The chemokine CCL20 and its receptor CCR6 in human malignancy with focus on colorectal cancer

Locked nucleic acid anti-miR-21 inhibits cell growth and invasive behaviors of a colorectal adenocarcinoma cell line: LNA-anti-miR as a novel approach

Colorectal cancer (CRC) is the third leading cause of cancer-related death and has an extremely poor prognosis. Dysregulation of microRNAs (miRNAs) has been shown to be involved in the pathogenesis and progression of many malignancies. Recent data suggest that microRNA-21 (miR-21) is significantly elevated in different types of cancer, especially colon adenocarcinoma. Against this background, locked nucleic acid (LNA)-modified oligonucleotides have recently been suggested as a novel approach for targeting miRNAs as antisense-based gene silencing. The aim of the current study was to explore the functional role of LNA-anti-miR-21 in a colon adenocarcinoma LS174T cell line. LS174T cells were transfected with LNA-anti-miR-21 for 24, 48 and 72 h. Quantitative real-time reverse transcriptase-PCR (qRT-PCR) was performed to assess miR-21 expression by LNA-anti-miR-21. The viability of the cells was evaluated by MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide) assay and Annexin V/propidium iodide staining assay was used to detect apoptosis. Moreover, invasive behavior of the cells was evaluated before and after therapy by transwell assay. LNA-anti-miR-21 was successfully transfected in human LS174T cells and suppressed the endogenous miR-21. LNA-anti-miR-21 inhibited the cells' growth followed by induction of apoptosis. LNA-anti-miR-21 (50 pmol/μl) reduced the invasive behaviors of LS174T cells after 24 h, compared with untreated cells and scrambled LNA-transfected cells. However, this effect was more pronounced after 72 h. Our findings suggest the therapeutic potential of LNA-anti-miR-21 in a colon adenocarcinoma for targeting miR-21 expression. Further studies are warranted to investigate the molecular mechanisms underlying this novel inhibitor in colorectal cancer to establish its potential value for treatment of CRC patients with high miR-21 expression.

MicroRNAs: Novel immunotherapeutic targets in colorectal carcinoma

Colorectal carcinoma (CRC) is one of the most common types of cancer worldwide and the prognosis for CRC patients with recurrence or metastasis is extremely poor. Although chemotherapy and radiation therapy can improve survival, there are still numerous efforts to be performed. Immunotherapy is frequently used, either alone or in combination with other therapies, for the treatment of CRC and is a safe and feasible way to improve CRC treatment. Furthermore, the significance of the immune system in the biology of CRC has been demonstrated by retrospective assessments of immune infiltrates in resected CRC tumors. MicroRNAs (miRNAs) are short, non-coding RNAs that can regulate multiple target genes at the post-transcriptional level and play critical roles in cell proliferation, differentiation and apoptosis. MiRNAs are required for normal immune system development and function. Nevertheless, aberrant expression of miRNAs is often observed in various tumor types and leads to immune disorders or immune evasion. The immunomodulatory function of miRNAs indicates that miRNAs may ultimately be part of the portfolio of anti-cancer targets. Herein, we will review the potential roles of miRNAs in the regulation of the immune response in CRC and then move on to discuss how to utilize different miRNA targets to treat CRC. We also provide an overview of the major limitations and challenges of using miRNAs as immunotherapeutic targets.

The Role of Chemokines in Promoting Colorectal Cancer Invasion/Metastasis

Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. Although most of the primary CRC can be removed by surgical resection, advanced tumors sometimes show recurrences in distant organs such as the liver, lung, lymph node, bone or peritoneum even after complete resection of the primary tumors. In these advanced and metastatic CRC, it is the tumor-stroma interaction in the tumor microenvironment that often promotes cancer invasion and/or metastasis through chemokine signaling. The tumor microenvironment contains numerous host cells that may suppress or promote cancer aggressiveness. Several types of host-derived myeloid cells reside in the tumor microenvironment, and the recruitment of them is under the control of chemokine signaling. In this review, we focus on the functions of chemokine signaling that may affect tumor immunity by recruiting several types of bone marrow-derived cells (BMDC) to the tumor microenvironment of CRC.

Regulatory T Cells from Colon Cancer Patients Inhibit Effector T-cell Migration through an Adenosine-Dependent Mechanism

T cell-mediated immunity is a major component of antitumor immunity. In order to be efficient, effector T cells must leave the circulation and enter into the tumor tissue. Regulatory T cells (Treg) from gastric cancer patients, but not from healthy volunteers, potently inhibit migration of conventional T cells through activated endothelium. In this study, we compared T cells from colon cancer patients and healthy donors to determine the mechanisms used by Tregs from cancer patients to inhibit conventional T-cell migration. Our results showed that circulating Tregs from cancer patients expressed high levels of CD39, an ectoenzyme mediating hydrolysis of ATP to AMP, as a rate-determining first step in the generation of immunosuppressive adenosine. Tumor-associated Tregs expressed even more CD39, and we therefore examined the importance of adenosine in Treg-mediated inhibition of T-cell transendothelial migration in vitro. Exogenous adenosine significantly reduced migration of conventional T cells from healthy volunteers, and blocking either adenosine receptors or CD39 enzymatic activity during transmigration restored the ability of conventional T cells from cancer patients to migrate. Adenosine did not directly affect T cells or endothelial cells, but reduced the ability of monocytes to activate the endothelium. Taken together, our results indicate that Treg-derived adenosine acts on monocytes and contributes to reduced transendothelial migration of effector T cells into tumors. This effect of Tregs is specific for cancer patients, and our results indicate that Tregs may affect not only T-cell effector functions but also their migration into tumors.

Chemokine/chemokine receptor pair CCL20/CCR6 in human colorectal malignancy: An overview

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.

TNF-α increases the membrane expression of the chemokine receptor CCR6 in thyroid tumor cells, but not in normal thyrocytes: potential role in the metastatic spread of thyroid cancer

The chemokine receptor CCR6, selectively bound by CCL20, is involved in the metastatic spread of cancer cells. Tumor necrosis factor-α (TNF-α) displays a complex pro-tumorigenic actions, but it is unknown whether this cytokine could modulate the expression of chemokine receptors in thyroid tumors. The membrane expression of CCR6 was assessed by flow cytometry and immunofluorescence, in primary cultures of normal human thyroid (NHT) cells and in thyroid cancer cell lines (TPC-1 and BCPAP), both in basal conditions and after stimulation with TNF-α. In basal conditions, CCR6+ cells were virtually absent in NHT cells (0.4 ± 0.4 %), while they were detected in TPC-1 (23.6 ± 6.6 %) and in BCPAP (12.9 ± 9.4 %) tumor cells (ANOVA F: 10.534; p < 0.005). The incubation with TNF-α significantly increased the percentage of CCR6+ cells in TPC-1 (23.6 ± 6.6 % vs. 33.1 ± 8.7; p < 0.033) and in BCPAP (12.9 ± 9.4 % vs. 18.1 ± 11.5; p < 0.030), but not in NHT (0.4 ± 0.4 % vs. 0.2 ± 0.3; NS) cells. The magnitude of the TNF-α effect was similar for TPC-1 and BCPAP (∼40 % vs. baseline) cells. TPC-1 cells were characterized by a greater amount of CCR6 per cell as compared with BCPAP cells, both in basal conditions (148.3 ± 33.7 fluorescence intensity vs. 102.5 ± 22.1 p < 0.016) and after TNF-α stimulation (147.8 ± 46.3 fluorescence intensity vs. 95.3 ± 18.5; p < 0.025). Cell migration assays showed that TNF-α treatment significantly increased the rate of migrated cells in those cells in which it also increased the membrane expression of CCR6 (TPC-1 and BCPAP) as compared to basal condition (p < 0.05 for both TPC-1 and BCPAP cells). No effect was observed in NHT cells in which TNF-α stimulation had no effect in terms of CCR6 expression. We first report that TNF-α enhances the expression of CCR6 in thyroid tumor cells, thus providing evidence that TNF-α increases the metastatic potential of thyroid tumors.

