Identification of CXCL5/ENA-78 as a factor involved in the interaction between cholangiocarcinoma cells and cancer-associated fibroblasts

Screening of targeted genes in extrahepatic bile ducts of mice with experimental biliary atresia

Biliary atresia (BA) is an infantile disease resulting from a severe cholangiopathy, which can obstruct extrahepatic bile ducts, disrupt bile flow and lead to end‑stage cirrhosis. The current study aimed to develop a genetic method to investigate the pathogenesis of BA. The gene expression profile of BA (GSE46967) was downloaded from the Gene Expression Omnibus database and included 18 samples from newborn mice. These samples were collected at three time points following the induction of BA with rhesus rotavirus. The differentially expressed genes (DEGs) in mice with BA were identified using the limma package in R language, followed by hierarchical clustering analysis. Gene ontology functional analysis and Kyoto Enrichment of Genes and Genomes pathway analysis of the selected common DEGs was conducted using the Database for Annotation, Visualization and Integrated Discovery. In total, 306 DEGs were identified in the samples from the 3 day time point, 721 at 7 days and 370 at 14 days. A total of 74 common DEGs were identified in these three sample groups, which are reported to function in multiple immune biological processes, including the defense response, leukocyte migration, cell chemotaxis and leukocyte chemotaxis. In addition, 'cytokine‑cytokine receptor interaction' and 'chemokine signaling pathway' were observed to be significantly enriched in BA. A total of six common DEGs (CCL3, CXCL5, CXCL13, CXCR2, CCL5 and CCL6) were identified that were involved in the significantly enriched functions and the significantly enriched pathways. The data from the current study suggested that the immune response is a critical biological process in the development of BA. The six critical hub genes identified (CCL3, CXCL5, CXCL13, CXCR2, CCL5 and CCL6) may be used as specific target genes in the treatment of BA.

The possible link between elevated serum levels of epithelial cell-derived neutrophil-activating peptide-78 (ENA-78/CXCL5) and autoimmunity in autistic children

Background

In autoimmune disorders, the underlying pathogenic mechanism is the formation of antigen-antibody complexes which trigger an inflammatory response by inducing the infiltration of neutrophils. Epithelial cell-derived neutrophil-activating peptide-78 (ENA-78) is a chemokine that recruits and activates neutrophils, thus it could play a pathogenic role in inflammation and autoimmune disorders. Some autistic children have elevated levels of brain specific auto-antibodies. We are the first to evaluate serum expression of ENA-78 and its relation to antineuronal auto-antibodies in autistic children.

Methods

Serum ENA-78 and antineuronal auto-antibodies were measured by ELISA test in 62 autistic children aged between 4–11 years and 62 health-matched controls.

Results

Serum levels of ENA-78 were significantly higher in autistic children than healthy controls (P < 0.001). Increased serum levels of ENA-78 have been found in 69.35% of autistic patients. In addition, autistic children had significantly higher percent positivity of serum antineuronal auto-antibodies (64.5%) than healthy controls (6.45%), P < 0.001. There was a significant positive association between the positivity of serum antineuronal auto-antibodies and the elevated levels of serum ENA-78 (P < 0.001) in autistic children.

Conclusions

Serum levels of ENA-78 were elevated in autistic children and they were significantly associated with the increased levels of serum antineuronal auto-antibodies. However, these data should be treated with caution until further research is conducted to determine the pathogenic role of ENA-78 in autism and its relation to brain specific auto-antibodies that have been found in some autistic children. The possible therapeutic role of ENA-78 antagonist in autistic children should be also studied.

Transcriptional Regulation of CXCL5 in HIV-1-Infected Macrophages and Its Functional Consequences on CNS Pathology

Human immunodeficiency virus-1 (HIV-1)-infected monocytes/macrophages and microglia release increased levels of proinflammatory cytokines and chemokines, including ELR+ (containing glutamic acid-leucine-arginine motif) chemokines. To investigate the role of HIV-1 infection on chemokine regulation, monocyte-derived macrophages (MDMs) from normal donors were infected with HIV-1 and the expression of chemokines and their downstream biological functions were evaluated. Among the tested chemokines, CXCL5 was upregulated significantly both at the mRNA and protein level in the HIV-1-infected MDMs compared with mock-infected cultures. Upregulation of CXCL5 in the HIV-1-infected MDMs is, in part, regulated by increased interleukin-1β (IL-1β) production and phosphorylation of ERK1/2. Functional analyses indicate that HIV-1-induced overexpression of CXCL5 has enhanced the ability to attract neutrophils, as observed by chemotaxis assay. However, exposure of NT2, SH-SY5Y cells, and primary neurons to HIV-1-infected MDM supernatants resulted in cell death that was not rescued by anti-CXCL5 antibody suggesting that CXCL5 does not have direct effect on neuronal death. Together, these results suggest that the increased level of CXCL5 in tissue compartments, including the central nervous system of HIV-1-infected individuals might alter the inflammatory response through the infiltration of neutrophils into tissue compartment, thus causing secondary effects on resident cells.

