Interleukin-8/CXCR1 Signaling Contributes to the Progression of Pulmonary Adenocarcinoma Resulting in Malignant Pleural Effusion.

Pulmonary adenocarcinoma (PADC) treatment limited efficacy in preventing tumor progression, often resulting in malignant pleural effusion (MPE). MPE is filled with various mediators, especially interleukin-8 (IL-8). However, the role of IL-8 and its signaling mechanism within the fluid microenvironment (FME) implicated in tumor progression warrants further investigation. Primary cultured cells from samples of patients with MPE from PADC, along with a commonly utilized lung cancer cell line, were employed to examine the role of IL-8 and its receptor, CXCR1, through comparative analysis. Our study primarily assessed migration and invasion capabilities, epithelial-mesenchymal transition (EMT), and cancer stem cell (CSC) properties. Additionally, IL-8 levels in MPE fluid versus serum, along with immunohistochemical expression of IL-8/CXCR1 signaling in tumor tissue and cell blocks were analyzed. IL-8/CXCR1 overexpression enhanced EMT and CSC properties. Furthermore, the immunocytochemical examination of 17 cell blocks from patients with PADC and MPE corroborated the significant correlation between upregulated IL-8 and CXCR1 expression and the co-expression of IL-8 and CXCR1 in MPE with distant metastasis. In summary, the IL-8/ CXCR1 axis in FME is pivotal to tumor promotion via paracrine and autocrine signaling. Our study provides a therapeutic avenue for improving the prognosis of PADC patients with MPE.

CXCL8 and its cognate receptors CXCR1/CXCR2 in primary myelofibrosis.

BCR::ABL1 negative myeloproliferative neoplasms (MPN) form a distinct group of hematologic malignancies characterized by sustained proliferation of cells from multiple myeloid lineages. With a median survival of 16-35 months in patients with high-risk disease, primary myelofibrosis (PMF) is considered the most aggressive entity amongst all BCR::ABL1 MPN. Additionally, for a significant subset of patients, MPN evolve into secondary acute myeloid leukemia (AML), which has an even poorer prognosis compared to de novo AML. As the exact mechanisms of disease development and progression remain to be elucidated, current therapeutic approaches fail to prevent disease progression or transformation into secondary AML. As each MPN entity is characterized by sustained activation of various immune cells and raised cytokine concentrations within bone marrow (BM) and peripheral blood (PB), MPN may be considered to be typical inflammation-related malignancies. However, the exact role and consequences of increased cytokine concentrations within BM and PB plasma has still not been completely established. Up-regulated cytokines can stimulate cellular proliferation, or contribute to the development of an inflammation-related BM niche resulting in genotoxicity and thereby supporting mutagenesis. The neutrophil chemoattractant CXCL8 is of specific interest as its concentration is increased within PB and BM plasma of patients with PMF. Increased concentration of CXCL8 negatively correlates with overall survival. Furthermore, blockage of the CXCR1/2 axis appears to be able to reduce BM fibrosis and megakaryocyte dysmorphia in murine models. In this review, we summarize available evidence on the role of the CXCL8-CXCR1/2 axis within the pathogenesis of PMF, and discuss potential therapeutic modalities targeting either CXCL8 or its cognate receptors CXCR1/2.

Circ_0026579 knockdown ameliorates lipopolysaccharide-induced human lung fibroblast cell injury by regulating CXCR1 via miR-370-3p.

Pneumonia is an inflammatory disease in lower respiratory tracts and its development involves the regulation of RNAs. Circular RNAs are a class of RNA subgroups that can mediate the progression of pneumonia. However, the molecular mechanism of circ_0026579 in regulating pneumonia occurrence remains unclear. The study is designed to reveal the role of circ_0026579 in lipopolysaccharide (LPS)-induced human lung fibroblast cell injury and the underlying mechanism. The expression levels of circ_0026579, miR-370-3p and C-X-C motif chemokine receptor 1 (CXCR1) were detected by quantitative real-time polymerase chain reaction or by western blotting. The production of tumour necrosis factor-α, interleukin (IL)-1ß and IL-6 was assessed by enzyme-linked immunosorbent assays. Malondialdehyde and superoxide dismutase levels were analysed using commercial kits. Cell viability, proliferation and apoptosis were analysed by cell counting kit-8 assay, 5-Ethynyl-2'-deoxyuridine assay and flow cytometry analysis, respectively. The binding relationship between miR-370-3p and circ_0026579 or CXCR1 was identified by dual-luciferase reporter assay, RNA immunoprecipitation assay and RNA pull-down assay. Circ_0026579 and CXCR1 expression were significantly upregulated, whereas miR-370-3p was downregulated in the serum of pneumonia patients. LPS treatment induced inflammatory response, oxidative stress and cell apoptosis and inhibited cell proliferation in MRC-5 cells; however, these effects were reversed after circ_0026579 depletion. In terms of the mechanism, circ_0026579 acted as a miR-370-3p sponge, and miR-370-3p combined with CXCR1. Additionally, circ_0026579 depletion ameliorated LPS-induced MRC-5 cell disorder by increasing miR-370-3p expression. CXCR1 overexpression also relieved the miR-370-3p-mediated effects in LPS-treated MRC-5 cells. Further, circ_0026579 induced CXCR1 expression by interacting with miR-370-3p. Circ_0026579 absence ameliorated MRC-5 cell dysfunction induced by LPS through the regulation of the miR-370-3p/CXCR1 axis.

