Suppressor of cytokine signaling 3 (SOCS3) limits damage-induced crypt hyper-proliferation and inflammation-associated tumorigenesis in the colon

Vinpocetine attenuates 5-fluorouracil-induced intestinal injury: role of the Keap1/Nrf2/HO-1, NF-κB/TLR4/SOCS3 and RIPK1/RIPK3/MLKL signals

OBJECTIVES

5-Fluorouracil (5-FU) is a chemotherapy drug commonly prescribed in cancer management. Unfortunately, intestinal mucositis restricts 5-FU clinical use. Vinpocetine (VNP) is a synthetic alkaloid that is derived from vincamine. Our study was conducted to elucidate the intestinal protective effects of VNP on 5-FU intestinal injury in rats and explore the underlying mechanisms.

MATERIALS AND METHODS

5-FU was injected i.p. for five days, while VNP was given P.O (5 and 10 mg/kg).

RESULTS

VNP effectively mitigates oxidative stress by a significant increase in GSH and SOD and decreasing MDA content mediated by Nrf2, HO-1 upregulation, and significant Keap1 downregulation. VNP mitigated inflammatory perturbations by decreasing MPO, TNF-α, IL-1β, and IL-6 facilitated by downregulating NF-κB and TLR4 and upregulating SOCS3 levels. In addition, the RIPK1, RIPK3, MLKL, and caspase-8 expression levels were significantly decreased, evidenced improvement of intestinal necroptosis by VNP.

CONCLUSION

Hence, VNP potently prevents intestinal injury induced by 5-FU by modulating Keap1/Nrf2/HO-1, NF-κB/TLR4/SOCS3, and RIPK1/RIPK3/MLKL signals.

A Negative Regulatory Feedback Loop within the JAK-STAT Pathway Mediated by the Protein Tyrosine Phosphatase DUSP14 in Shrimp

The JAK-STAT pathway is a central communication node for various biological processes. Its activation is characterized by phosphorylation and nuclear translocation of the transcription factor STAT. The regulatory balance of JAK-STAT signaling is important for maintenance of immune homeostasis. Protein tyrosine phosphatases (PTPs) induce dephosphorylation of tyrosine residues in intracellular proteins and generally function as negative regulators in cell signaling. However, the roles of PTPs in JAK-STAT signaling, especially in invertebrates, remain largely unknown. Pacific white shrimp Penaeus vannamei is currently an important model for studying invertebrate immunity. This study identified a novel member of the dual-specificity phosphatase (DUSP) subclass of the PTP superfamily in P. vannamei, named PvDUSP14. By interacting with and dephosphorylating STAT, PvDUSP14 inhibits the excessive activation of the JAK-STAT pathway, and silencing of PvDUSP14 significantly enhances humoral and cellular immunity in shrimp. The promoter of PvDUSP14 contains a STAT-binding motif and can be directly activated by STAT, suggesting that PvDUSP14 is a regulatory target gene of the JAK-STAT pathway and mediates a negative feedback regulatory loop. This feedback loop plays a role in maintaining homeostasis of JAK-STAT signaling and is involved in antibacterial and antiviral immune responses in shrimp. Therefore, the current study revealed a novel inhibitory mechanism of JAK-STAT signaling, which is of significance for studying the regulatory mechanisms of immune homeostasis in invertebrates.

M2 Macrophage-Derived Extracellular Vesicles Containing MicroRNA-501-3p Promote Colon Cancer Progression Through the SETD7/DNMT1/SOCS3 Axis

BACKGROUND

Macrophage-derived extracellular vesicles with microRNAs can cause and develop colon cancer.

OBJECTIVE

To investigate M2 macrophage-derived extracellular vesicles and colon cancer.

DESIGN

A prospective and experimental study of M2 macrophage-derived extracellular vesicles in colon cancer.

SETTING

This study was completed at the Fourth Hospital of Hebei Medical University.

PATIENTS

Patients with colon cancer who had undergone surgical resection.

MAIN OUTCOME MEASURES

Suppressor of cytokine signaling 3, miR-501-3p, SET domain containing 7, and DNA methyltransferase 1 were measured in colon cancer samples. Multiple experiments determined suppressor of cytokine signaling 3, miR-501-3p, SET domain containing 7, and DNA methyltransferase 1 binding affinity. M2 macrophages were cultivated from M0 macrophages isolated from peripheral blood mononuclear cells of a healthy donor and polarized to produce extracellular vesicles. Gain- or loss-of-function tests using colon cancer cells and M2 macrophage-derived extracellular vesicles revealed cell biological processes. Finally, animal models were created to test how miR-501-3p from M2-extracellular vesicles affects tumor growth via the SET domain containing 7/DNA methyltransferase 1/suppressor of cytokine signaling 3.

RESULTS

Colon cancer increased miR-501-3p and DNA methyltransferase 1 and downregulated suppressor of cytokine signaling 3 and SET domain containing 7. miR-151-3p inhibited SET domain containing 7, upregulating DNA methyltransferase 1. Increased promoter methylation by DNA methyltransferase 1 decreased suppressor of cytokine signaling 3 expression. M2-EVs with miR-501-3p regulated the SET domain containing 7/DNA methyltransferase 1/suppressor of cytokine signaling 3 axis to induce apoptosis and colon cancer cell growth, invasion, and migration. M2-EV-delivered miR-501-3p also regulated the SET domain containing 7/DNA methyltransferase 1/suppressor of cytokine signaling 3 axis to promote tumor growth in animals.

LIMITATIONS

Further research is needed in clinical application of M2 macrophage-derived extracellular vesicles containing miR-501-3p as a biomarker of colon cancer.

CONCLUSIONS

M2 macrophage-derived extracellular vesicles with miR-501-3p regulate the SET domain containing 7/DNA methyltransferase 1/suppressor of cytokine signaling 3 axis to promote colon cancer.

LAS VESCULAS EXTRACELULARES DERIVADAS DE MACRFAGOS M QUE CONTIENEN MICROARNP PROMUEVEN LA PROGRESIN DEL CNCER DE COLON A TRAVS DEL EJE SETD/DNMT/SOCS

ANTECEDENTES:Las vesículas extracelulares derivadas de macrófagos con microARN pueden causar y desarrollar cáncer de colon.OBJETIVO:Investigamos las vesículas extracelulares derivadas de macrófagos M2 y el cáncer de colon.DISEÑO:Un estudio prospectivo y experimental de vesículas extracelulares derivadas de macrófagos M2 en el cáncer de colon.ESCENARIO:Este estudio se completó en el Cuarto Hospital de la Universidad Médica de Hebei.PACIENTES:Pacientes con cáncer de colon sometidos a resección quirúrgica.PRINCIPALES MEDIDAS DE RESULTADO:Se midieron el supresor de la señalización de citoquinas 3, miR-501-3p, SETD7 y la ADN metiltransferasa 1 en muestras de cáncer de colon. Múltiples experimentos determinaron la afinidad de unión del supresor de la señalización de citoquinas 3, de miR-501-3p, de SETD7 y de la ADN metiltransferasa 1. Los macrófagos M2 se cultivaron a partir de macrófagos M0 aislados de células mononucleares de sangre periférica de donantes sanos y se polarizaron para producir vesículas extracelulares. Las pruebas de ganancia o pérdida de función utilizando células de cáncer de colon y vesículas extracelulares derivadas de macrófagos M2 revelaron procesos biológicos celulares. Finalmente, se crearon modelos animales para probar cómo miR-501-3p de vesículas extracelulares M2 afecta el crecimiento tumoral a través del SETD7/ADN metiltransferasa 1/supresor de la señalización de citocinas 3.RESULTADOS:El cáncer de colon aumentó el miR-501-3p y la ADN metiltransferasa 1 y reguló negativamente el supresor de la señalización de citoquinas 3 y SETD7. miR-151-3p inhibió SETD7, regulando positivamente la ADN metiltransferasa 1. El aumento de la metilación del promotor por la ADN metiltransferasa 1 produjo disminución de la expresión del supresor de señalización de citocinas 3. Los M2-EV con miR-501-3p regularon el eje SETD7/ADN metiltransferasa 1/supresor de la señalización de citocinas 3 para inducir apoptosis y crecimiento, invasión y migración de células de cáncer de colon. El miR-501-3p administrado por M2-EV también reguló el eje SETD7/ADN metiltransferasa 1/supresor de la señalización de citocinas 3 para promover el crecimiento tumoral en animales.LIMITACIONES:Se necesita más investigación en la aplicación clínica de vesículas extracelulares derivadas de macrófagos M2 que contienen miR-501-3p como biomarcador de cáncer de colon.CONCLUSIONES:Las vesículas extracelulares derivadas de macrófagos M2 con miR-501-3p regulan el eje SETD7/ADN metiltransferasa 1/supresor de la señalización de citocinas 3 para promover el cáncer de colon. (Traducción-Dr. Felipe Bellolio ).

