

MiR-490-5p Suppresses Cell Proliferation and Invasion by Targeting BUB1 in Hepatocellular Carcinoma Cells

OBJECTIVE

To verify that miR-490-5p could influence hepatocellular carcinoma (HCC) cells' proliferation, invasion, cycle, and apoptosis by targeting BUB1.

METHODS

Quantitative real time-PCR (QRT-PCR) was used to determine the miR-490-5p expression. Immunohistochemistry, qRT-PCR, and Western blot were employed to detect BUB1 and transforming growth factor-beta (TGFβ/Smad) signaling-related proteins expression in hepatic tissues and cells. The luciferase assay was used to confirm the targeting relationship between miR-490-5p and BUB1. The Cell Counting Kit-8, colony formation, Transwell invasion, scratch healing assays, and flow cytometry analysis were conducted to evaluate HCC cells proliferation, invasion, migration, and apoptosis alteration after transfection.

RESULTS

In HCC tissues and cells, lower expression of miR-490-5p was detected, while BUB1 was overexpressed than controls. The upregulation of miR-490-5p inhibited BUB1 expression and the overexpression of miR-490-5p or the under-expression of BUB1 inhibited HCC cells proliferation, migration, invasion, and increased the apoptosis rate.

CONCLUSION

MiR-490-5p could regulate TGFβ/Smad signaling pathways by inhibiting BUB1, which could then inhibit HCC cells proliferation, invasion, and migration as well as decrease cell viability and increase apoptosis.

The Role of Proinflammatory Pathways in the Pathogenesis of Colitis-Associated Colorectal Cancer

Patients with inflammatory bowel disease (IBD) are at an increased risk of developing colorectal cancer (CRC). The risk factors of CRC in IBD patients include long disease duration, extensive colitis, severe histological inflammation, and coexistence with primary sclerosing cholangitis (PSC). Several molecular pathways that contribute to sporadic CRC are also involved in the pathogenesis of colitis-associated CRC. It is well established that long-standing chronic inflammation is a key predisposing factor of CRC in IBD. Proinflammatory pathways, including nuclear factor kappa B (NF-κB), IL-6/STAT3, cyclooxygenase-2 (COX-2)/PGE2, and IL-23/Th17, promote tumorigenesis by inducing the production of inflammatory mediators, upregulating the expression of antiapoptotic genes, and stimulating cell proliferation as well as angiogenesis. Better understanding of the underlying mechanisms may provide some promising targets for prevention and therapy. This review aims to elucidate the role of these signaling pathways in the pathogenesis of colitis-associated CRC using evidence-based approaches.

Cancer secretome and inflammation: The bright and the dark sides of NF-κB

Tumour promoting inflammation is widely recognized as a hallmark of cancer. The source of this chronic inflammation in cancer has been ascribed to the progressive activation over time of immune cells, mostly of the innate arm of the immune system. However, recent evidence has shown that chronic inflammation may also derive, at least in part, from senescent cells. Hence, due to the prominent role of inflammation in cancer, the cancer secretome definition includes all the secretory factors ensuing from the crosstalk between the cancer cell and the tumour microenvironment. The mechanistic basis underlying the paracrine signalling between the cancer cell and the surrounding tumour microenvironment in malignancy have been widely investigated by using in vivo models of cancers, thus identifying the NF-κB transcription factor as the molecular hub linking inflammation and cancer. In this review, we highlight the roles of NF-κB in regulating the inflammation-derived secretome emanating from immune and senescent cells, with a special focus on the bright and the dark sides of their pro-inflammatory signalling on tumorigenesis.

Therapeutic Targeting of the IL-6 Trans-Signaling/Mechanistic Target of Rapamycin Complex 1 Axis in Pulmonary Emphysema

RATIONALE

The potent immunomodulatory cytokine IL-6 is consistently up-regulated in human lungs with emphysema and in mouse emphysema models; however, the mechanisms by which IL-6 promotes emphysema remain obscure. IL-6 signals using two distinct modes: classical signaling via its membrane-bound IL-6 receptor (IL-6R), and trans-signaling via a naturally occurring soluble IL-6R.

OBJECTIVES

To identify whether IL-6 trans-signaling and/or classical signaling contribute to the pathogenesis of emphysema.

METHODS

We used the gp130^F/F genetic mouse model for spontaneous emphysema and cigarette smoke-induced emphysema models. Emphysema in mice was quantified by various methods including in vivo lung function and stereology, and terminal deoxynucleotidyl transferase dUTP nick end labeling assay was used to assess alveolar cell apoptosis. In mouse and human lung tissues, the expression level and location of IL-6 signaling-related genes and proteins were measured, and the levels of IL-6 and related proteins in sera from emphysematous mice and patients were also assessed.

MEASUREMENTS AND MAIN RESULTS

Lung tissues from patients with emphysema, and from spontaneous and cigarette smoke-induced emphysema mouse models, were characterized by excessive production of soluble IL-6R. Genetic blockade of IL-6 trans-signaling in emphysema mouse models and therapy with the IL-6 trans-signaling antagonist sgp130Fc ameliorated emphysema by suppressing augmented alveolar type II cell apoptosis. Furthermore, IL-6 trans-signaling-driven emphysematous changes in the lung correlated with mechanistic target of rapamycin complex 1 hyperactivation, and treatment of emphysema mouse models with the mechanistic target of rapamycin complex 1 inhibitor rapamycin attenuated emphysematous changes.

CONCLUSIONS

Collectively, our data reveal that specific targeting of IL-6 trans-signaling may represent a novel treatment strategy for emphysema.

