Chemokines belong to a superfamily of small, cytokine-like proteins, which induce multiple physiological functions, particularly cytoskeletal rearrangement and compartment-specific migration through their interaction with G-protein-coupled receptors. Chemokines and their receptors have been widely acknowledged as essential and selective mediators in leukocyte migration in inflammatory response. It is now established that the chemokine/chemokine receptor system is also used by cancer cells to direct lymphatic and haematogenous spreading and additionally has an impact on the site of metastatic growth of different tumours. In recent years an increasing number of studies have drawn attention to CC-chemokine cysteine motif chemokine ligand 20 (CCL20) and its physiological sole receptor CCR6 to play a role in the onset, development and metastatic spread of various gastrointestinal cancer entities. Among various cancer types CCR6 was also demonstrated to be significantly overexpressed in colorectal cancer (CRC) and stimulation by its physiological ligand CCL20 has been reported to promote CRC cell proliferation and migration in vitro. Further, the CCL20/CCR6 system apparently plays a role in the organ-selective liver metastasis of CRC. Here we review the literature on expression patterns of CCL20 and CCR6 and their physiological interactions as well as the currently presumed role of CCL20 and CCR6 in the formation of CRC and the development of liver metastasis, providing a potential basis for novel treatment strategies.

Primary breast carcinoma are frequently infiltrated by dendritic cells (DC). The mechanisms involved in the localization and status of activation of DC within primary breast carcinoma were investigated. CCL20/MIP3alpha, a chemokine involved in immature DC and their precursors attraction, was detected by immunohistochemistry on cryopreserved tissue sections of primary breast tumors and by ELISA and biological assay in metastatic effusion fluids from breast cancer patients but not from other tumors. In vitro, irradiated breast carcinoma cell lines (BCC) as well as their conditioned media promoted CD34+ cell differentiation into CD1a+ Langerhans cells (LC) precursors as early as day 6, while at day 12, 2 different CCR6+ subpopulations of DC with a Langerhans cell (CD1a(+)Langerin(+)CD86+) and an immature DC (CD1a(high)Langerin-CD86(-)HLA-DR(low)CD40(low)) phenotype were observed. This phenomenon was partly driven by a TGFbeta-dependent mechanism since a pan TGFbeta polyclonal antibody completely blocks BCC-induced LC differentiation and partly reduces immature DC development. These DC failed to maturate in response to sCD40L or LPS stimuli and CD1a(high)Langerin(-)CD86- cells have a reduced T-cell stimulatory capacity in MLR experiments. The absolute number of T cells was reduced by 50% in both the CD4+ or CD8+ compartments, these T cells expressing lower levels of the CD25 Ag and producing less IFNgamma. These results show that breast carcinoma cells produce soluble factors, which may attract DC and their precursors in vivo, and promote the differentiation of the latter into LC and immature DC with altered functional capacities. The infiltration of BCC by these altered DC may contribute to the impaired immune response against the tumor.

CC chemokine ligand 20 (CCL20) attracts CC chemokine receptor 6 (CCR6)-expressing cells. Using endoscopic biopsies taken from the gastric antrum of 42 subjects infected with H. pylori and 42 uninfected subjects, mucosal CCL20 mRNA and protein levels were measured by real-time polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. CCL19 mRNA and protein levels, as well as CCL21 mRNA levels, were also measured. The CCL20 mRNA and protein levels were significantly elevated in H. pylori-positive patients and substantially decreased after successful eradication. CCL19 and CCL21 expression levels were comparable in the H. pylori-infected and the uninfected groups. The CCL20 concentrations correlated with the degree of chronic gastritis. Immunohistochemistry and the in vitro infection assay showed that CCL20 was principally produced by the gastric epithelium. CCR6-expressing cells, including CD45RO(+) memory T lymphocytes and fascin(+)-CD1a(+) immature dendritic cells, infiltrated close to the CCL20-expressing epithelial cells. The CCL20/CCR6 interaction may be involved in the development of H. pylori-associated gastritis.