CXCR1 drives the pathogenesis of EAE and ARDS via boosting dendritic cells-dependent inflammation.

Chemokines secreted by dendritic cells (DCs) play a key role in the regulation of inflammation and autoimmunity through chemokine receptors. However, the role of chemokine receptor CXCR1 in inflammation-inducing experimental autoimmune encephalomyelitis (EAE) and acute respiratory distress syndrome (ARDS) remains largely enigmatic. Here we reported that compared with healthy controls, the level of CXCR1 was aberrantly increased in multiple sclerosis (MS) patients. Knockout of CXCR1 not only ameliorated disease severity in EAE mice but also suppressed the secretion of inflammatory factors (IL-6/IL-12p70) production. We observed the same results in EAE mice with DCs-specific deletion of CXCR1 and antibody neutralization of the ligand CXCL5. Mechanically, we demonstrated a positive feedback loop composed of CXCL5/CXCR1/HIF-1α direct regulating of IL-6/IL-12p70 production in DCs. Meanwhile, we found CXCR1 deficiency in DCs limited IL-6/IL-12p70 production and lung injury in LPS-induced ARDS, a disease model caused by inflammation. Overall, our study reveals CXCR1 governs DCs-mediated inflammation and autoimmune disorders and its potential as a therapeutic target for related diseases.

Structural basis of CXC chemokine receptor 1 ligand binding and activation.

Neutrophil granulocytes play key roles in innate immunity and shaping adaptive immune responses. They are attracted by chemokines to sites of infection and tissue damage, where they kill and phagocytose bacteria. The chemokine CXCL8 (also known as interleukin-8, abbreviated IL-8) and its G-protein-coupled receptors CXCR1 and CXCR2 are crucial elements in this process, and also the development of many cancers. These GPCRs have therefore been the target of many drug development campaigns and structural studies. Here, we solve the structure of CXCR1 complexed with CXCL8 and cognate G-proteins using cryo-EM, showing the detailed interactions between the receptor, the chemokine and Gαi protein. Unlike the closely related CXCR2, CXCR1 strongly prefers to bind CXCL8 in its monomeric form. The model shows that steric clashes would form between dimeric CXCL8 and extracellular loop 2 (ECL2) of CXCR1. Consistently, transplanting ECL2 of CXCR2 onto CXCR1 abolishes the selectivity for the monomeric chemokine. Our model and functional analysis of various CXCR1 mutants will assist efforts in structure-based drug design targeting specific CXC chemokine receptor subtypes.

CXCR1 participates in bone cancer pain induced by Walker 256 breast cancer cells in female rats.

Bone cancer pain (BCP) is a clinically intractable mixed pain, involving inflammation and neuropathic pain, and its mechanisms remain unclear. CXC chemokine receptor 1 (CXCR1, IL-8RA) and 2 (CXCR2, IL-8RB) are high-affinity receptors for interleukin 8 (IL8). According to previous studies, CXCR2 plays a crucial role in BCP between astrocytes and neurons, while the role of CXCR1 remains unclear. The objective of this study was to investigate the role of CXCR1 in BCP. We found that CXCR1 expression increased in the spinal dorsal horn. Intrathecal injection of CXCR1 siRNA effectively attenuated mechanical allodynia and pain-related behaviors in rats. It was found that CXCR1 was predominantly co-localized with neurons. Intrathecal injection of CXCR1-siRNA reduced phosphorylated JAK2/STAT3 protein levels and the NLRP3 inflammasome (NLRP3, caspase1, and IL-1ß) levels. Furthermore, in vitro cytological experiments confirmed this conclusion. The study results suggest that the spinal chemokine receptor CXCR1 activation mediates BCP through JAK2/STAT3 signaling pathway and NLRP3 inflammasome (NLRP3, caspase1, and IL-1ß).