Increase in dietary protein content exacerbates colonic inflammation and tumorigenesis in azoxymethane-induced mouse colon carcinogenesis

BACKGROUND/OBJECTIVE

The incidence of colorectal cancer (CRC) has been attributed to higher intake of fat and protein. However, reports on the relationship between protein intake and CRC are inconsistent, possibly due to the complexity of diet composition. In this study, we addressed a question whether alteration of protein intake is independently associated with colonic inflammation and colon carcinogenesis.

MATERIALS/METHODS

Balb/c mice were randomly divided into 4 experimental groups: 20% protein (control, 20P, 20% casein/kg diet), 10% protein (10P, 10% casein/kg diet), 30% protein (30P, 30% casein/kg diet), and 50% protein (50P, 50% casein/kg diet) diet groups and were subjected to azoxymethane-dextran sodium sulfate induced colon carcinogenesis.

RESULTS

As the protein content of the diet increased, clinical signs of colitis including loss of body weight, rectal bleeding, change in stool consistency, and shortening of the colon were worsened. This was associated with a significant decrease in the survival rate of the mice, an increase in proinflammatory protein expression in the colon, and an increase in mucosal cell proliferation. Further, colon tumor multiplicity was dramatically increased in the 30P (318%) and 50P (438%) groups compared with the control (20P) group.

CONCLUSIONS

These results suggest that a high protein diet stimulates colon tumor formation by increasing colonic inflammation and proliferation.

Risk of colorectal cancer in chronic liver diseases: a systematic review and meta-analysis

BACKGROUND AND AIMS

The risk of colorectal cancer (CRC) in various chronic liver diseases compared with the general population remains unclear. We performed a systematic review and meta-analysis to assess the risk of CRC in patients with chronic liver diseases before and after liver transplantation.

METHODS

Electronic databases were searched for studies assessing the risk of CRC in patients with chronic liver diseases. The primary outcome was the pooled risk of CRC among studies that reported the risk as standardized incidence rate (SIR).

RESULTS

Fifty studies that included 55,991 patients were identified. Among studies that included hepatitis and cirrhotic patients, the pooled SIR was 2.06 (P < .0001; 95% confidence interval (CI), 1.46-2.90) with moderate heterogeneity (I² = 49.2%), which appeared to be because of the difference between subgroup of diseases and the power of studies. Three studies reported an increased risk of CRC in primary sclerosing cholangitis patients (pooled SIR 6.70; P < .0001; 95% CI, 3.48-12.91) with moderate heterogeneity (I² = 36.3%), which appeared to be because of the difference between the power of studies. Among studies that included post-transplant patients, the pooled SIR was 2.16 (P < .0001; 95% CI, 1.59-2.94) with moderate heterogeneity (I² = 56.4%). Meta-regression showed a correlation between the proportion of autoimmune-related liver diseases and the risk of CRC.

CONCLUSIONS

Patients with chronic liver diseases had an increased risk of CRC compared with the general population, which persisted after liver transplantation. A more intensive surveillance for CRC is warranted in this population.

Di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), an anticancer agent, exerts an anti-inflammatory effect in activated human mast cells

OBJECTIVE

Inflammation has been closely associated with the development and progression of cancer. Previously, we reported that mast cells play a critical role in tumor growth. The purpose of this study is to investigate the anti-inflammatory effect of an anticancer agent, di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), on an activated human mast cell line, in this case HMC-1 cells.

METHODS

We evaluated the effect and specific molecular mechanism of Dp44mT on phorbol 12-myristate 13-acetate and calcium ionophore A23187 (PMACI) using HMC-1 cells.

RESULTS

Here, we demonstrated that Dp44mT significantly decreased the protein levels of hypoxia-inducible factor-1α and vascular endothelial growth factor without exposing activated HMC-1 cells to any cytotoxicity. In activated mast cells, Dp44mT mitigated the strong production and mRNA expression of inflammatory cytokines, in this case, interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and thymic stromal lymphopoietin, through a blockade of caspase-1 and nuclear factor-κB activities. Furthermore, phosphorylations of the mitogen-activated protein kinase family included in inflammatory signaling cascades were significantly inhibited by a Dp44mT treatment.

CONCLUSIONS

Overall, our results indicate that the anticancer agent Dp44mT has an anti-inflammatory effect and may be of therapeutic importance for the treatment of mast cell-mediated inflammatory diseases.

The Therapeutic Potential of Anti-Inflammatory Exerkines in the Treatment of Atherosclerosis

Although many cardiovascular (CVD) medications, such as antithrombotics, statins, and antihypertensives, have been identified to treat atherosclerosis, at most, many of these therapeutic agents only delay its progression. A growing body of evidence suggests physical exercise could be implemented as a non-pharmacologic treatment due to its pro-metabolic, multisystemic, and anti-inflammatory benefits. Specifically, it has been discovered that certain anti-inflammatory peptides, metabolites, and RNA species (collectively termed “exerkines”) are released in response to exercise that could facilitate these benefits and could serve as potential therapeutic targets for atherosclerosis. However, much of the relationship between exercise and these exerkines remains unanswered, and there are several challenges in the discovery and validation of these exerkines. This review primarily highlights major anti-inflammatory exerkines that could serve as potential therapeutic targets for atherosclerosis. To provide some context and comparison for the therapeutic potential of exerkines, the anti-inflammatory, multisystemic benefits of exercise, the basic mechanisms of atherosclerosis, and the limited efficacies of current anti-inflammatory therapeutics for atherosclerosis are briefly summarized. Finally, key challenges and future directions for exploiting these exerkines in the treatment of atherosclerosis are discussed.