Sparassis latifolia polysaccharides inhibit colon cancer in mice by modulating gut microbiota and metabolism

Sparassis latifolia polysaccharides (SLPs) can regulate inflammatory cytokines. However, little is known about the regulation mechanism of SLPs on colon cancer. In this study, we investigated the mechanism of SLPs on metabolism in mice with colon cancer. The results showed that SLPs could improve the colon morphology and physiological indices, and inhibit the infiltration of immune cells in colon. Moreover, it could improve metabolism disorder of colon cancer via reducing the levels of TNF-α, IL-6, NF-κB, COX-2 and IL-1β mRNA or protein, increasing IκB mRNA or protein expression. In addition, it could comprehensively regulate the colon cancer related metabolism by changing the abundance of key intestinal flora and 35 metabolites including phosphatidylcholine, tryptophan and tetrahydrobiopterin. Some biomarkers associated with colon cancer metabolism were related significantly with the abundance of specific intestinal flora. These findings indicate that SLPs can attenuate metabolism disorder of colon cancer by modulating gut microbiota and metabolites.

Insights into radiation carcinogenesis based on dose-rate effects in tissue stem cells

PURPOSE

Increasing epidemiological and biological evidence suggests that radiation exposure enhances cancer risk in a dose-dependent manner. This can be attributed to the 'dose-rate effect,' where the biological effect of low dose-rate radiation is lower than that of the same dose at a high dose-rate. This effect has been reported in epidemiological studies and experimental biology, although the underlying biological mechanisms are not completely understood. In this review, we aim to propose a suitable model for radiation carcinogenesis based on the dose-rate effect in tissue stem cells.

METHODS

We surveyed and summarized the latest studies on the mechanisms of carcinogenesis. Next, we summarized the radiosensitivity of intestinal stem cells and the role of dose-rate in the modulation of stem-cell dynamics after irradiation.

RESULTS

Consistently, driver mutations can be detected in most cancers from past to present, supporting the hypothesis that cancer progression is initiated by the accumulation of driver mutations. Recent reports demonstrated that driver mutations can be observed even in normal tissues, which suggests that the accumulation of mutations is a necessary condition for cancer progression. In addition, driver mutations in tissue stem cells can cause tumors, whereas they are not sufficient when they occur in non-stem cells. For non-stem cells, tissue remodeling induced by marked inflammation after the loss of tissue cells is important in addition to the accumulation of mutations. Therefore, the mechanism of carcinogenesis differs according to the cell type and magnitude of stress. In addition, our results indicated that non-irradiated stem cells tend to be eliminated from three-dimensional cultures of intestinal stem cells (organoids) composed of irradiated and non-irradiated stem cells, supporting the stem-cell competition.

CONCLUSIONS

We propose a unique scheme in which the dose-rate dependent response of intestinal stem cells incorporates the concept of the threshold of stem-cell competition and context-dependent target shift from stem cells to whole tissue. The concept highlights four key issues that should be considered in radiation carcinogenesis: i.e. accumulation of mutations; tissue reconstitution; stem-cell competition; and environmental factors like epigenetic modifications.

SOCS3 as a potential driver of lung metastasis in colon cancer patients

Background

The suppressor of cytokine signaling 3 (SOCS3) is the negative feedback regulator of the JAK-STAT signaling pathway. The purpose of our study was to investigate the SOCS3 status in colon primary tumor and lung metastasis and its relationship with macrophages.

Methods

The SOCS3 expression pattern and its relationship with the immune response in pan-cancer was investigated using multiple methods. Samples and corresponding clinical information of 32 colon cancer patients with lung metastasis were collected, and the CD68, CD163, and SOCS3 status were conducted using immunohistochemistry (IHC). The relationship between SOCS3 status and macrophage markers was analyzed. Besides, we explored the molecular mechanisms of SOCS3 in lung metastasis via the TCGA database.

Results

High SOCS3 expression was more inclined to poor prognosis and was positively correlated with main immune cell infiltration in almost each cancer type, especially in colon cancer. Compared with the colon primary tumor, lung metastasis harbored higher CD163 and SOCS3 expression, and high SOCS3 expression was more likely to be associated with high CD163 expression in lung metastasis. Besides, the exceptional differentially expressed genes in lung metastasis significantly enriched in immune responses and regulations.

Conclusions

SOCS3 possessed value as a prognostic marker and target for immunotherapeutic intervention in different tumors and might be a potential target of tumor progression and tumor immunotherapy in colon cancer.

SMRT and NCoR1 fine-tune inflammatory versus tolerogenic balance in dendritic cells by differentially regulating STAT3 signaling

Dendritic cell (DC) fine-tunes inflammatory versus tolerogenic responses to protect from immune-pathology. However, the role of co-regulators in maintaining this balance is unexplored. NCoR1-mediated repression of DC immune-tolerance has been recently reported. Here we found that depletion of NCoR1 paralog SMRT (NCoR2) enhanced cDC1 activation and expression of IL-6, IL-12 and IL-23 while concomitantly decreasing IL-10 expression/secretion. Consequently, co-cultured CD4+ and CD8+ T-cells depicted enhanced Th1/Th17 frequency and cytotoxicity, respectively. Comparative genomic and transcriptomic analysis demonstrated differential regulation of IL-10 by SMRT and NCoR1. SMRT depletion represses mTOR-STAT3-IL10 signaling in cDC1 by down-regulating NR4A1. Besides, Nfkbia and Socs3 were down-regulated in Ncor2 (Smrt) depleted cDC1, supporting increased production of inflammatory cytokines. Moreover, studies in mice showed, adoptive transfer of SMRT depleted cDC1 in OVA-DTH induced footpad inflammation led to increased Th1/Th17 and reduced tumor burden after B16 melanoma injection by enhancing oncolytic CD8+ T-cell frequency, respectively. We also depicted decreased Ncor2 expression in Rheumatoid Arthritis, a Th1/Th17 disease.

Augmented leptin-induced trefoil factor 3 expression and epidermal growth factor receptor transactivation differentially influences neoplasia progression in the stomach and colorectum of dietary fat-induced obese mice

Obesity is a risk factor for gastrointestinal malignancies and tumors. However, which factors either protect or predispose the gastrointestinal organs to high-fat diet (HFD)-induced neoplasia remains unclear. Here, we demonstrate that HFD impacts the stomach to a greater extent as compared to the colorectum, resulting in leptin receptor (LepR) signaling-mediated neoplasia in the tissues. HFD activated leptin signaling, which in turn, accelerates the pathogenesis in the gastric mucosa more than that in the colorectum along with ectopic TFF3 expression. Moreover, in the stomach, higher levels of phosphorylated epidermal growth factor receptor (EGFR) in addition to the activation of STAT3 and Akt were observed as compared to the colorectum. The mice with LepR deletion in the gastrointestinal epithelium exhibited a suppressed induction of leptin, TFF3, and phosphorylated EGFR in the stomach, whereas the levels in the colorectum were insignificant. In co-transfected COS-7 cells with LepR and EGFR plasmid DNA, leptin transactivated EGFR to accelerate TFF3 induction along with activation of STAT3, ERK1/2, Akt, and PI3K p85/p55. Furthermore, TFF3 could bind to EGFR but did not transactivate LepR. Leptin-induced TFF3 induction was markedly suppressed by inhibitors of PI3K (LY294002) and EGFR (Erlotinib). Together, these results suggest a novel role of LepR-mediated signaling in transactivating EGFR that leads to TFF3 expression via the PI3K-Akt pathway. Therefore, this study sheds light on the identification of potentially new therapeutic targets for the treatment of pre-cancerous symptoms in stomach and colorectum.