Infection by human T cell leukemia virus type (HTLV)-I is associated with several diseases, including adult T cell leukemia and HTLV-I-associated myelopathy/tropical spastic paraparesis. Leukocytes are attracted to the sites of inflammation by chemotactic factors. Macrophage inflammatory protein (MIP)-3 alpha/CCL20 is a recently isolated member of the CC subfamily of chemokines and has been proposed as a crucial factor to elicit inflammatory reactions. We now report that endogenous MIP-3 alpha mRNA levels are elevated in HTLV-I-infected T cell lines and in a human T cell line following the induced expression of the HTLV-I-encoded transactivator, Tax. Analysis of the human MIP-3 alpha promoter revealed that this gene is activated by Tax, via the activation of nuclear factor (NF)-kappa B, whose responsive element, -82-kappa B, is located at a position between -82 and -91 relative to the putative transcription start site. With an electromobility shift assay we further demonstrated that the -82-kappa B element was bound by the Tax-activated p50/p65 heterodimers of NF-kappa B. Expression of the specific receptor of MIP-3 alpha, CCR6, was also increased in HTLV-I-infected T cell lines, suggesting an autocrine and/or paracrine mechanism to establish the pathogenesis of HTLV-I-associated diseases.

BACKGROUND

Psoriasis is a common, chronic autoimmune disease of the skin. Despite a number of effective treatments, new therapies are needed with enhanced efficacy, safety and convenience. Chemokine receptors are GPCRs that control leukocyte trafficking, and like other GPCRs, are good potential drug targets. The chemokine receptor CCR6 is expressed on the T(H)17 subset of CD4(+) T cells, which produces IL-17A/F, IL-22, TNF-alpha and other cytokines, and which has been implicated in the pathogenesis of psoriasis. CCR6 and its ligand, CCL20/MIP-3alpha, are highly expressed in psoriatic skin and CCR6 is necessary for the pathology induced in a mouse model of psoriasis-like inflammation.

METHODS

This review summarizes the evidence for the importance of the IL-23/T(H)17 axis, and in particular CCR6 and CCL20 in psoriasis, dating from 2000 to the present, and discusses the possibility of inhibiting CCR6 as a treatment for the disease.

RESULTS

The review informs the reader of the current thinking on the mechanisms of inflammation in psoriasis and the possible roles for CCR6 (and CCL20) in disease pathogenesis.

CONCLUSIONS

We conclude that CCR6 should be investigated as a potential therapeutic target in psoriasis.

OBJECTIVE

Although it is known that the chemokines CXCL12 and CCL20 are expressed in the intestine, their contribution to lymphocyte homing has not been investigated in detail. The authors investigated whether the CXCL12-CXCR4 and CCL20-CCR6 systems are involved in T lymphocyte-endothelial interaction in microvessels of the small and large intestines.

METHODS

Labeled lamina proprial lymphocytes (LPLs) were administered to mice, and their adhesion to microvessels of normal and TNF-alpha -induced inflamed intestinal mucosa was observed under an intravital microscope. Antibodies against CXCL12, CCL-20, or CCL-25 were administered prior to lymphocyte administration, and in some experiments CXCR4 or CCR6 on LPLs was desensitized with an excess amount of chemokine.

RESULTS

LPLs adhered to microvessels of the ileum and colon, and TNF-alpha induced a significant accumulation at both sites. Blocking of the CXCL12-CXCR4 system significantly inhibited the LPL adhesion in the ileum and colon under both normal and TNF-alpha -treated conditions. However, blocking of the CCL20-CCR6 system significantly attenuated LPL adhesion only under a TNF-alpha -treated condition. There was an additive inhibitory effect on LPL adherence by CXCL12 and CCL20 blocking in TNF-alpha -induced inflamed intestines. There was also an additive function of the CCL25-CCR9 system in LPL accumulation in the small intestine.

CONCLUSIONS

Several chemokine systems may play significant roles cooperatively in vivo in LPL adherence to microvessels of intestinal mucosa.