Proinflammatory Cytokines IL-6 and TNF-α Increased Telomerase Activity through NF-κB/STAT1/STAT3 Activation, and Withaferin A Inhibited the Signaling in Colorectal Cancer Cells

There are increasing evidences of proinflammatory cytokine involvement in cancer development. Here, we found that two cytokines, IL-6 and TNF-α, activated colorectal cancer cells to be more invasive and stem-like. Combined treatment of IL-6 and TNF-α phosphorylated transcription factors STAT3 in a synergistic manner. STAT3, STAT1, and NF-κB physically interacted upon the cytokine stimulation. STAT3 was bound to the promoter region of human telomerase reverse transcriptase (hTERT). IL-6 and TNF-α stimulation further enhanced STAT3 binding affinity. Stem cell marker Oct-4 was upregulated in colorectal cancer cells upon IL-6 and TNF-α stimulation. Withaferin A, an anti-inflammatory steroidal lactone, inhibited the IL-6- and TNF-α-induced cancer cell invasion and decreased colonosphere formation. Notably, withaferin A inhibited STAT3 phosphorylation and abolished the STAT3, STAT1, and NF-κB interactions. Oct-4 expression was also downregulated by withaferin A inhibition. The binding of STAT3 to the hTERT promoter region and telomerase activity showed reduction with withaferin A treatments. Proinflammatory cytokine-induced cancer cell invasiveness is mediated by a STAT3-regulated mechanism in colorectal cancer cells. Our data suggest that withaferin A could be a promising anticancer agent that effectively inhibits the progression of colorectal cancer.

Reelin protects from colon pathology by maintaining the intestinal barrier integrity and repressing tumorigenic genes

We previously reported that reelin, an extracellular matrix protein first known for its key role in neuronal migration, reduces the susceptibility to dextran sulphate sodium (DSS)-colitis. The aim of the current study was to determine whether reelin protects from colorectal cancer and how reelin defends from colon pathology. In the colon of wild-type and of mice lacking reelin (reeler mice) we have analysed the: i) epithelium cell renewal processes, ii) morphology, iii) Sox9, Cdx2, Smad5, Cyclin D1, IL-6 and IFNγ mRNA abundance in DSS-treated and untreated mice, and iv) development of azoxymethane/DSS-induced colorectal cancer, using histological and real time-PCR methodologies. The reeler mutation increases colitis-associated tumorigenesis, with increased tumours number and size. It also impairs the intestinal barrier because it reduces cell proliferation, migration, differentiation and apoptosis; decreases the number and maturation of goblet cells, and expands the intercellular space of the desmosomes. The intestinal barrier impairment might explain the increased susceptibility to colon pathology exhibited by the reeler mice and is at least mediated by the down-regulation of Sox9 and Cdx2. In response to DSS-colitis, the reeler colon increases the mRNA abundance of IL-6, Smad5 and Cyclin D1 and decreases that of IFNγ, conditions that might result in the increased colitis-associated tumorigenesis found in the reeler mice. In conclusion, the results highlight a role for reelin in maintaining intestinal epithelial cell homeostasis and providing resistance against colon pathology.

IL-6 Signaling Regulates Small Intestinal Crypt Homeostasis

Gut homeostasis is a tightly regulated process requiring finely tuned complex interactions between different cell types, growth factors, or cytokines and their receptors. Previous work has implicated a role for IL-6 and mucosal immune cells in intestinal regeneration following injury and in promoting inflammation and cancer. We hypothesized that IL-6 signaling could also modulate crypt homeostasis. Using mouse in vitro crypt organoid and in vivo models, this study first demonstrated that exogenous IL-6 promoted crypt organoid proliferation and increased stem cell numbers through pSTAT3 activation in Paneth cells. Immunolabeling studies showed that the IL-6 receptor was restricted to the basal membrane of Paneth cells both in vitro and in vivo and that the crypt epithelium also expressed IL-6. Either a blocking Ab to the IL-6 receptor or a neutralizing Ab to IL-6 significantly reduced in vitro basal crypt organoid proliferation and budding, and in vivo significantly reduced the number of nuclei and the number of Lgr5EGFP-positive stem cells per crypt compared with IgG-treated mice, with the number of Paneth cells per crypt also significantly reduced. Functional studies demonstrated that IL-6-induced in vitro crypt organoid proliferation and crypt budding was abrogated by the Wnt inhibitor IWP2. This work demonstrates that autocrine IL-6 signaling in the gut epithelium regulates crypt homeostasis through the Paneth cells and the Wnt signaling pathway.

Relationship of IL-17A and IL-17F genetic variations to cervical cancer risk: a meta-analysis

Aim: We performed a meta-analysis to determine a more precise relationship of IL-17A and IL-17F polymorphisms with cervical cancer risk. Materials & methods: PubMed, CNKI and Wan Fang databases were searched for studies on these associations using STATA version 10.0 software. Results: Five studies were included. The AG and AA genotypes and A allele of IL-17A rs2275913 were correlated with an elevated risk of cervical cancer. The TT genotype and T allele of IL-17A rs3748067 and the CC genotype and C allele of IL-17F rs763780 carried a moderate risk of cervical cancer, when compared with the wild-type genotype. Conclusion: IL-17A and IL-17F polymorphisms therefore have the potential to act as predictive biomarkers for cervical cancer risk.