Analysis of CXCL8 and its receptors CXCR1/CXCR2 at the mRNA level in neoplastic tissue, as well as in serum and peritoneal fluid in patients with ovarian cance.

Understanding the relationship between the coexistence of inflammatory and neoplastic processes in ovarian cancer, particularly those involving chemokines and their receptors, may help to elucidate the involvement of the studied parameters in tumor pathogenesis and could lead to improved clinical applications. Therefore, the present study aimed to analyze the levels of C­X­C motif chemokine ligand 8 (CXCL8), and its receptors C­X­C chemokine receptor (CXCR)1 and CXCR2, in the serum and peritoneal fluid of women with ovarian cancer, and to evaluate the association between the expression of these parameters in tumor tissue and patient characteristics, particularly the degree of histological differentiation. The study group included women with ovarian cancer diagnosed with serous cystadenocarcinoma International Federation of Gynecology and Obstetrics stage IIIc and a control group, which consisted of women who were diagnosed with a benign lesion (serous cystadenoma). The transcript levels of CXCL8, CXCR1 and CXCR2 were evaluated using reverse transcription­quantitative PCR (RT­qPCR). The quantitative analysis was carried out using the LightCycler® 480 System and GoTaq® 1­Step RT­qPCR System, according to the manufacturers' instructions. The concentration of CXCL8 in serum and peritoneal fluid was determined using a Human Interleukin­8 ELISA kit, and the concentrations of CXCR1 and CXCR2 were determined using the CLOUD­CLONE ELISA kit. Local and systemic disturbances in immune and inflammatory responses involving the CXCL8 chemokine and its receptors indicated the involvement of these studied parameters in the pathogenesis of ovarian cancer. Immunoregulation of the CXCL8­CXCR1 system may influence the course of the inflammatory process accompanying ovarian cancer development, which may result in the identification of novel clinical applications; however, further studies are required.

Long non-coding RNA PCED1B antisense RNA 1 promotes gastric cancer progression via modulating microRNA-215-3p / C-X-C motif chemokine receptor 1 axis.

Long non-coding RNAs (lncRNAs) emerge as vital modulators and tissue-specific biomarkers of multiple cancers, including gastric cancer (GC). Instead, the expression characteristics, biological function and molecular mechanism of lncRNA PCED1B antisense RNA 1 (PCED1B-AS1) in GC await more elaboration. In this study, 48 cases of GC tissues and matched non-cancerous tissues were collected, and PCED1B-AS1, microRNA-215-3p (miR-215-3p) and C-X-C motif chemokine receptor 1 (CXCR1) expression levels were detected by qRT-PCR. Besides, CCK-8, EdU, Transwell and Western blot assays were conducted to assess the impact of PCED1B-AS1 or miR-215-3p on cell growth, migration, invasion and epithelial-mesenchymal transition (EMT). The interaction between genes was verified by bioinformatics analysis, rna immunoprecitipation (RIP) and dual-luciferase reporter gene assays. We demonstrated that, PCED1B-AS1 expression level was raised in GC tissues and cell lines, and increased expression of PCED1B-AS1 was in association with tumor size, TNM stage and lymph node metastasis in GC patients. Additionally, PCED1B-AS1 overexpression promoted GC cells proliferation, migration, invasion and EMT, and miR-215-3p overexpression counteracted the biological effects of PCED1B-AS1. Mechanistically, PCED1B-AS1 specifically inhibited miR-215-3p expressions, thus up-regulating CXCR1 expressions. In conclusion, PCED1B-AS1 accelerates GC progression via adsorbing miR-215-3p and up-regulating CXCR1, indicating that PCED1B-AS1 is a novel therapeutic target for treating GC.

CXCL1-CXCR1/2 signaling is induced in human temporal lobe epilepsy and contributes to seizures in a murine model of acquired epilepsy.