Although enhanced lymphocyte trafficking is associated with colitis formation, little information about its regulation is available. The aim of this study was to examine how the murine liver and activation-regulated chemokine (mLARC/CCL20) contributes to lymphocyte recruitment in concert with vascular adhesion molecules in murine chronic experimental colitis. T and B lymphocytes isolated from the spleen were fluorescence-labelled and administered to recipient mice. Lymphocyte adhesion to microvessels of the colonic mucosa and submucosa was observed with an intravital microscope. To induce colitis, the mice received two cycles of treatment with 2% dextran sodium sulphate (DSS). In some of the experiments antibodies against the adhesion molecules or anti-mLARC/CCL20 were administered, or CC chemokine receptor 6 (CCR6) of the lymphocytes was desensitized with excess amounts of mLARC/CCL20. Significant increases in T and B cell adhesion to the microvessels of the DSS-treated mucosa and submucosa were observed. In chronic colitis, the accumulation of lymphocytes was significantly inhibited by anti-mucosal addressin cell adhesion molecule (MAdCAM)-1 mAb, but not by anti-vascular cell adhesion molecule-1. In DSS-treated colonic tissue, the expression of mLARC/CCL20 was significantly increased, the blocking of mLARC/CCL20 by monoclonal antibody or the desensitization of CCR6 with mLARC/CCL20 significantly attenuated the DSS-induced T and B cell accumulation. However, the combination of blocking CCR6 with MAdCAM-1 did not further inhibit these accumulations. These results suggest that in chronic DSS-induced colitis, both MAdCAM-1 and mLARC/CCL20 may play important roles in T and B lymphocyte adhesion in the inflamed colon under flow conditions.

The immune system is called into action by alarm signals generated from injured tissues. We examined the nature of these alarm signals after exposure of skin residential cells to contact allergens (nickel sulfate and potassium dichromate) and a contact irritant [sodium dodecyl sulfate (SDS)]. Nickel sulfate, potassium dichromate, and SDS were applied topically to the stratum corneum of human skin equivalents. A similar concentration-dependent increase in chemokine (CCL20, CCL27, and CXCL8) secretion was observed for all three chemicals. Exposure to nickel sulfate and SDS was investigated in more detail: similar to chemokine secretion, no difference was observed in the time- and concentration-dependent increase in pro-inflammatory cytokine [interleukin-1alpha (IL-1alpha) and tumor necrosis factor-alpha (TNF-alpha)] secretion. Maximal increase in IL-1alpha secretion occurred within 2 h after exposure to both nickel sulfate and SDS and prior to increased chemokine secretion. TNF-alpha secretion was detectable 8 h after chemical exposure. After allergen or irritant exposure, increased CCL20 and CXCL8, but not CCL27, secretion was inhibited by neutralizing human antibodies to either IL-1alpha or TNF-alpha. Our data show that alarm signals consist of primary and secondary signals. IL-1alpha and TNF-alpha are released as primary alarm signals, which trigger the release of secondary chemokine (CCL20 and CXCL8) alarm signals. However, some chemokines, for example, CCL27 can be secreted in an IL-1alpha and TNF-alpha independent manner. Our data suggest that skin residential cells respond to both allergen and irritant exposure by releasing mediators that initiate infiltration of immune responsive cells into the skin.

We have previously demonstrated that rat uterine epithelial cells (UEC) produce CCL20/macrophage inflammatory protein 3 alpha (MIP3alpha) and tumor necrosis factor alpha (TNF-alpha) in response to live and heat-killed Escherichia coli and to the pathogen-associated molecular patterns (PAMP) lipopolysaccharide (LPS) and Pam3Cys. To determine whether estradiol (E2) modulates PAMP-induced CCL20/MIP3alpha and TNF-alpha secretion, primary cultures of rat UEC were incubated with E2 for 24 h and then treated with LPS or Pam3Cys or not treated for an additional 12 h. E2 inhibited the constitutive secretion of TNF-alpha and CCL20/MIP3alpha into culture media. Interestingly, E2 pretreatment enhanced CCL20/MIP3alpha secretion due to LPS and Pam3Cys administration. In contrast, and at the same time, E2 lowered the TNF-alpha response to both PAMP. To determine whether estrogen receptors (ER) mediated the effects of E2, epithelial cells were incubated with E2 and/or ICI 182,780, a known ER antagonist. ICI 182,780 had no effect on E2 inhibition of constitutive TNF-alpha and CCL20/MIP3alpha secretion. In contrast, ICI 182,780 reversed the stimulatory effect of E2 on LPS- and/or Pam3Cys-induced CCL20/MIP3alpha secretion as well as partially reversed the inhibitory effect of E2 on TNF-alpha production by epithelial cells. Overall, these results indicate that E2 regulates the production of TNF-alpha and CCL20/MIP3alpha by UEC in the absence as well as presence of PAMP. Since CCL20/MIP3alpha has antimicrobial activity and is chemotactic for immune cells, these studies suggest that regulation of CCL20/MIP3alpha and TNF-alpha by E2 and PAMP may have profound effects on innate and adaptive immune responses to microbial challenge in the female reproductive tract.