Inhibition of Hematopoietic Cell Kinase Activity Suppresses Myeloid Cell-Mediated Colon Cancer Progression

Aberrant activation of the SRC family kinase hematopoietic cell kinase (HCK) triggers hematological malignancies as a tumor cell-intrinsic oncogene. Here we find that high HCK levels correlate with reduced survival of colorectal cancer patients. Likewise, increased Hck activity in mice promotes the growth of endogenous colonic malignancies and of human colorectal cancer cell xenografts. Furthermore, tumor-associated macrophages of the corresponding tumors show a pronounced alternatively activated endotype, which occurs independently of mature lymphocytes or of Stat6-dependent Th2 cytokine signaling. Accordingly, pharmacological inhibition or genetic reduction of Hck activity suppresses alternative activation of tumor-associated macrophages and the growth of colon cancer xenografts. Thus, Hck may serve as a promising therapeutic target for solid malignancies.

The molecular landscape of colitis-associated carcinogenesis

In spite of the well-established histopathological phenotyping of IBD-associated preneoplastic and neoplastic lesions, their molecular landscape remains to be fully elucidated. Several studies have pinpointed the initiating role of longstanding/relapsing inflammatory insult on the intestinal mucosa, with the activation of different pro-inflammatory cytokines (TNF-α, IL-6, IL-10, IFN-γ), chemokines and metabolites of arachidonic acid resulting in the activation of key transcription factors such as NF-κB. Longstanding inflammation may also modify the intestinal microbiota, prompting the overgrowth of genotoxic microorganisms, which may act as further cancer promoters. Most of the molecular dysregulation occurring in sporadic colorectal carcinogenesis is documented in colitis-associated adenocarcinoma too, but marked differences have been established in both their timing and prevalence. Unlike sporadic cancers, TP53 alterations occur early in IBD-related carcinogenesis, while APC dysregulation emerges mainly in the most advanced stages of the oncogenic cascade. From the therapeutic standpoint, colitis-associated cancers are associated with a lower prevalence of KRAS mutations than the sporadic variant. Epigenetic changes, including DNA methylation, histone modifications, chromatin remodeling, and non-coding RNAs, are significantly involved in colitis-associated cancer development and progression. The focus now is on identifying diagnostic and prognostic biomarkers, with a view to ultimately designing patient-tailored therapies.

Mesenchymal Cells in Colon Cancer

Mesenchymal cells in the intestine comprise a variety of cell types of diverse origins, functions, and molecular markers. They provide mechanical and structural support and have important functions during intestinal organogenesis, morphogenesis, and homeostasis. Recent studies of the human transcriptome have revealed their importance in the development of colorectal cancer, and studies from animal models have provided evidence for their roles in the pathogenesis of colitis-associated cancer and sporadic colorectal cancer. Mesenchymal cells in tumors, called cancer-associated fibroblasts, arise via activation of resident mesenchymal cell populations and the recruitment of bone marrow-derived mesenchymal stem cells and fibrocytes. Cancer-associated fibroblasts have a variety of activities that promote colon tumor development and progression; these include regulation of intestinal inflammation, epithelial proliferation, stem cell maintenance, angiogenesis, extracellular matrix remodeling, and metastasis. We review the intestinal mesenchymal cell-specific pathways that regulate these processes, with a focus on their roles in mediating interactions between inflammation and carcinogenesis. We also discuss how increasing our understanding of intestinal mesenchymal cell biology and function could lead to new strategies to identify and treat colitis-associated cancers.

Acetamides: chemotherapeutic agents for inflammation-associated cancers

Now clear evidences are available to support the hypothesis that inflammation accelerates the conditions including events and molecules that reach to various types of cancers. Inflammation is a normal response to infection containing the innate and adaptive immune systems. However, when allowed to continue, unresolved, perturbation of cellular microenvironment takes place; therefore, it leads to adaptations in genes that are linked to cancer. In addition, a lot of data are accessible confirming the concept that tumour microenvironment is orchestrated by various inflammatory cells and goes to neoplastic process and finally invasion, migration and metastasis. However, infiltrations of leucocytes lead to angiogenesis, propagation and invasion. An inflammatory microenvironment that perhaps fostering impact of angiogenesis include cytokines, chemokines, enzymes and growth factors that play key role for expansion and invasion of cancer cells. This insight highlights the pathogenesis of inflammation-associated cancers and also touches and fosters the role of acetamides for the treatment and chemoprevention of carcinomas that are allied with inflammation.

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.