CXCL1, a functional murine orthologue of the human chemokine CXCL8 (IL-8), and its CXCR1 and CXCR2 receptors were investigated in a murine model of acquired epilepsy developing following status epilepticus (SE) induced by intra-amygdala kainate. CXCL8 and its receptors were also studied in human temporal lobe epilepsy (TLE). The functional involvement of the chemokine in seizure generation and neuronal cell loss was assessed in mice using reparixin (formerly referred to as repertaxin), a non-competitive allosteric inhibitor of CXCR1/2 receptors. We found a significant increase in hippocampal CXCL1 level within 24 h of SE onset that lasted for at least 1 week. No changes were measured in blood. In analogy with human TLE, immunohistochemistry in epileptic mice showed that CXCL1 and its two receptors were increased in hippocampal neuronal cells. Additional expression of these molecules was found in glia in human TLE. Mice were treated with reparixin or vehicle during SE and for additional 6 days thereafter, using subcutaneous osmotic minipumps. Drug-treated mice showed a faster SE decay, a reduced incidence of acute symptomatic seizures during 48 h post-SE, and a delayed time to spontaneous seizures onset compared to vehicle controls. Upon reparixin discontinuation, mice developed spontaneous seizures similar to vehicle mice, as shown by EEG monitoring at 14 days and 2.5 months post-SE. In the same epileptic mice, reparixin reduced neuronal cell loss in the hippocampus vs vehicle-injected mice, as assessed by Nissl staining at completion of EEG monitoring. Reparixin administration for 2 weeks in mice with established chronic seizures, reduced by 2-fold on average seizure number vs pre-treatment baseline, and this effect was reversible upon drug discontinuation. No significant changes in seizure number were measured in vehicle-injected epileptic mice that were EEG monitored in parallel. Data show that CXCL1-IL-8 signaling is activated in experimental and human epilepsy and contributes to acute and chronic seizures in mice, therefore representing a potential new target to attain anti-ictogenic effects.

An updated review on the role of the CXCL8-CXCR1/2 axis in the progression and metastasis of breast cancer.

Chronic inflammation is a major factor in tumor growth and progression. Cancer cells secrete C-X-C chemokine ligand 8 (CXCL8) along with its receptor C-X-C chemokine receptor 1 (CXCR1) and chemokine receptor 2 (CXCR2). It plays a significant role in the activation and trafficking of inflammatory mediators, tumor proliferation and interferes in breast cancer development by controlling cell adhesion, proliferation, migration, and metastasis. This axis also plays a significant role in driving different cancers and melanomas, including breast cancer progression, by controlling stem cell masses. Few small-molecule CXCR1/2 inhibitors and CXCL8 releasing inhibitors have been identified in the past two decades that bind these receptors in their inactive forms and blocks their signaling as well as the biological activities associated with inflammation. Inhibitors of certain inflammatory molecules are projected to be more efficient in different inflammatory diseases. Preclinical trials indicate that patients may be benefitted from combined treatment with targeted drugs, chemotherapies, and immunotherapies. Thus, targeting the CXCL8-CXCR1/2 signaling axis in breast cancer could be a promising approach for its therapeutics. This review examines the roles of the CXCL8-CXCR1/2 signaling axis and how it is implicated in the tumor microenvironment in breast cancer. In addition, we also discuss the potential role of the CXCL8-CXCR1/2 axis in targeted therapeutics for breast cancer.

MiR-144-induced KLF2 inhibition and NF-kappaB/CXCR1 activation promote neutrophil extracellular trap-induced transfusion-related acute lung injury.

Transfusion-related acute lung injury (TRALI) is a clinical syndrome which is associated with the formation of neutrophil extracellular trap (NET). Recent studies have demonstrated the roles of microRNAs (miRNAs) in the pathophysiological process of TRALI. Here, the study focused on the role of miR-144 and the molecular mechanisms in NET-induced TRALI. Up-regulated miR-144 and under-expressed KLF2 were determined in patients with TRALI. In the mouse model of a two-event TRALI induced by intraperitoneal injections with lipopolysaccharide and anti-H-2Kd mAb, we determined expression patterns of miR-144, Krüppel-like factor 2 (KLF2), chemokine (C-X-C motif) receptor 1 (CXCR1) and nuclear factor kappa-B (NF-kappaB) p65. The results confirmed that miR-144 was highly expressed, while KLF2 was poorly expressed in mice with TRALI. Dual-luciferase reporter gene assay identified that miR-144 could target KLF2. Using gain- and loss-of-function approaches, we analysed the effects of miR-144 and its interaction with KLF2 on TRALI. Enforced expression of miR-144 was found to aggravate NET-induced TRALI by down-regulating KLF2 and activating the NF-kappaB/CXCR1 signalling pathway in TRALI mice. Collectively, miR-144-targeted inhibition of KLF2 and activation of NF-kappaB/CXCR1 are possible mechanisms responsible for NET-caused TRALI. These findings aid in the development of therapeutic modalities for the treatment of TRALI.

