Fluoxetine inhibits NF-κB signaling in intestinal epithelial cells and ameliorates experimental colitis and colitis-associated colon cancer in mice

Research progress on anti-inflammatory drugs for preventing colitis-associated colorectal cancer

Colorectal cancer (CRC) is the third most prevalent malignancy worldwide. Inflammatory bowel diseases (IBD) encompass a group of chronic intestinal inflammatory disorders, including ulcerative colitis (UC) and Crohn's disease (CD). As a chronic inflammatory bowel disease, UC may persist and elevate the risk of malignancy, thereby contributing to the development of colorectal cancer, known as colitis-associated colorectal cancer (CAC). Chronic intestinal inflammation is a significant risk factor for colorectal cancer, and the incidence of colitis-associated colorectal cancer continues to rise. Current studies indicate that therapeutic agents targeting inflammation and key molecules or signaling pathways involved in the inflammatory process may effectively prevent and treat CAC. Mechanistically, drugs with anti-inflammatory or modulatory effects on inflammation-related pathways may exert preventive or therapeutic roles in CAC through multiple molecules or signaling pathways implicated in tumor development. Moreover, the development or discovery of novel drugs with anti-inflammatory properties to prevent or delay CAC progression is becoming an emerging field in fighting against CRC. Therefore, this review aims to summarize drugs that prevent or delay CAC through modulating anti-inflammatory pathways. First, we categorize the published studies exploring the role of anti-inflammatory in CAC prevention. Second, we highlight the specific molecular mechanisms underlying the anti-inflammatory effect of the above-mentioned drugs. Finally, we discuss the potential and challenges associated with clinical application of these drugs. It is hoped that this review offers new insights for further drug development and mechanism exploration.

iRhom2 deficiency reduces sepsis-induced mortality associated with the attenuation of lung macrophages in mice

Sepsis has a high mortality rate and leads to multi-organ failure, including lung injury. Inactive rhomboid protease family protein (iRhom2) has been identified as accountable for the release of TNF-α, a crucial mediator in the development of sepsis. This study aimed to evaluate the role of iRhom2 in sepsis and sepsis-induced acute lung injury (ALI). TNF-α and IL-6 secretion in vitro by peritoneal macrophages from wild-type (WT) and iRhom2 knoukout (KO) mice was assessed by enzyme-linked immunosorbent assay. Cecal ligation and puncture (CLP)-induced murine sepsis model was used for in vivo experiments. To evaluate the role of iRhom2 deficiency on survival during sepsis, both WT and iRhom2 KO mice were monitored for 8 consecutive days following the CLP. For histologic and biochemical examination, the mice were killed 18 h after CLP. iRhom2 deficiency improved the survival of mice after CLP. iRhom2 deficiency decreased CD68+ macrophage infiltration in lung tissues. Multiplex immunohistochemistry revealed that the proportion of Ki-67+ CD68+ macrophages was significantly lower in iRhom2 KO mice than that in WT mice after CLP. Moreover, CLP-induced release of TNF-α and IL-6 in the serum were significantly inhibited by iRhom2 deficiency. iRhom2 deficiency reduced NF-kB p65 and IκBα phosphorylation after CLP. iRhom2 deficiency reduces sepsis-related mortality associated with attenuated macrophage infiltration and proliferation in early lung injury. iRhom2 may play a pivotal role in the pathogenesis of sepsis and early stage of sepsis-induced ALI. Thus, iRhom2 may be a potential therapeutic target for the management of sepsis and sepsis-induced ALI.

The Diagnostic and Prognostic Value of Neurotransmitter Receptor-Related Genes in Colon Adenocarcinoma

Colorectal cancer (CRC) is a malignant tumor with high morbidity and mortality in the world. This study aimed to find receptor-related genes (NRGs) with diagnostic and prognostic value in colon adenocarcinoma (COAD). The Cancer Genome Atlas (TCGA) and the Human Protein Atlas database databases were applied to find differential expression NRGs between COAD and normal colonic tissues. Subsequently, Cox regression analysis and minimum absolute contraction and selection operator algorithm were used to construct a prognosis nomogram based on TCGA and Gene Expression Omnibus databases. Expression levels of 35 NRGs were significant differences in COAD and normal colonic tissues. ROC curves showed that 24 NRGs had high diagnostic accuracy (AUC > 0.850) in COAD. Risk score was constructed based on 10 NRGs for the first time. Cox regression analysis revealed risk score was an independent risk factor and a higher risk score predicts a later TNM stage. Finally, a prognostic nomogram containing risk score and clinical features was established. Calibration curves and C-index suggested the powerful predictable value of the model. This study identified the NRGs with diagnostic value and prognostic value, providing a direction for treatment of COAD patients.

The beneficial effect of fluoxetine on behavioral and cognitive changes in chronic experimental Chagas disease unveils the role of serotonin fueling astrocyte infection by Trypanosoma cruzi

BACKGROUND

In Chagas disease (CD), a neglected tropical disease caused by the parasite Trypanosoma cruzi, the development of mental disorders such as anxiety, depression, and memory loss may be underpinned by social, psychological, and biological stressors. Here, we investigated biological factors underlying behavioral changes in a preclinical model of CD.

METHODOLOGY/PRINCIPAL FINDINGS

In T. cruzi-infected C57BL/6 mice, a kinetic study (5 to 150 days postinfection, dpi) using standardized methods revealed a sequential onset of behavioral changes: reduced innate compulsive behavior, followed by anxiety and depressive-like behavior, ending with progressive memory impairments. Hence, T. cruzi-infected mice were treated (120 to 150 dpi) with 10 mg/Kg/day of the selective serotonin reuptake inhibitor fluoxetine (Fx), an antidepressant that favors neuroplasticity. Fx therapy reversed the innate compulsive behavior loss, anxiety, and depressive-like behavior while preventing or reversing memory deficits. Biochemical, histological, and parasitological analyses of the brain tissue showed increased levels of the neurotransmitters GABA/glutamate and lipid peroxidation products and decreased expression of brain-derived neurotrophic factor in the absence of neuroinflammation at 150 dpi. Fx therapy ameliorated the neurochemical changes and reduced parasite load in the brain tissue. Next, using the human U-87 MG astroglioma cell line, we found no direct effect of Fx on parasite load. Crucially, serotonin/5-HT (Ser/5-HT) promoted parasite uptake, an effect increased by prior stimulation with IFNγ and TNF but abrogated by Fx. Also, Fx blocked the cytokine-driven Ser/5-HT-promoted increase of nitric oxide and glutamate levels in infected cells.

CONCLUSION/SIGNIFICANCE

We bring the first evidence of a sequential onset of behavioral changes in T. cruzi-infected mice. Fx therapy improves behavioral and biological changes and parasite control in the brain tissue. Moreover, in the central nervous system, cytokine-driven Ser/5-HT consumption may favor parasite persistence, disrupting neurotransmitter balance and promoting a neurotoxic environment likely contributing to behavioral and cognitive disorders.

Venlafaxine antagonizes the noradrenaline-promoted colon cancer progression by inhibiting the norepinephrine transporter

Epidemiological studies have demonstrated that the use of antidepressants is associated with a decreased risk of colorectal cancer (CRC); however, the mechanisms behind this association are yet unknown. Adrenergic system contributes to the stress-related tumor progression, with norepinephrine (NE) mainly secreted from adrenergic nerve fibers. Norepinephrine serotonin reuptake inhibitors are successfully used antidepressants. This study demonstrates that a widely used antidepressant venlafaxine (VEN) antagonizes NE-promoted colon cancer in vivo and in vitro. Bioinformatic analysis suggested that NE transporter (NET, SLC6A2), a target of VEN, was closely associated with the prognosis of clinical patients with CRC. In addition, the knockdown of NET antagonized the effect of NE. The NET-protein phosphatase 2 scaffold subunit alpha/phosphorylated Akt/vascular endothelial growth factor pathway partially mediates the antagonizing effect of VEN on NE's actions in colon cancer cells. These were also confirmed by in vivo experiments. Our findings revealed for the first time that, in addition to its primary function as a transporter, NET also promotes NE-enhanced colon cancer cell proliferation, tumor angiogenesis, and tumor growth. This provides direct experimental and mechanistic evidence for the use of antidepressant VEN in the treatment of CRC and a therapeutic potential for repurposing existing drugs as an anti-cancer approach to improve the prognosis of patients with CRC.

Anxiety, depression, and memory loss in Chagas disease: a puzzle far beyond neuroinflammation to be unpicked and solved

Mental disorders such as anxiety, depression, and memory loss have been described in patients with chronic Chagas disease (CD), a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi. Social, psychological, and biological stressors may take part in these processes. There is a consensus on the recognition of an acute nervous form of CD. In chronic CD patients, a neurological form is associated with immunosuppression and neurobehavioural changes as sequelae of stroke. The chronic nervous form of CD has been refuted, based on the absence of histopathological lesions and neuroinflammation; however, computed tomography shows brain atrophy. Overall, in preclinical models of chronic T. cruzi infection in the absence of neuroinflammation, behavioural disorders such as anxiety and depression, and memory loss are related to brain atrophy, parasite persistence, oxidative stress, and cytokine production in the central nervous system. Interferon-gamma (IFNγ)-bearing microglial cells are colocalised with astrocytes carrying T. cruzi amastigote forms. In vitro studies suggest that IFNγ fuels astrocyte infection by T. cruzi and implicate IFNγ-stimulated infected astrocytes as sources of TNF and nitric oxide, which may also contribute to parasite persistence in the brain tissue and promote behavioural and neurocognitive changes. Preclinical trials in chronically infected mice targeting the TNF pathway or the parasite opened paths for therapeutic approaches with a beneficial impact on depression and memory loss. Despite the path taken, replicating aspects of the chronic CD and testing therapeutic schemes in preclinical models, these findings may get lost in translation as the chronic nervous form of CD does not fulfil biomedical model requirements, as the presence of neuroinflammation, to be recognised. It is hoped that brain atrophy and behavioural and neurocognitive changes are sufficient traits to bring the attention of researchers to study the biological and molecular basis of the central nervous system commitment in chronic CD.