OBJECTIVE

Subarachnoid hemorrhage (SAH) results in the expression of inflammatory and extracellular matrix (ECM)-related genes and various G protein-coupled receptors. In the present study, the authors evaluated the time course and sequence of the transduction pathways, p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase-1 and 2 (ERK1/2), and associated transcription factor activation as well as gene regulation and associated protein levels.

METHODS

Subarachnoid hemorrhage was induced in rats by injecting 250 microl of blood into the suprachiasmatic cistern, and gene regulation in the cerebral arteries was examined at various points in time following SAH by using quantitative polymerase chain reaction (PCR) and immunohistochemistry.

RESULTS

Immunohistochemical findings demonstrated that SAH phosphorylates and activates p38 and ERK1/2 as well as the downstream transcription factors Elk-1 and activating transcription factor-2. The pattern of activation consists of a rapid phase within the first few hours and a late phase that occurs from 24 to 48 hours. Activation is followed by an increase in the transcription of the inflammatory and ECM-related genes (IL6, TNFalpha, IL1beta, CXCL1, CXCL2, CCL20, MMP8, MMP9, MMP13, and iNOS), as demonstrated using real-time PCR. For MMP13 and iNOS, the changes in transcription were translated into functional proteins, as revealed on immunohistochemistry.

CONCLUSIONS

Activation of the p38 and ERK1/2 signaling pathways and their downstream transcription factors can explain the increase in the transcription of the genes studied. This increase and the subsequent augmentation in protein levels suggest that the inflammatory response may in part explain the remodeling that occurs in cerebral arteries following SAH.

Salmonella enterica serovar typhimurium (S. typhimurium) is an intracellular pathogen causing localized gastroenteritis in humans. Macrophages (Mphis) and dendritic cells (DCs) play an important role in innate immunity against Salmonella. In this report, we have compared the consequences of infection of human Mphis and DCs with wild-type S. typhimurium and an isogenic PgtE-defective strain. PgtE is an outer membrane protein hypothesized to have a role in intracellular survival of Salmonella. We observed that DCs undergo full maturation in response to Salmonella infection, as indicated by up-regulation of cell-surface marker proteins CD80, CD83, CD86, and human leukocyte antigen class II. CC chemokine ligand 5 (CCL5), CXC chemokine ligand 10, tumor necrosis factor alpha, interleukin (IL)-12, and IL-18 gene expression and protein production were readily induced by Salmonella-infected Mphis and DCs. CCL20 was preferentially produced by Mphis, whereas DCs secreted higher levels of CCL19 as compared with Mphis. DCs and Mphis infected with S. typhimurium also produced high levels of interferon-gamma (IFN-gamma). Cytokine neutralization and stimulation experiments suggest that the production was partly regulated by Salmonella-induced type I IFNs, IL-12, and IL-18. DC cytokine production induced by Salmonella was much higher as compared with the responses induced by Salmonella lipopolysaccharide or flagellin. Mphis and DCs were capable of internalizing and harboring Salmonella for several days. S. enterica PgtE provided no survival advantage for the bacteria in human Mphis or DCs. Our results demonstrate that although Mphis and DCs share similar functions, they may have different roles during Salmonella infection as a result of differential production of certain chemokines and cytokines.