Hepatitis B-Induced IL8 Promotes Hepatocellular Carcinoma Venous Metastasis and Intrahepatic Treg Accumulation.

Hepatitis B-associated hepatocellular carcinoma (HCC) is often accompanied by severe vascular invasion and portal vein tumor thrombus, leading to a poor prognosis. However, the underlying mechanism of this disease remains obscure. In this study, we demonstrate that the hepatitis B virus (HBV)-encoded gene HBx induces high IL8 production through MEK-ERK signal activation, leading to enhanced endothelial permeability to facilitate tumor vascular invasion. In a vascular metastatic model using a tail vein injection in a transgenic mouse with selective expression of human CXCR1 in the endothelium, activation of the IL8-CXCR1 cascade by overexpression of IL8 in tumor cells dramatically enhanced liver metastasis. Mechanistically, IL8 selectively induced GARP-latent-TGFß in liver sinusoidal endothelial cells and subsequently provoked preferential regulatory T-cell polarization to suppress antitumor immunity. Collectively, these findings reveal a hepatitis B-associated IL8-CXCR1 signaling axis that mediates vascular invasion and local microenvironmental immune escape of HCC to induce intrahepatic metastasis, which may serve as potential therapeutic targets for HBV-associated HCC. SIGNIFICANCE: This study identifies a hepatitis B-induced IL8/CXCR1/TGFß signaling cascade that suppresses antitumor immunity and enhances metastasis in hepatocellular carcinoma, providing new potential targets for therapeutic intervention.

Impaired capillary tube formation induced by elevated secretion of IL8 involves altered signaling via the CXCR1/PI3K/MMP2 pathway.

Angiogenesis is a multistep process requiring endothelial cell activation, migration, proliferation and tube formation. We recently reported that elevated secretion of interlukin 8 (IL8) by myotubes (MT) from subjects with Type-2 Diabetes (T2D) reduced angiogenesis by human umbilical vein endothelial cells (HUVEC) and human skeletal muscle explants. This lower vascularization was mediated through impaired activation of the phosphatidylinositol 3-kinase (PI3K)-pathway. We sought to investigate additional signaling elements that might mediate reduced angiogenesis. HUVEC were exposed to levels of IL8 equal to those secreted by MT from non-diabetic (ND) and T2D subjects and the involvement of components in the angiogenic response pathway examined. Cellular content of reactive oxygen species and Nitrate secretion were similar after treatment with [ND-IL8] and [T2D-IL8]. CXCR1 protein was down-regulated after treatment with [T2D-IL8] (p < 0.01 vs [ND-IL8] treatment); CXCR2 expression was unaltered. Addition of neutralizing antibodies against CXCR1 and CXCR2 to HUVEC treated with IL8 confirmed that CXCR1 alone mediated the angiogenic response to IL8. A key modulator of angiogenesis is matrix metalloproteinase-2 (MMP2). MMP2 secretion was higher after treatment with [ND-IL8] vs [T2D-IL8] (p < 0.01). MMP2 inhibition reduced tube formation to greater extent with [ND-IL8] than with [T2D-IL8] (p < 0.005). The PI3K-pathway inhibitor LY294002 reduced IL8-induced MMP2 release. IL8 regulation of MMP2 release was CXCR1 dependent, as anti-CXCR1 significantly reduced MMP2 release (p < 0.05). These results suggest that high levels of IL8 secreted by T2D MT trigger reduced capillarization via lower activation of a CXCR1-PI3K pathway, followed by impaired release and activity of MMP2.

Development of a Novel SNAP-Epitope Tag/Near-Infrared Imaging Assay to Quantify G Protein-Coupled Receptor Degradation in Human Cells.