CXCL12/CXCR4 activation by cancer-associated fibroblasts promotes integrin β1 clustering and invasiveness in gastric cancer

Cancer-associated fibroblasts (CAFs) are reportedly involved in invasion and metastasis in several types of cancer, including gastric cancer (GC), through the stimulation of CXCL12/CXCR4 signaling. However, the mechanisms underlying these tumor-promoting effects are not well understood, which limits the potential to develop therapeutic targets against CAF-mediated CXCL12/CXCR4 signaling. CXCL12 expression was analyzed in resected GC tissues from 110 patients by immunohistochemistry (IHC). We established primary cultures of normal fibroblasts (NFs) and CAFs from the GC tissues and examined the functional differences between these primary fibroblasts using co-culture assays with GC cell lines. We evaluated the efficacy of a CXCR4 antagonist (AMD3100) and a FAK inhibitor (PF-573,228) on the invasive ability of GC cells. High CXCL12 expression levels were significantly associated with larger tumor size, increased tumor depth, lymphatic invasion and poor prognosis in GC. CXCL12/CXCR4 activation by CAFs mediated integrin β1 clustering at the cell surface and promoted the invasive ability of GC cells. Notably, AMD3100 was more efficient than PF-573,228 at inhibiting GC cell invasion through the suppression of integrin β1/FAK signaling. These results suggest that CXCL12 derived from CAFs promotes GC cell invasion by enhancing the clustering of integrin β1 in GC cells, resulting in GC progression. Taken together, the inhibition of CXCL12/CXCR4 signaling in GC cells may be a promising therapeutic strategy against GC cell invasion.

Chemokine Ligand 20: A Signal for Leukocyte Recruitment During Human Ovulation?

Ovulation is one of the cornerstones of female fertility. Disruption of the ovulatory process results in infertility, which affects approximately 10% of couples. Using a unique model in which the dominant follicle is collected across the periovulatory period in women, we have identified a leukocyte chemoattractant, chemokine ligand 20 (CCL20), in the human ovary. CCL20 mRNA is massively induced after an in vivo human chorionic gonadotropin (hCG) stimulus in granulosa (>10 000-fold) and theca (>4000-fold) cells collected during the early ovulatory (12-18 h) and late ovulatory (18-34 h) periods after hCG administration. Because the LH surge sets in motion an inflammatory reaction characterized by an influx of leukocytes and CCL20 is known to recruit leukocytes in other systems, the composition of ovarian leukocytes (CD45+) containing the CCL20 receptor CCR6 was determined immediately prior to ovulation. CD45+/CCR6+ cells were primarily natural killer cells (41%) along with B cells (12%), T cells (11%), neutrophils (10%), and monocytes (9%). Importantly, exogenous CCL20 stimulated ovarian leukocyte migration 59% within 90 minutes. Due to the difficulties in obtaining human follicles, an in vitro model was developed using granulosa-lutein cells to explore CCL20 regulation. CCL20 expression increased 40-fold within 6 hours after hCG, was regulated partially by the epithelial growth factor pathway, and was positively correlated with progesterone production. These results demonstrate that hCG dramatically increases CCL20 expression in the human ovary, that ovarian leukocytes contain the CCL20 receptor, and that CCL20 stimulates leukocyte migration. Our findings raise the prospect that CCL20 may aid in the final ovulatory events and contribute to fertility in women.

Human Mucosa-Associated Invariant T Cells Accumulate in Colon Adenocarcinomas but Produce Reduced Amounts of IFN-γ

Mucosa-associated invariant T (MAIT) cells are innate-like T cells with a conserved TCR α-chain recognizing bacterial metabolites presented on the invariant MHC-related 1 molecule. MAIT cells are present in intestinal tissues and liver, and they rapidly secrete IFN-γ and IL-17 in response to bacterial insult. In colon cancer, IL-17-driven inflammation promotes tumor progression, whereas IFN-γ production is essential for antitumor immunity. Thus, tumor-associated MAIT cells may affect antitumor immune responses by their secreted cytokines. However, the knowledge of MAIT cell presence and function in tumors is virtually absent. In this study, we determined the frequency, phenotype, and functional capacity of MAIT cells in colon adenocarcinomas and unaffected colon lamina propria. Flow cytometric analyses showed significant accumulation of MAIT cells in tumor tissue, irrespective of tumor stage or localization. Colonic MAIT cells displayed an activated memory phenotype and expression of chemokine receptors CCR6 and CCR9. Most MAIT cells in unaffected colon tissues produced IFN-γ, whereas only few produced IL-17. Colonic MAIT cells also produced TNF-α, IL-2, and granzyme B. In the tumors, significantly lower frequencies of IFN-γ-producing MAIT cells were seen, whereas there were no differences in the other cytokines analyzed, and in vitro studies showed that secreted factors from tumor tissue reduced IFN-γ production from MAIT cells. In conclusion, MAIT cells infiltrate colon tumors but their ability to produce IFN-γ is substantially reduced. We suggest that MAIT cells have the capacity to promote local immune responses to tumors, but factors in the tumor microenvironment act to reduce MAIT cell IFN-γ production.

Nutlin-3a: A Potential Therapeutic Opportunity for TP53 Wild-Type Ovarian Carcinomas

Epithelial ovarian cancer is a diverse molecular and clinical disease, yet standard treatment is the same for all subtypes. TP53 mutations represent a node of divergence in epithelial ovarian cancer histologic subtypes and may represent a therapeutic opportunity in subtypes expressing wild type, including most low-grade ovarian serous carcinomas, ovarian clear cell carcinomas and ovarian endometrioid carcinomas, which represent approximately 25% of all epithelial ovarian cancer. We therefore sought to investigate Nutlin-3a--a therapeutic which inhibits MDM2, activates wild-type p53, and induces apoptosis--as a therapeutic compound for TP53 wild-type ovarian carcinomas. Fifteen epithelial ovarian cancer cell lines of varying histologic subtypes were treated with Nutlin-3a with determination of IC50 values. Western Blot (WB) and quantitative real-time polymerase chain reaction (qRT-PCR) analyses quantified MDM2, p53, and p21 expression after Nutlin-3a treatment. DNA from 15 cell lines was then sequenced for TP53 mutations in exons 2-11 including intron-exon boundaries. Responses to Nutlin-3a were dependent upon TP53 mutation status. By qRT-PCR and WB, levels of MDM2 and p21 were upregulated in wild-type TP53 sensitive cell lines, and p21 induction was reduced or absent in mutant cell lines. Annexin V assays demonstrated apoptosis in sensitive cell lines treated with Nutlin-3a. Thus, Nutlin-3a could be a potential therapeutic agent for ovarian carcinomas expressing wild-type TP53 and warrants further investigation.

Chemokine-Derived Peptides: Novel Antimicrobial and Antineoplasic Agents

Chemokines are a burgeoning family of chemotactic cytokines displaying a broad array of functions such as regulation of homeostatic leukocyte traffic and development, as well as activating the innate immune system. Their role in controlling early and late inflammatory stages is now well recognized. An improper balance either in chemokine synthesis or chemokine receptor expression contributes to various pathological disorders making chemokines and their receptors a useful therapeutic target. Research in this area is progressing rapidly, and development of novel agents based on chemokine/chemokine receptors antagonist functions are emerging as attractive alternative drugs. Some of these novel agents include generation of chemokine-derived peptides (CDP) with potential agonist and antagonist effects on inflammation, cancer and against bacterial infections. CDP have been generated mainly from N- and C-terminus chemokine sequences with subsequent modifications such as truncations or elongations. In this review, we present a glimpse of the different pharmacological actions reported for CDP and our current understanding regarding the potential use of CDP alone or as part of the novel therapies proposed in the treatment of microbial infections and cancer.