Epigenetic modulation and repression of miR-200b by cancer-associated fibroblasts contribute to cancer invasion and peritoneal dissemination in gastric cancer

Cancer-associated fibroblasts (CAFs) have recently been linked to the invasion and metastasis of gastric cancer. In addition, the microRNA (miR)-200 family plays a central role in the regulation of the epithelial-mesenchymal transition process during cancer metastasis, and aberrant DNA methylation is one of the key mechanisms underlying regulation of the miR-200 family. In this study, we clarified whether epigenetic changes of miR-200b by CAFs stimulate cancer invasion and peritoneal dissemination in gastric cancer. We evaluated the relationship between miR-200b and CAFs using a coculture model. In addition, we established a peritoneal metastasis mouse model and investigated the expression and methylation status of miR-200b. We also investigated the expression and methylation status of miR-200b and CAFs expression in primary gastric cancer samples. CAFs (CAF-37 and CAF-50) contributed to epigenetic changes of miR-200b, reduced miR-200b expression and promoted tumor invasion and migration in NUGC3 and OCUM-2M cells in coculture. In the model mice, epigenetic changes of miR-200b were observed in the inoculated high-frequency peritoneal dissemination cells. In the 173 gastric cancer samples, the low miR-200b expression group demonstrated a significantly poorer prognosis compared with the high miR-200b expression group and was associated with peritoneal metastasis. In addition, downregulation of miR-200b in cancer cells was significantly correlated with alpha-smooth muscle actin expression. Our data provide evidence that CAFs reduce miR-200b expression and promote tumor invasion through epigenetic changes of miR-200b in gastric cancer. Thus, CAFs might be a therapeutic target for inhibition of gastric cancer.

Roles for chemokines in liver disease

Sustained hepatic inflammation is an important factor in progression of chronic liver diseases, including hepatitis C or non-alcoholic steatohepatitis. Liver inflammation is regulated by chemokines, which regulate the migration and activities of hepatocytes, Kupffer cells, hepatic stellate cells, endothelial cells, and circulating immune cells. However, the effects of the different chemokines and their receptors vary during pathogenesis of different liver diseases. During development of chronic viral hepatitis, CCL5 and CXCL10 regulate the cytopathic versus antiviral immune responses of T cells and natural killer cells. During development of nonalcoholic steatohepatitis, CCL2 and its receptor are up-regulated in the liver, where they promote macrophage accumulation, inflammation, fibrosis, and steatosis, as well as in adipose tissue. CCL2 signaling thereby links hepatic and systemic inflammation related to metabolic disorders and insulin resistance. Several chemokine signaling pathways also promote hepatic fibrosis. Recent studies have shown that other chemokines and immune cells have anti-inflammatory and antifibrotic activities. Chemokines and their receptors can also contribute to the pathogenesis of hepatocellular carcinoma, promoting proliferation of cancer cells, the inflammatory microenvironment of the tumor, evasion of the immune response, and angiogenesis. We review the roles of different chemokines in the pathogenesis of liver diseases and their potential use as biomarkers or therapeutic targets.

Fibroblast α11β1 integrin regulates tensional homeostasis in fibroblast/A549 carcinoma heterospheroids