Molecular characterization and immunoregulatory analysis of suppressors of cytokine signaling 1 (SOCS1) in black rockfish, Sebastes schlegeli

The suppressors of cytokine signaling (SOCS) family are important soluble mediators to inhibit signal transduction via the Janus kinase/signal transducer and activator of transcription (JAK-STAT) pathway in the innate and adaptive immune responses. SOCS1 is the primary regulator of a number of cytokines. In this study, two spliced transcripts of SOCS1 were identified and characterized from black rockfish (Sebastes schlegeli), named SsSOCS1a and SsSOCS1b. SsSOCS1a and SsSOCS1b contained conserved structural and functional domains including KIR region, ESS region, SH2 domain and SOCS box. SsSOCS1a and SsSOCS1b were distributed ubiquitously in all the detected tissues with the higher expression level in liver and spleen. After stimulation in vivo with Vibrio anguillarum and Edwardsiella tarda, the mRNA expression of SsSOCS1a and SsSOCS1b were induced in most of the immune-related tissues, including head kidney, spleen and liver. Meanwhile, poly I:C and IFNγ up-regulated the expression of SsSOCS1a and SsSOCS1b that reached the highest level at 24 h in macrophages in vitro. Luciferase assays in HEK293 cells showed SsSOCS1a and SsSOCS1b had the similar function in inhibiting ISRE activity after poly I:C and IFNγ treatment. Furthermore, KIR domain in black rockfish was determined to have a negative regulatory role in IFN signaling. SsSOCS1a and SsSOCS1b were found to interact strongly with each other by Co-immunoprecipitation analyses. These results indicated that the function of SOCS1 in the negative regulation of IFN signaling is conserved from teleost to mammals which will be helpful to further understanding of the biological functions of teleosts SOCS1 in innate immunity.

Loss of aryl hydrocarbon receptor suppresses the response of colonic epithelial cells to IL22 signaling by upregulating SOCS3

IL22 signaling plays an important role in maintaining gastrointestinal epithelial barrier function, cell proliferation, and protection of intestinal stem cells from genotoxicants. Emerging studies indicate that the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, promotes production of IL22 in gut immune cells. However, it remains to be determined if AhR signaling can also affect the responsiveness of colonic epithelial cells to IL22. Here, we show that IL22 treatment induces the phosphorylation of STAT3, inhibits colonic organoid growth, and promotes colonic cell proliferation in vivo. Notably, intestinal cell-specific AhR knockout (KO) reduces responsiveness to IL22 and compromises DNA damage response after exposure to carcinogen, in part due to the enhancement of suppressor of cytokine signaling 3 (SOCS3) expression. Deletion of SOCS3 increases levels of pSTAT3 in AhR KO organoids, and phenocopies the effects of IL22 treatment on wild-type (WT) organoid growth. In addition, pSTAT3 levels are inversely associated with increased azoxymethane/dextran sulfate sodium (AOM/DSS)-induced colon tumorigenesis in AhR KO mice. These findings indicate that AhR function is required for optimal IL22 signaling in colonic epithelial cells and provide rationale for targeting AhR as a means of reducing colon cancer risk.NEW & NOTEWORTHY AhR is a key transcription factor controlling expression of IL22 in gut immune cells. In this study, we show for the first time that AhR signaling also regulates IL22 response in colonic epithelial cells by modulating SOCS3 expression.

SOCS Proteins in Immunity, Inflammatory Diseases, and Immune-Related Cancer

Cytokine signaling represents one of the cornerstones of the immune system, mediating the complex responses required to facilitate appropriate immune cell development and function that supports robust immunity. It is crucial that these signals be tightly regulated, with dysregulation underpinning immune defects, including excessive inflammation, as well as contributing to various immune-related malignancies. A specialized family of proteins called suppressors of cytokine signaling (SOCS) participate in negative feedback regulation of cytokine signaling, ensuring it is appropriately restrained. The eight SOCS proteins identified regulate cytokine and other signaling pathways in unique ways. SOCS1–3 and CISH are most closely involved in the regulation of immune-related signaling, influencing processes such polarization of lymphocytes and the activation of myeloid cells by controlling signaling downstream of essential cytokines such as IL-4, IL-6, and IFN-γ. SOCS protein perturbation disrupts these processes resulting in the development of inflammatory and autoimmune conditions as well as malignancies. As a consequence, SOCS proteins are garnering increased interest as a unique avenue to treat these disorders.

Benzo[a]pyrene stimulates miR-650 expression to promote the pathogenesis of fatty liver disease and hepatocellular carcinoma via SOCS3/JAK/STAT3 cascades

Modern diets, which often feature high levels of fat and charcoal-grilled meat, contribute to the pathogenesis of obesity and nonalcoholic fatty liver disease (NAFLD), resulting in liver cancer progression. Benzo(a)pyrene (B[a]P) is a common environmental and foodborne pollutant found in smoke and fire-grilled foods, which can have an adverse effect on human health. Hepatocellular carcinoma (HCC) is the fifth leading cause of cancer and the second leading cause of cancer-related deaths worldwide. The epidemiological studies suggest that both environmental risk factors and chronic liver injury including NAFL are important for HCC development, but the precise mechanisms linking eating habits to hepato-carcinogenesis remain unclear. In the present study, we demonstrated that various miRNAs in B[a]P-exposed tumor cells contribute to tumor metastasis, among which miR-650 could be the most potent inducer. Furthermore, we found that suppressor of cytokine signaling 3 (SOCS3) is directly regulated by miR-650 and its suppression regulates the activation of the Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) cascade. Our findings reveal a possible adverse outcome pathway of SOCS3/JAK/STAT3 regulation in B[a]P-induced HCC progress. These results provide a better understanding of the adverse effects of chronic exposure to B[a]P on human health.

The Use of Bio-Active Compounds of Citrus Fruits as Chemopreventive Agents and Inhibitor of Cancer Cells Viability

Common therapy of cancer, such as chemotherapy, has various side effects for the patients. In recent studies, new therapeutic approaches in cancer treatment are adjuvant therapy, along with a reduction in side effects of chemotherapy drugs. Treatment by herbal medicines may have some advantages over treatment with single purified chemicals, also in terms of side effects, the use of plants in cancer treatment is a more secure method. Citrus fruits are one of the most consumed natural products in the world due to the presence of various metabolites and bioactive compounds, such as phenols, flavonoids and, carotenoids. Bioactive compounds of citrus modulate signaling pathways and interact with signaling molecules such as apoptotic and cell cycle (P53, P21, etc.) and thus have a wide range of pharmacological activities, including anti-inflammatory, anti-cancer and oxidative stress. The findings discussed in this review strongly support their potential as anti-cancer agents. Therefore, the purpose of this review was to examine the effects of active compounds in citrus as a therapy agent in cancer treatment.

From inflammation to colitis-associated colorectal cancer in inflammatory bowel disease: Pathogenesis and impact of current therapies

The risk of colorectal cancer (CRC) is higher in patients with inflammatory bowel disease (IBD). Population-based data from patients with ulcerative colitis (UC) estimate that the risk of CRC is approximately 2- to 3-fold that of the general population; patients with Crohn's disease appear to have a similar increased risk. However, the true extent of colitis-associated cancer (CAC) in undertreated IBD is unclear. Data suggest that the size (i.e., severity and extent) and persistence of the inflammatory process is largely responsible for the development of CRC in IBD. As patients with IBD and CRC have a worse prognosis than those without a history of IBD, the impact of current therapies for IBD on CAC is of importance. Chronic inflammation of the gut has been shown to increase the risk of developing CAC in both UC and CD. Therefore, control of inflammation is pivotal to the prevention of CAC. This review presents an overview of the current knowledge of CAC in IBD patients, focusing on the role of inflammation in the pathogenesis of CAC and the potential for IBD drugs to interfere with the process of carcinogenesis by reducing the inflammatory process or by modulating pathways directly involved in carcinogenesis.