Cytokine Signatures in Mucocutaneous and Ocular Behçet's Disease

Behçet's disease (BD) is a multi-systemic inflammatory disorder consisting of recurrent oral aphthosis, genital ulcers, and chronic relapsing bilateral uveitis; however, many other organs may be affected. Several pro-inflammatory cytokines, mainly derived from Th1 and Th17 lymphocytes, seem to be involved in different pathogenic pathways leading to development of the clinical manifestations. On this basis, the primary aim of our study was to compare a core set of pro-inflammatory cytokines between patients with BD and healthy control (HC). The secondary goal was to evaluate potential correlations between these putative circulating biomarkers, the status of disease activity, and the specific organ involvement at the time of sample collection. Fifty-four serum samples were collected from 46 BD patients (17 males, 29 females, mean age 45.5 ± 11.3 years), and 19 HC (10 males, 9 females, mean age 43 ± 8.3 years). Twenty-five serum cytokines (APRIL/TNFS13, BAFF/TNFSF13B, sCD30/TNFRSF8, sCD163, Chitinase3-like1, gp130/sIL-6Rb, IFNb, sIL-6Ra, IL-10, IL-11, IL-19, IL-20, IL-26, IL-27 (p28), IL-28A/IFN-lambda2, IL-29/IFN-lambda1, IL-32, IL-34, IL-35, LIGHT/TNFSF-14, Pentraxin-3, sTNF-R1, sTNF-R2, TSLP, and TWEAK/TNFSF-12) were simultaneously quantified using a Bio-Rad cytokine bead arrays. Serum concentration of sTNF-R1 (p < 0.01) and sTNF-R2 (p < 0.01) resulted higher in both active and inactive BD than HC, while Chitinase3-like1 (p < 0.05) and gp130/sIL-6Rb (p < 0.01) serum levels were significantly higher in inactive BD, and IL-26 (p < 0.01) in active BD than HC. No differences were observed between inactive and active BD group. In addition, we observed that gp130/sIL-6Rb, sIL-6Ra, IL-35, and TSLP serum levels were significantly enhanced in patients with mucocutaneous manifestations plus ocular involvement (MO-BD) compared to subgroup with only mucocutaneous involvement (M-BD). Our findings may suggest a signature of IL-6, tumor necrosis factor-α as well as of Th17 response in BD patients due to increased levels of gp130/sIL-6Rb, sTNF-R1, sTNF-R2, IL-26, respectively. This evidence could contribute to improve the knowledge regarding the role of these citokines in the induction of specific BD clinical features.

A food-based approach that targets interleukin-6, a key regulator of chronic intestinal inflammation and colon carcinogenesis

Studies have shown a causal link between high-calorie diet (HCD) and colon cancer. However, molecular mechanisms are not fully elucidated. To understand etiology of HCD-induced colon carcinogenesis, we screened 10 pathways linked to elevated colonic cell proliferation and chronic inflammation in an HCD-consuming human-relevant pig model. We observed elevated colonic mucosal interleukin-6 (IL-6) expression in HCD-consuming pigs compared to standard diet controls (SD, P=.04), and IL-6 strongly correlated with Ki-67 proliferative index and zone, early biomarkers of colon cancer risk (r=0.604 and 0.743 and P=.017 and .002, respectively). Liquid chromatography-tandem mass spectrometry-based proteomic analysis and Ingenuity Pathway Analysis showed that HCD consumption altered IL-6 signaling pathway proteins (PI3KR4, IL-1α, Mapk10, Akt3, PIK3CG, PIK3R5, Map2k2). Furthermore, these proteins also correlated with Ki-67 proliferative index/zone. Anti-IL-6 therapeutics are available for treating colon cancer; however, they are expensive and induce negative side effects. Thus, whole foods could be a better way to combat low-grade chronic colonic inflammation and colon cancer. Whole plant foods have been shown to decrease chronic diseases due to the potential of anti-inflammatory dietary compounds acting synergistically. We observed that supplementation of HCD with anthocyanin-containing purple-fleshed potatoes (10% w/w), even after baking, suppressed HCD-induced IL-6 expression (P=.03) and the IL-6-related proteins IL-1α and Map2k1 (P≤.1). Our results highlight the importance of IL-6 signaling in diet-linked induction/prevention of colonic inflammation/cancer and demonstrate the potential of a food-based approach to target IL-6 signaling.

Interleukins 1 and 6 as Main Mediators of Inflammation and Cancer

The idea of a potential link between cancer and inflammation was first proposed by R. Virchow in the nineteenth century. However, clear evidence regarding a key role of inflammation in oncogenesis appeared only during the last decade. Now the tumor microenvironment is commonly considered as an obligatory and significant component of almost all types of cancer, and the cells infiltrating such microenvironment are a source of inflammatory cytokines. Such cytokines play a key role in regulating inflammation during both normal immune response and developing cancer. In this review, we explore the role of two inflammatory cytokines interleukin 1 and interleukin 6 in cancer development. These cytokines have pleiotropic effects on various cell types in the tumor microenvironment, particularly being able to regulate pro-oncogenic transcription factors NF-κB and STAT3. For this reason, such cytokines influence key parameters of oncogenesis, increasing cell resistance to apoptosis, proliferation of cancer cells, angiogenesis, invasion and malignancy as well as the ability of tumor cells to respond to anticancer therapy. Here we summarize novel experimental data regarding mechanisms underlying the interaction between chronic inflammation and malignant neoplasms.

The Effect of Sex on the Azoxymethane/Dextran Sulfate Sodium-treated Mice Model of Colon Cancer

Background

The colitis-associated cancer exhibits different characteristics according to sex in the initiation and progression of the tumors. The aim of this study was to investigate the sex-associated difference in the azoxymethane/dextran sulfate sodium (AOM/DSS)-induced colitis-associated cancer model.

Methods

The AOM/DSS ICR mouse model was established to compare male with female, and then the severity of colitis-associated carcinogenesis was examined macroscopically and histologically regarding the number, size, and location of tumors. Subsequently, levels of colonic mucosal cytokine, interleukin (IL)-1β and myeloperoxidase (MPO) were assessed.

Results

At the 16th week, the tumor multiplicity and the pro-inflammatory factors differed according to sex. The total tumor number was significantly higher in male (P = 0.020) and the number of large tumors (diameter > 2 mm) was higher in male (P = 0.026). In male, the tumors located more in distal colon (P = 0.001). MPO was significantly higher in AOM/DSS-treated male mice compared to the control group (P = 0.003), whereas the corresponding female group showed no significant change (P = 0.086). Colonic IL-1β level significantly increased in AOM/DSS groups compared to control groups both in male and female (male, P = 0.014; female, P = 0.005). It was higher in male group; however, there was no statistical significance (P = 0.226).