Interplay between Serotonin, Immune Response, and Intestinal Dysbiosis in Inflammatory Bowel Disease

Inflammatory Bowel Disease (IBD) is a chronic gastrointestinal disorder characterized by periods of activity and remission. IBD includes Crohn's disease (CD) and ulcerative colitis (UC), and even though IBD has not been considered as a heritable disease, there are genetic variants associated with increased risk for the disease. 5-Hydroxytriptamine (5-HT), or serotonin, exerts a wide range of gastrointestinal effects under both normal and pathological conditions. Furthermore, Serotonin Transporter (SERT) coded by Solute Carrier Family 6 Member 4 (SLC6A4) gene (located in the 17q11.1-q12 chromosome), possesses genetic variants, such as Serotonin Transporter Gene Variable Number Tandem Repeat in Intron 2 (STin2-VNTR) and Serotonin-Transporter-linked promoter region (5-HTTLPR), which have an influence over the functionality of SERT in the re-uptake and bioavailability of serotonin. The intestinal microbiota is a crucial actor in normal human gut physiology, exerting effects on serotonin, SERT function, and inflammatory processes. As a consequence of abnormal serotonin signaling and SERT function under these inflammatory processes, the use of selective serotonin re-uptake inhibitors (SSRIs) has been seen to improve disease activity and extraintestinal manifestations, such as depression and anxiety. The aim of this study is to integrate scientific data linking the intestinal microbiota as a regulator of gut serotonin signaling and re-uptake, as well as its role in the pathogenesis of IBD. We performed a narrative review, including a literature search in the PubMed database of both review and original articles (no date restriction), as well as information about the SLC6A4 gene and its genetic variants obtained from the Ensembl website. Scientific evidence from in vitro, in vivo, and clinical trials regarding the use of selective serotonin reuptake inhibitors as an adjuvant therapy in patients with IBD is also discussed. A total of 194 articles were used between reviews, in vivo, in vitro studies, and clinical trials.

Repurposing fluoxetine to treat lymphocytic leukemia: Apoptosis induction, sigma-1 receptor upregulation, inhibition of IL-2 cytokine production, and autophagy induction

BACKGROUND

Childhood cancer has a cure rate of as low as 15% in low-income countries, suggesting a need for cheaper treatment options. Fluoxetine is a thoroughly safety-tested drug that may target the sigma-1 receptor (σ1-R).

RESEARCH DESIGN AND METHODS

Using the human leukemic cell line, Jurkat, we investigated the effects of fluoxetine on cell survival using XTT and trypan blue staining. Apoptosis was measured using AnnexinV/PI staining and western blot analysis of caspase cleavage. IL-2 secretion of Jurkat cells in response to PHA/PMA was measured using ELISA, and the expression of AKT/pAKT and the σ1-R were measured using western blotting.

RESULTS

Fluoxetine-induced apoptosis and G-2 cell cycle arrest. Fluoxetine reduced IL-2 secretion dose-dependently and could be further potentiated by σ1-R antagonist BD1047 (P < 0.05). Fluoxetine inhibited pAKT six hours post-treatment (P < 0.05). The expression of the σ1-R showed a significant increase between 12 to 48 hours in Jurkat cells (P < 0.05). At the same time, there was a substantial increase in autophagy.

CONCLUSIONS

Fluoxetine may have the potential for acute leukemia treatment. Co-treatment with a σ1-R antagonist increases fluoxetine-induced apoptosis, possibly targeting AKT phosphorylation and autophagy activation.

Supplementation with High or Low Iron Reduces Colitis Severity in an AOM/DSS Mouse Model

The relationship between colitis-associated colorectal cancer (CAC) and the dysregulation of iron metabolism has been implicated. However, studies on the influence of dietary iron deficiency on the incidence of CAC are limited. This study investigated the effects of dietary iron deficiency and dietary non-heme iron on CAC development in an azoxymethane/dextran sodium sulfate (AOM/DSS) mouse model. The four-week-old mice were divided into the following groups: iron control (IC; 35 ppm iron/kg) + normal (NOR), IC + AOM/DSS, iron deficient (ID; <5 ppm iron/kg diet) + AOM/DSS, and iron overload (IOL; approximately 2000 ppm iron/kg) + AOM/DSS. The mice were fed the respective diets for 13 weeks, and the AOM/DSS model was established at week five. FTH1 expression increased in the mice’s colons in the IC + AOM/DSS group compared with that observed in the ID and IOL + AOM/DSS groups. The reduced number of colonic tumors in the ID + AOM/DSS and IOL + AOM/DSS groups was accompanied by the downregulated expression of cell proliferation regulators (PCNA, cyclin D1, and c-Myc). Iron overload inhibited the increase in the expression of NF-κB and its downstream inflammatory cytokines (IL-6, TNFα, iNOS, COX2, and IL-1β), likely due to the elevated expression of antioxidant genes (SOD1, TXN, GPX1, GPX4, CAT, HMOX1, and NQO1). ID + AOM/DSS may hinder tumor development in the AOM/DSS model by inhibiting the PI3K/AKT pathway by increasing the expression of Ndrg1. Our study suggests that ID and IOL diets suppress AOM/DSS-induced tumors and that long-term iron deficiency or overload may negate CAC progression.

Overcoming Therapy Resistance in Colon Cancer by Drug Repurposing

Simple Summary

Despite improvements in standardized screening methods and the development of promising therapies for colorectal cancer (CRC), survival rates are still low. Drug repurposing offers an affordable solution to achieve new indications for previously approved drugs that could play a protagonist or adjuvant role in the treatment of CRC. In this review, we summarize the current data supporting drug repurposing as a feasible option for patients with CRC.

Abstract

Colorectal cancer (CRC) is the third most common cancer in the world. Despite improvement in standardized screening methods and the development of promising therapies, the 5-year survival rates are as low as 10% in the metastatic setting. The increasing life expectancy of the general population, higher rates of obesity, poor diet, and comorbidities contribute to the increasing trends in incidence. Drug repurposing offers an affordable solution to achieve new indications for previously approved drugs that could play a protagonist or adjuvant role in the treatment of CRC with the advantage of treating underlying comorbidities and decreasing chemotherapy toxicity. This review elaborates on the current data that supports drug repurposing as a feasible option for patients with CRC with a focus on the evidence and mechanism of action promising repurposed candidates that are widely used, including but not limited to anti-malarial, anti-helminthic, anti-inflammatory, anti-hypertensive, anti-hyperlipidemic, and anti-diabetic agents.

Integrative genomic analysis of a novel small nucleolar RNAs prognostic signature in patients with acute myelocytic leukemia

This study mainly used The Cancer Genome Atlas (TCGA) RNA sequencing dataset to screen prognostic snoRNAs of acute myeloid leukemia (AML), and used for the construction of prognostic snoRNAs signature for AML. A total of 130 AML patients with RNA sequencing dataset were used for prognostic snoRNAs screenning. SnoRNAs co-expressed genes and differentially expressed genes (DEGs) were used for functional annotation, as well as gene set enrichment analysis (GSEA). Connectivity Map (CMap) also used for potential targeted drugs screening. Through genome-wide screening, we identified 30 snoRNAs that were significantly associated with the prognosis of AML. Then we used the step function to screen a prognostic signature composed of 14 snoRNAs (SNORD72, SNORD38, U3, SNORA73B, SNORD79, SNORA73, SNORD12B, SNORA74, SNORD116-12, SNORA65, SNORA14, snoU13, SNORA75, SNORA31), which can significantly divide AML patients into high- and low-risk groups. Through GSEA, snoRNAs co-expressed genes and DEGs functional enrichment analysis, we screened a large number of potential functional mechanisms of this prognostic signature in AML, such as phosphatidylinositol 3-kinase-Akt, Wnt, epithelial to mesenchymal transition, T cell receptors, NF-kappa B, mTOR and other classic cancer-related signaling pathways. In the subsequent targeted drug screening using CMap, we also identified six drugs that can be used for AML targeted therapy, they were alimemazine, MG-262, fluoxetine, quipazine, naltrexone and oxybenzone. In conclusion, our current study was constructed an AML prognostic signature based on the 14 prognostic snoRNAs, which may serve as a novel prognostic biomarker for AML.