Originally, chemokines and their G-protein-coupled receptors were described to regulate multiple physiological functions, particularly tissue architecture and compartment-specific migration of white blood cells. Now, it is established that the chemokine/chemokine receptor system is also used by cancer cells for migration and metastatic spread. Here, we examined the relative levels of CC-chemokine CCL20 and its corresponding receptor CCR6 in resection specimens from patients with different malignant and non-malignant colorectal diseases as well as in colorectal liver metastases (CRLM). CCL20/CCR6 mRNA and protein expression profiles were assessed by quantitative real-time PCR (qRT-PCR), enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) in resection specimens from patients with ulcerative colitis (UC, n = 15), colorectal adenoma (CRA, n = 15), colorectal adenocarcinoma (CRC, n = 61) and colorectal liver metastases (CRLM, n = 16). Corresponding non-diseased tissues served as control. In contrast to UC tissues, the CCL20/CCR6 system showed a distinct upregulation in CRA, CRC and CRLM related to corresponding non-affected tissues (P < 0.05, respectively). Furthermore, CRA, CRC and CRLM tissue samples displayed significantly higher protein amounts of CCL20 in comparison with UC specimens (P < 0.05, respectively). Our results strongly suggest an association between CCL20/CCR6 expression and the induction of CRA, CRC and the development of CRLM. Therefore, CCL20 and CCR6 may provide potential targets for novel treatment strategies of CRC.

We have examined the expression of MIP-3alpha/CCL20 in oral squamous cell carcinoma (SCC) in vivo and in vitro. In addition, we have investigated whether the expression of MIP-3alpha/CCL20 is regulated by bacterial infection and inflammatory cytokines. In order to determine the mRNA level of MIP-3alpha, quantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed with LightCycler using the double-stranded DNA dye, SYBR Green I. Oral epithelial cells and six SCC cell lines (SCC-9, SAS, BSC-OF, HSC-4, HSC, Ca9-22) were found to express MIP-3alpha mRNA. The expression of MIP-3alpha was upregulated by infection with Actinobacillus actinomycetemcomitans and by stimulation with lipopolysaccharide and TNF-alpha. By in situ hybridization, the detectable MIP-3alpha expression in SCC was localized primarily at the epithelial pearls corresponding to the spinous layer. These results suggest that MIP-3alpha contributes to the oral immunoresponse to bacterial infection, and may be involved in the growth of SCC.

Monocytes play a major role in the cellular defence against Aspergillus fumigatus in immunocompromised patients. To obtain a better understanding of the mechanisms involved in this interaction, phagocytosis and gene expression profiling of human monocytes was carried out after incubation with A. fumigatus resting, swollen and germinating conidia and hyphae (for 3, 6 and 9 h). The majority of monocytes phagocytosed up to three conidia during the first 3 h of incubation. Microarray analysis showed an increased expression level of immune-relevant genes, which was dependent on the germination state of the fungus and the incubation period. Among these genes, those encoding interleukin-8, macrophage inflammatory protein 3-alpha (CCL20) and monocyte chemotactic protein-1 (CCL2) were found to be potential key regulators involved in the A. fumigatus-induced immune response. In addition, A. fumigatus was found to be an inducer of the genes encoding urokinase type plasminogen activator (uPA), urokinase type plasminogen activator receptor (uPAR),plasminogen activator inhibitor (PAI), pentraxin-3 (PTX3) and intercellular adhesion molecule-1 (ICAM-1), which, in combination, may contribute to thrombosis and local lung tissue injury.

OBJECTIVE

Our aim was to analyze the regulation of CC Chemokine ligand 20 (CCL20) by LDL in human vascular smooth muscle cells (VSMC).

RESULTS

In asymptomatic subjects, circulating CCL20 levels were higher in patients with hypercholesterolemia (18.5±3.2 versus 9.1±1.3 pg/mL; P<0.01). LDL induced the expression of CCL20 in VSMC in a dose- and time-dependent manner. Increased levels of CCL20 secreted by LDL-treated VSMC significantly induced human lymphocyte migration, an effect reduced by CCL20 silencing. The upregulation of CCL20 by LDL was dependent on the activation of kinase signaling pathways and NF-κB. By site-directed mutagenesis, electrophoretic mobility shift assay, and chromatin immunoprecipitation, we identified a NF-κB site (-80/-71) in CCL20 promoter critical for LDL responsiveness. Lysophosphatidic acid mimicked the upregulation of CCL20 induced by LDL, and minimal oxidation of LDL increased the ability of LDL to induce CCL20 through a mechanism that involves lysophosphatidic acid receptors. CCL20 was overexpressed in atherosclerotic lesions from coronary artery patients, colocalizing with VSMC. CCL20 was detected in conditioned media from healthy human aorta and its levels were significantly higher in secretomes from carotid endarterectomy specimens.