We have developed a novel reporter assay that leverages SNAP-epitope tag/near-infrared (NIR) imaging technology to monitor G protein-coupled receptor (GPCR) degradation in human cell lines. N-terminal SNAP-tagged GPCRs were subcloned and expressed in human embryonic kidney (HEK) 293 cells and then subjected to 24 h of cycloheximide (CHX)-chase degradation assays to quantify receptor degradation half-lives (t1/2) using LICOR NIR imaging-polyacrylamide gel electrophoresis (PAGE) analysis. Thus far, we have used this method to quantify t1/2 for all nine adrenergic (ADRA1A, ADRA1B, ADRA1D, ADRA2A, ADRA2B, ADRA2C, ADRB1, ADRB2, ADRB3), five somatostatin (SSTR1, SSTR2, SSTR3, SSTR4, SSTR5), four chemokine (CXCR1, CXCR2, CXCR3, CXCR5), and three 5-HT2 (5HT2A, 5HT2B, 5HT2C) receptor subtypes. SNAP-GPCR-CHX degradation t1/2 values ranged from 0.52 h (ADRA1D) to 5.5 h (SSTR3). On the contrary, both the SNAP-tag alone and SNAP-tagged and endogenous ß-actin were resistant to degradation with CHX treatment. Treatment with the proteasome inhibitor bortezomib produced significant but variable increases in SNAP-GPCR protein expression levels, indicating that SNAP-GPCR degradation primarily occurs through the proteasome. Remarkably, endogenous ß2-adrenergic receptor/ADRB2 dynamic mass redistribution functional responses to norepinephrine were significantly decreased following CHX treatment, with a time course equivalent to that observed with the SNAP-ADRB2 degradation assay. We subsequently adapted this assay into a 96-well glass-bottom plate format to facilitate high-throughput GPCR degradation screening. t1/2 values quantified for the α1-adrenergic receptor subtypes (ADRA1A, ADRA1B, ADR1D) using the 96-well-plate format correlated with t1/2 values quantified using NIR-PAGE imaging analysis. In summary, this novel assay permits precise quantitative analysis of GPCR degradation in human cells and can be readily adapted to quantify degradation for any membrane protein of interest.

The rs1008562, rs2234671, and rs3138060 polymorphisms of the CXCR1 gene are associated with breast cancer risk in a Mexican population.

OBJECTIVE: The rs1008562, rs2234671 and rs3138060 polymorphisms of the CXCR1 gene have been shown to be associated with many diseases, but in breast cancer (BC) their association has not been detected. The purpose of this study was to determine the frequency and association of the rs1008562, rs2234671 and rs3138060 polymorphisms of CXCR1 gene in BC patients in the Mexican population. PATIENTS AND METHODS: The CXCR1 polymorphisms were determined by Polymerase Chain Reaction (PCR) and real time-PCR in healthy Mexican subjects and BC patients. RESULTS: The prevalent patron in BC patients was observed, the majority were overweight and obesity (72%) with metastatic lymph nodes (48%), luminal A/B subtypes (63%), and advanced stages (60%). Triple negative breast cancer (TNBC) patients: they were younger (58%) than 43 years old, overweight (33%), obesity (42%), ductal type histological (98%), metastasis to lymph nodes (47%), advanced stages III-IV (61%) and metastasis (33%). The rs2234671 polymorphism was associated with BC susceptibility when BC patients and the control group were compared for the CC genotype (p=0.037), CG (heterozygous model: p=0.018), GC/CC (dominant model: p=0.004), and the C allele (p=0.001), as well as the GC/CC genotype with hormone replace therapy (HRT, p=0.016). The rs3138060 polymorphism was associated with BC susceptibility for CG/GG genotype (dominant model: p=0.032) and G allele (p=0.018). Although the association between the dominant model of rs1008562, rs2234671, rs3138060 polymorphisms and BC patients and control was evident for tobacco and alcohol consumption (p<0.05). The rs1008562, rs2234671, and rs3138060 polymorphisms of the CXCR1 gene classified by molecular subtype and stage were also associated with BC patients, indicating that these factors may significantly contribute to BC risk. The CCC (OR 1.75, 95% CI 1.03- 2.97, p=0.046), GGG (OR 3.73, 95% CI 1.61- 8.65, p=0.0018) haplotypes were also associated with BC susceptibility. CONCLUSIONS: Rs2234671 and rs3138060 polymorphisms in the CXCR1 gene were associated with BC susceptibility in the Mexican population. The dominant model of the rs1008562, rs2234671 and rs3138060 polymorphisms could significantly contribute to BC risk in tobacco and alcohol consumption, molecular subtype and stage. The rs1008562, rs2234671 and rs3138060 polymorphisms, and the haplotypes CCC and GGG could significantly contribute to BC risk in the Mexican population analyzed.

Ascites-derived ALDH+CD44+ tumour cell subsets endow stemness, metastasis and metabolic switch via PDK4-mediated STAT3/AKT/NF-κB/IL-8 signalling in ovarian cancer.