Interleukin-17 induces CC chemokine receptor 6 expression and cell migration in colorectal cancer cells

The CC chemokine receptor 6 (CCR6) and its ligand CCL20 are involved in human colorectal cancer (CRC) carcinogenesis and can promote the progression of CRC. In addition, interleukin-17 (IL-17), produced by a T cell subset named "Th17," has been identified as an important player in inflammatory responses, and has emerged as a mediator in inflammation-associated cancer. However, the relevance of IL-17 in the development and progression of CRC still remains to be explored. This study aimed to investigate the effect of IL-17 on the cell migration of CRC cells. Human CRC HCT-116 cells were used to study the effect of IL-17 on CCR6 expression and cell migration in CRC cells. IL-17 treatment induced migration of HCT-116 cells across the Boyden chamber membrane and increased the expression level of the CCR6. Inhibition of CCR6 by small interfering RNA (siRNA) and neutralizing antibody inhibited IL-17-induced cell migration. By using specific inhibitors and short hairpin RNA (shRNA), we demonstrated that the activation of ERK and p38 pathways are critical for IL-17-induced CCR6 expression and cell migration. Promoter activity and transcription factor ELISA assays showed that IL-17 increased NF-κB-DNA binding activity in HCT-116 cells. Inhibition of NF-κB activation by specific inhibitors and siRNA blocked the IL-17-induced CCR6 expression. Our findings support the hypothesis that CCR6 up-regulation stimulated by IL-17 may play an active role in CRC cell migration.

Tobacco smoke induces production of chemokine CCL20 to promote lung cancer

Tobacco kills nearly 6 million people each year, and 90% of the annual 1.59 million lung cancer deaths worldwide are caused by cigarette smoke. Clinically, a long latency is required for individuals to develop lung cancer since they were first exposed to smoking. In this study, we aimed to identify clinical relevant inflammatory factors that are critical for carcinogenesis by treating normal human lung epithelial cells with tobacco carcinogen nicotine-derived nitrosaminoketone (NNK) for a long period (60 days) and systematic screening in 84 cytokines/chemokines. We found that a chemokine CCL20 was significantly up-regulated by NNK, and in 78/173 (45.1%) patients the expression of CCL20 was higher in tumor samples than their adjacent normal lung tissues. Interestingly, CCL20 was up-regulated in 48/92 (52.2%) smoker and 29/78 (37.2%) nonsmoker patients (p = 0.05), and high CCL20 was associated with poor prognosis. NNK induced the production of CCL20, which promoted lung cancer cell proliferation and migration. In addition, an anti-inflammation drug, dexamethasone, inhibited NNK-induced CCL20 production and suppressed lung cancer in vitro and in vivo. These results indicate that CCL20 is crucial for tobacco smoke-caused lung cancer, and anti-CCL20 could be a rational approach to fight against this deadly disease.

The involvement of cell surface nucleolin in the initiation of CCR6 signaling in human hepatocellular carcinoma

In recent years, the chemokine CC receptor 6 (CCR6) and its ligand CCL20 were reported to play an essential role in hepatocellular carcinoma (HCC). However, the role of cell surface nucleolin in the CCR6 pathway of HCC is not well featured. Using immunohistochemistry, Western blotting, siRNA, wound healing and transwell assay, we investigated the relationships of cell surface nucleolin and CCR6 signaling in HCC. In the present study, our findings identified that cell surface nucleolin and CCR6 protein were stained in most of HCC tissues (64, 68 %, respectively) and differently expressed in HCC cell lines; meanwhile, both expression has an association with advanced stage, lymph node metastasis and poor 5-year prognosis. According to in vitro assays, we found that the silencing of either cell surface nucleolin or CCR6 inhibited the protein expression of p-ERK, p-AKT, MMP2, MMP9 and ICAM-1 in the CCL20-stimulated HCCLM6 cells. Functional analysis revealed that cell surface nucleolin or CCR6 silencing significantly hampered HCCLM6 cell motility and invasiveness ability, when compared with control. In conclusion, this work suggests that cell surface nucleolin participates in the initiation of CCR6 pathway and biological behaviors of HCC, leading to HCC cell adhesion, migration and invasive behavior. In the clinical practice, cell surface nucleolin and CCR6 are recommended to predict poor prognosis and be used as a useful target for HCC patients.

Advances in understanding of colorectal liver metastasis and implications for the clinic

Colorectal cancer is one of the most common cancers in both the USA and Europe. Over the course of diagnosis, treatment and surveillance, up to 50% of these patients will develop metastases to their liver. In the past 20 years alone, there have been multiple advances in the management of these colorectal metastases to the liver. These advances have been made in characterization of these tumors, diagnosis and in treatment, both locally and systemically. Because of this progress, there are subsets of patients with this stage IV disease who are cured of their disease. While significant progress has been made, there still exist limitations in the management of metastatic colorectal cancer to the liver. This review outlines current strategies and highlights recent advances in the management of colorectal liver metastases.

The Increased Expression of CCL20 and CCR6 in Rectal Mucosa Correlated to Severe Inflammation in Pediatric Ulcerative Colitis

Background/Aims. The aim of this study is to clarify the differences of CCL20 and CCR6 expression, chemokine correlated to intestinal homeostasis, between pediatric and adult ulcerative colitis (UC) patients. Methods. Onehundred forty-one patients who underwent proctocolectomy were divided to two groups including childhood-onset UC (CUC, <16 years old, n = 24) and adult-onset UC (AUC, ≧16 years old, n = 117). A total of 141 formalin-fixed, paraffin-embedded tissue samples of rectum were obtained from these patients. Histological inflammation of rectum in resected specimen was evaluated by using Geboes histological assessment. In immunohistochemistry study, the CCL20 expression was evaluated by intensity and the stained area, and the CCR6 expression was evaluated by lymphocytes infiltration pattern. Results. CCL20 score and CCR6 positive lymphocytes infiltration pattern were statistically significantly correlated with histological inflammation severity of UC in all patients (P < 0.05). CCL20 and CCR6 expression in CUC were statistically significantly higher than that in AUC in all or pathologically severe cases (P < 0.05). Conclusions. CCL20 and CCR6 may play a significant role in local damage and pathological changes in UC especially pediatric patients. In the future, our understanding of the differences in CCL-CCR6 interaction between adults and children may lead to the pathogenesis of IBD.

Chemokines in tumor progression and metastasis

Chemokines play a vital role in tumor progression and metastasis. Chemokines are involved in the growth of many cancers including breast cancer, ovarian cancer, pancreatic cancer, melanoma, lung cancer, gastric cancer, acute lymphoblastic leukemia, colon cancer, non-small lung cancer, non-hodgkin's lymphoma, etc. The expression of chemokines and their receptors is altered in many malignancies and leads to aberrant chemokine receptor signaling. This review focuses on the role of chemokines in key processes that facilitate tumor progression including proliferation, senescence, angiogenesis, epithelial mesenchymal transition, immune evasion and metastasis.