The Multifaceted Role of Serotonin in Intestinal Homeostasis

The monoamine serotonin, 5-hydroxytryptamine (5-HT), is a remarkable molecule with conserved production in prokaryotes and eukaryotes and a wide range of functions. In the gastrointestinal tract, enterochromaffin cells are the most important source for 5-HT production. Some intestinal bacterial species are also able to produce 5-HT. Besides its role as a neurotransmitter, 5-HT acts on immune cells to regulate their activation. Several lines of evidence indicate that intestinal 5-HT signaling is altered in patients with inflammatory bowel disease. In this review, we discuss the current knowledge on the production, secretion, and signaling of 5-HT in the intestine. We present an inventory of intestinal immune and epithelial cells that respond to 5-HT and describe the effects of these signaling processes on intestinal homeostasis. Further, we detail the mechanisms by which 5-HT could affect inflammatory bowel disease course and describe the effects of interventions that target intestinal 5-HT signaling.

Fluoxetine as an anti-inflammatory therapy in SARS-CoV-2 infection

Hyperinflammatory response caused by infections such as Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) increases organ failure, intensive care unit admission, and mortality. Cytokine storm in patients with Coronavirus Disease 2019 (COVID-19) drives this pattern of poor clinical outcomes and is dependent upon the activity of the transcription factor complex nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappaB) and its downstream target gene interleukin 6 (IL6) which interacts with IL6 receptor (IL6R) and the IL6 signal transduction protein (IL6ST or gp130) to regulate intracellular inflammatory pathways. In this study, we compare transcriptomic signatures from a variety of drug-treated or genetically suppressed (i.e. knockdown) cell lines in order to identify a mechanism by which antidepressants such as fluoxetine demonstrate non-serotonergic, anti-inflammatory effects. Our results demonstrate a critical role for IL6ST and NF-kappaB Subunit 1 (NFKB1) in fluoxetine's ability to act as a potential therapy for hyperinflammatory states such as asthma, sepsis, and COVID-19.

Association between antidepressant medication use and steroid dependency in patients with ulcerative colitis: a population-based study

Background

Animal studies indicate a potential protective role of antidepressant medication (ADM) in models of colitis but the effect of their use in humans with ulcerative colitis (UC) remains unclear.

Objective

To study the relationship between ADM use and corticosteroid dependency in UC.

Design

Using the Clinical Practice Research Datalink we identified patients diagnosed with UC between 2005 and 2016. We grouped patients according to serotonin selective reuptake inhibitor (SSRI) and tricyclic antidepressant (TCA) exposure in the 3 years following diagnosis: ‘continuous users’, ‘intermittent users’ and ‘non-users’. We used logistic regression to estimate the adjusted risk of corticosteroid dependency between ADM exposure groups.

Results

We identified 6373 patients with UC. Five thousand two hundred and thirty (82%) use no ADMs, 627 (10%) were intermittent SSRI users and 282 (4%) were continuous SSRI users, 246 (4%) were intermittent TCA users and 63 (1%) were continuous TCA users.

Corticosteroid dependency was more frequent in continuous SSRI and TCA users compared with non-users (19% vs 24% vs 14%, respectively, χ² p=0.002). Intermittent SSRI and TCA users had similar risks of developing corticosteroid dependency to non-users (SSRI: OR 1.19, 95% CI 0.95 to 1.50, TCA: OR 1.14, 95% CI 0.78 to 1.66). Continuous users of both SSRIs and TCAs had significantly higher risks of corticosteroid dependency compared with non-users (SSRI: OR 1.62, 95% CI 1.15 to 2.27, TCA: OR 2.02, 95% CI 1.07 to 3.81).

Conclusions

Continuous ADM exposure has no protective effect in routine clinical practice in UC and identifies a population of patients requiring more intensive medical therapy. ADM use is a flag for potentially worse clinical outcomes in UC.

M1/M2 polarization in major depressive disorder: Disentangling state from trait effects in an individualized cell-culture-based approach

Accumulating evidence indicates the specific involvement of inflammatory processes in major depressive disorder (MDD), particularly affecting innate immunity. Most immune alterations have so far been determined based on plasma or cerebrospinal fluid cytokine levels. To precisely characterize putative innate immune-mediated mechanisms in MDD pathogenesis, we sought to disentangle "state" from "trait" effects in a patient-specific cell model by quantifying the impact of patient-derived autologous sera (AS) on patient-specific monocyte-derived macrophages (Mo-MФs) polarization in vitro. Mo-MФs were generated from 28 patients with moderate to severe MDD and 28 age-, sex-, smoking status- and BMI-matched healthy controls (HC). Cells were treated either with AS or fetal calf serum (FCS) and polarized into M1 (LPS), M2 (IL-10, IL-4, TGF-β) or M0 (unstimulated) macrophages. Polarization capacity was quantified by means of specific M1 (CCR7, CD86, CXCL10, IL-12p70, TNF-α, IL-6, IL-1β, IL-12p40, IL-23, IP-10) and M2 (CD206, IL-10, TARC, IL-1RA) markers. Compared to HC, significantly increased M1-polarization was observed for MDD patients in the presence of FCS, however, polarization in AS enriched media determined an increased M2-polarization in patients. Moreover, female MDD patients exhibited increased M1- and decreased M2-polarization in both conditions compared to male MDD patients. Our data suggests that Mo-MФs derived from patients with MDD exhibit facilitated M1-polarization under traditional cell culture conditions and an increased potential for M2-polarization when cultured in AS. Striking inter-individual variation and pronounced gender effects highlight the potential utility of our personalized cell model-based approach to aid diagnostic and therapeutic decisions.

Clinical and Translational Considerations for Understanding Depression and Anxiety in Patients with Inflammatory Bowel Disease

Depression and anxiety are comorbidities of inflammatory bowel disease (IBD). Though previous studies have proposed a relationship between anxiety, depression, and IBD, causality and directionality are largely unknown. Current and future research in these areas is aimed at exploring the biological underpinnings of this relationship, specifically pertaining to small molecule metabolism, such as tryptophan. Tryptophan is acquired through the diet and is the precursor to several vital bioactive metabolites including the hormone melatonin, the neurotransmitter serotonin, and vitamin B3. In this review, we discuss previous findings relating mental health comorbidities with IBD and underline ongoing research of tryptophan catabolite analysis.

Probing the chemoprevention potential of the antidepressant fluoxetine combined with epigallocatechin gallate or kaempferol in rats with induced early stage colon carcinogenesis

The enhanced chemopreventive action against 1,2 Dimethylhydrazine (DMH)-induced preneoplastic lesion in rats could be achieved via simultaneous administration of the antidepressant fluoxetine (FLX) with two natural polyphenolic compounds viz., kaempferol (KMP) and/or epigallocatechin-gallate (EGCG). The obtained results revealed that single FLX pre-treatment possess a significant apoptotic effect by increasing the activity of serum and colon tissue caspase 3. It also attenuated the DMH driven increase in, colon tissue MDA, NO, PCNA and COX-2 expression as well as serum and colon tissue β-catenin, with a decrease in the multiplicity of ACF and number of MPLs. The combination of FLX with either KMP or EGCG improved the antioxidant, anti-inflammatory and antiproliferating activities but with higher apoptotic activity in case of KMP. Eventually, histopathological assessment of colon tissues exposed that while sole pre-treatment can improve DMH-induced hyperplasia with only moderate inflammatory infiltration, tissues from the combined pre-treatment regimens groups exhibited almost a normal colonic architecture with slight submucosal edema. The study proved that single FLX administration prior to DMH exerts a chemopreventive effect and that the investigated combined pre-treatment regimens demonstrated more potent chemopreventive and antiproliferative actions.

Toll-like receptor 4 regulates intestinal fibrosis via cytokine expression and epithelial-mesenchymal transition

Intestinal fibrosis induced by chronic and recurrent colitis, which is exacerbated by bowel stenosis, stricture, and obstruction, is challenging to treat. Toll-like receptor 4 (TLR4) stimulates innate and acquired immunity in response to specific microbial components, but the role of TLR4 in intestinal fibrosis is largely unknown. We investigated its role in intestinal fibrosis using not only a murine fibrosis model but also human myofibroblasts and intestinal epithelial cells. Colon fibrosis was induced in TLR4-deficient (TLR4^−/−) mice and its wild-type counterparts with 3% dextran sulfate sodium. Absence of TLR4 gene attenuated chronic inflammation and colonic macrophages infiltration; intestinal fibrosis and collagen deposition were suppressed. Also, the production of tumor necrosis factor-α, interleukin-12p40, and transforming growth factor-β was reduced in TLR4-deficient peritoneal macrophages. TLR4 was silenced in CCD-18Co cells by small interfering RNA (siRNA), and matrix metalloproteinase-1, tissue inhibitor of metalloproteinase, and collagen α1 expression was evaluated. Role of TLR4 in epithelial-mesenchymal transition (EMT) was evaluated in HCT116 cells. Suppression of TLR4 transcription by siRNAs affected myofibroblasts activity, collagen synthesis, and EMT in the human cancer cell line. Thus, we suggest that TLR4 can be an essential mediator in intestinal chronic inflammation and fibrosis, indicating that TLR4 signaling is a potential therapeutic target for intestinal fibrosis.