BACKGROUND: Ovarian cancer is characterised by frequent recurrence due to persistent presence of residual cancer stem cells (CSCs). Here, we identify and characterise tumour subsets from ascites-derived tumour cells with stemness, metastasis and metabolic switch properties and to delineate the involvement of pyruvate dehydrogenase kinase 4 (PDK4) in such process. METHODS: Ovarian cancer cells/cell lines derived from ascites were used for tumourspheres/ALDH+CD44+ subset isolation. The functional roles and downstream signalling of PDK4 were explored. Its association with clinical outcome of ovarian cancer was analysed. RESULTS: We demonstrated enhanced CSC characteristics of tumour cells derived from ovarian cancer ascites, concomitant with ALDH and CD44 subset enrichment and high PDK4 expression, compared to primary tumours. We further showed tumourspheres/ALDH+CD44+ subsets from ascites-derived tumour cells/cell lines with CSC properties and enhanced glycolysis. Clinically, PDK4 expression was correlated with aggressive features. Notably, blockade of PDK4 in tumourspheres/ALDH+CD44+ subsets led to inhibition of CSC characteristics, glycolysis and activation of STAT3/AKT/NF-κB/IL-8 (signal transducer and activator of transcription 3/protein kinases B/nuclear factor-κB/interleukin-8) signalling. Conversely, overexpression of PDK4 in ALDH-CD44- subsets exerted the opposite effects. CONCLUSION: Ascites-derived ALDH+CD44+ tumour cell subsets endow stemness, metastatic and metabolic switch properties via PDK4-mediated STAT3/AKT/NF-κB/IL-8 signalling, suggesting PDK4 as a viable therapeutic molecular target for ovarian cancer management.

MMP9, CXCR1, TLR6, and MPO participant in the progression of coronary artery disease.

Coronary artery disease (CAD) is the most frequent cardiovascular disease, which is induced by the decreased myocardial blood supply. The present study is conducted to understand the mechanisms of CAD. The GSE98583, GSE69587, and GSE71226 datasets from the Gene Expression Omnibus database were obtained. The differentially expressed genes (DEGs) were analyzed by the limma package, then the DEGs appeared in two or three datasets were selected as the coregulated genes using the VENNY tool, followed by enrichment analysis using DAVID tool. Protein-protein interaction (PPI) network, microRNA-transcription factor-target regulatory network, and drug-gene network were visualized. Finally, quantitative PCR and dual-luciferase reporter assay were conducted to validate the expression of key genes and the target relationship. There were 221 coregulated genes in GSE98583, GSE69587, and GSE71226. Besides, four pathways and 23 functional terms for co-upregulated genes, and 11 functional terms for co-downregulated genes were enriched. The degrees of PPI network nodes matrix metallopeptidase 9 (MMP9), C-X-C motif chemokine receptor 1 (CXCR1), toll-like receptor 6 (TLR6), and myeloperoxidase (MPO) were relatively higher. Moreover, MPO could interact with MMP9, CXCR1, and TLR6 in the PPI network. In the regulatory network, TLR6 and MMP9 separately were targeted by miR-3960 and v-rel avian reticuloendotheliosis viral oncogene homolog A (RELA). Additionally, MMP9, CXCR1, and MPO were involved in the drug-gene network. The expression of MMP9, CXCR1, TLR6, and MPO were significantly upregulated in CAD samples than control, and miR-3960 could bind to TLR6 to inhibit its expression. CXCR1 and MPO might be involved in the progression of CAD. Besides, miR-3960 might function in the pathogenesis of CAD through targeting TLR6, and RELA might exert its role in CAD via targeting MMP9.

Circular RNA circ_0067934 exhaustion expedites cell apoptosis and represses cell proliferation, migration and invasion in thyroid cancer via sponging miR-1304 and regulating CXCR1 expression.