Mutations in BALB mitochondrial DNA induce CCL20 up-regulation promoting tumorigenic phenotypes

mtDNA mutations are common in human cancers and are thought to contribute to the process of neoplasia. We examined the role of mtDNA mutations in skin cancer by generating fibroblast cybrids harboring a mutation in the gene encoding the mitochondrial tRNA for arginine. This somatic mutation (9821insA) was previously reported in UV-induced hyperkeratotic skin tumors in hairless mice and confers specific tumorigenic phenotypes to mutant cybrids. Microarray analysis revealed and RT-PCR along with Western blot analysis confirmed the up-regulation of CCL20 and its receptor CCR6 in mtBALB haplotype containing the mt-Tr 9821insA allele compared to wild type mtB6 haplotype. Based on reported role of CCL20 in cancer progression we examined whether the hyper-proliferation and enhanced motility of mtBALB haplotype would be associated with CCL20 levels. Treatment of both genotypes with recombinant CCL20 (rmCCL20) resulted in enhanced growth and motility of mtB6 cybrids. Furthermore, the acquired somatic alteration increased the in vivo tumor growth of mtBALB cybrids through the up-regulation of CCL20 since neutralizing antibody significantly decreased in vivo tumor growth of these cells; and tumors from anti-CCL20 treated mice injected with mtBALB cybrids showed significantly decreased CCL20 levels. When rmCCL20 or mtBALB cybrids were used as chemotactic stimuli, mtB6 cybrids showed increased motility while anti-CCL20 antibody decreased the migration and in vivo tumor growth of mtBALB cybrids. Moreover, the inhibitors of MAPK signaling and NF-κB activation inhibited CCL20 expression in mtBALB cybrids and decreased their migratory capabilities. Thus, acquired mtDNA mutations may promote tumorigenic phenotypes through up-regulation of chemokine CCL20.

Comparison of bioactivities of talactoferrin and lactoferrins from human and bovine milk

OBJECTIVES

Lactoferrin (Lf) is an iron-binding glycoprotein present in high concentration in human milk. It is a pleiotropic protein and is involved in diverse bioactivities, such as stimulation of cell proliferation and differentiation, immune competence, antimicrobial activities, anti-infection, and anticancer activities. Lf has been shown to be partly resistant to proteolysis in the gastrointestinal tract and may thus play important roles in the intestine and liver during infancy. Talactoferrin alfa (TLf) is a recombinant human Lf shown to protect against sepsis and necrotizing enterocolitis as well as cancer. Because bovine Lf (bLf) and human Lf have different amino acid composition and all 3 Lfs differ in glycosylation, they may have different functions/potency. The objective of the present study was to investigate and compare bioactivities of TLf and Lfs from human and bovine milk and thus to provide a better understanding of the bioactivities of different forms of Lf and their potential applications.

METHODS

In the present study, Caco-2 and C3A cells were used as intestine and liver models to evaluate internalization of Lfs by intestine and liver cells, effects of Lfs on cell proliferation and differentiation, growth of enteropathogenic Escherichia coli (EPEC), chemokine (C-C motif) ligand 20 (CCL20) secretion, and transforming growth factor (TGF)-β1 expression. In addition, HT-29 cells were used as a colon cancer cell model to examine the effects of Lfs on apoptosis.

RESULTS

All Lfs significantly enhanced cell proliferation and differentiation, apoptosis, CCL20 secretion, and TGF-β1 expression. They also markedly suppressed growth of EPEC. Compared with bLf, TLf showed stronger effects on suppression of EPEC growth and enhancement of TGF-β1 secretion, whereas bLf exhibited more potent effects on cell differentiation, apoptosis, and CCL20 secretion.

CONCLUSIONS

Our results demonstrate that TLf has several bioactivities similar to human Lf and bLf from milk and may play critical roles in immune and intestinal development in infants as well as having anti-cancer activities in adults. TLf and bLf may be used for different applications owing to their various potencies. TLf may preferentially be used for anti-bacterial applications, whereas bLf may be used for cancer therapy because it exhibits stronger effects on CCL20 secretion, cell differentiation, and apoptosis.

The role of toll-like receptors in colorectal cancer progression: evidence for epithelial to leucocytic transition

Toll-like receptors (TLRs) are expressed by immune cells, intestinal epithelium, and tumor cells. In the homeostatic setting, they help to regulate control over invading pathogens and maintain the epithelial lining of the large and small intestines. Aberrant expression of certain TLRs by tumor cells can induce growth inhibition while others contribute to tumorigenesis and progression. Activation of these TLRs can induce inflammation, tumor cell proliferation, immune evasion, local invasion, and distant metastasis. These TLR-influenced behaviors have similarities with properties observed in leukocytes, suggesting that tumors may be hijacking immune programs to become more aggressive. The concept of epithelial to leucocytic-transition (ELT) is proposed, akin to epithelial to mesenchymal transition, in which tumors develop the ability to activate leucocytic traits otherwise inaccessible to epithelial cells. Understanding the mechanisms of ELT could lead to novel therapeutic strategies for inhibiting tumor metastasis.

High serum macrophage inflammatory protein-3α is associated with the early recurrence or metastasis of non-small cell lung cancer following primary pulmonary resection

The present study sought to characterize the role of macrophage inflammatory protein-3α (MIP-3α) in non-small cell lung cancer (NSCLC) patients with early recurrence or metastasis after primary pulmonary resection. Follow-up examinations were conducted for 203 NSCLC patients with primary pulmonary resection for two years post-operatively, and data was also collected for 20 healthy subjects. Serum MIP-3α levels were determined prior to surgery and at post-operative days (PODs) 30, 90 and 180, and the relevant clinical and operative variables were collected. Serum MIP-3α was measured using a commercially available enzyme-linked immunosorbent assay. There were no significant differences in age, gender and histological type among all groups (P>0.05). Serum MIP-3α levels on POD 180 were significantly higher in the recurrence group than in the non-recurrence group and healthy subjects (P=0.001). There was no significant difference in the serum MIP-3α level at PODs 90 and 180 in the patients with or without adjuvant chemotherapy (P>0.05). The recurrence rate in the high serum MIP-3α level group was 41.67%, much higher than the 23.53% observed in the low level group (P=0.006). The patients with high serum levels of MIP-3α had a significantly shorter overall recurrence-free time compared with those with low levels (P=0.004). Multivariate Cox’s regression analyses showed that only serum MIP-3α level was significant, with a hazard ratio of 1.061, a 95% confidence interval of 1.044–1.078 and a P-value of 0.001. The serum MIP-3α level in the patients with liver and bone metastases were remarkably higher than those with recurrence at other sites. The high post-operative serum MIP-3α levels were associated with an increased risk of post-operative early recurrence or metastasis in the lung cancer patients, specifically in those with bone or liver metastases.

Chemokines in cancer development and progression and their potential as targeting molecules for cancer treatment

Chemokines were initially identified as bioactive substances, which control the trafficking of inflammatory cells including granulocytes and monocytes/macrophages. Moreover, chemokines have profound impacts on other types of cells associated with inflammatory responses, such as endothelial cells and fibroblasts. These observations would implicate chemokines as master regulators in various inflammatory responses. Subsequent studies have further revealed that chemokines can regulate the movement of a wide variety of immune cells including lymphocytes, natural killer cells, and dendritic cells in both physiological and pathological conditions. These features endow chemokines with crucial roles in immune responses. Furthermore, increasing evidence points to the vital effects of several chemokines on the proliferative and invasive properties of cancer cells. It is widely acknowledged that cancer develops and progresses to invade and metastasize in continuous interaction with noncancerous cells present in cancer tissues, such as macrophages, lymphocytes, fibroblasts, and endothelial cells. The capacity of chemokines to regulate both cancerous and noncancerous cells highlights their crucial roles in cancer development and progression. Here, we will discuss the roles of chemokines in carcinogenesis and the possibility of chemokine targeting therapy for the treatment of cancer.