We have previously shown that fibroblast expression of α11β1 integrin stimulates A549 carcinoma cell growth in a xenograft tumor model. To understand the molecular mechanisms whereby a collagen receptor on fibroblast can regulate tumor growth we have used a 3D heterospheroid system composed of A549 tumor cells and fibroblasts without (α11+/+) or with a deletion (α11-/-) in integrin α11 gene. Our data show that α11-/-/A549 spheroids are larger than α11+/+/A549 spheroids, and that A549 cell number, cell migration and cell invasion in a collagen I gel are decreased in α11-/-/A549 spheroids. Gene expression profiling of differentially expressed genes in fibroblast/A549 spheroids identified CXCL5 as one molecule down-regulated in A549 cells in the absence of α11 on the fibroblasts. Blocking CXCL5 function with the CXCR2 inhibitor SB225002 reduced cell proliferation and cell migration of A549 cells within spheroids, demonstrating that the fibroblast integrin α11β1 in a 3D heterospheroid context affects carcinoma cell growth and invasion by stimulating autocrine secretion of CXCL5. We furthermore suggest that fibroblast α11β1 in fibroblast/A549 spheroids regulates interstitial fluid pressure by compacting the collagen matrix, in turn implying a role for stromal collagen receptors in regulating tensional hemostasis in tumors. In summary, blocking stromal α11β1 integrin function might thus be a stroma-targeted therapeutic strategy to increase the efficacy of chemotherapy.

Role of leukocyte cell-derived chemotaxin 2 as a biomarker in hepatocellular carcinoma

We sought to identify a secreted biomarker for β-catenin activation commonly seen in hepatocellular carcinoma (HCC). By examination of our previously published genearray of hepatocyte-specific β-catenin knockout (KO) livers, we identified secreted factors whose expression may be β-catenin-dependent. We verified expression and secretion of the leading factor in HCC cells transfected with mutated (Hep3B^S33Y)-β-catenin. Serum levels of biomarker were next investigated in a mouse model of HCC with β-catenin gene (Ctnnb1) mutations and eventually in HCC patients. Leukocyte cell-derived chemotaxin-2 (LECT2) expression was decreased in KO livers. Hep3B^S33Y expressed and secreted more LECT2 in media as compared to Hep3B^WT. Mice developing HCC with Ctnnb1 mutations showed significantly higher serum LECT2 levels. However patients with CTNNB1 mutations showed LECT2 levels of 54.28±22.32 ng/mL (Mean ± SD; n = 8) that were insignificantly different from patients with non-neoplastic chronic liver disease (32.8±21.1 ng/mL; n = 15) or healthy volunteers (33.2±7.2 ng/mL; n = 11). Intriguingly, patients without β-catenin mutations showed significantly higher serum LECT2 levels (54.26 ± 22.25 ng/mL; n = 46). While β-catenin activation was evident in a subset of non-mutant β-catenin HCC group with high LECT2 expression, serum LECT2 was unequivocally similar between β-catenin-active and -normal group. Further analysis showed that LECT2 levels greater than 50 ng/ml diagnosed HCC in patients irrespective of β-catenin mutations with specificity of 96.1% and positive predictive value of 97.0%. Thus, LECT2 is regulated by β-catenin in HCC in both mice and men, but serum LECT2 reflects β-catenin activity only in mice. Serum LECT2 could be a potential biomarker of HCC in patients.

CXCL5 as a potential novel prognostic factor in early stage non-small cell lung cancer: results of a study of expression levels of 23 genes

As the current staging system is imprecise for estimating prognosis of early stage non-small cell lung cancer (NSCLC), it is important to identify other methods for selecting high-risk patients after failed surgical treatment. The aim of the study was to evaluate the expression of 23 genes as putative prognostic markers in early stage NSCLC. The study was performed on 109 pairs of tumor and matched unaffected lung tissue surgical specimens taken from stage I and II NSCLC patients. We evaluated the mRNA level of 23 genes using the real-time PCR method. The difference in the expression between the tumor and normal tissue for each gene was analyzed using a general linear model. The influence of gene expression on survival was analyzed by using the proportional hazards model. Eighteen out of the 23 genes showed statistically significant differences in expression between the tumor and non-tumor tissue. For 12 genes (ITGB1, ITGB3, CXCL1, CXCL8, CXCL9, CXCL10, CXCL11, CXCR3, CXCR4, TNF, CHKA, AGFG1, and CTC1), the expression was lower, and for six genes (ITGA5, IL8, IL6, CXCL2, CXCL3, and CXCL12), it was higher in the tumor tissue as compared to the matched normal tissue. Expression changes were more pronounced in squamous cell carcinomas than in adenocarcinomas or large cell carcinomas. Of all the analyzed genes, only CXCL5 was found to statistically significantly (p = 0.04) influence both overall and disease-free survival. Among the 23 genes previously suggested to be relevant for early staged NSCLC patients’ postoperative outcome, only CXCL5 showed a statistically significant prognostic effect.