CONCLUSIONS

This study identifies CCL20 in atherosclerotic lesions and recognizes this chemokine as a mediator highly sensitive to the inflammatory response elicited by LDL.

OBJECTIVE

CCL20 is a chemokine that regulates the homeostatic and inflammatory trafficking of leukocytes to the small intestine and regulates the development of the gastrointestinal lymphoid architecture. T cells expressing T helper cell (Th) 2 cytokines are critical for experimental food allergy, and we hypothesized that CCL20 is involved in the localization of these cells to the gut.

METHODS

We evaluated the role of CCR6 in allergic diarrhea induced by sensitization and oral challenge with ovalbumin (OVA) using CCR6(+/+) and CCR6(-/-) mice.

RESULTS

CCR6(-/-) mice were protected from OVA-induced diarrhea but surprisingly were not impaired in mastocytosis or allergen-specific immunoglobulin E. CCR6(-/-) mice were also protected from T cell-mediated diarrhea induced by anti-CD3 antibody. Allergic diarrhea was associated with an increased expression of Th2 cytokines within the intestinal mucosa that was significantly reduced in CCR6(-/-) mice. Inhibition of lymphocyte homing by treatment with FTY720 did not impair allergic diarrhea, indicating that reactivation of T cells could occur locally within the small intestine. Finally, T-cell transfer studies demonstrated that CCR6 was required both on the transferred T cells and in the recipient mouse to manifest allergic disease in the gastrointestinal tract.

CONCLUSIONS

These studies highlight a mast cell- and immunoglobulin E-independent role for CCR6-bearing T cells in the pathogenesis of gastrointestinal allergic disease.

Inflammatory chemokine CCL20 and its receptor CCR6 have been reported to correlate with colorectal cancer patients' metastasis. However, the role of CCL20 in patients with NSCLC is not well defined. In this study, we detected the expression of CCL20 in tumor samples and corresponding adjacent ones (n=71) from patients with NSCLC using RT-PCR and observed that CCL20 showed higher expression in tumor samples (0.28±0.17) than in adjacent ones (0.20±0.13) (n=71, P=0.0056), which was also verified in protein level using IHC. Analysis results showed that CCL20 expression was positively associated with CD4 (n=80, P=0.0046), Foxp3 (n=80, P=0.0020) and IL-10 (n=61, P=0.0003) in tumor samples. And the flow data showed that Treg cells accumulated in TIL (MFI: 961±760) compared with PBMC (MFI: 683±460) (n=40, P=0.0046); and the percentage of CCR6 - the sole receptor of CCL20 - on Treg cells was higher in TIL (MFI: 1311±1268) than in PBMC (MFI: 976±780) (n=40, P=0.0219). It was interesting to find that the expression of CCL20 in tumor sites was almost 1.5-fold higher in samples from high-stage patients (III-IV stage, 0.34±0.17) compared with those from low-stage patients (I-II stage, 0.22±0.11) (P=0.0056). Furthermore, the higher expression of CCL20 was associated with a lower overall survival (P=0.0198). The IHC data showed that tumor cells were the main source of CCL20, and after treated cell line A549 with docetaxel, we found that the secretion of CCL20 was decreased heavily (n=3, P=0.0046). Our results demonstrated that CCL20 cooperated with CCR6 could recruit Treg cells to tumor sites, and chemotherapy medicine docetaxel could decrease the expression of CCL20.