MicroRNA-150 inhibits tumor invasion and metastasis by targeting the chemokine receptor CCR6, in advanced cutaneous T-cell lymphoma

In this study, we show that microRNA-150 (miR-150) is significantly downregulated in advanced cutaneous T-cell lymphoma (CTCL), and that this downregulation is strongly associated with tumor invasion/metastasis. Inoculation of CTCL cell lines into nonobese diabetic/Shi-scid interleukin 2γ (IL-2γ) null mice led to CTCL cell migration to multiple organs; however, prior transfection of the cells with miR-150 substantially reduced the invasion/metastasis by directly downregulating CCR6, a specific receptor for the chemokine CCL20. We also found that IL-22 and its specific receptor subunit, IL22RA1, were aberrantly overexpressed in advanced CTCL, and that production of IL-22 and CCL20 was increased in cultured CTCL cells. IL22RA1 knockdown specifically reduced CCL20 production in CTCL cells, suggesting that IL-22 upregulation may activate the production of CCL20 and its binding to CCR6, thereby enhancing the multidirectional migration potential of CTCL cells. CTCL cells also exhibited nutrition- and CCL20-dependent chemotaxis, which were inhibited by miR-150 transfection or CCR6 knockdown. From these findings, we conclude that, in the presence of continuous CCR6 upregulation accompanied by miR-150 downregulation, IL-22 activation leads to continuous CCL20-CCR6 interaction in CTCL cells and, in turn, autocrine metastasis to distal organs. This suggests miR-150, CCL20, and CCR6 could be key targets for the treatment of advanced CTCL.

Chemokine receptor CCR6 expression is regulated by miR-518a-5p in colorectal cancer cells

Background

Recently, involvement of the chemokine/receptor system CCL20/CCR6 in colorectal cancer (CRC) progression was shown. Here, we analyzed the functional interaction of miRNA-518-5p (miR-518a-5p) with CCR6 and its impact on CCR6 expression in CRC cells.

Methods

MiR-518a-5p was identified by computer software to potentially interact with CCR6. Hence, functional implications of miR-518a-5p with the 3′UTR of CCR6 were analyzed using the Dual Luciferase Reporter assay system. Confirmation of the predicted target site for miR-518a-5p was achieved by site-directed mutagenesis of the seed sequence in the 3′UTR of CCR6 and subsequent application of the mutated seed sequence in a luciferase assay with miR-518a-5p mimics. Accordingly, two CRC cell lines (Caco-2 and HT-29) were transfected with miR-518a-5p miRNA mimics and gene and protein expression of CCR6 was monitored using qRT PCR and immunocytochemistry, respectively.

Results

Addition of miR-518a-5p led to significant down-regulation of luciferase activity (P < 0.05), which was significantly reversed in a reporter test system containing the mutated seed sequences in the 3′UTR of CCR6. Following transfection of CRC cell lines with miR-518a-5p mimics and subsequent monitoring of CCR6 expression showed significant down-regulation of CCR6 mRNA and CCR6 protein expression in both CRC cell lines under investigation (P < 0.05).

Conclusions

We have shown that miR-518a-5p functionally interacts with CCR6 and that transfection of CRC cells with miR-518a-5p leads to significant CCR6 down-regulation. Consequently, CCR6 expression is regulated by miR-518a-5p in CRC cells indicating that regulation of CCR6 expression by miR-518a-5p might be a regulatory mechanism involved in CRC pathogenesis.

Autophagy facilitates TLR4- and TLR3-triggered migration and invasion of lung cancer cells through the promotion of TRAF6 ubiquitination

Autophagy contributes to the pathogenesis of cancer, whereas toll-like receptors (TLRs) also play an important role in cancer development and immune escape. However, little is known about the potential interaction between TLR signaling and autophagy in cancer cells. Here we show that autophagy induced by TLR4 or TLR3 activation enhances various cytokine productions through promoting TRAF6 (TNF receptor-associated factor 6, E3 ubiquitin protein ligase) ubiquitination and thus facilitates migration and invasion of lung cancer cells. Stimulation of TLR4 and TLR3 with lipopolysaccharide (LPS) and polyinosinic-polycytidylic acid [poly(I:C)] respectively triggered autophagy in lung cancer cells. This was mediated by the adaptor protein, toll-like receptor adaptor molecule 1 (TICAM1/TRIF), and was required for TLR4- and TLR3-induced increases in the production of IL6, CCL2/MCP-1 [chemokine (C-C motif) ligand 2], CCL20/MIP-3α [chemokine (C-C motif) ligand 20], VEGFA (vascular endothelial growth factor A), and MMP2 [matrix metallopeptidase 2 (gelatinase A, 72 kDa gelatinase, 72 kDa type IV collagenase)]. These cytokines appeared to be necessary for enhanced migration and invasion of lung cancer cells upon TLR activation. Remarkably, inhibition of autophagy by chemical or genetic approaches blocked TLR4- or TLR3-induced Lys63 (K63)-linked ubiquitination of TRAF6 that was essential for activation of MAPK and NFKB (nuclear factor of kappa light polypeptide gene enhancer in B-cells) pathways, both of which were involved in the increased production of the cytokines. Collectively, these results identify induction of autophagy by TLR4 and TLR3 as an important mechanism that drives lung cancer progression, and indicate that inhibition of autophagy may be a useful strategy in the treatment of lung cancer.

Correlation of CCL20 expression in rectal mucosa with the development of ulcerative colitis-associated neoplasia

Chronic inflammation increases the risk of developing several gastrointestinal malignancies. Chemokines that are produced by colonic epithelial cells play significant roles in the maintenance and repair of the epithelial barrier. The present study aimed to clarify whether the expression of CCL20 and its receptor, CCR6, was correlated with the development of ulcerative colitis (UC)-associated neoplasia. A total of 93 patients with UC who underwent proctocolectomies were enrolled in the present study. Immunohistochemical analysis for CCL20 and CCR6 expression in the rectal mucosa was performed and the correlation between expression and the pathogenesis of UC-associated neoplasia was investigated. A total of 16 (17.2%) patients presented with UC-associated neoplasia. The immunohistochemistry (IHC) score for CCL20 was significantly increased in the patients with a mild form of the disease (P=0.0363). The IHC score for CCL20 expression in the patients with UC-associated neoplasia was higher compared with the patients without neoplasia (P=0.0294). In contrast, there was no significant correlation between CCR6 expression and the clinicopathological variables. The logistic regression analysis revealed that a high IHC score for CCL20 expression in the rectal mucosa and a disease duration of more than eight years were significantly correlated with the development of UC-associated neoplasia (P<0.05). The results suggest that an evaluation of CCL20 expression in the rectal mucosa may be useful to identify patients who are at a high risk for developing UC-associated neoplasia. However, a selection bias existed in the present study due to the fact that the patient population that was enrolled was not representative of a typical surveillance patient population.

Sphingosine kinase 1 regulates tumor necrosis factor-mediated RANTES induction through p38 mitogen-activated protein kinase but independently of nuclear factor κB activation

Sphingosine kinase 1 (SK1) produces the pro-survival sphingolipid sphingosine 1-phosphate and has been implicated in inflammation, proliferation, and angiogenesis. Recent studies identified TRAF2 as a sphingosine 1-phosphate target, implicating SK1 in activation of the NF-κB pathway, but the functional consequences of this connection on gene expression are unknown. Here, we find that loss of SK1 potentiates induction of the chemokine RANTES (regulated on activation, normal T cell expressed and secreted; also known as CCL5) in HeLa cells stimulated with TNF-α despite RANTES induction being highly dependent on the NF-κB pathway. Additionally, we find that SK1 is not required for TNF-induced IKK phosphorylation, IκB degradation, nuclear translocation of NF-κB subunits, and transcriptional NF-κB activity. In contrast, loss of SK1 prevented TNF-induced phosphorylation of p38 MAPK, and inhibition of p38 MAPK, like SK1 knockdown, also potentiates RANTES induction. Finally, in addition to RANTES, loss of SK1 also potentiated the induction of multiple chemokines and cytokines in the TNF response. Taken together, these data identify a potential and novel anti-inflammatory function of SK1 in which chemokine levels are suppressed through SK1-mediated activation of p38 MAPK. Furthermore, in this system, activation of NF-κB is dissociated from SK1, suggesting that the interaction between these pathways may be more complex than currently thought.