Inflammatory modulation of fluoxetine use in patients with depression: A systematic review and meta-analysis

There is growing evidence that there is a relationship between major depressive disorder (MDD), also simply known as "depression", and inflammatory processes. Selective serotonin inhibitors, such as fluoxetine, are used as a first-line treatment for depression, and it is hypothesized that its use can reduce levels of proinflammatory cytokines. The aim of this systematic review and meta-analysis is to enable a better understanding of how treatment with the antidepressant fluoxetine modulates inflammation, and the roles of the main cytokines in this process. Risk of bias (RoB) in the included studies was assessed using the Cochrane Risk of Bias Assessment tool for Non-randomized studies (RoBANS). In the meta-analysis, standardized mean difference (SMD) was used as a summary statistic and grouped statistics using the generic inverse variation method in RevMan 5 with random effects model. Heterogeneous changes in cytokine levels were also evaluated from the SMD forest plot of individual studies. After analysis, we observed that fluoxetine was able to decrease TNF-α levels (SMD ± 0.90, 95% CI = 0.16, 1.165, Z ± 2.40, p = 0.02), but not change IL-6 levels (SMD ± 0.37, 95% CI = 0.21, 0.95, Z ± 1.25, p = 0.21).Fluoxetine acts by modulating neuroimmunology, and not only by acting only on the independent restoration of neurotransmission and neuroinflammation pathways.

Beneficial effect of fluoxetine on anti-tumor progression on hepatocellular carcinoma and non-small cell lung cancer bearing animal model

Fluoxetine, an antidepressant, has been indicated to elicit anti-cancer response in hepatocellular carcinoma (HCC) and non-small cell lung cancer (NSCLC) in vitro. However, anticancer effect and mechanism of fluoxetine in HCC and NSCLC in vivo still needs to be elucidated. In this study, we showed anticancer efficacy and inhibitory mechanism of fluoxetine on the tumor progression of HCC and NSCLC in vivo. Tumor growth was significantly inhibited with fluoxetine treatment in HCC and NSCLC in vivo. Fluoxetine obviously decreased expression of cell proliferative, anti-apoptotic, invasion-associated proteins including Cyclin-D1, survivin, vascular endothelial growth factor (VEGF), matrix metallopeptidase 9 (MMP-9) and urokinase-type plasminogen activator (uPA). Importantly, fluoxetine diminished the phosphorylation of NF-κB p65 which recognized as one of the critical transcription factors in tumor progression. Inhibition of AKT or extracellular signal-regulated kinases (ERK) phosphorylation was linked to NF-κB inactivation in NSCLC or HCC in vitro. Furthermore, expression of AKT or ERK phosphorylation was effectively attenuated by fluoxetine treatment in NSCLC or HCC in vivo. In addition, fluoxetine also triggered extrinsic/intrinsic apoptotic signaling by activating caspase-3, -8, and -9 in HCC and NSCLC. Our findings suggest that fluoxetine may represent as a promising adjuvant for patients with HCC or NSCLC. In conclude, the results also suggested the blockage of AKT/NF-κB or ERK/NF-κB activation and the induction of apoptosis are associated with fluoxetine-inhibited tumor progression of HCC or NSCLC in vivo.

Role of the NF-κB signaling pathway in the pathogenesis of colorectal cancer

The NF-κB signaling pathway is a key regulator of CRC cell proliferation, apoptosis, angiogenesis, inflammation, metastasis, and drug resistance. Over-activation of the NF-κB pathway is a feature of colorectal cancer (CRC). While new combinatorial treatments have improved overall patient outcome; quality of life, cost of care, and patient survival rate have seen little improvement. Suppression of the NF-κB signaling pathway using biological or specific pharmacological inhibitors is a potential therapeutic approach in the treatment of colon cancer. This review summarizes the regulatory role of NF-κB signaling pathway in the pathogenesis of CRC for a better understanding and hence a better management of the disease.

Norepinephrine transporter promotes the invasion of human colon cancer cells

Epidemiological studies suggested the use of antidepressants to be associated with decreased risk of colorectal cancer (CRC). However, the underlying mechanism through which this decreased risk occurs remains elusive. The norepinephrine transporter (NET) is a target of antidepressants that maintains noradrenergic transmission homeostasis; however, little is known about its function in human CRC cells. The present study, using public datasets and immunohistochemistry approaches, revealed that NET was highly expressed in human CRC tissues with metastasis and in human colon cancer cells. Furthermore, knockdown of NET inhibited the invasive capability of human colon cancer cells. Additionally, epithelial (E)-cadherin expression was increased and Notch1 signaling was inhibited in NET-depleted colon cancer cells. These findings suggest that NET is highly expressed in human colon cancer, which is associated with the invasion of human colon cancer cells by influencing cell-cell adhesion through the Notch1-E-cadherin pathway. Thus, the present study revealed a novel function for NET and its downstream effectors in colon cancer cells, which will be valuable for future studies in a clinical setting.

Apoptotic effect of fluoxetine through the endoplasmic reticulum stress pathway in the human gastric cancer cell line AGS

Gastric cancer is the fourth most common cancer in the world. Fluoxetine (FLX), a selective serotonin reuptake inhibitor, can inhibit the growth of cancer cells by inducing apoptotic cell death through various signaling pathways. This study was aimed to determine the mechanism of apoptotic cell death induced by FLX in AGS cells. MTT assay for cell viability test and colony forming assay was performed for detection of cell proliferation. Western blot analysis was conducted for protein expression. Increased fluorescence intensity and chromatin condensation were observed using DAPI staining. Production of reactive oxygen species (ROS) was measured by DCFDA assay. AGS cell proliferation was remarkedly inhibited by FLX in a dose-dependent manner starting at a concentration of 20 μM. The expression of death receptors was increased, which resulted in elevated expression of activated caspases and cleaved PARP, leading to FLX-induced apoptosis. Moreover, FLX significantly increased production of ROS, and N-acetyl cysteine, which scavenges ROS, attenuated the cytotoxic effects of FLX. In addition, treatment with FLX increased the expression of the endoplasmic reticulum (ER) stress marker, CHOP. P53 protein expression in AGS cells also decreased significantly with FLX treatment. Inhibition of ER stress significantly decreased the expressions of death receptor 5 (DR5), cleaved caspase 3, and cleaved PARP, but not to control levels. FLX-induced apoptosis in AGS involved upregulation of death receptors, ROS generation, and activation of ER stress.

Tauroursodeoxycholic acid attenuates colitis-associated colon cancer by inhibiting nuclear factor kappaB signaling

BACKGROUND AND AIM

Inflammatory bowel diseases is associated with an increased risk for the development of colorectal cancer. However, the mechanism of immune signaling pathways linked to colitis-associated cancer (CAC) has not been fully elucidated. Tauroursodeoxycholic acid (TUDCA) exhibits anti-inflammatory and anti-cancer activities. The aim of this study is to investigate the role of TUDCA in the pathogenesis of CAC.

METHODS

Colitis-associated cancer was induced in mice using azoxymethane and dextran sodium sulfate administration, and TUDCA's effect on tumor development was evaluated. HCT 116 and COLO 205 were treated with TUDCA or vehicle and then stimulated with tumor necrosis factor-α (TNF-α). Expression of interleukin (IL)-8 was determined by real-time reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay, and IκBα phosphorylation and degradation was evaluated by immunoblot assay. The DNA-binding activity of NF-κB was assessed by electrophoretic mobility shift assay. Cell viability assay and real-time reverse transcription-polymerase chain reaction of bcl-xL, MCL1, c-FLIP-L, and VEGF were performed.

RESULTS

Tauroursodeoxycholic acid significantly attenuated the development of CAC in mice. Exposure to TUDCA resulted in extensive epithelial apoptosis and reduced levels of phospho-IκB kinase in the colon. In HCT 116 cells stimulated with TNF-α, TUDCA significantly inhibited IL-8 and IL-1α expression and suppressed TNF-α-induced IκBα phosphorylation/degradation and DNA-binding activity of NF-κB. Furthermore, in both HCT 116 and COLO 205 cells, TUDCA reduced cell viability and downregulated the expression of bcl-xL, MCL1, c-FLIP-L, and VEGF.

CONCLUSION

These results demonstrated that TUDCA suppresses NF-κB signaling and ameliorates colitis-associated tumorigenesis, suggesting that TUDCA could be a potential treatment for CAC.

Fluoxetine attenuates neuroinflammation in early brain injury after subarachnoid hemorrhage: a possible role for the regulation of TLR4/MyD88/NF-κB signaling pathway

Background

Neuroinflammation is closely associated with functional outcome in subarachnoid hemorrhage (SAH) patients. Our recent study demonstrated that fluoxetine inhibited NLRP3 inflammasome activation and attenuated necrotic cell death in early brain injury after SAH, while the effects and potential mechanisms of fluoxetine on neuroinflammation after SAH have not been well-studied yet.

Methods

One hundred and fifty-three male SD rats were subjected to the endovascular perforation model of SAH. Fluoxetine (10 mg/kg) was administered intravenously at 6 h after SAH induction. TAK-242 (1.5 mg/kg), an exogenous TLR4 antagonist, was injected intraperitoneally 1 h after SAH. SAH grade, neurological scores, brain water content, Evans blue extravasation, immunofluorescence/TUNEL staining, quantitative real-time polymerase chain reaction (qRT-PCR), and western blot were performed.