Conclusions

In AOM/DSS murine model, colitis-associated colon tumorigenesis are induced more severely in male mice than female probably by way of inflammatory mediators such as IL-1β and MPO. The sex-related differences at the animal model of colon cancer suggest the importance of approach to disease with sex-specific medicine in human.

The PD1:PD-L1/2 Pathway from Discovery to Clinical Implementation

The immune system maintains a critically organized network to defend against foreign particles, while evading self-reactivity simultaneously. T lymphocytes function as effectors and play an important regulatory role to orchestrate the immune signals. Although central tolerance mechanism results in the removal of the most of the autoreactive T cells during thymic selection, a fraction of self-reactive lymphocytes escapes to the periphery and pose a threat to cause autoimmunity. The immune system evolved various mechanisms to constrain such autoreactive T cells and maintain peripheral tolerance, including T cell anergy, deletion, and suppression by regulatory T cells (TRegs). These effects are regulated by a complex network of stimulatory and inhibitory receptors expressed on T cells and their ligands, which deliver cell-to-cell signals that dictate the outcome of T cell encountering with cognate antigens. Among the inhibitory immune mediators, the pathway consisting of the programed cell death 1 (PD-1) receptor (CD279) and its ligands PD-L1 (B7-H1, CD274) and PD-L2 (B7-DC, CD273) plays an important role in the induction and maintenance of peripheral tolerance and for the maintenance of the stability and the integrity of T cells. However, the PD-1:PD-L1/L2 pathway also mediates potent inhibitory signals to hinder the proliferation and function of T effector cells and have inimical effects on antiviral and antitumor immunity. Therapeutic targeting of this pathway has resulted in successful enhancement of T cell immunity against viral pathogens and tumors. Here, we will provide a brief overview on the properties of the components of the PD-1 pathway, the signaling events regulated by PD-1 engagement, and their consequences on the function of T effector cells.

Pharmacological and immunological targeting of tumor mesenchymalization

Controlling the spread of carcinoma cells to distant organs is the foremost challenge in cancer treatment, as metastatic disease is generally resistant to therapy and is ultimately incurable for the majority of patients. The plasticity of tumor cell phenotype, in which the behaviors and functions of individual tumor cells differ markedly depending upon intrinsic and extrinsic factors, is now known to be a central mechanism in cancer progression. Our expanding knowledge of epithelial and mesenchymal phenotypic states in tumor cells, and the dynamic nature of the transitions between these phenotypes has created new opportunities to intervene to better control the behavior of tumor cells. There are now a variety of innovative pharmacological approaches to preferentially target tumor cells that have acquired mesenchymal features, including cytotoxic agents that directly kill these cells, and inhibitors that block or revert the process of mesenchymalization. Furthermore, novel immunological strategies have been developed to engage the immune system in seeking out and destroying mesenchymalized tumor cells. This review highlights the relevance of phenotypic plasticity in tumor biology, and discusses recently developed pharmacological and immunological means of targeting this phenomenon.

Anti-inflammatory natural product goniothalamin reduces colitis-associated and sporadic colorectal tumorigenesis

The tumor microenvironment offers multiple targets for cancer therapy, including pro-tumorigenic inflammation. Natural compounds represent an enormous source of new anti-inflammatory and anticancer agents. We previously showed that the styryl lactone goniothalamin (GTN) has promising antiproliferative and anti-inflammatory activities. Because inflammation is a major driver of colorectal cancer (CRC), we therefore evaluated the therapeutic and preventive potentials of GTN in colitis, colitis-associated cancer (CAC) and spontaneous CRC. First, in a simplistic model of inflammation in vitro, GTN was able to inhibit cytokine production in bone marrow-derived macrophages induced by lipopolysaccharide. Next, in dextran sulfate sodium (DSS) induced-colitis model, mice treated with GTN displayed restored tissue architecture, increased cell proliferation in the colonic crypts and reduced epithelial damage. Moreover, colon tissue from GTN-treated mice had significantly less expression of the inflammatory genes interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), S100A9, interleukin 23A (IL-23A), IL-22 and IL-17A In the azoxymethane/DSS model of CAC, GTN reduced tumor multiplicity, load and size. Additionally, GTN suppressed production of IL-6, IL-17 and TNF-α in tumor tissue, as well as abrogated stromal immune cell activation and nuclear translocation of NF-κB. Finally, in a tamoxifen inducible model of sporadic CRC, GTN-treated mice had significantly fewer tumors and decreased levels of IL-17A, IL-6, S100A9 and TNF-α protein within the tumors. These results suggest that GTN possesses anti-inflammatory and antitumor activities and represents a preventive and therapeutic agent modulating the inflammatory environment in the colon during colitis as well as CAC and CRC development.

Survivin is a guardian of the intestinal stem cell niche and its expression is regulated by TGF-β

As an inhibitor of apoptosis (IAP) family member, Survivin is known for its role during regulation of apoptosis. More recently its function as a cell cycle regulator has become evident. Survivin was shown to play a pivotal role during embryonic development and is highly expressed in regenerative tissue as well as in many cancer types. We examined the function of Survivin during mouse intestinal organogenesis and in gut pathophysiology. We found high expression of Survivin in experimentally induced colon cancer in mice but also in colon tumors of humans. Moreover, Survivin was regulated by TGF-β and was found to be highly expressed during mucosal healing following intestinal inflammation. We identified that expression of Survivin is essential early on in life, as specific deletion of Survivin in Villin expressing cells led to embryonic death around day 12 post coitum. Together with our recent study on the role of Survivin in the gut of adult mice our data demonstrate that Survivin is an essential guardian of embryonic gut development and adult gut homeostasis protecting the epithelium from cell death promoting the proliferation of intestinal stem and progenitor cells.