CD44s signals the acquisition of the mesenchymal phenotype required for anchorage-independent cell survival in hepatocellular carcinoma

Background:

Circulating tumour cells (CTCs) have an important role in metastatic processes, but details of their basic characteristics remain elusive. We hypothesised that CD44-expressing CTCs show a mesenchymal phenotype and high potential for survival in hepatocellular carcinoma (HCC).

Methods:

Circulating CD44⁺CD90⁺ cells, previously shown to be tumour-initiating cells, were sorted from human blood and their genetic characteristics were compared with those of tumour cells from primary tissues. The mechanism underlying the high survival potential of CD44-expressing cells in the circulatory system was investigated in vitro.

Results:

CD44⁺CD90⁺ cells in the blood acquired epithelial–mesenchymal transition, and CD44 expression remarkably increased from the tissue to the blood. In Li7 and HLE cells, the CD44^high population showed higher anoikis resistance and sphere-forming ability than did the CD44^low population. This difference was found to be attributed to the upregulation of Twist1 and Akt signal in the CD44^high population. Twist1 knockdown showed remarkable reduction in anoikis resistance, sphere formation, and Akt signal in HLE cells. In addition, mesenchymal markers and CD44s expression were downregulated in the Twist1 knockdown.

Conclusions:

CD44s symbolises the acquisition of a mesenchymal phenotype regulating anchorage-independent capacity. CD44s-expressing tumour cells in peripheral blood are clinically important therapeutic targets in HCC.

CXCL5 contributes to tumor metastasis and recurrence of intrahepatic cholangiocarcinoma by recruiting infiltrative intratumoral neutrophils

CXCL5 is a member of the CXC-type chemokine family that may play a role in carcinogenesis and cancer progression. This study investigates the biological function and clinical significance of CXCL5 in intrahepatic cholangiocarcinoma (ICC). We demonstrated that CXCL5 was overexpressed in ICC cell lines and tumor samples compared with paired normal tissues. CXCL5 had a direct chemoattractant effect on neutrophils in vitro through PI3K-Akt and extracellular signal-regulated kinase 1/2 signaling pathways. In animal studies, CXCL5 promoted tumor growth and metastasis without altering in vitro proliferative and invasive ability of ICC cells, and this effect was mediated by the recruitment of intratumoral infiltrative neutrophils by tumor-derived CXCL5. Immunohistochemical analysis of ICC samples showed that overexpression of CXCL5 correlated strongly with intratumoral neutrophil infiltration, shorter overall survival and high tumor recurrence. Multivariate analysis revealed that CXCL5 overexpression alone, or combined with the presence of intratumoral neutrophils, was an independent prognostic indicator for ICC. In conclusion, our data showed that CXCL5 promotes ICC growth and metastasis by recruiting intratumoral neutrophils. CXCL5 alone or combined with intratumoral neutrophils is a novel prognostic predictor for ICC patients and a potential therapeutic target.

Modulation of neutrophil granulocytes in the tumor microenvironment: mechanisms and consequences for tumor progression

Accumulating evidence indicates a critical role of myeloid cells in the pathophysiology of human cancers. In contrast to the well-characterized tumor-associated macrophages (TAMs), the significance of granulocytes in cancer has only recently begun to emerge. Increased numbers of neutrophil granulocytes have been observed both in the peripheral blood and in the tumor tissues of patients with different types of cancer. Importantly, these studies linked neutrophils to poor clinical outcome in cancer patients which suggests that these cells might have important tumor-promoting activities. Indeed, a number of functional in vitro and in vivo studies demonstrated that tumors stimulated neutrophils to promote angiogenesis and immunosuppression, as well as migration, invasion and metastasis of the tumor cells. Therefore, it became necessary to understand the mechanisms modulating the changes in the biology and functions of neutrophils in the context of the tumor microenvironment. In this review we will discuss several functions of neutrophils that might contribute to tumor progression. Furthermore, we will address in detail the cellular and molecular mechanisms that control modulation of neutrophils in the tumor microenvironment, such as recruitment to the tumor site (chemotaxis), prolonged survival and enhanced release of protumoral mediators.