Results

Fluoxetine administration attenuated BBB disruption, brain edema, and improved neurological function after SAH. In addition, fluoxetine alleviated the number of Iba-1-positive microglia/macrophages, neutrophil infiltration, and cell death. Moreover, fluoxetine reduced the levels of pro-inflammatory cytokines, downregulated the expression of TLR4 and MyD88, and promoted the nuclear translocation of NF-κB p65, which were also found in rats with TAK-242 administration. Combined administration of fluoxetine and TAK-242 did not enhance the neuroprotective effects of fluoxetine.

Conclusion

Fluoxetine attenuated neuroinflammation and improved neurological function in SAH rats. The potential mechanisms involved, at least in part, TLR4/MyD88/NF-κB signaling pathway.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1388-x) contains supplementary material, which is available to authorized users.

Harnessing drug/radiation interaction through daily routine practice: Leverage medical and methodological point of view (MORSE 02-17 study)

BACKGROUND

Safety profile of the interaction between anticancer drugs and radiation is a recurrent question. However, there are little data regarding the non-anticancer treatment (NACT)/radiation combinations. The aim of the present study was to investigate concomitant NACTs in patients undergoing radiotherapy in a French comprehensive cancer center.

METHODS

A prospective cross-sectional study was conducted. All cancer patients undergoing a palliative or curative radiotherapy were consecutively screened for six weeks in 2016. Data on NACTs were collected.

RESULTS

Out of 214 included patients, a NACT was concomitantly prescribed to 155 patients (72%), with a median number of 5 NACTs per patient (range: 1-12). The most prescribed drugs were anti-hypertensive drugs (101 patients, 47.2%), psychotropic drugs (n = 74, 34.6%), analgesics (n = 78, 36.4%), hypolipidemic drugs (n = 57, 26.6%), proton pump inhibitors (n = 46, 21.5%) and antiplatelet drugs (n = 38, 17.8%). Although 833 different molecules were reported, only 20 possible modifiers of cancer biological pathways (prescribed to 74 patients (34.5%)) were identified. Eight out of the 833 molecules (0.9%), belonging to six drug families, have been investigated in 28 ongoing or published clinical trials in combo with radiotherapy. They were prescribed to 63 patients (29.4%).

CONCLUSION

Drug-radiation interaction remains a subject of major interest, not only for conventional anticancer drugs, but also for NACTs. New trial designs are thus required.

Walnut phenolic extract inhibits nuclear factor kappaB signaling in intestinal epithelial cells, and ameliorates experimental colitis and colitis-associated colon cancer in mice

PURPOSE

Walnuts (Juglans regia) are known to have anti-cancer and immunomodulatory effects. However, little information is available on the effects of walnut phenolic extract (WPE) on intestinal inflammation and colitis-associated colon cancer.

METHODS

COLO205 cells were pretreated with WPE and then stimulated with tumor necrosis factor (TNF)-α. In the acute colitis model, wild type mice (C57BL/6) were administered 4% dextran sulfate sodium (DSS) for 5 days. In the chronic colitis model, interleukin (IL)-10^-/- mice were administered with either the vehicle or WPE (20 mg/kg) by oral gavage daily for 2 weeks. In an inflammation-associated tumor model, wild type mice were administered a single intraperitoneal injection of azoxymethane followed by three cycles of 2% DSS for 5 days and 2 weeks of free water consumption.

RESULTS

WPE significantly inhibited IL-8 and IL-1α expression in COLO205 cells. WPE attenuated both the TNF-α-induced IκB phosphorylation/degradation and NF-κB DNA binding activity. The administration of oral WPE significantly reduced the severity of colitis in both acute and chronic colitis models, including the IL-10^-/- mice. In immunohistochemical staining, WPE attenuated NF-κB signaling in the colons of both colitis models. Finally, WPE also significantly reduced tumor development in a murine model of colitis-associated colon cancer (CAC).

CONCLUSIONS

WPE ameliorates acute and chronic colitis and CAC in mice, suggesting that WPE may have potentials for the treatment of inflammatory bowel disease.

The Onset and Progression of Chronic Colitis Parallels Increased Mucosal Serotonin Release via Enterochromaffin Cell Hyperplasia and Downregulation of the Serotonin Reuptake Transporter

BACKGROUND

Serotonin (5-hydroxytryptamine, 5-HT) has been linked with several inflammation-associated intestinal diseases, including ulcerative colitis (UC). The largest pool of 5-HT in the body is in enterochromaffin (EC) cells located throughout the intestinal tract. EC cells are mechanosensitive and detect noxious stimuli, inducing secretion of 5-HT, which plays an important role in enteric reflexes and immunomodulation. In this study, we evaluated intestinal 5-HT levels in the Winnie mouse model of spontaneous chronic colitis, which closely replicates UC.

METHODS

Real-time electrochemical recordings of 5-HT oxidation currents were obtained from ex vivo preparations of jejunum, ileum, proximal, and distal colon from Winnie (5-25 weeks old) and age matched C57BL/6 mice. EC cells were examined by immunohistochemistry, and the gene expression of tryptophan hydroxylase 1 (5-HT synthesis) and the serotonin reuptake transporter (SERT) were determined by quantitative Real-Time Polymerase Chain Reaction (RT-qPCR).

RESULTS

Compression-evoked and basal 5-HT concentrations were elevated in the distal and proximal colon of Winnie mice. EC cell hyperplasia and downregulation of SERT on the transcriptional level were identified as mechanisms underlying increased levels of 5-HT. Increase in mucosal 5-HT release was observed at the onset of disease at 7-14 weeks, confirmed by disease activity scores. Furthermore, increases in 5-HT levels and progression of disease activity correlated linearly with age, but not sex.

CONCLUSIONS

Our findings in the Winnie mouse model of spontaneous chronic colitis demonstrate for the first time that the onset and progression of chronic UC-like intestinal inflammation is associated with increased 5-HT levels in the colonic mucosa.

Role of iRhom2 in intestinal ischemia-reperfusion-mediated acute lung injury

Intestinal ischemia-reperfusion (I/R) may cause acute systemic and lung inflammation. However, the detailed mechanism of this inflammatory cascade has not been fully elucidated. Inactive rhomboid protein 2 (iRhom2) is essential for the maturation of TNF-α converting enzyme (TACE), which is required for TNF-α secretion. We evaluated the role of iRhom2 in a mouse model of intestinal I/R using iRhom2 knockout (KO) and wild-type (WT) mice. Lung injury following intestinal I/R was significantly attenuated in iRhom2 KO mice compared with WT mice. After intestinal I/R, lungs from iRhom2 KO mice showed significantly lower myeloperoxidase (MPO) activity and markedly reduced cell apoptosis associated with a decreased level of active caspase 3 and decreased TUNEL staining compared with lungs from WT mice. TNF-α levels were elevated in the serum and lungs of WT mice with intestinal I/R and significantly reduced in iRhom2 KO mice with intestinal I/R. iRhom2 may play a critical role in the pathogenesis of acute lung injury (ALI) after intestinal I/R and thus may be a novel therapeutic target for ALI after intestinal I/R injury.

Review article: the many potential roles of intestinal serotonin (5-hydroxytryptamine, 5-HT) signalling in inflammatory bowel disease

BACKGROUND

Serotonin (5-hydroxytryptamine, 5-HT) is an important mediator of every major gut-related function. Recent investigations also suggest that 5-HT can influence the development and severity of inflammation within the gut, particularly in the setting of inflammatory bowel disease (IBD).

AIM

To review the roles that the intestinal serotonin signalling system plays in gut function, with a specific focus on IBD.

METHODS

We reviewed manuscripts from 1952 to 2017 that investigated and discussed roles for 5-HT signalling in gastrointestinal function and IBD, as well as the influence of inflammation on 5-HT signalling elements within the gut.

RESULTS

Inflammation appears to affect every major element of intestinal 5-HT signalling, including 5-HT synthesis, release, receptor expression and reuptake capacity. Importantly, many studies (most utilising animal models) also demonstrate that modulation of selective serotonergic receptors (via agonism of 5-HT₄ R and antagonism of 5-HT₃ R) or 5-HT signal termination (via serotonin reuptake inhibitors) can alter the likelihood and severity of intestinal inflammation and/or its complicating symptoms. However, there are few human studies that have studied these relationships in a targeted manner.

CONCLUSIONS

Insights discussed in this review have strong potential to lead to new diagnostic and therapeutic tools to improve the management of IBD and other related disorders. Specifically, strategies that focus on modifying the activity of selective serotonin receptors and reuptake transporters in the gut could be effective for controlling disease activity and/or its associated symptoms. Further studies in humans are required, however, to more completely understand the pathophysiological mechanisms underlying the roles of 5-HT in this setting.