RIPK3 Suppresses the Progression of Spontaneous Intestinal Tumorigenesis

Receptor-interacting protein 3 (RIPK3), a member of the family of serine/threonine protein kinases, emerged as a critical regulator of necroptosis. Downregulated expression of RIPK3 is correlated with poor prognosis in multiple tumor types. Here, we show that RIPK3 is involved in the progression of spontaneous intestinal tumorigenesis. As a clinical correlate, reduced expression of RIPK3 is positively associated with histological grade, lymphatic metastasis and poor prognosis in CRC patients. RIPK3-deficient (Ripk3-/- ) mice exhibit increased tumor formation in Apcmin/+ spontaneous intestinal tumorigenesis. Apcmin/+Ripk3-/- tumors promote hyperactivation of IL-6/STAT3 signaling, which exacerbates proliferation and inhibits apoptosis. Blocking IL-6 signaling suppressed tumor formation and reduced STAT3 activation in Apcmin/+Ripk3-/- mice. Thus, our results reveal that RIPK3 is a tumor suppressor in spontaneous intestinal tumorigenesis, and implicate targeting the IL-6/STAT3 signaling axis as a potential therapeutic strategy for intestinal tumor patients with reduced RIPK3.

Cells of the Innate and Adaptive Immune Systems in Kaposi's Sarcoma

Kaposi's sarcoma (KS) is an angioproliferative malignancy whose associated etiologic agent is the Kaposi's sarcoma-associated herpesvirus (KSHV). KS is the most prevalent malignancy among HIV-infected individuals globally and is considered an AIDS-defining malignancy. The different forms of KS including HIV-associated KS, iatrogenic (immunosuppression-related) KS, and classical KS in elderly males suggest that immune cell dysregulation is among the key components in promoting KS development in KSHV-infected individuals. It is therefore expected that different cell types of the immune system likely play distinct roles in promoting or inhibiting KS development. This narrative review is focused on discussing cells of the innate and adaptive immune systems in KSHV infection and KS pathogenesis, including how these cells can be useful in the control of KSHV infection and treatment of KS.

Farnesoid X receptor activation induces antitumour activity in colorectal cancer by suppressing JAK2/STAT3 signalling via transactivation of SOCS3 gene

Farnesoid X receptor (FXR, encoded by NR1H4), a bile acid‐activated nuclear receptor, is widely implicated in human tumorigenesis. The FXR agonist obeticholic acid (OCA) has preliminarily displayed tumour suppressor potential. However, the anticancer effects of this agent on colorectal cancer (CRC) remain unclear. In this study, the treatment of colon cancer cells with OCA inhibited cell proliferation and invasion in vitro, retarded tumour growth in vivo and prevented the G₀/G₁ to S phase transition. Moreover, the expression of active caspase‐3, p21 and E‐cadherin was up‐regulated and the expression of cyclin D1, c‐Myc, vimentin, N‐cadherin and MMP9 was down‐regulated in OCA‐treated colon cancer cells. Mechanistic studies indicated that OCA treatment suppressed the activity of JAK2/STAT3 pathway by up‐regulating SOCS3 expression. Colivelin, an agonist of JAK2/STAT3 pathway, antagonized the tumour‐suppressive effect of OCA on colon cancer cells. Dual‐luciferase reporter and quantitative chromatin immunoprecipitation (qChIP) assays further confirmed that OCA promoted SOCS3 transcription by enhancing the binding of FXR to the FXRE/IR9 of the SOCS3 promoter. In conclusion, our study demonstrates that targeting FXR and improving its function might be a promising strategy for CRC treatment.

Transcriptome Changes in Colorectal Cancer Cells upon Treatment with Avicequinone B

Purpose: Naphtho[2,3-b]furan-4,9-dione (Avicequinone B), a natural naphthoquinone isolated from the mangrove tree Avicennia alba , is recognized as a valuable synthetic precursor with anti-proliferative effect. However, the molecular mechanism involved in its bioactivity has not been investigated. This study aimed to determine the selectivity of avicequinone B against cancer cells and the transcriptomic changes induced in colorectal cancer (CRC).

Methods: The cytotoxic effect against adenocarcinoma-derived cells or fibroblasts was evaluated using MTT assay. In addition, CRC cells were treated with avicequinone B in different settings to evaluate colony-forming ability, cell cycle progression, apoptosis/necrosis induction, and transcriptome response by RNA-seq.

Results: Avicequinone B effectively reduced the viability of breast, colorectal, and lung adenocarcinoma cells with IC₅₀ lower than 10 μM, while fibroblasts were less affected. The induction of G2/M arrest and necrosis-like cell death were observed in avicequinone B-treated HT-29 cells. Furthermore, RNA-seq revealed 490 differentially expressed genes, highlighting the reduction of interferon stimulated genes and proliferative signaling pathways (JAK-STAT, MAPK, and PI3K-AKT), as well as the induction of ferroptosis and miR-21 expression.

Conclusion: In short, these results demonstrated the therapeutic potential of avicequinone B and paved the foundation for elucidating its mechanisms in the context of CRC.

Identification of integrin β6 gene promoter and analysis of its transcription regulation in colon cancer cells

BACKGROUND

The integrin β6 gene, which is expressed in epithelial cancer, plays a pivotal role in various aspects of cancer progression. The present research for integrin β6 regulation mainly focuses on the post-transcription and translation related regulation mechanism and its role in tumorigenesis. The mechanisms of how the integrin β6 gene is regulated transcriptionally, and the promoter and transcription factors responsible for basic transcription of integrin β6 gene remain unknown.

AIM

To clone and characterize the integrin β6 promoter.

METHODS

Software analysis was used to predict the region of integrin β6 promoter. Luciferase reporter plasmids, which contained the integrin β6 promoter, were constructed. Element deletion analysis was performed to identify the location of core promoter and binding sites for transcription factors.

RESULTS

The regulatory elements for the transcription of the integrin β6 gene were located between -286 and -85 and contained binding sites for transcription factors such as STAT3 and Ets-1.

CONCLUSION

For the first time, we found the region of β6 core promoter and demonstrated the binding sites for transcription factors such as Ets-1 and STAT3, which are important for integrin β6 promoter transcription activity. These findings are important for investigating the mechanism of integrin β6 activation in cancer progression.

Trillin prevents proliferation and induces apoptosis through inhibiting STAT3 nuclear translocation in hepatoma carcinoma cells

Trillin is a constituent of total Trillium Tschonoskii Maxim (TTM), which is extracted from TTM and displayed anti-tumor effect in many tumor cell lines. However, the anti-tumor mechanism of trillin is still unclear. This study demonstrated that trillin could dramatically inhibit hepatoma carcinoma cell proliferation, induce apoptosis and decrease migration and invasion through suppressing phosphorylated STAT3 translocated to nucleus. Trillin could down-regulate Bcl-2 and Survivin, up-regulate cleaved PRAP, leading to dramatically apoptosis; trillin could also down-regulate MMP1, MMP2, MucI and VEGF, which displayed an inhibition effect on hepatocellular tumor cells invasion and development. The results of this study indicated the potential utility of trillin as a STAT3 inhibitor for the treatment of cancers.

STAT3 and STAT5 Activation in Solid Cancers

The Signal Transducer and Activator of Transcription (STAT)3 and 5 proteins are activated by many cytokine receptors to regulate specific gene expression and mitochondrial functions. Their role in cancer is largely context-dependent as they can both act as oncogenes and tumor suppressors. We review here the role of STAT3/5 activation in solid cancers and summarize their association with survival in cancer patients. The molecular mechanisms that underpin the oncogenic activity of STAT3/5 signaling include the regulation of genes that control cell cycle and cell death. However, recent advances also highlight the critical role of STAT3/5 target genes mediating inflammation and stemness. In addition, STAT3 mitochondrial functions are required for transformation. On the other hand, several tumor suppressor pathways act on or are activated by STAT3/5 signaling, including tyrosine phosphatases, the sumo ligase Protein Inhibitor of Activated STAT3 (PIAS3), the E3 ubiquitin ligase TATA Element Modulatory Factor/Androgen Receptor-Coactivator of 160 kDa (TMF/ARA160), the miRNAs miR-124 and miR-1181, the Protein of alternative reading frame 19 (p19ARF)/p53 pathway and the Suppressor of Cytokine Signaling 1 and 3 (SOCS1/3) proteins. Cancer mutations and epigenetic alterations may alter the balance between pro-oncogenic and tumor suppressor activities associated with STAT3/5 signaling, explaining their context-dependent association with tumor progression both in human cancers and animal models.