OBJECTIVE: Distant metastasis or local recurrence is the leading cause of death in some patients with thyroid cancer (TC), a malignant tumor of the endocrine system. Circular RNA circ_0067934 (circ_0067934) has been reported to be connected with the tumorigenesis of multiple tumors. However, there are few reports on the role and regulatory mechanisms of circ_0067934 in TC. MATERIALS AND METHODS: The expression levels of circ_0067934, protein kinase C iota (PRKCI), microRNA-1304 (miR-1304), and C-X-C chemokine receptor types 1 (CXCR1) were detected with quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The proliferation, apoptosis, migration, and invasion of TC cells were evaluated by Cell Counting Kit-8 (CCK8) assay, flow cytometry assay, and transwell assay, respectively. The relationship between circ_0067934 or CXCR1 and miR-1304 was confirmed with Dual-Luciferase reporter assay or RNA immunoprecipitation (RIP) assay. Protein level of CXCR1 was analyzed via Western blot analysis. Xenograft assay was executed to verify the role of circ_0067934 in vivo. RESULTS: Circ_0067934 and CXCR1 were enhanced and miR-1304 decreased in TC tissues and cells. Circ_0067934 downregulation triggered apoptosis and curbed proliferation, migration, and invasion of TC cells in vitro, as well as repressed tumor growth in vivo. Notably, circ_0067934 regulated CXCR1 expression via sponging miR-1304 in TC cells. Both miR-1304 silencing and CXCR1 elevation reversed the facilitation of apoptosis and the retardation of proliferation, migration, and invasion induced by circ_0067934 reduction in TC cells. CONCLUSIONS: Circ_0067934 downregulation expedited apoptosis and retarded proliferation, migration, and invasion of TC cells through miR-1304/CXCR1 axis.

The antagonist of CXCR1 and CXCR2 protects db/db mice from metabolic diseases through modulating inflammation.

Interleukin-8 (IL-8, also named CXCL8) binds to its receptors (CXCR1 and CXCR2) with subsequent recruitment of neutrophils and enhancement of their infiltration into inflamed sites, which exaggerates inflammation in many diseases. Recent studies have proposed that metabolic disorders can be attenuated by counteracting certain inflammatory signal pathways. In this study, we examined whether intervention with G31P, an antagonist of CXCL8, could attenuate tissue inflammation and development of metabolic disorders in db/db mice. The db/m and db/db mice were subcutaneously injected with G31P or equivalent normal saline once a day for 6 wk. The physical and metabolic parameters, glucose tolerance, insulin sensitivity, hepatic lipid accumulation, and inflammation markers were measured. G31P improved hepatic insulin sensitivity by modulating expression of genes related to gluconeogenesis and phosphorylated Akt levels. The expressions of several genes encoding proteins involved in de novo lipogenesis were decreased in G31P-treated db/db mice. Meanwhile, immune cell infiltration and cytokine release were attenuated in db/db mice with G31P treatment. G31P also improved the ratio of proinflammatory M1 and anti-inflammatory M2 macrophages. Furthermore, G31P ameliorates metabolic disturbances via inhibition of CXCR1 and CXCR2 pathways in db/db mice. These data suggest that the selective inhibition of CXC chemokines may have therapeutic effects on symptoms associated with obesity and diabetes.

Regulation of Staphylococcus aureus-induced CXCR1 expression via inhibition of receptor mobilization and receptor shedding during dual receptor (TNFR1 and IL-1R) neutralization.

Our earlier studies proposed a radically new idea suggesting interdependency between TNF-α/TNFR1 and IL-1ß/IL-1R pathways in modulation of Staphylococcus aureus-induced CXCL8/CXCR1 axis. However, the effects of inhibition of cytokine receptor mobilization at intracellular level and surface TNFR1 and IL-1R shedding on S. aureus-induced CXCR1 expression have not been studied so far in peritoneal macrophages. This study aimed to investigate the role of inhibition of receptor mobilization from the intracellular pool (using brefeldin A) and surface receptor shedding (using TAPI-1) on CXCR1 expression during dual receptor (TNFR1 plus IL-1R) neutralization in peritoneal macrophages isolated from wild-type Swiss Albino mice. Release of superoxide anion, nitric oxide, and hydrogen peroxide was measured and cytokine production was done by ELISA. Expression of surface receptors (TNFR1, IL-1R, and CXCR1) and inflammatory mediators was studied by Western blot. It was observed that S. aureus-infected macrophages showed elevated ROS production, secretion of TNF-α, IL-1ß, and CXCL8, along with increased expression of surface receptors (TNFR1, IL-1R, and CXCR1), and inflammatory markers (iNOS and COX-2) compared with control or treated groups (p < 0.05). However, prior treatment of macrophages with BFA or TAPI-1 in the presence of anti-TNFR1 antibody and IRAP during S. aureus infection showed significant reduction of all these parameters (p < 0.05). We can conclude that targeting of TNFR1 and IL-1R (with major focus on surface expression study) either through blockage of intracellular receptor trafficking pathway or via surface receptor shedding diminishes TNFR1/IL-1R interaction and consequently downregulates CXCR1 expression along with inflammatory signalling pathways during bacterial infections.