Evaluation of central and peripheral effects of doxepin on acetic acid-induced colitis in rat and the involved mechanisms

Anti-colitis effect of antidepressants has been demonstrated recently. Doxepin, a tricyclic antidepressant drug (TCA), with potent H₁, H₂, alpha₁ adrenergic and muscarinic receptor blocking effects could be a good candidate for investigation for its anti-colitis activity. Moreover high prevalence of depression in patients who suffer from IBD (inflammatory bowel disease), defends this idea that adjuvant therapy with an antidepressant drug which has anti-inflammatory effect, may exert favorable effects in the control of the disease. In this study colitis was induced by acetic acid instillation into rat's colon. Doxepin was injected by intraperitoneal (10, 20, 40 mg/kg, twice daily, i.p.) or intracerebroventricular (50 and 100 microgram/rat, i.c.v.) routes to separate the mechanisms are absolutely exerted centrally or mediated both centrally and peripherally prior to induction of colitis. Dexamethasone (2 mg/kg/day, i.p.) was used as reference drug. All the treatments continued for three successive days. The effectiveness of drug was evaluated by determination of cytokines (TNFα, IL6 and IL1β) and myeloperoxidase (MPO) activity as well as macroscopic scores and histopathological parameters. Doxepin after i.p. administration was effective to reduce colitis severity through reduction in the macroscopic and microscopic colonic parameters, MPO activity and cytokines levels. Intracerebroventricular administration of the drug in contrast, did not show any significant protective effect suggesting no important central mechanisms for anti-colitis activity of doxepin. Doxepin as an ancient antidepressive drug has anti-colitis and anti-inflammatory properties which are mainly exerted peripherally so it could be introduced as a good candidate for depressed people who suffered from IBD disorders.

Fluoxetine for Maintenance of Remission and to Improve Quality of Life in Patients with Crohn's Disease: a Pilot Randomized Placebo-Controlled Trial

BACKGROUND AND AIMS

Previous studies have shown that antidepressants reduce inflammation in animal models of colitis. The present trial aimed to examine whether fluoxetine added to standard therapy for Crohn's disease [CD] maintained remission, improved quality of life [QoL] and/or mental health in people with CD as compared to placebo.

METHODS

A parallel randomized double-blind placebo controlled trial was conducted. Participants with clinically established CD, with quiescent or only mild disease, were randomly assigned to receive either fluoxetine 20 mg daily or placebo, and followed for 12 months. Participants provided blood and stool samples and completed mental health and QoL questionnaires. Immune functions were assessed by stimulated cytokine secretion [CD3/CD28 stimulation] and flow cytometry for cell type. Linear mixed-effects models were used to compare groups.

RESULTS

Of the 26 participants, 14 were randomized to receive fluoxetine and 12 to placebo. Overall, 14 [54%] participants were male. The mean age was 37.4 [SD=13.2] years. Fluoxetine had no effect on inflammatory bowel disease activity measured using either the Crohn's Disease Activity Index [F(3, 27.5)=0.064, p=0.978] or faecal calprotectin [F(3, 32.5)=1.08, p=0.371], but did have modest effects on immune function. There was no effect of fluoxetine on physical, psychological, social or environmental QoL, anxiety or depressive symptoms as compared to placebo [all p>0.05].

CONCLUSIONS

In this small pilot clinical trial, fluoxetine was not superior to placebo in maintaining remission or improving QoL. [ID: ACTRN12612001067864.].

Combined Parthenolide and Balsalazide Have Enhanced Antitumor Efficacy Through Blockade of NF-κB Activation

Balsalazide is a colon-specific prodrug of 5-aminosalicylate that is associated with a reduced risk of colon cancer in patients with ulcerative colitis. Parthenolide, a strong NF-κB inhibitor, has recently been demonstrated to be a promising therapeutic agent, promoting apoptosis of cancer cells. In the current study, the antitumor effect of balsalazide combined with parthenolide in human colorectal cancer cells and colitis-associated colon cancers (CAC) was investigated. The results demonstrate that the combination of balsalazide and parthenolide markedly suppress proliferation, nuclear translocation of NF-κB, IκB-α phosphorylation, NF-κB DNA binding, and expression of NF-κB targets. Apoptosis via NF-κB signaling was confirmed by detecting expression of caspases, p53 and PARP. Moreover, treatment of a CAC murine model with parthenolide and balsalazide together resulted in significant recovery of body weight and improvement in histologic severity. Administration of parthenolide and balsalazide to CAC mice also suppressed carcinogenesis as demonstrated by uptake of 18F-fluoro-2-deoxy-D-glucose (FDG) using micro-PET/CT scans. These results demonstrate that parthenolide potentiates the efficacy of balsalazide through synergistic inhibition of NF-κB activation and the combination of dual agents prevents colon carcinogenesis from chronic inflammation.

IMPLICATIONS

This study represents the first evidence that combination therapy with balsalazide and parthenolide could be a new regimen for colorectal cancer treatment. Mol Cancer Res; 15(2); 141-51. ©2016 AACR.

The antidepressant fluoxetine induces necrosis by energy depletion and mitochondrial calcium overload

Selective Serotonin Reuptake Inhibitor antidepressants, such as fluoxetine (Prozac), have been shown to induce cell death in cancer cells, paving the way for their potential use as cancer therapy. These compounds are able to increase cytosolic calcium concentration ([Ca2+]cyt), but the involved mechanisms and their physiological consequences are still not well understood. Here, we show that fluoxetine induces an increase in [Ca2+]cyt by emptying the endoplasmic reticulum (ER) through the translocon, an ER Ca2+ leakage structure. Our data also show that fluoxetine inhibits oxygen consumption and lowers mitochondrial ATP. This latter is essential for Ca2+ reuptake into the ER, and we postulated therefore that the fluoxetine-induced decrease in mitochondrial ATP production results in the emptying of the ER, leading to capacitative calcium entry. Furthermore, Ca2+ quickly accumulated in the mitochondria, leading to mitochondrial Ca2+ overload and cell death. We found that fluoxetine could induce an early necrosis in human peripheral blood lymphocytes and Jurkat cells, and could also induce late apoptosis, especially in the tumor cell line. These results shed light on fluoxetine-induced cell death and its potential use in cancer treatment.

TNFAIP3, a negative regulator of the TLR signaling pathway, is a potential predictive biomarker of response to antidepressant treatment in major depressive disorder

Inflammation and abnormalities in Toll-like receptor (TLR) expression and activation have been linked to major depressive disorder (MDD). However, negative regulators of TLR pathways have not been previously investigated in this context. Here, we sought to investigate the association of depression severity, measured by the 17-item Hamilton Depression Rating Scale (HAMD-17), with mRNA expression levels of negative regulators of the TLR pathway, including SOCS1, TOLLIP, SIGIRR, MyD88s, NOD2 and TNFAIP3, in peripheral blood mononuclear cells (PBMCs) from 100 patients with MDD and 53 healthy controls, before and after treatment with antidepressants. Positive regulators of the TLR4 pathway, including Pellino 1, TRAF6 and IRAK1, were also investigated. Among all patients, MyD88s, and TNFAIP3 mRNAs were expressed at lower levels in PBMCs from patients with MDD. Multiple linear regression analyses revealed that TNFAIP3 mRNA expression before treatment was inversely correlated with severity of depression and effectively predicted improvement in HAMD-17 scores. Among 79 treatment-completers, only TNFAIP3 mRNA was significantly increased by treatment with antidepressants for 4 weeks. Treatment of human monocytes (THP-1) and mouse microglia (SIM-A9) cell lines with fluoxetine significantly increased TNFAIP3 mRNA expression and suppressed IL-6 levels. The suppressive effect of fluoxetine on IL-6 was attenuated by knockdown of TNFAIP3 expression. These findings suggest that both dysfunction of the negative regulatory system in patients with MDD and antidepressant treatment exert anti-inflammatory effects, at least in part through increased expression of the TNFAIP3 gene. They also indicate that modulating expression of the TNFAIP3 gene to rebalance TLR-mediated inflammatory signaling may be potential therapeutic strategy for treating MDD.

Sam68/KHDRBS1 is critical for colon tumorigenesis by regulating genotoxic stress-induced NF-κB activation

Nuclear factor kappa B (NF-κB)-mediated transcription is an important mediator for cellular responses to DNA damage. Genotoxic agents trigger a 'nuclear-to-cytoplasmic' NF-κB activation signaling pathway; however, the early nuclear signaling cascade linking DNA damage and NF-κB activation is poorly understood. Here we report that Src-associated-substrate-during-mitosis-of-68kDa/KH domain containing, RNA binding, signal transduction associated 1 (Sam68/KHDRBS1) is a key NF-κB regulator in genotoxic stress-initiated signaling pathway. Sam68 deficiency abolishes DNA damage-stimulated polymers of ADP-ribose (PAR) production and the PAR-dependent NF-κB transactivation of anti-apoptotic genes. Sam68 deleted cells are hypersensitive to genotoxicity caused by DNA damaging agents. Upregulated Sam68 coincides with elevated PAR production and NF-κB-mediated anti-apoptotic transcription in human and mouse colon cancer. Knockdown of Sam68 sensitizes human colon cancer cells to genotoxic stress-induced apoptosis and genetic deletion of Sam68 dampens colon tumor burden in mice. Together our data reveal a novel function of Sam68 in the genotoxic stress-initiated nuclear signaling, which is crucial for colon tumorigenesis.

DOI:http://dx.doi.org/10.7554/eLife.15018.001

Cells use signaling pathways to detect and respond to harmful conditions by switching on genes that keep the cell healthy. One important pathway is the nuclear factor kappa B (NF-κB) signaling pathway, which is activated by many stimuli. These stimuli may come from infections from outside the cell or may originate inside the cell, as seen for DNA damage caused by irradiation, chemicals or rapid DNA replication in cancer cells.