Polyisoprenylated methylated protein methyl esterase is both sensitive to curcumin and overexpressed in colorectal cancer: implications for chemoprevention and treatment

Inhibition of PMPMEase, a key enzyme in the polyisoprenylation pathway, induces cancer cell death. In this study, purified PMPMEase was inhibited by the chemopreventive agent, curcumin, with a K(i) of 0.3 μM (IC50 = 12.4 μM). Preincubation of PMPMEase with 1 mM curcumin followed by gel-filtration chromatography resulted in recovery of the enzyme activity, indicative of reversible inhibition. Kinetics analysis with N-para-nitrobenzoyl-S-trans,trans-farnesylcysteine methyl ester substrate yielded K M values of 23.6 ± 2.7 and 85.3 ± 15.3 μM in the absence or presence of 20 μM curcumin, respectively. Treatment of colorectal cancer (Caco2) cells with curcumin resulted in concentration-dependent cell death with an EC50 of 22.0 μg/mL. PMPMEase activity in the curcumin-treated cell lysate followed a similar concentration-dependent profile with IC50 of 22.6 μg/mL. In colorectal cancer tissue microarray studies, PMPMEase immunoreactivity was significantly higher in 88.6% of cases compared to normal colon tissues (P < 0.0001). The mean scores ± SEM were 91.7 ± 11.4 (normal), 75.0 ± 14.4 (normal adjacent), 294.8 ± 7.8 (adenocarcinoma), and 310.0 ± 22.6 (mucinous adenocarcinoma), respectively. PMPMEase overexpression in colorectal cancer and cancer cell death stemming from its inhibition is an indication of its possible role in cancer progression and a target for chemopreventive agents.

Recruitment of CCR6-expressing Th17 cells by CCL20 secreted from plasmin-stimulated macrophages

In the present study, monocyte-derived human macrophages were differentiated from buffy coats. Naïve CD4⁺ T-cells enriched from peripheral blood mononuclear cells using anti-CD4 magnetic beads and the autoMACS separation system were polarized under T-helper 17 (Th17)-promoting conditions for 6 days to get Th17 cells. The frequency of Th17 cell differentiation and the expression of C-C chemokine receptor type 6 (CCR6) on Th17 cells were investigated by flow cytometry. Plasmin-triggered induction of macrophage inflammatory protein-3alpha/C-C chemokine ligand 20 (CCL20) genes in macrophages was assessed by reverse transcription-polymerase chain reaction, and secreted protein levels were measured by enzyme-linked immunosorbent assay. Th17 cell migration induced by CCL20 secreted from plasmin-stimulated macrophages was tested in vitro by chemotaxis using a transwell system. These results demonstrate that plasmin triggers the expression of chemokine CCL20 messenger RNA and the release of CCL20 protein in human monocyte-derived macrophages, which critically depend on the proteolytic activity of plasmin and activation of p38 mitogen-activated protein kinase and nuclear factor-kappaB signaling pathways. Expression of CCR6 was detected on 87.23 ± 8.6% of Th17 cells in vitro. Similar to chemotaxis triggered by recombinant human CCL20, supernatants collected from plasmin-stimulated macrophage-induced chemotactic migration of Th17 cells, which could be inhibited by an anti-CCL20 neutralizing antibody. These results suggest that plasmin generated in inflamed tissues might elicit production of chemokine CCL20 by human macrophages leading to the recruitment of CCR6 positive Th17 cells to the inflammatory sites.

The expression of chemokine receptors CCR6, CXCR2 and CXCR4 is not organ-specific for distant metastasis in colorectal cancer: a comparative study

AIMS

The liver and lung are the organs most commonly affected by metastasis in colorectal cancer (CRC), and the interaction of chemokines and chemokine receptors (CKRs) plays an important role in the metastatic process. The aim of this study was to investigate the organ specificity of CKRs in CRC distant metastasis.

METHODS AND RESULTS

Surgical specimens of primary tumours from 46 patients with metachronous distant metastases were retrieved retrospectively (20 lung metastases; 26 liver metastases). As a control, the records of 29 patients without distant metastases were randomly retrieved from our database, and their specimens were reassessed. The expression rates of CKRs, including CCR6, CXCR2, and CXCR4, were determined by immunohistochemistry, and were compared among the groups. The expression rates of CCR6 and CXCR2 were both significantly higher in the metastasis group than in the non-metastasis group (P < 0.05), but there was no statistical difference between the lung metastasis and liver metastasis subgroups. The expression of CXCR4 was not significantly different between the metastasis and non-metastasis groups. Multivariable analysis suggested that preoperative serum carcinoembryonic antigen level, CCR6 and CXCR2 were independent factors associated with distant metastasis.

CONCLUSIONS

The expression of CCR6 and CXCR2 in CRC could predict metachronous distant metastasis, but they have no organ specificity for metastasis.

Impaired migration of IgA-secreting cells to colon adenocarcinomas

Local inflammation is a strong risk factor for the development of gastrointestinal adenocarcinomas. Mucosal regulatory T cells and IgA-secreting cells both contribute to reduce inflammatory responses, and their recruitment to tissues is dependent on local production of chemokines. More specifically, IgA-secreting cells are recruited to mucosal tissues by CCL28 signalling through CCR10. Here, we examined the recruitment of IgA-secreting plasma cells to tumor-associated mucosa in patients suffering from colon adenocarcinoma. Flow cytometric analyses of single cell suspensions from tumor-associated and unaffected colon mucosa showed a marked decrease in CD19(+)CD38(high)IgA(+) plasmablasts in the tumor-associated mucosa, while the total frequencies of B and T cells were similar. This finding was confirmed in ELISPOT assays, demonstrating a 64 % reduction in the frequencies of IgA-secreting cells among cells from the tumor-associated mucosa. The few IgA(+) plasmablasts present in the tumor did not express CCR10, and functional migration assays demonstrated that IgA-secreting cells from tumor-associated mucosa did not migrate in response to CCL28. Taken together, our results show an impaired migration of IgA-secreting cells to colon tumors, presumably caused by a decreased production of CCL28 in the tumor. The lack of local IgA antibodies may lead to impaired barrier function and increased bacterial colonization, driving further inflammatory responses and promoting tumor growth.

The role of CXCR3 and CXCR4 in colorectal cancer metastasis

Chemokines and their receptors play key roles in leukocyte trafficking and are also implicated in cancer metastasis. We previously demonstrated that forced expression of CXCR3 promotes colon cancer metastasis preferentially to the draining lymph nodes (LNs), with poor prognosis. Using clinical colorectal cancer (CRC) samples, here, we show that expressions of CXCR3 and CXCR4 are significantly higher in metastatic foci within LNs and liver compared to primary tumors, whereas ligands for CXCR3 and CXCR4 are not. We also have demonstrated that some human CRC cell lines constitutively express both CXCR3 and CXCR4, and that activation of CXCR3 strengthens the CXCR4-mediated cell migration in vitro in a synergistic manner. By constructing SW620 cell lines with reduced expression of CXCR3 and/or CXCR4 using microRNA, we investigated in vivo metastatic activities in a mouse rectal transplantation model. Six weeks after inoculation, CXCR3-, CXCR4-, and CXCR3/CXCR4 double-knockdowns significantly reduced metastasis to LNs, liver and lungs, compared to the control (p < 0.05). Importantly, its suppressive effect on LN metastasis was significantly stronger in CXCR3- and CXCR3/CXCR4 double-knockdowns. In addition, CXCR3- and CXCR3/CXCR4 double-knockdowns significantly decreased the dissemination of cancer cells to liver and lungs, even after 2 weeks. These results indicate that targeting CXCR3 and CXCR4 can be a promising therapy against CRC metastasis.