Interleukin-6 promotes tumor progression in colitis-associated colorectal cancer through HIF-1α regulation

Interleukin-6 (IL-6) is a well-known etiological factor of colitis-associated colorectal cancer (CAC) and has a significant role in CAC progression. In addition, hypoxia-inducible factor 1α (HIF-1α) serves a primary role in the progression of CAC. However, the association between IL-6 and HIF-1α during the progression of CAC remains unclear. To investigate this association, the present study induced CAC in a mouse model using azoxymethane and dextran sulfate sodium. In addition, an anti-IL-6 receptor antibody was used to inhibit IL-6. In this model, anti-IL-6 receptor antibody treatment significantly inhibited the development of CAC and the expression of HIF-1α, in colorectal adenomas and adenocarcinomas. In patients with CAC, the HIF-1α gene was demonstrated to be overexpressed in tumor tissue compared with adjacent non-malignant tissue. Furthermore, HIF-1α mRNA expression was positively correlated with serum IL-6 concentration. The results of the present study suggest that IL-6 promotes CAC progression, in the early stage of the disease, through HIF-1α regulation.

Regulatory T Cells and Cancer: A Two-Sided Story

Regulatory T cells (Tregs) play pivotal roles in limiting the duration and magnitude of immune response against infectious agents and self-antigens. This is accomplished through contact-dependent and -independent mechanisms that involve crosstalk between Treg cells and other immune and tissue-specific cell types. The same machinery is employed by Tregs to regulate immune responses to cancer, limiting both pro-tumor inflammation and anti-tumor immunity. Factors produced by Treg cells also act directly on transformed epithelial cells and exert opposing effects during different stages of cancer development. Therefore, the immune regulatory cell population serves as a double-edged sword for the development, progression, and treatment of cancers. In this review, we summarize current knowledge on the roles of Treg lymphocytes during cancer development, as well as the underlying cellular and molecular mechanism.

RAID3--An interleukin-6 receptor-binding aptamer with post-selective modification-resistant affinity

Aptamers are an emerging class of highly specific targeting ligands. They can be selected in vitro for a large variety of targets, ranging from small molecules to whole cells. Most aptamers selected are nucleic acid-based, allowing chemical synthesis and easy modification. Although their properties make them interesting drug candidates for a broad spectrum of applications and an interesting alternative to antibodies or fusion proteins, they are not yet broadly used. One major drawback of aptamers is their susceptibility to abundant serum nucleases, resulting in their fast degradation in biological fluids. Using modified nucleic acids has become a common strategy to overcome these disadvantages, greatly increasing their half-life under cell culture conditions or even in vivo. Whereas pre-selective modifications of the initial library for aptamer selection are relatively easy to obtain, post-selective modifications of already selected aptamers are still generally very labor-intensive and often compromise the aptamers ability to bind its target molecule. Here we report the selection, characterization and post-selective modification of a 34 nucleotide (nt) RNA aptamer for a non-dominant, novel target site (domain 3) of the interleukin-6 receptor (IL-6R). We performed structural analyses and investigated the affinity of the aptamer to the membrane-bound and soluble forms (sIL-6R) of the IL-6R. Further, we performed structural analyses of the aptamer in solution using small-angle X-ray scattering and determined its overall shape and oligomeric state. Post-selective exchange of all pyrimidines against their 2'-fluoro analogs increased the aptamers stability significantly without compromising its affinity for the target protein. The resulting modified aptamer could be shortened to its minimal binding motif without loss of affinity.

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.

STAT3 in the systemic inflammation of cancer cachexia

Weight loss is diagnostic of cachexia, a debilitating syndrome contributing mightily to morbidity and mortality in cancer. Most research has probed mechanisms leading to muscle atrophy and adipose wasting in cachexia; however cachexia is a truly systemic phenomenon. Presence of the tumor elicits an inflammatory response and profound metabolic derangements involving not only muscle and fat, but also the hypothalamus, liver, heart, blood, spleen and likely other organs. This global response is orchestrated in part through circulating cytokines that rise in conditions of cachexia. Exogenous Interleukin-6 (IL6) and related cytokines can induce most cachexia symptomatology, including muscle and fat wasting, the acute phase response and anemia, while IL-6 inhibition reduces muscle loss in cancer. Although mechanistic studies are ongoing, certain of these cachexia phenotypes have been causally linked to the cytokine-activated transcription factor, STAT3, including skeletal muscle wasting, cardiac dysfunction and hypothalamic inflammation. Correlative studies implicate STAT3 in fat wasting and the acute phase response in cancer cachexia. Parallel data in non-cancer models and disease states suggest both pathological and protective functions for STAT3 in other organs during cachexia. STAT3 also contributes to cancer cachexia through enhancing tumorigenesis, metastasis and immune suppression, particularly in tumors associated with high prevalence of cachexia. This review examines the evidence linking STAT3 to multi-organ manifestations of cachexia and the potential and perils for targeting STAT3 to reduce cachexia and prolong survival in cancer patients.