Negative regulators of STAT3 signaling pathway in cancers

STAT3 is the most ubiquitous member of the STAT family and involved in many biological processes, such as cell proliferation, differentiation, and apoptosis. Mounting evidence has revealed that STAT3 is aberrantly activated in many malignant tumors and plays a critical role in cancer progression. STAT3 is usually regarded as an effective molecular target for cancer treatment, and abolishing the STAT3 activity may diminish tumor growth and metastasis. Recent studies have shown that negative regulators of STAT3 signaling such as PIAS, SOCS, and PTP, can effectively retard tumor progression. However, PIAS, SOCS, and PTP have also been reported to correlate with tumor malignancy, and their biological function in tumorigenesis and antitumor therapy are somewhat controversial. In this review, we summarize actual knowledge on the negative regulators of STAT3 in tumors, and focus on the potential role of PIAS, SOCS, and PTP in cancer treatment. Furthermore, we also outline the STAT3 inhibitors that have entered clinical trials. Targeting STAT3 seems to be a promising strategy in cancer therapy.

Control of Tyrosine Kinase Signalling by Small Adaptors in Colorectal Cancer

Tyrosine kinases (TKs) phosphorylate proteins on tyrosine residues as an intracellular signalling mechanism to coordinate intestinal epithelial cell communication and fate decision. Deregulation of their activity is ultimately connected with carcinogenesis. In colorectal cancer (CRC), it is still unclear how aberrant TK activities contribute to tumour formation because TK-encoding genes are not frequently mutated in this cancer. In vertebrates, several TKs are under the control of small adaptor proteins with potential important physiopathological roles. For instance, they can exert tumour suppressor functions in human cancer by targeting several components of the oncogenic TK signalling cascades. Here, we review how the Src-like adaptor protein (SLAP) and the suppressor of cytokine signalling (SOCS) adaptor proteins regulate the SRC and the Janus kinase (JAK) oncogenic pathways, respectively, and how their loss of function in the intestinal epithelium may influence tumour formation. We also discuss the potential therapeutic value of these adaptors in CRC.

Identification of potential biomarkers related to glioma survival by gene expression profile analysis

BACKGROUND

Recent studies have proposed several gene signatures as biomarkers for different grades of gliomas from various perspectives. However, most of these genes can only be used appropriately for patients with specific grades of gliomas.

METHODS

In this study, we aimed to identify survival-relevant genes shared between glioblastoma multiforme (GBM) and lower-grade glioma (LGG), which could be used as potential biomarkers to classify patients into different risk groups. Cox proportional hazard regression model (Cox model) was used to extract relative genes, and effectiveness of genes was estimated against random forest regression. Finally, risk models were constructed with logistic regression.

RESULTS

We identified 104 key genes that were shared between GBM and LGG, which could be significantly correlated with patients' survival based on next-generation sequencing data obtained from The Cancer Genome Atlas for gene expression analysis. The effectiveness of these genes in the survival prediction of GBM and LGG was evaluated, and the average receiver operating characteristic curve (ROC) area under the curve values ranged from 0.7 to 0.8. Gene set enrichment analysis revealed that these genes were involved in eight significant pathways and 23 molecular functions. Moreover, the expressions of ten (CTSZ, EFEMP2, ITGA5, KDELR2, MDK, MICALL2, MAP 2 K3, PLAUR, SERPINE1, and SOCS3) of these genes were significantly higher in GBM than in LGG, and comparing their expression levels to those of the proposed control genes (TBP, IPO8, and SDHA) could have the potential capability to classify patients into high- and low- risk groups, which differ significantly in the overall survival. Signatures of candidate genes were validated, by multiple microarray datasets from Gene Expression Omnibus, to increase the robustness of using these potential prognostic factors. In both the GBM and LGG cohort study, most of the patients in the high-risk group had the IDH1 wild-type gene, and those in the low-risk group had IDH1 mutations. Moreover, most of the high-risk patients with LGG possessed a 1p/19q-noncodeletion.

CONCLUSION

In this study, we identified survival relevant genes which were shared between GBM and LGG, and those enabled to classify patients into high- and low-risk groups based on expression level analysis. Both the risk groups could be correlated with the well-known genetic variants, thus suggesting their potential prognostic value in clinical application.

[Role of cytokine signal suppressor 3 in the regulatory mechanism of colon cancer invasion and proliferation]

OBJECTIVE

To investigate the expression of cytokine signal suppressor 3 (SOCS3) in colon cancer tissue and the mechanism by which SOCS3 regulates the proliferation and invasion of colon cancer.

METHODS

We collected the specimens of tumor tissues and paired adjacent tissues from 80 patients with colon cancer undergoing radical resection in our hospital between July, 2014 and May, 2017, and the expression of SOCS3 in the tissue samples was analyzed using Western blotting. We also transfected colon cancer cell line SW480 with a SOCS3-overexpressing plasmid or a small interference RNA (siRNA) for SOCS3 knockdown, and the changes in the cell proliferation and invasion capacity were evaluated using CCK-8 assay and Transwell assay, respectively. The effect of demethylation and IL-6 treatment on SOCS3 expression and the proliferation and invasion of SW480 cells were observed.

RESULTS

Colon cancer tissues showed a lowered expression of SOCS3 compared with the adjacent tissues. Over-expression of SOCS3 significantly inhibited while SOCS3 knockdown obviously promoted the proliferation and invasion of SW480 cells in vitro. Demethylation treatment up-regulated SOCS3 expression and inhibited the proliferation and invasion capacity of SW480 cells; IL-6 treatment of the cells caused the reverse changes.

CONCLUSIONS

SOCS3 participates in the development and progression of colon cancer and serves as a potential target for colon cancer treatment. In patients with colon cancer, the low expression of SOCS3 possibly as a result of methylation may promote the proliferation and invasion of the cancer cells.

JAK/STAT signaling in stem cells and regeneration: from Drosophila to vertebrates

The JAK/STAT pathway is a conserved metazoan signaling system that transduces cues from extracellular cytokines into transcriptional changes in the nucleus. JAK/STAT signaling is best known for its roles in immunity. However, recent work has demonstrated that it also regulates critical homeostatic processes in germline and somatic stem cells, as well as regenerative processes in several tissues, including the gonad, intestine and appendages. Here, we provide an overview of JAK/STAT signaling in stem cells and regeneration, focusing on Drosophila and highlighting JAK/STAT pathway functions in proliferation, survival and cell competition that are conserved between Drosophila and vertebrates.

Quantitative assessment of gene promoter methylation in non-small cell lung cancer using methylation-sensitive high-resolution melting

DNA methylation is closely associated with aberrant epigenetic changes. Previous studies have identified various genes associated with non-small cell lung cancer (NSCLC), but the precise combination responsible for its etiology is still debated. The aim of the present study was to select a new set of NSCLC-related genes using methylation-sensitive high-resolution melting. The promoter methylation status of six selected genes, consisting of protocadherin γ subfamily B, 6 (PCDHGB6), homeobox A9 (HOXA9), O₆-methylguanine-DNA methyltransferase (MGMT), microRNA (miR)-126, suppressor of cytokine signaling 3 (SOCS3) and Ras association domain family member 5, also termed NORE1A, was evaluated in 54 NSCLC patients. From these samples, genome-wide DNA was extracted and bisulfite conversion was performed along with fluorogenic quantitative polymerase chain reaction to detect methylation values of the six selected promoters. The present results revealed frequent methylation on PCDHGB6, HOXA9 and miR-126, which contrasted with infrequent methylation on MGMT. The results indicated no methylation on either SOCS3 or NORE1A. The sensitivity and specificity of the methylation assessment were 85.2 and 81.5%, respectively, and the analysis results were validated by pyrosequencing. Furthermore, minute comparison of the association between DNA methylation and clinical features was performed. Overall, these results may provide potential information for the development of better clinical diagnostics and more targeted and effective therapies for NSCLC.