Sinusoidal obstruction syndrome (SOS; formerly veno-occlusive disease) is a well-established complication of hematopoietic stem cell transplantation, pyrrolizidine alkaloid intoxication, and widely used chemotherapeutic agents such as oxaliplatin. It is associated with substantial morbidity and mortality. Pathogenesis of SOS in humans is poorly understood. To explore its molecular mechanisms, we used Affymetrix U133 Plus 2.0 microarrays to investigate the gene expression profile of 11 human livers with oxaliplatin-related SOS and compared it to 12 matched controls. Hierarchical clustering analysis showed that profiles from SOS and controls formed distinct clusters. To identify functional networks and gene ontologies, data were analyzed by the Ingenuity Pathway Analysis Tool. A total of 913 genes were differentially expressed in SOS: 613 being upregulated and 300 downregulated. Reverse transcriptase-PCR results showed excellent concordance with microarray data. Pathway analysis showed major gene upregulation in six pathways in SOS compared with controls: acute phase response (notably interleukin 6), coagulation system (Serpine1, THBD, and VWF), hepatic fibrosis/hepatic stellate cell activation (COL3a1, COL3a2, PDGF-A, TIMP1, and MMP2), and oxidative stress. Angiogenic factors (VEGF-C) and hypoxic factors (HIF1A) were upregulated. The most significant increase was seen in CCL20 mRNA. In conclusion, oxaliplatin-related SOS can be readily distinguished according to morphologic characteristics but also by a molecular signature. Global gene analysis provides new insights into mechanisms underlying chemotherapy-related hepatotoxicity in humans and potential targets relating to its diagnosis, prevention, and treatment. Activation of VEGF and coagulation (vWF) pathways could partially explain at a molecular level the clinical observations that bevacizumab and aspirin have a preventive effect in SOS.

BACKGROUND

Burkholderia pseudomallei, a facultative intracellular pathogen, causes systemic infection in humans with high mortality especially when infection occurs through an infectious aerosol. Previous studies indicated that the epithelial cells in the lung are an active participant in host immunity. In this study, we aimed to investigate the innate immune responses of lung epithelial cells against B. pseudomallei.

RESULTS

Using a murine lung epithelial cell line, primary lung epithelial cells and an inhalational murine infection model, we characterized the types of innate immunity proteins and peptides produced upon B. pseudomallei infection. Among a wide panel of immune components studied, increased levels of major pro-inflammatory cytokines IL-6 and TNFalpha, chemokine MCP-1, and up-regulation of secretory leukocyte protease inhibitor (SLPI) and chemokine (C-C motif) ligand 20 (CCL20) were observed. Inhibition assays using specific inhibitors suggested that NF-kappaB and p38 MAPK pathways were responsible for these B. pseudomallei-induced antimicrobial peptides.

CONCLUSIONS

Our findings indicate that the respiratory epithelial cells, which form the majority of the cells lining the epithelial tract and the lung, have important roles in the innate immune response against B. pseudomallei infection.

RORγt and RORα are transcription factors of the RAR-related orphan nuclear receptor (ROR) family. They are expressed in Th17 cells and have been suggested to play a role in Th17 differentiation. Although RORγt signature genes have been characterized in mouse Th17 cells, detailed information on its transcriptional control in human Th17 cells is limited and even less is known about RORα signature genes which have not been reported in either human or mouse T cells. In this study, global gene expression of human CD4 T cells activated under Th17 skewing conditions was profiled by RNA sequencing. RORγt and RORα signature genes were identified in these Th17 cells treated with specific siRNAs to knock down RORγt or RORα expression. We have generated selective small molecule RORγt modulators and they were also utilized as pharmacological tools in RORγt signature gene identification. Our results showed that RORγt controlled the expression of a very selective number of genes in Th17 cells and most of them were regulated by RORα as well albeit a weaker influence. Key Th17 genes including IL-17A, IL-17F, IL-23R, CCL20 and CCR6 were shown to be regulated by both RORγt and RORα. Our results demonstrated an overlapping role of RORγt and RORα in human Th17 cell differentiation through regulation of a defined common set of Th17 genes. RORγt as a drug target for treatment of Th17 mediated autoimmune diseases such as psoriasis has been demonstrated recently in clinical trials. Our results suggest that RORα could be involved in same disease mechanisms and gene signatures identified in this report could be valuable biomarkers for tracking the pharmacodynamic effects of compounds that modulate RORγt or RORα activities in patients.