Most of a cell’s DNA is located in the cell nucleus. However, NF-κB proteins are normally located outside the nucleus, in the cell’s cytoplasm. Damage to DNA triggers a signal from the nucleus to the cytoplasm. This signal activates the NF-κB proteins, which move into the nucleus and turn on genes that help the cell to recover from the damage. These genes include those that prevent the cell from self-destructing. In one step of the NF-κB activation process, chain-like molecules called polymers are made from a compound called poly(ADP-ribose), or PAR for short. However, few other details are known about how the damaged DNA in the nucleus signals to the cytoplasm.

A protein called Sam68, which is found in the cell nucleus, has been linked to DNA damage signaling. Fu, Sun et al. now present evidence that suggests that if mouse cells lack Sam68, they do not produce PAR polymers in response to DNA damage. In addition, these cells could not trigger the PAR-dependent signaling cascade that is essential for activating NF-κB and for turning on the protective genes. Consequently, cells that lacked Sam68 were extremely sensitive to agents that cause DNA damage, such as chemicals and irradiation.

The NF-κB pathway is regulated incorrectly in some cancers, but is also activated by DNA damage caused by cancer treatments. Therefore, Fu, Sun et al. also explored the role of Sam68 in cancer. Reducing the levels of Sam68 made human colon cancer cells more likely to self-destruct when they were exposed to DNA-damaging agents. Furthermore, removing Sam68 from mice that spontaneously grow colon cancer caused their tumors to develop more slowly than mice that retained Sam68 in their cells.

Overall, the findings presented by Fu, Sun et al. suggest that Sam68 regulates the signal from the nucleus to the cytoplasm that activates NF-κB proteins in response to DNA damage. Sam68 also appears to be important for helping colon cancer cells grow and survive. Future challenges will be to understand how Sam68 regulates the production of the PAR polymer in this response and to explore whether Sam68 can be targeted for treating cancer.

DOI:http://dx.doi.org/10.7554/eLife.15018.002

The role of macrophages in anti-inflammatory activity of antidepressant drugs

Depression is a common disease influencing patients' quality of life, whose etiology involves complex interactions of environmental, genetic and immunological factors. The latter factors include proinflammatory activation of monocytes and macrophages and increased serum levels of proinflammatory cytokines, altogether formulated as the "macrophage theory of depression". Our current review summarizes the impact of the most commonly used antidepressant drugs on the immune response with special emphasis on the role of macrophages in the clinically observed effects. The anti-inflammatory action of antidepressants mainly results from their direct interaction with immune cells and from changes in the concentration and the relations of neurotransmitters sensed by these cells. The summarized data revealed that Mφs are one of the leading cell populations involved in drug-mediated immune effects that can be observed both in subjects with depression as well as in individuals not suffering from depression. Thus, currently reviewed immunomodulatory effects of the experimental use of different antidepressant drugs suggest the possibility of utilizing them in complex therapeutic strategies dedicated to various inflammatory and immune-mediated diseases. It is worth noting that an excessive inflammatory reaction is also associated with the pathogenesis of various cardiovascular, metabolic and neuro-endocrine diseases. Thus, the inclusion of antidepressants in the complex therapy of these disorders may have beneficial effects through the enhancement of the mood of the patient and alleviation of chronic inflammation. On the other hand, presented data suggest that the influence of chronically used antidepressants on anti-microbial and anti-tumor immunity could also be taken into consideration.

Nimbolide Inhibits Nuclear Factor-КB Pathway in Intestinal Epithelial Cells and Macrophages and Alleviates Experimental Colitis in Mice

Nimbolide is a limonoid extracted from neem tree (Azadirachta indica) that has antiinflammatory properties. The effect of nimbolide on the nuclear factor-kappa B (NF-κB) pathway in intestinal epithelial cells (IECs), macrophages and in murine colitis models was investigated. The IEC COLO 205, the murine macrophage cell line RAW 264.7, and peritoneal macrophages from interleukin-10-deficient (IL-10^-/- ) mice were preconditioned with nimbolide and then stimulated with tumor necrosis factor-α (TNF-α) or lipopolysaccharide. Dextran sulfate sodium-induced acute colitis model and chronic colitis model in IL-10^-/- mice were used for in vivo experiments. Nimbolide significantly suppressed the expression of inflammatory cytokines (IL-6, IL-8, IL-12, and TNF-α) and inhibited the phosphorylation of IκBα and the DNA-binding affinity of NF-κB in IECs and macrophages. Nimbolide ameliorated weight loss, colon shortening, disease activity index score, and histologic scores in dextran sulfate sodium colitis. It also improved histopathologic scores in the chronic colitis of IL-10^-/- mice. Staining for phosphorylated IκBα was significantly decreased in the colon tissue after treatment with nimbolide in both models. Nimbolide inhibits NF-κB signaling in IECs and macrophages and ameliorates experimental colitis in mice. These results suggest nimbolide could be a potentially new treatment for inflammatory bowel disease. Copyright © 2016 John Wiley & Sons, Ltd.

Fluoxetine synergizes with temozolomide to induce the CHOP-dependent endoplasmic reticulum stress-related apoptosis pathway in glioma cells

Although temozolomide (TMZ) is the most effective chemotherapy agent for glioma, chemotherapy resistance has limited its clinical use. Fluoxetine (FLT), which is widely used in cancer-related depression, has exhibited potent anticancer properties in different cancer cell types. The aim of this study was i) to evaluate the antitumor mechanism of FLT, and ii) to further evaluate the effects of a combination of FLT and TMZ on glioma cells. Glioma cell lines were exposed to FLT and/or TMZ. Cell viability and apoptosis were examined by CCK-8 assay, flow cytometry and caspase-3 activity assay, respectively. The expression of endoplasmic reticulum-stress (ERS) apoptosis-related proteins was measured using real-time PCR and western blotting. Synergism between the two drugs was evaluated by the combination index (CI) through CompuSyn software. FLT significantly and dose-dependently inhibited the proliferation of various glioma cell lines, and rat glioma C6 cells had a highly sensitive response to the addition of FLT. FLT treatment increased the early apoptosis rate, induced typical apoptotic morphology in the C6 cells and activated caspase-3 with no change in the mitochondrial membrane potential. Further study showed that FLT activated the ERS marker, CHOP. This induction was associated with activation of the PERK-eIF2α-ATF4 and ATF6 cascade. Concomitantly, GADD34, a downstream molecule of CHOP, was also increased. Combined FLT and TMZ treatment showed a synergistic cytotoxic effect in the C6 glioma cells. Knockdown of CHOP expression abolished the synergistic effect of FLT and TMZ in the C6 cells, which suggests that FLT may sensitize glioma cells to TMZ through activation of the CHOP-dependent apoptosis pathway. These results revealed that FLT induced glioma cell apoptosis and sensitized glioma cells to TMZ through activation of the CHOP-dependent apoptosis pathway. The present study provides a primary basis for using the combination of these drugs in patients with advanced glioma.

Repeatedly administered antidepressant drugs modulate humoral and cellular immune response in mice through action on macrophages

Depression is associated with an altered immune response, which could be normalized by antidepressant drugs. However, little is known about the influence of antidepressants on the peripheral immune response and function of macrophages in individuals not suffering from depression. Our studies were aimed at determining the influence of antidepressant drugs on the humoral and cellular immune response in mice. Mice were treated intraperitoneally with imipramine, fluoxetine, venlafaxine, or moclobemide and contact immunized with trinitrophenyl hapten followed by elicitation and measurement of contact sensitivity by ear swelling response. Peritoneal macrophages from drug-treated mice were either pulsed with sheep erythrocytes or conjugated with trinitrophenyl and transferred into naive recipients to induce humoral or contact sensitivity response, respectively. Secretion of reactive oxygen intermediates, nitric oxide, and cytokines by macrophages from drug-treated mice was assessed, respectively, in chemiluminometry, Griess-based colorimetry and enzyme-linked immunosorbent assay, and the expression of macrophage surface markers was analyzed cytometrically. Treatment of mice with fluoxetine, venlafaxine, and moclobemide results in suppression of humoral and cell-mediated immunity with a reduction of the release of macrophage proinflammatory mediators and the expression of antigen-presentation markers. In contrast, treatment with imipramine enhanced the humoral immune response and macrophage secretory activity but slightly suppressed active contact sensitivity. Our studies demonstrated that systemically delivered antidepressant drugs modulate the peripheral humoral and cell-mediated immune responses, mostly through their action on macrophages. Imipramine was rather proinflammatory, whereas other tested drugs expressed immunosuppressive potential. Current observations may be applied to new therapeutic strategies dedicated to various disorders associated with excessive inflammation.

Matricellular Protein Periostin Mediates Intestinal Inflammation through the Activation of Nuclear Factor κB Signaling

Periostin is a matricellular protein that interacts with various integrin molecules on the cell surface. Although periostin is expressed in inflamed colonic mucosa, its role in the regulation of intestinal inflammation remains unclear. We investigated the role of periostin in intestinal inflammation using Postn-deficient (Postn-/-) mice. Intestinal epithelial cells (IECs) were transfected by Postn small interfering RNAs. Periostin expression was determined in colon tissue samples from ulcerative colitis (UC) patients. Oral administration of dextran sulfate sodium (DSS) or rectal administration of trinitrobenzene sulfonic acid, induced severe colitis in wild-type mice, but not in Postn-/- mice. Administration of recombinant periostin induced colitis in Postn-/- mice. The periostin neutralizing-antibody ameliorated the severity of colitis in DSS-treated wild-type mice. Silencing of Postn inhibited inteleukin (IL)-8 mRNA expression and NF-κB DNA-binding activity in IECs. Tumor necrosis factor (TNF)-α upregulated mRNA expression of Postn in IECs, and recombinant periostin strongly enhanced IL-8 expression in combination with TNF-α, which was suppressed by an antibody against integrin αv (CD51). Periostin and CD51 were expressed at significantly higher levels in UC patients than in controls. Periostin mediates intestinal inflammation through the activation of NF-κB signaling, which suggests that periostin is a potential therapeutic target for inflammatory bowel disease.