Zinc chelation and Klf9 knockdown cooperatively promote axon regeneration after optic nerve injury

The inability of axons to regenerate over long-distances in the central nervous system (CNS) limits the recovery of sensory, motor, and cognitive functions after various CNS injuries and diseases. Although pre-clinical studies have identified a number of manipulations that stimulate some degree of axon growth after CNS damage, the extent of recovery remains quite limited, emphasizing the need for improved therapies. Here, we used traumatic injury to the mouse optic nerve as a model system to test the effects of combining several treatments that have recently been found to promote axon regeneration without the risks associated with manipulating known tumor suppressors or oncogenes. The treatments tested here include TPEN, a chelator of mobile (free) zinc (Zn2+); shRNA against the axon growth-suppressing transcription factor Klf9; and the atypical growth factor oncomodulin combined with a cAMP analog. Whereas some combinatorial treatments produced only marginally stronger effects than the individual treatments alone, co-treatment with TPEN and Klf9 knockdown had a substantially stronger effect on axon regeneration than either one alone. This combination also promoted a high level of cell survival at longer time points. Thus, Zn2+ chelation in combination with Klf9 suppression holds therapeutic potential for promoting axon regeneration after optic nerve injury, and may also be effective for treating other CNS injuries and diseases.

Bacteriophages targeting intestinal epithelial cells: a potential novel form of immunotherapy

In addition to their established role as a physical barrier to invading pathogens and other harmful agents, intestinal epithelial cells (IEC) are actively involved in local immune reactions. In the past years, evidence has accumulated suggesting the role of IEC in the immunopathology of intestinal inflammatory disorders (IBD). Recent advances in research on bacteriophages strongly suggest that-in addition to their established antibacterial activity-they have immunomodulating properties that are potentially useful in the clinic. We suggest that these immunomodulating phage activities targeting IEC may open novel treatment perspectives in disorders of the alimentary tract, particularly IBD.

The role of small adaptor proteins in the control of oncogenic signalingr driven by tyrosine kinases in human cancer

Protein phosphorylation on tyrosine (Tyr) residues has evolved as an important mechanism to coordinate cell communication in multicellular organisms. The importance of this process has been revealed by the discovery of the prominent oncogenic properties of tyrosine kinases (TK) upon deregulation of their physiological activities, often due to protein overexpression and/or somatic mutation. Recent reports suggest that TK oncogenic signaling is also under the control of small adaptor proteins. These cytosolic proteins lack intrinsic catalytic activity and signal by linking two functional members of a catalytic pathway. While most adaptors display positive regulatory functions, a small group of this family exerts negative regulatory functions by targeting several components of the TK signaling cascade. Here, we review how these less studied adaptor proteins negatively control TK activities and how their loss of function induces abnormal TK signaling, promoting tumor formation. We also discuss the therapeutic consequences of this novel regulatory mechanism in human oncology.

Tissue-resident stem cell activity: a view from the adult Drosophila gastrointestinal tract

The gastrointestinal tract serves as a fast-renewing model for unraveling the multifaceted molecular mechanisms underlying remarkably rapid cell renewal, which is exclusively fueled by a small number of long-lived stem cells and their progeny. Stem cell activity is the best-characterized aspect of mucosal homeostasis in mitotically active tissues, and the dysregulation of regenerative capacity is a hallmark of epithelial immune defects. This dysregulation is frequently associated with pathologies ranging from chronic enteritis to malignancies in humans. Application of the adult Drosophila gastrointestinal tract model in current and future studies to analyze the immuno-physiological aspects of epithelial defense strategies, including stem cell behavior and re-epithelialization, will be necessary to improve our general understanding of stem cell participation in epithelial turnover. In this review, which describes exciting observations obtained from the adult Drosophila gastrointestinal tract, we summarize a remarkable series of recent findings in the literature to decipher the molecular mechanisms through which stem cells respond to nonsterile environments.

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.

Intestinal epithelial suppressor of cytokine signaling 3 (SOCS3) impacts on mucosal homeostasis in a model of chronic inflammation

Introduction

Suppressor of cytokine signaling 3 (SOCS3) is a tumour suppressor, limiting intestinal epithelial cell (IEC) proliferation in acute inflammation, and tumour growth, but little is known regarding its role in mucosal homeostasis. Resistance to the intestinal helminth Trichuris muris relies on an “epithelial escalator” to expel the parasite. IEC turnover is restricted by parasite‐induced indoleamine 2,3‐dioxygenase (IDO).

Methods

Mice with or without conditional knockout of SOCS3 were infected with T. muris. Crypt depth, worm burden, and proliferating cells and IDO were quantified. SOCS3 knockdown was also performed in human IEC cell lines.

Results

Chronic T. muris infection increased expression of SOCS3 in wild‐type mice. Lack of IEC SOCS3 led to a modest increase in epithelial turnover. This translated to a lower worm burden, but not complete elimination of the parasite suggesting a compensatory mechanism, possibly IDO, as seen in SOCS3 knockdown.

Conclusions

We report that SOCS3 impacts on IEC turnover following T. muris infection, potentially through enhancement of IDO. IDO may dampen the immune response which can drive IEC hyperproliferation in the absence of SOCS3, demonstrating the intricate interplay of immune signals regulating mucosal homeostasis, and suggesting a novel tumour suppressor role of SOCS3.

Resistin causes G1 arrest in colon cancer cells through upregulation of SOCS3

Resistin, a proinflammatory cytokine, is elevated in a number of pathological disorders, including cancer. The serum resistin level in colon cancer patients is elevated and correlates with tumor grade. However, the implications of increased resistin on colon cancer cells remain unclear. In the present study, we find that resistin binds to TLR4 on colon cancer cell membrane and initiates TLR4-MyD88-dependent activation of ERK. In addition, the upregulation of SOCS3 by ERK downregulates the JAK2/TAT3 pathway and causes the arrest of cells in G1 phase. Interestingly, we observe that resistin-exposed cells survive 5-fluorouracil treatment because of a decrease in drug uptake due to the arrest of cells in G1 phase.

Inflammasomes in Inflammation-Induced Cancer

The inflammasome is an important multiprotein complex that functions during inflammatory immune responses. The activation of inflammasome will lead to the autoactivation of caspase-1 and subsequent cleavage of proIL-1β and proIL-18, which are key sources of inflammatory manifestations. Recently, the roles of inflammasomes in cancers have been extensively explored, especially in inflammation-induced cancers. In different and specific contexts, inflammasomes exhibit distinct and even contrasting effects in cancer development. In some cases, inflammasomes initiate carcinogenesis through the extrinsic pathway and maintain the malignant cancer microenvironment through the intrinsic pathway. On the contrary, inflammasomes also exert anticancer effects by specialized programmed cell death called pyroptosis and immune regulatory functions. The phases and compartments in which inflammasomes are activated strongly influence the final immune effects. We systemically summarize the functions of inflammasomes in inflammation-induced cancers, especially in gastrointestinal and skin cancers. Besides, information about the current therapeutic use of inflammasome-related products and potential future developing directions are also introduced.

Cooperation between the bacterial-derived short-chain fatty acid butyrate and interleukin-22 detected in human Caco2 colon epithelial/carcinoma cells

By generating biologically active factors luminal microbiota shape the intestinal micro-milieu thereby regulating pathological processes such as inflammation and carcinogenesis. Preclinical data suggest that bacterial-derived butyrate and the signal transducer and activator of transcription (STAT)-3 activating cytokine interleukin (IL)-22 display concordant protective properties at the inflamed colonic epithelium. Herein, biochemical cooperation between the short-chain fatty acid butyrate and IL-22 was investigated by focusing on human Caco2 colon epithelial/carcinoma cells. We report that physiological levels of butyrate enhance IL-22 signaling thereby enforcing expression of the prototypic STAT3-downstrean target genes α1-antichymotrypsin and suppressor of cytokine signaling (SOCS)-3. A dual mode of butyrate action on the IL-22/STAT3 axis was identified. Butyrate acted by upregulating IL-22R1, the decisive chain of the heterodimeric IL-22 receptor, and, independent from that, has the potential to directly amplify STAT3-mediated gene activation as detected by chromatin immunoprecipitation analysis of STAT3 binding to the SOCS3 promoter. Since trichostatin A acted similarly, inhibition of histone deacetylases is likely at the root of these butyrate biological properties. The mutual benefit gained from interactions between the host and commensal intestinal bacteria-derived factors is an expanding field of research beginning to affect clinical practice. Data presented herein propose a supportive and fine-tuning role for butyrate in IL-22 signaling that might be therapeutically exploited by local butyrate administration or by increasing its bacterial production in the context of a fiber-rich diet. © 2016 BioFactors, 43(2):283-292, 2017.