The cell surface heparan sulfate proteoglycan, syndecan-1, has been reported to be a negative regulator of various inflammatory processes, but its precise mode of action is poorly defined. In this study, we use the murine model of the 35-55 peptide of myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis (EAE), a T lymphocyte-mediated inflammation where the steps in disease development and recovery are well characterized, to decipher how syndecan-1 impacts on the inflammatory reaction. Syndecan-1 knockout (Sdc-1(-/-)) mice show enhanced disease severity and impaired recovery. The use of bone marrow chimeric mice reveals that both an immune cell and a CNS-resident source of syndecan-1 contribute to this phenotype. Epithelial cells of the choroid plexus, where initial CCL20-induced leukocyte recruitment to the brain occurs, are identified as the predominant site of syndecan-1 expression. Syndecan-1 is lost from this site during the course of EAE by shedding into the cerebrospinal fluid, which correlates with loss of epithelial cell surface-bound CCL20 and is associated with the upregulation of IL-6 expression. In Sdc-1(-/-) mice, early leukocyte recruitment via the choroid plexus is enhanced, and IL-6 is elevated, which collectively results in higher numbers of the disease inducing Th17 cells in the CNS, thereby contributing to enhanced disease severity. Furthermore, Sdc-1(-/-) mice have intrinsically elevated plasma cell numbers and higher myelin oligodendrocyte glycoprotein-specific Ab levels during EAE, which we propose contributes to impaired recovery. Our data identify the choroid plexus epithelium as a novel source of IL-6 in EAE and demonstrate that its expression negatively correlates with syndecan-1 expression at this site.

RANK/RANKL facilitates migration/invasion via epithelial-mesenchymal transition (EMT) in certain malignant tumors. The relationship and mechanism between RANK/RANKL and EMT in endometrial cancer (EC) cells, however, remain unclear. In this study, we firstly showed that RANK/RANKL activation was correlated with EC staging and EMT markers in human EC tissue specimen. RANK/RANKL promoted migration/invasion and initiated EMT of EC cell lines. Then, protein chip analysis and enzyme-linked immunosorbent assay (ELISA) revealed that the expression and secretion of chemokine ligand 20 (CCL20) was dramatically enhanced in RANKL-treated RANK over-expressed EC cells. Moreover, the higher level of CCL20 in both serum and tumor tissue was detected in orthotopic transplantation mouse models. Finally, we confirmed that CCL20 contributed to invasion and EMT of RANK over-expressed EC cells. In summary, all data supported the hypothesis that RANK/RANKL elevated the expression and secretion of CCL20 in EC cells, which promoted cancer progression through EMT.

CC chemokines, a subfamily of 27 chemotactic cytokines, are a component of intercellular communication, which is crucial for the functioning of the tumor microenvironment. Although many individual chemokines have been well researched, there has been no comprehensive review presenting the role of all known human CC chemokines in the hallmarks of cancer, and this paper aims at filling this gap. The first part of this review discusses the importance of CCL1, CCL3, CCL4, CCL5, CCL18, CCL19, CCL20, CCL21, CCL25, CCL27, and CCL28 in cancer. Here, we discuss the significance of CCL2 (MCP-1), CCL7, CCL8, CCL11, CCL13, CCL14, CCL15, CCL16, CCL17, CCL22, CCL23, CCL24, and CCL26. The presentation of each chemokine includes its physiological function and then the role in tumor, including proliferation, drug resistance, migration, invasion, and organ-specific metastasis of tumor cells, as well as the effects on angiogenesis and lymphangiogenesis. We also discuss the effects of each CC chemokine on the recruitment of cancer-associated cells to the tumor niche (eosinophils, myeloid-derived suppressor cells (MDSC), tumor-associated macrophages (TAM), tumor-associated neutrophils (TAN), regulatory T cells (T_reg)). On the other hand, we also present the anti-cancer properties of CC chemokines, consisting in the recruitment of tumor-infiltrating lymphocytes (TIL).

Keywords: CC chemokine; MCP-1; angiogenesis; anti-cancer therapy; cancer; chemokine; lymphangiogenesis; organ-specific metastasis; tumor; tumor microenvironment.