Restraint stress induces and exacerbates intestinal inflammation in interleukin-10 deficient mice

AIM: To investigate the effects of restraint stress on chronic colitis in interleukin (IL)-10 deficient (IL-10^-/-) mice.

METHODS: The first experiment compared the effect of restraint stress on the development of intestinal inflammation in wild-type and IL-10^-/- mice. Both wild-type and IL-10^-/- mice were physically restrained in a well-ventilated, 50 cm³ conical polypropylene tube for 2 h per day for three consecutive days. The second experiment was performed to assess the effect of restraint stress on exacerbation of colitis induced by piroxicam in IL-10^-/- mice. The IL-10^-/- mice were exposed to restraint stress for 2 h per day for 3 consecutive days, and then treated with piroxicam for 4 d at a dose of 200 ppm administered in the rodent chow.

RESULTS: In the first experiment, none of the wild-type mice with or without restraint stress showed clinical and histopathological abnormality in the gut. However, IL-10^-/- mice exposed to restraint stress exhibited histologically significant intestinal inflammation as compared to those without restraint stress. In the second experiment, restraint stress significantly reduced body weight and increased the severity of intestinal inflammation assessed by histopathologic grading in IL-10^-/- mice. Colonic IL12p40 mRNA expression was strongly increased in mice exposed to restraint stress.

CONCLUSION: This novel animal model could be useful in future study of psychological stress in the pathogenesis of inflammatory bowel disease.

Roxithromycin inhibits nuclear factor kappaB signaling and endoplasmic reticulum stress in intestinal epithelial cells and ameliorates experimental colitis in mice

Roxithromycin is known to have anti-inflammatory and immunoregulatory activity. However, little information is available on the effect of roxithromycin in intestinal inflammation. The aim of this study was to investigate the effect of roxithromycin on NF- κB signaling and ER stress in intestinal epithelial cells (IECs) and the effect of roxithromycin on dextran sulfate sodium (DSS)-induced acute colitis in a murine model. HCT116 cells and COLO205 cells were pretreated with roxithromycin and then stimulated with tumor necrosis factor-α (TNF-α). Interleukin (IL)-8 expression was determined by real-time reverse transcription-polymerase chain reaction. Nuclear factor kappaB (NF-κB) DNA-binding activity and IκB phosphorylation/degradation were evaluated by electrophoretic mobility shift assay and Western blot analysis. The molecular markers of endoplasmic reticulum stress, including p-JNK, phosphorylated eukaryotic initiation factor 2 (p-eIF2α), C/EBP homologous protein (CHOP), and X-box binding protein 1 (XBP1) were evaluated using western blotting and PCR. Mice were given 4% DSS for five days with or without roxithromycin. Primary IECs were isolated from mice with DSS-induced colitis. Roxithromycin significantly inhibited the upregulated expression of IL-8. Pretreatment with roxithromycin markedly attenuated NF-κB DNA-binding activity and IκB phosphorylation/degradation. CHOP and XBP1 mRNA expression were enhanced in the presence of TNF-α, and it was dampened by pretreatment of roxithromycin. c-Jun-N-terminal kinase (JNK) phosphorylation and the level of p-eIF2α were also downregulated by the pretreatment of roxithromycin. Roxithromycin significantly reduced the severity of DSS-induced murine colitis, as assessed by the disease activity index, colon length, and histology. In addition, the DSS-induced phospho-IκB kinase activation was significantly decreased in roxithromycin-pretreated mice. Finally, IκB degradation was reduced in primary IECs from mice treated with roxithromycin. These results suggest that roxithromycin may have potential usefulness in the treatment of inflammatory bowel disease.

Paroxetine differentially modulates LPS-induced TNFα and IL-6 production in mouse macrophages

Paroxetine is a selective serotonin reuptake inhibitor (SSRI) that is clinically used for the treatment of depression in human patients. Because of recent reports on the role of serotonin in modulating inflammation and the link between inflammation and depression, we sought to test the effect of paroxetine directly on macrophage response to an inflammatory stimulus. Lipopolysaccharide (LPS) treatment of mouse macrophages significantly enhanced TNFα and IL-6 production. Paroxetine treatment of macrophages, however, significantly inhibited LPS-induced IL-6 production. In contrast, paroxetine enhanced LPS-induced TNFα production in macrophages. These effects of paroxetine were mimicked by fluoxetine, another SSRI. To determine if the effects of paroxetine are mediated via modulation of the 5-HT system, we treated macrophages with 5-HT or 5-HT receptor antagonist (LY215840) in the presence of LPS and/or paroxetine. 5-HT treatment by itself did not affect LPS-induced cytokine production. LY215840, however, reversed paroxetine's effect on LPS-induced TNFα production but not IL-6. To understand the signaling mechanisms, we examined paroxetine's effect on MAPK and NFκB pathways. While paroxetine inhibited LPS-induced IκBα phosphorylation, MAPK pathways were mostly unaffected. Together these data demonstrate that paroxetine has critical but differential effects on IL-6 and TNFα production in macrophages and that it likely regulates these cytokines via distinct mechanisms.

Fexofenadine regulates nuclear factor-κB signaling and endoplasmic reticulum stress in intestinal epithelial cells and ameliorates acute and chronic colitis in mice

The aim of this study was to evaluate the effect of fexofenadine on intestinal inflammation. HCT116 and COLO205 cells were pretreated with fexofenadine and then stimulated with tumor necrosis factor (TNF)-α. Interleukin (IL)-8 expression was determined by real-time reverse-transcription polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay. DNA-binding activity of nuclear factor-κB was assessed by electrophoretic mobility shift assay. The molecular markers of endoplasmic reticulum (ER) stress were evaluated by Western blot analysis and PCR. In the acute colitis model, mice were given 4% dextran sulfate sodium (DSS) for 5 days with or without fexofenadine. IL-10(-/-) mice were used to evaluate the effect of fexofenadine on chronic colitis. Fexofenadine significantly inhibited the upregulated expression of IL-8 in HCT116 and COLO205 cells stimulated with TNF-α. Fexofenadine suppressed nuclear factor-κB DNA-binding activity. C/EBP homologous protein mRNA expression was enhanced in the presence of TNF-α, and it was dampened by pretreatment of fexofenadine. In addition, the induction of ER stress markers caspase-12 and p-eukaryotic initiation factor 2 (eIF2)-α was significantly suppressed by the pretreatment of fexofenadine. Administration of fexofenadine significantly reduced the severity of DSS-induced murine colitis, as assessed by the disease activity index, colon length, and histology. In addition, the DSS-induced phospho-IκB kinase activation was significantly decreased in fexofenadine-pretreated mice. Finally, fexofenadine significantly reduced the severity of colitis and the immunoreactivity of caspase-12 and p-eIF2-α in IL-10(-/-) mice as compared with controls. These results suggest that fexofenadine is a potential therapeutic agent for the treatment of inflammatory bowel disease.

Fluoxetine inhibits hyperresponsive lamina propria mononuclear cells and bone marrow-derived dendritic cells, and ameliorates chronic colitis in IL-10-deficient mice

BACKGROUND/AIMS

We aimed to study the effect of fluoxetine on chronic colitis and its anti-inflammatory mechanism in interleukin-10-deficient (IL-10(-/-)) mice.

METHODS

IL-10(-/-) mice were administered with either the vehicle or one of the two dosages of fluoxetine (1 or 5 mg/kg) by oral gavage daily for 2 weeks. Lamina propria mononuclear cells (LPMCs) were isolated from IL-10(-/-) mice treated with or without fluoxetine, and cytokine expression was measured. Bone marrow-derived dendritic cells (BMDCs) isolated from IL-10(-/-), and wild-type mice were pretreated with fluoxetine and then stimulated with lipopolysaccharide. IL-12p40 and tumor necrosis factor (TNF)-α gene expression was determined by real-time PCR. DNA-binding activity of nuclear factor-κB (NF-κB) was evaluated by electrophoretic mobility shift assay.

RESULTS

Fluoxetine significantly reduced intestinal inflammation as assessed by body weight, colon length, and histopathological grading, and it inhibited the level of TNF-α gene expression in IL-10(-/-) mice. LPMCs were isolated from IL-10(-/-) mice, and cellular expression of IL-12p40 and interferon-γ was suppressed by fluoxetine treatment. Fluoxetine significantly inhibited IL-12p40 and TNF-α gene expression and protein secretion in BMDCs from IL-10(-/-) mice. DNA-binding activity of NF-κB was suppressed by fluoxetine pretreatment.

CONCLUSIONS

These results indicate that fluoxetine ameliorates intestinal inflammation in IL-10(-/-) mice and inhibits hyperresponsive LPMCs and BMDCs, which suggests that fluoxetine could be a potential therapeutic agent for inflammatory bowel disease.