Prognostic significance of neutrophil-to-lymphocyte ratio in rectal cancer: a meta-analysis

BACKGROUND

Inflammatory responses play decisive roles in tumor development, immune surveillance, and responses to therapy. High neutrophil-to-lymphocyte ratio (NLR), as an inflammation index, has been reported to be a predictor for poor prognosis of various cancers. The purpose of this meta-analysis was to evaluate the prognostic value of NLR in patients with rectal cancer.

METHODS

A comprehensive search of the literature was conducted through PubMed and EMBASE. Pooled hazard ratio (HR) with 95% confidence interval (CI) was used to evaluate the association between NLR and three outcomes: overall survival, disease-free survival, and recurrence-free survival.

RESULTS

Seven cohorts involving 959 patients were included in this meta-analysis. Our pooled results demonstrated that elevated NLR was associated with poor overall survival (HR: 13.41, 95% CI: 4.90-36.72), disease-free survival (HR: 4.37, 95% CI: 2.33-8.19), and recurrence-free survival (HR: 3.64, 95% CI: 1.88-7.05).

CONCLUSION

An elevated NLR is a valuable and easily available prognostic marker for rectal cancer. It is associated with unfavorable overall survival, disease-free survival, and recurrence-free survival. NLR could be a useful candidate factor for making treatment decisions for individual patients with rectal cancer.

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.

Reparative inflammation takes charge of tissue regeneration

Inflammation underlies many chronic and degenerative diseases, but it also mitigates infections, clears damaged cells and initiates tissue repair. Many of the mechanisms that link inflammation to damage repair and regeneration in mammals are conserved in lower organisms, indicating that it is an evolutionarily important process. Recent insights have shed light on the cellular and molecular processes through which conventional inflammatory cytokines and Wnt factors control mammalian tissue repair and regeneration. This is particularly important for regeneration in the gastrointestinal system, especially for intestine and liver tissues in which aberrant and deregulated repair results in severe pathologies.

Cytokine-Induced Modulation of Colorectal Cancer

The emergence of novel immunomodulatory cancer therapies over the last decade, above all immune checkpoint blockade, has significantly advanced tumor treatment. For colorectal cancer (CRC), a novel scoring system based on the immune cell infiltration in tumors has greatly improved disease prognostic evaluation and guidance to more specific therapy. These findings underline the relevance of tumor immunology in the future handling and therapeutic approach of malignant disease. Inflammation can either promote or suppress CRC pathogenesis and inflammatory mediators, mainly cytokines, critically determine the pro- or anti-tumorigenic signals within the tumor environment. Here, we review the current knowledge on the cytokines known to be critically involved in CRC development and illustrate their mechanisms of action. We also highlight similarities and differences between CRC patients and murine models of CRC and point out cytokines with an ambivalent role for intestinal cancer. We also identify some of the future challenges in the field that should be addressed for the development of more effective immunomodulatory therapies.

Expression of the novel adipokine C1qTNF-related protein 4 (CTRP4) suppresses colitis and colitis-associated colorectal cancer in mice

Inflammatory bowel disease (IBD) is an important factor in the induction of colon cancer, but its mechanism is unclear. Colitis and colitis-associated colorectal cancer (CAC) models induced using both dextran sulfate sodium (DSS) and the azoxymethane/DSS protocol were established in wild-type (WT) and CTRP4 transgenic (CTRP4-tg) C57BL6/J mice. Body weight, stool consistency and the presence of blood in the stool were analyzed; tumor quantity, size and histological characteristics were analyzed during the development of CAC. The CTRP4-tg mice exhibited significantly reduced colitis and developed far fewer macroscopic tumors; these tumors were smaller in size, and a majority of the colon tumors in these mice were restricted to the superficial mucosa. Tumors of lower grades were observed in the CTRP4-tg mice. Interleukin-6 was markedly downregulated in the CTRP4-tg mice during CAC tumorigenesis. The phosphorylation of ERK, signal transducer and activator of transcription 3 and Akt in the colon and the proliferation of intestinal epithelial cells were decreased in the CTRP4-tg mice. The injection of recombinant CTRP4 protein significantly reduced the colitis symptoms of the WT mice. CTRP4 plays an important role in inflammation and inflammation-associated colon tumorigenesis, and our research may provide a novel method for the treatment of IBD and CAC.

Vancomycin-sensitive bacteria trigger development of colitis-associated colon cancer by attracting neutrophils

Inflammatory bowel disease confers an increased risk of developing colitis-associated colon cancer (CAC). During the active colitis or developing tumor stage, commensal bacteria show dynamic translocation. However, whether alteration of the bacterial composition in the gut causes CAC is still unclear. To clarify the effect of commensal bacteria on CAC development, we employed an azoxymethane (AOM) and dextran sodium sulfate (DSS)-induced murine CAC model treated with or without antibiotics. In addition, we analyzed the effects of antibiotics on infiltration of myeloid cells, colonic inflammatory responses, and colorectal cancer formation. We found that vancomycin treatment dramatically suppressed tumor development. In addition, AOM/DSS treatment greatly induced the infiltration of Gr-1^high/CD11b^high neutrophils to the colon, which led to the production of tumor necrosis factor α and inducible nitric oxide synthase. Vancomycin treatment suppressed the infiltration of neutrophils induced by AOM/DSS. Moreover, vancomycin treatment greatly reduced the colon injury and DNA damage caused by AOM/DSS-induced NO radicals. Our results indicate that vancomycin-sensitive bacteria induced colon inflammation and DNA damage by attracting neutrophils into damaged colon tissue, thus promoting tumor formation.