Highly synergistic effect of sequential treatment with epigenetic and anticancer drugs to overcome drug resistance in breast cancer cells is mediated via activation of p21 gene expression leading to G2/M cycle arrest

Epigenetic alterations such as aberrant DNA methylation and histone modifications contribute substantially to both the cause and maintenance of drug resistance. These epigenetic changes lead to silencing of tumor suppressor genes involved in key DNA damage-response pathways, making drug-resistant cancer cells nonresponsive to conventional anticancer drug therapies. Our hypothesis is that treating drug-resistant cells with epigenetic drugs could restore the sensitivity to anticancer drugs by reactivating previously silenced genes. To test our hypothesis, we used drug-resistant breast cancer cells (MCF-7/ADR) and two epigenetic drugs that act via different mechanisms--5-aza-2'-deoxycytidine (decitabine, DAC), a demethylating agent, and suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor--in combination with doxorubicin. We show that the sequential treatment of resistant cells, first with an epigenetic drug (DAC), and then with doxorubicin, induces a highly synergistic effect, thus reducing the IC(50) of doxorubicin by several thousand fold. The sequential treatment caused over 90% resistant cells to undergo G2/M cell cycle arrest, determined to be due to upregulation of p21(WAF1/CIP1) expression, which is responsible for cell-cycle regulation. The induction of p21(WAF1/CIP1) correlated well with the depletion of DNA methyltransferase1 (DNMT1), an enzyme that promotes methylation of DNA, suggesting that the p21(WAF1/CIP1) gene may have been methylated and hence is inactive in MCF-7/ADR cells. Microarray analysis shows expression of several tumor suppressor genes and downregulation of tumor promoter genes, particularly in sequentially treated resistant cells. Sequential treatment was found to be significantly more effective than simultaneous treatment, and DAC was more effective than SAHA in overcoming doxorubicin resistance. Synergistic effect with sequential treatment was also seen in drug-sensitive breast cancer cells, but the effect was significantly more pronounced in resistant cells. In conclusion, the sequential treatment of an epigenetic drug in combination with doxorubicin induces a highly synergistic effect that overcomes doxorubicin resistance in breast cancer cells.

A meta-analysis comparing simultaneous versus delayed resections in patients with synchronous colorectal liver metastases

INTRODUCTION

The traditional surgical management for patients presenting with synchronous colorectal liver metastases (SCLM) has been a delayed resection. However, in some centres, there has been a shift in favour of 'simultaneous' resections. The aim of this study was to use a meta-analytical model to compare the short-term and long-term outcomes in patients with synchronous colorectal liver metastases (SCLM) undergoing simultaneous resections versus delayed resections.

METHOD

Comparative studies published between 1991 and 2010 were included. Evaluated endpoints were intra-operative parameters, post-operative parameters, post-operative adverse events and survival. A random-effects meta-analytical model was used and sensitivity analysis performed to account for bias in patient selection.

RESULTS

Twenty-four non-randomized studies were included, reporting on 3159 patients of which 1381 (43.7%) had simultaneous resections and 1778 (56.3%) had delayed resections. The bilobar distribution (P = 0.01), size of liver metastases (P < 0.001) and the proportion of major liver resections (P < 0.001) was found to be higher in the delayed resection group compared to the simultaneous resection group. There was no significant difference in operative blood loss (95% CI, -279.28, 22.53; P = 0.1) or duration of surgery (WMD -23.83, 95% CI, -85.04, 37.38; P = 0.45). Duration of hospital stay was significantly reduced in simultaneous resections by 5.6 days (95% CI: 2.4-8.9 days, P = 0.007) No significant differences in post-operative complications (36% vs 37%, P = 0.27), overall survival (HR 1.00, 95% CI 0.86-1.15, P = 0.96) or disease free survival (HR 0.85, 95% CI 0.71-1.02, P = 0.08) were found. Sensitivity analysis revealed that these findings were consistent for the duration of hospital stay, post-operative complications, overall survival and disease free survival.

CONCLUSION

This study demonstrates that the selection criteria for patients undergoing simultaneous or delayed resections differs resulting in a discrepancy in the metastatic disease severity being compared between the two groups. The comparable intra-operative parameters, post-operative complications and survival found between the two groups suggest that delayed resections may result in better outcomes. Similarly, the reduced length of hospital stay in simultaneous resections may only be as a result of the reduced disease severity in this group. Simultaneous resections can only be recommended in patients with limited hepatic disease until prospective studies comparing similar disease burdens between the two resection groups are available.

The tumour biology of synchronous and metachronous colorectal liver metastases: a systematic review

Forty to fifty percent of colorectal cancer (CRC) patients develop colorectal liver metastases (CLM) that are either synchronous or metachronous in presentation. Clarifying whether there is a biological difference between the two groups of liver metastases or their primaries could have important clinical implications. A systematic review was performed using the following resources: MEDLINE from PubMed (1950 to present), Embase, Cochrane and the Web of Knowledge. Thirty-one articles met the inclusion criteria. The review demonstrated that the majority of studies found differences in molecular marker expression between colorectal liver metastases and their respective primaries in both the synchronous and metachronous groups. Studies investigating genetic aberrations demonstrated that the majority of changes in the primary tumour were 'maintained' in the colorectal liver metastases. A limited number of studies compared the primary tumours of the synchronous and metachronous groups and generally demonstrated no differences in marker expression. Although there were conflicting results, the colorectal liver metastases in the synchronous and metachronous groups demonstrated some differences in keeping with a more aggressive tumour subtype in the synchronous group. This review suggests that biological differences may exist between the liver metastases of the synchronous and metachronous groups. Whether there are biological differences between the primaries of the synchronous and metachronous groups remains undetermined due to the limited number of studies available. Future research is required to determine whether differences exist between the two groups and should include comparisons of the primary tumours.

Macrophage inflammatory protein-3 alpha (MIP-3a) is a novel serum prognostic marker in patients with colorectal cancer

BACKGROUND AND OBJECTIVES

A significant prognostic difference exists among metastatic colorectal cancer (CRC) patients despite of any treatments. We identify the specific cytokines related to prognosis of metastatic CRC and assess their prognostic significance.

METHODS

Stage IV CRC patients were divided into two groups according to their prognosis. Difference in serum cytokine level between these groups was determined by the cytokine array. Among the specific cytokines, macrophage inflammatory protein-3 alpha (MIP-3a) was measured using an enzyme-linked immunosorbent assay (ELISA) in the sera of 242 CRC patients.

RESULTS

Several cytokines related to prognostic difference in stage IV CRC were identified. The median MIP-3a level (28.2 pg/ml) was used as a cut-off value. Increased MIP-3a was significantly associated with synchronous liver metastases and age. In univariate analysis, high MIP-3a was correlated with poor prognosis (P < 0.001). Multivariate analysis showed that high MIP-3a was an independent prognostic factor in all CRC patients (P < 0.001). In subgroup analysis, high MIP-3a was significantly associated with poor survival in patients with stage II, II/III, and IV CRC, respectively.

CONCLUSIONS

Serum MIP-3a is not only an independent prognostic factor, but also an independent predictive factor for liver metastasis, which may guide the decision making of metastatic CRC patients.

High expression of CCL20 is associated with poor prognosis in patients with hepatocellular carcinoma after curative resection

INTRODUCTION

Chemokine ligand 20 (CCL20) plays an important role in the carcinogenesis, invasion, and progression of malignancies. This study aimed to investigate the prognostic significance of CCL20 in patients with hepatocellular carcinoma (HCC) after curative resection.

METHODS

Expression of CCL20 was evaluated by immunohistochemistry in tumor tissue from 125 patients who underwent curative resection of HCC. The relationship between CCL20 expression and clinicopathologic features was analyzed. Univariate and multivariate analyses were performed to evaluate its predictive value for tumor recurrence and survival of HCC patients.