Neutrophil-mediated tumour angiogenesis: subversion of immune responses to promote tumour growth

Neutrophils are rapidly responding, phagocytes that are an essential part of the host innate immune response to invading micro-organisms. Along with other leucocytes they also play a key role in directing repair at sites of tissue damage. Neutrophils accomplish many of their biological functions by releasing enzymes, anti-microbial agents and cytokines when stimulated to degranulate. There is now increasing evidence to show that tumours are able to recruit neutrophils by secreting a number of tumour cell or stromal-derived chemoattractants. Once within the tumour microenvironment neutrophils, like macrophages, are polarised into a pro-tumour phenotype that can foster tumour growth by secreting factors that directly influence tumour cell proliferation, drive immunosuppression and promote tumour angiogenesis. In this review we discuss the likely mechanisms by which neutrophils are recruited into the tumour and then elaborate on how these cells may induce tumour vascularisation by the secretion of powerful pro-angiogenic factors.

CD44v6 expression is related to mesenchymal phenotype and poor prognosis in patients with colorectal cancer

CD44 standard isoform (CD44s) is a cancer stem cell marker in many tumors, and is one of the CD44 isoforms.CD44v6 has been reported to correlate with tumor progression and poor prognosis in colorectal cancer. However, the relevance of CD44s and CD44v6 to epithelial-mesenchymal transition (EMT) remains unclear. Immunohistochemistry was performed to investigate the clinical importance of CD44s and CD44v6 and their relevance to EMT in 113 patients with stage II/III colorectal cancer treated by curative resection. The relevance of CD44v6 knockdown to the phenotype of colon cancer cells was examined using small interfering RNA (siRNA) specific for CD44v6 in vitro. CD44v6 expression showed a significant inverse correlation with E-cadherin expression (P=0.0007) and a positive correlation with vimentin expression (P=0.0096). A multivariate analysis showed that high CD44v6 expression was an independent poor prognostic factor for disease-free survival (P=0.01, HR=3.05) and overall survival (P=0.025, HR=3.16). The clinical significance and the relevance of CD44s expression to EMT markers was noted to a lesser extent compared to CD44v6 expression. The knockdown of CD44v6 decreased vimentin expression, cell invasion and HGF-induced cell migration, but conferred only a slight effect on E-cadherin expression in colon cancer cells (HCT116 and LoVo). CD44v6 is related to poor outcome of patients with colorectal cancer via upregulation of the mesenchymal phenotype.

CYLD downregulation is correlated with tumor development in patients with hepatocellular carcinoma

The cylindromatosis (CYLD) gene is involved in tumor progression by acting as a negative regulator of nuclear factor-κB (NF-κB). However, the clinical significance of CYLD in patients with hepatocellular carcinoma (HCC) remains unclear. To demonstrate the clinical significance of CYLD expression, we analyzed CYLD gene expression in 124 paired HCC and non-tumor tissues using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). CYLD gene expression was detected in the patients and the cut-off value was determined by the median value of tumor-to-non-tumor (T/N) ratio. qRT-PCR analysis showed that a low CYLD expression was associated with a high serum α-fetoprotein (AFP) value. Patients in the low CYLD expression group exhibited poorer overall survival compared to those in the high expression group (P=0.0406). Protein expression of CYLD was also investigated in 70 patients with HCC using immunohistochemistry. The findings showed that CYLD protein expression in tumor tissue was associated with CYLD gene expression (P=0.031). The findings of the present study suggest that CYLD is clinically associated with tumor development in HCC patients.

Cystine/glutamic acid transporter is a novel marker for predicting poor survival in patients with hepatocellular carcinoma

Cystine/glutamic acid transporter (xCT) plays a role in tumor progression by regulating the redox status in several types of cancers. To demonstrate the importance of xCT expression for predicting the prognosis of hepatocellular carcinoma (HCC), we analyzed xCT gene expression in 130 paired HCC and non-cancerous tissues. xCT protein expression was confirmed using 7 HCC cell lines and samples from human subjects. xCT mRNA expression was detected in 34 (26%) tumor tissues. Expression of xCT was higher in HCC tissues compared to the corresponding normal tissues according to quantitative reverse transcriptase-polymerase chain reaction findings (P<0.0001). Patients in the group presenting with xCT mRNA expression showed poorer overall and disease-free survival than did those with an absence of xCT mRNA (P=0.0130 and 0.0416, respectively). xCT mRNA expression proved to be an independent factor for poor prognosis in a multivariate analysis of overall survival (hazard ratio, 1.68; 95% CI, 1.03-2.92). We observed xCT protein expression in both the HCC cell lines and in human tissue samples. In conclusion, the findings of the present study suggest that xCT is useful as a predictive marker for patient prognosis and that it may be a novel therapeutic target for HCC.