Monocyte Subsets Coregulate Inflammatory Responses by Integrated Signaling through TNF and IL-6 at the Endothelial Cell Interface

Two major monocyte subsets, CD14⁺CD16⁻ (classical) and CD14^+/dimCD16⁺ (nonclassical/intermediate), have been described. Each has different functions ascribed in its interactions with vascular endothelial cells (EC), including migration and promoting inflammation. Although monocyte subpopulations have been studied in isolated systems, their influence on EC and on the course of inflammation has been ignored. In this study, using unstimulated or cytokine-activated EC, we observed significant differences in the recruitment, migration, and reverse migration of human monocyte subsets. Associated with this, and based on their patterns of cytokine secretion, there was a difference in their capacity to activate EC and support the secondary recruitment of flowing neutrophils. High levels of TNF were detected in cocultures with nonclassical/intermediate monocytes, the blockade of which significantly reduced neutrophil recruitment. In contrast, classical monocytes secreted high levels of IL-6, the blockade of which resulted in increased neutrophil recruitment. When cocultures contained both monocyte subsets, or when conditioned supernatant from classical monocytes cocultures (IL-6^hi) was added to nonclassical/intermediate monocyte cocultures (TNF^hi), the activating effects of TNF were dramatically reduced, implying that when present, the anti-inflammatory activities of IL-6 were dominant over the proinflammatory activities of TNF. These changes in neutrophil recruitment could be explained by regulation of E-selectin on the cocultured EC. This study suggests that recruited human monocyte subsets trigger a regulatory pathway of cytokine-mediated signaling at the EC interface, and we propose that this is a mechanism for limiting the phlogistic activity of newly recruited monocytes.

Metformin Improves Ileal Epithelial Barrier Function in Interleukin-10 Deficient Mice

Background and aims

The impairment of intestinal epithelial barrier is the main etiologic factor of inflammatory bowel disease. The proper intestinal epithelial proliferation and differentiation is crucial for maintaining intestinal integrity. Metformin is a common anti-diabetic drug. The objective is to evaluate the protective effects of metformin on ileal epithelial barrier integrity using interleukin-10 deficient (IL10KO) mice.

Methods

Wild-type and IL10KO mice were fed with/without metformin for 6 weeks and then ileum was collected for analyses. The mediatory role of AMP-activated protein kinase (AMPK) was further examined by gain and loss of function study in vitro.

Results

Compared to wild-type mice, IL10KO mice had increased proliferation, reduced goblet cell and Paneth cell lineage differentiation in the ileum tissue, which was accompanied with increased crypt expansion. Metformin supplementation mitigated intestinal cell proliferation, restored villus/crypt ratio, increased goblet cell and Paneth cell differentiation and improved barrier function. In addition, metformin supplementation in IL10KO mice suppressed macrophage pro-inflammatory activity as indicated by reduced M1 macrophage abundance and decreased pro-inflammatory cytokine IL-1β, TNF-α and IFN-γ expressions. As a target of metformin, AMPK phosphorylation was enhanced in mice treated with metformin, regardless of mouse genotypes. In correlation, the mRNA level of differentiation regulator including bmp4, bmpr2 and math1 were also increased in IL10KO mice supplemented with metformin, which likely explains the enhanced epithelial differentiation in IL10KO mice with metformin. Consistently, in Caco-2 cells, metformin promoted claudin-3 and E-cadherin assembly and mitigated TNF-α-induced fragmentation of tight junction proteins. Gain and loss of function assay also demonstrated AMPK was correlated with epithelial differentiation and proliferation.

Conclusions

Metformin supplementation promotes secretory cell lineage differentiation, suppresses inflammation and improves epithelial barrier function in IL10KO mice likely through activation of AMPK, showing its beneficial effects on gut epithelial.

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.

FXR induces SOCS3 and suppresses hepatocellular carcinoma

Suppressor of cytokine signaling 3 (SOCS3) is regarded as a vital repressor in the liver carcinogenesis mainly by inhibiting signal transducer and activator of transcription 3 (STAT3) activity. Farnesoid X Receptor (FXR), highly expressed in liver, has an important role in protecting against hepatocellular carcinoma (HCC). However, it is unclear whether the tumor suppressive activity of FXR involves the regulation of SOCS3. In the present study, we found that activation of FXR by its specific agonist GW4064 in HCC cells inhibited cell growth, induced cell cycle arrest at G1 phase, elevated p21 expression and repressed STAT3 activity. The above anti-tumor effects of FXR were dramatically alleviated by knockdown of SOCS3 with siRNA. Reporter assay revealed that FXR activation enhanced the transcriptional activity of SOCS3 promoter. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay displayed that FXR directly bound to IR9 DNA motif within SOCS3 promoter region. The in vivo study in nude mice showed that treatment with FXR ligand GW4064 could decelerate the growth of HCC xenografts, up-regulate SOCS3 and p21 expression and inhibit STAT3 phosphorylation in the xenografts. These results suggest that induction of SOCS3 may be a novel mechanism by which FXR exerts its anti-HCC effects, and the FXR-SOCS3 signaling may serve as a new potential target for the prevention/treatment of HCC.

Inflammation as a driver and vulnerability of KRAS mediated oncogenesis

While important strides have been made in cancer therapy by targeting certain oncogenes, KRAS, the most common among them, remains refractory to this approach. In recent years, a deeper understanding of the critical importance of inflammation in promoting KRAS-driven oncogenesis has emerged, and applies across the different contexts of lung, pancreatic, and colorectal tumorigenesis. Here we review why these tissue types are particularly prone to developing KRAS mutations, and how inflammation conspires with KRAS signaling to fuel carcinogenesis. We discuss multiple lines of evidence that have established NF-κB, STAT3, and certain cytokines as key transducers of these signals, and data to suggest that targeting these pathways has significant clinical potential. Furthermore, recent work has begun to uncover how inflammatory signaling interacts with other KRAS regulated survival pathways such as autophagy and MAPK signaling, and that co-targeting these multiple nodes may be required to achieve real benefit. In addition, the impact of KRAS associated inflammatory signaling on the greater tumor microenvironment has also become apparent, and taking advantage of this inflammation by incorporating approaches that harness T cell anti-tumor responses represents another promising therapeutic strategy. Finally, we highlight the likelihood that the genomic complexity of KRAS mutant tumors will ultimately require tailored application of these therapeutic approaches, and that targeting inflammation early in the course of tumor development could have the greatest impact on eradicating this deadly disease.

MK2: an unrecognized regulator of tumor promoting macrophages in colorectal cancer?

Colorectal cancer (CRC) is one of the most common malignancies and is associated closely with inflammation before and after development. Macrophages promote colitis and colitis-associated CRC. M1 macrophages contribute to colitis directly through the production of proinflammatory cytokines and through activation of proinflammatory immune cell phenotypes. In cancer, both M1 and M2 macrophages participate in tumor development and progression through cytokine production, changes in cell signaling and activation of T cells. We have identified the mitogen-activated protein kinase-activated protein kinase 2 (MK2) as a regulator of macrophages during colitis-associated CRC (CAC). MK2 is a proinflammatory kinase that promotes production of IL-1α, IL-1β, IL-6 and TNF-α. MK2^−/− mice have decreases in macrophages, macrophage-associated chemokines, and proinflammatory cytokines. Most significantly, MK2^−/− mice do not develop neoplasms in an inflammatory model of CRC. However, addition of MK2^+/+ macrophages to MK2^−/− mice increases production of proinflammatory cytokines. In wild type mice, both cytokines and tumor burdens increase upon addition of additional macrophages. These data support the importance of MK2 in macrophage regulation during inflammation-associated CRC.

Naringin, a natural dietary compound, prevents intestinal tumorigenesis in Apc (Min/+) mouse model

PURPOSE

Naringin is a natural dietary flavonoid compound. We aimed to evaluate the effects of naringin on intestinal tumorigenesis in the adenomatous polyposis coli multiple intestinal neoplasia (Apc (Min/+)) mouse model.

METHODS

Apc (Min/+) mice were given either naringin (150 mg/kg) or vehicle by p.o. gavage daily for 12 consecutive weeks. Mice were killed with ether, and blood samples were collected to assess the concentrations of IL-6 and PGE2. Total intestines were removed, and the number of polyps was examined. Tissue samples of intestinal polyps were subjected to the assays of histopathology, immunohistochemical analysis and Western blotting analysis.

RESULTS

Apc (Min/+) mice fed with naringin developed less and smaller polyps in total intestines. Naringin prevented intestinal tumorigenesis without adverse effects. Histopathologic analysis revealed the reduction of dysplastic cells and dysplasia in the adenomatous polyps. The treatments' effects might arise from its anti-proliferation, induction of apoptosis and modulation of GSK-3β and APC/β-catenin signaling pathways. Naringin also exerted its effects on tumorigenesis through anti-chronic inflammation.

CONCLUSION

Naringin prevented intestinal tumorigenesis likely through a collection of activities including anti-proliferation, induction of apoptosis, modulation of GSK-3β and APC/β-catenin pathways and anti-inflammation. Naringin is a potential chemopreventive agent for reducing the risk of colonic cancers.

Prognostic value of ZFP36 and SOCS3 expressions in human prostate cancer

PURPOSE

ZFP36 ring finger protein (ZFP36) and the suppressor of cytokine signaling 3 (SOCS3) have been reported to, respectively, regulate NF-κB and STAT3 signaling pathways. To better understand the correlation of NF-κB and STAT3 negative regulates pathway, we have investigated the involvement of ZFP36 and SOCS3 expressions in human prostate cancer (PCa).

METHODS

In the present study, paired patient tissue microarrays were analyzed by immunohistochemistry, and the ZFP36 protein expression was quantitated as immunoreactive scores in patients with PCa. Associations between ZFP36/SOCS3 expression and various clinicopathological features and prognosis of PCa patients were statistically analyzed based on the Taylor database. Then, the functions of ZFP36 and SOCS3 in cancerous inflammation were determined using qPCR and immunohistochemistry in vitro and in vivo.

RESULTS

ZFP36 protein expression in PCa tissues was significantly lower than those in non-cancerous prostate tissues (P < 0.05). In mRNA level, ZFP36 and SOCS3 had a close correlation with each other (P < 0.01, Pearson r = 0.848), and its upregulation was both significantly associated with low Gleason score (P < 0.001 and P < 0.001, respectively), negative metastasis (P < 0.001 and P < 0.001, respectively), favorable overall survival (P < 0.001 and P < 0.05, respectively), and negative biochemical recurrence (P < 0.001 and P < 0.001, respectively). Functionally, LPS treatment could lead to the overexpression of ZFP36 and SOCS3 in vitro and vivo.

CONCLUSIONS

Our data offer the convincing evidence for the first time that the aberrant expressions of ZFP36 and SOCS3 may be involved into the progression and patients' prognosis of PCa, implying their potentials as candidate markers of this cancer.

Interleukin-6 stimulates aerobic glycolysis by regulating PFKFB3 at early stage of colorectal cancer

Chronic inflammation is a well-known etiological factor for colorectal cancer (CRC) and cancer cells are known to preferentially metabolize glucose through aerobic glycolysis. However, the connection between chronic inflammation and aerobic glycolysis in the development of CRC is largely unexplored. The present study investigated whether interleukin-6 (IL-6), a pro-inflammatory cytokine, promotes the development of CRC by regulating the aerobic glycolysis and the underlying molecular mechanisms. In colitis-associated CRC mouse, anti-IL-6 receptor antibody treatment reduced the incidence of CRC and decreased the expression of key genes in aerobic glycolysis, whereas the plasma concentrations of glucose and lactate were not affected. Consistently, IL-6 treatment stimulated aerobic glycolysis, upregulated key genes in aerobic glycolysis and promoted cell proliferation and migration in SW480 and SW1116 CRC cells. 6-phoshofructo-2-kinase/fructose-2,6-bisphosphatase-3 (PFKFB3) was the most downregulated gene by anti-IL-6 receptor antibody in colorectal adenoma tissues. Further analysis in human samples revealed overexpression of PFKFB3 in colorectal adenoma and adenocarcinoma tissues, which was also associated with lymph node metastasis, intravascular cancer embolus and TNM stage. In addition, the effect of IL-6 on CRC cells can be abolished by knocking down PRKFB3 through siRNA transfection. Our data suggest that chronic inflammation promotes the development of CRC by stimulating aerobic glycolysis and IL-6 is functioning, at least partly, through regulating PFKFB3 at early stage of CRC.

The JAK/STAT signaling cascade in gastric carcinoma (Review)

Gastric carcinoma remains one of the most prevalent forms of cancer worldwide, despite the decline in incidence rates, increased awareness of the disease and advancement in treatment strategies. Helicobacter pylori infection, dietary factors, lifestyle influences and various genetic aberrations have been shown to contribute to the development and progression of gastric cancer. Recent studies on the genomic landscape of gastric adenocarcinoma have identified several key signaling molecules, including epidermal growth factor receptor family (ErbB) members, vascular endothelial growth factor receptor family (VEGFR) members and PI3K/Akt/mTOR pathway components, that have been implicated in the molecular pathogenesis of gastric cancers. However, clinical trials with compounds that target these molecules have failed to show a significant improvement in overall survival rates when supplemented with conventional therapies. Therefore, it is essential to identify effective prognostic and/or diagnostic biomarkers and develop molecular targeted therapies. The JAK/STAT cascade is a principal signal transduction pathway in cytokine and growth factor signaling, regulating various cellular processes such as cell proliferation, differentiation, migration and survival. Numerous in vivo and in vitro studies have shown that dysregulated JAK/STAT signaling is a driving force in the pathogenesis of various solid cancers as well as hematopoietic malignancies. Hence, a large number of preclinical and clinical studies of drugs targeting this pathway are currently underway. Notably, aberrant JAK/STAT signaling has also been implicated in gastric cancers. In this review, we focus on the ongoing research on the JAK/STAT cascade in gastric carcinoma and discuss the therapeutic potential of targeting JAK/STAT signaling for the treatment of gastric cancer.

Chronic inflammation up-regulates P-gp in peripheral mononuclear blood cells via the STAT3/Nf-κb pathway in 2,4,6-trinitrobenzene sulfonic acid-induced colitis mice

Patients with inflammatory bowel diseases, including Crohn’s disease and ulcerative colitis, often suffer drug intolerance. This resistance can be divided into intrinsic resistance and acquired resistance. Although there is agreement on acquired resistance, studies regarding intrinsic resistance have demonstrated inconsistencies, especially for Crohn’s disease. For this reason, an animal model of Crohn’s disease was induced with 2,4,6-trinitrobenzene sulfonic acid solution (TNBS), and intrinsic resistance was analyzed by measuring the function and expression of P-glycoprotein (P-gp) in peripheral mononuclear blood cells (PMBC), followed by mechanistic studies. The results revealed reduced retention of cyclosporine A in PMBC over-expressing P-gp in a TNBS-treated group and enhanced secretion of the cytokines IL-1β, IL-6, IL-17, and TNF-α as well as LPS in plasma. These cytokines and LPS can induce P-gp expression through the STAT3/Nf-κb pathway, contributing to a decrease of cyclosporine A retention, which can be reversed by the application of a P-gp inhibitor. Our results demonstrated that the sustained chronic inflammation could induce the intrinsic resistance presented as P-gp over-expression in PBMC in Crohn’s disease through STAT3/Nf-κb pathway and this resistance might be reversed by combinational usage of P-gp inhibitors.