RESULTS

CCL20 expression was verified in all tumor specimens. CCL20 expression was associated with tumor size (P = 0.002), tumor number (P = 0.031), vascular invasion (P = 0.003), tumor differentiation (P = 0.024), and tumor recurrence (P < 0.001). Patients with high CCL20 expression had poorer recurrence-free survival and overall survival (both P < 0.001) than those with low CCL20 expression. Multivariate analysis showed CCL20 expression was an independent predictor of tumor recurrence (Hazard ratio 3.934, P = 0.002), recurrence-free survival (Hazard ratio 2.573, P = 0.001), and overall survival (Hazard ratio 2.930, P = 0.001).

CONCLUSION

CCL20 expression was associated with tumor recurrence and survival of HCC patients. It may be used to predict prognosis of patients with HCC and may be a new target of postoperative adjuvant therapy.

Human intestinal mast cells are a potent source of multiple chemokines

Mast cells are key effector cells of immediate type allergic reactions. Upon activation they release a broad array of pre-stored and de novo synthesized mediators including immunoregulatory cytokines and chemokines. Here, we analyzed the chemokine profile expressed by mature human mast cells. Human mast cells were isolated from intestinal tissue and cultured with stem cell factor (SCF) in the presence or absence of IL-4 for 10d. Cells were stimulated by cross-linking of the high affinity IgE receptor (FcεRI) and/or by SCF. Chemokine and chemokine receptor mRNA expression was determined by real-time RT-PCR and chemokine release was measured by multiplex bead immunoassay. Out of 43 chemokines and 19 chemokine receptors human intestinal mast cells express 27 chemokines and nine chemokine receptors. Twelve chemokines (CCL1, CCL2, CCL3, CCL4, CCL5, CCL7, CCL18, CCL20, CXCL2, CXCL3, CXCL8, and XCL1) were more than four-fold up-regulated in response to FcεRI cross-linking. Combination of pre-culture with IL-4 and/or stimulation with SCF in addition to FcεRI cross-linking further increased the antigen-dependent expression of mRNA for most chemokines. In contrast, the expression of CCL20, CXCL2, and CXCL3 was strongly inhibited by IL-4 treatment. In conclusion, human intestinal mast cells express a broad spectrum of different chemokines underlining their important role as immunoregulatory cells. Furthermore, combined treatment with IL-4 and SCF increases the antigen-mediated expression and release of multiple chemokines, but IL-4 priming inhibits the expression of CCL20, CXCL2, and CXCL3.

CCL20 is increased in hypercholesterolemic subjects and is upregulated by LDL in vascular smooth muscle cells: role of NF-κB

OBJECTIVE

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

METHODS AND 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.

CONCLUSION

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

Chemokines in tumor development and progression

Chemokines were originally identified as mediators of the inflammatory process and regulators of leukocyte trafficking. Subsequent studies revealed their essential roles in leukocyte physiology and pathology. Moreover, chemokines have profound effects on other types of cells associated with the inflammatory response, such as endothelial cells and fibroblasts. Thus, chemokines are crucial for cancer-related inflammation, which can promote tumor development and progression. Increasing evidence points to the vital effects of several chemokines on the proliferative and invasive properties of tumor cells. The wide range of activities of chemokines in tumorigenesis highlights their roles in tumor development and progression.

Uncoordinated regulation of atrial natriuretic factor and brain natriuretic peptide in lipopolysaccharide-treated rats

We investigated the expression and secretion of the natriuretic peptides (NPs) ANF and BNP in lipopolysaccharide (LPS)-induced sepsis and its association with cytokines and other biologically active substances. LPS treatment increased plasma levels of ANF and BNP. The latter increase was larger than the increase in plasma ANF. LPS also increased cardiac content and gene expression of BNP but not of ANF. LPS treatment significantly increased gene expression cytokines, chemokines and proteases, which significantly correlated with BNP gene expression. SB203580, a p38 MAP kinase inhibitor, inhibited the elevation of BNP in plasma. The present work suggests that during inflammation, BNP gene expression and secretion is uniquely related to changes in gene expression in the absence of hemodynamic changes and hence differentiates ANF and BNP as biomarkers of cardiac disease.

Radiation-induced damage in different segments of the rat intestine after external beam irradiation of the liver

INTRODUCTION

The out-of-field effects on the intestine, caused by radiation treatment of a parenchymatous organ, have not previously been studied.

METHODS

A single dose of 25Gy was administered percutaneously to the liver of male Wistar rats after a planning CT-scan. Sham-irradiated animals served as controls. At 1, 6, 24, 96h, 1.5 and 3months the duodenum, jejunum, ileum and distal colon were removed, washed and deep-frozen or prepared for paraffin staining.

RESULTS

All animals survived the treatment. Epithelial cell damage occurred in all small-intestinal segments. However, prolonged denudation of the villi together with destruction of the crypt lining was only observed in the ileum, resulting in deficient regeneration. In the colon, changes were minor. Radiation mucositis with granulocyte (MP0+) infiltration was seen from 1 to 24h in the duodenum and jejunum, when ED1+ macrophages, CD3+ T-lymphocytes, and CD34+ hematopoietic precursor cells were recruited, accompanied by an increase in the chemokines MCP-1, MIP-1α, MIP3α and Il-8. In the ileum, early granulocyte infiltration was delayed but continuous. Recruitment of macrophages and lymphocytes was deficient and induction of chemokines as of the adhesion molecules PECAM-1, ICAM-1 was lacking.

CONCLUSION

Post-irradiation damage to the ileum was delayed and followed by an altered repair process with structural changes of the villi. The observed changes might result from a higher sensitivity to oxidative stress mechanisms with subsequent damage of the regenerative capacity of the crypt-villus axis, accompanied by a sustained "inflammatory response" and vascular damage with a lack of regeneratory cell recruitment.

Differential gene expression from microarray analysis distinguishes woven and lamellar bone formation in the rat ulna following mechanical loading

Formation of woven and lamellar bone in the adult skeleton can be induced through mechanical loading. Although much is known about the morphological appearance and structural properties of the newly formed bone, the molecular responses to loading are still not well understood. The objective of our study was to use a microarray to distinguish the molecular responses between woven and lamellar bone formation induced through mechanical loading. Rat forelimb loading was completed in a single bout to induce the formation of woven bone (WBF loading) or lamellar bone (LBF loading). A set of normal (non-loaded) rats were used as controls. Microarrays were performed at three timepoints after loading: 1 hr, 1 day and 3 days. Confirmation of microarray results was done for a select group of genes using quantitative real-time PCR (qRT-PCR). The micorarray identified numerous genes and pathways that were differentially regulated for woven, but not lamellar bone formation. Few changes in gene expression were evident comparing lamellar bone formation to normal controls. A total of 395 genes were differentially expressed between formation of woven and lamellar bone 1 hr after loading, while 5883 and 5974 genes were differentially expressed on days 1 and 3, respectively. Results suggest that not only are the levels of expression different for each type of bone formation, but that distinct pathways are activated only for woven bone formation. A strong early inflammatory response preceded an increase in angiogenic and osteogenic gene expression for woven bone formation. Furthermore, at later timepoints there was evidence of bone resorption after WBF loading. In summary, the vast coverage of the microarray offers a comprehensive characterization of the early differences in expression between woven and lamellar bone formation.

Modulation of chemotactic and pro-inflammatory activities of endothelial progenitor cells by hepatocellular carcinoma

Endothelial progenitor cells (EPCs) participate in the neovascularization processes in the development of hepatocellular carcinoma (HCC). We investigated whether interactions between EPCs and HCC cells affect chemotactic and pro-inflammatory activities of EPCs. Two distinct phenotypes of circulating EPCs, i.e., myeloid-derived EPCs (colony forming unit-endothelial cells, CFU-ECs) and outgrowth EPCs (endothelial-colony forming cells, ECFCs), were co-cultured with Huh7 and Hep3B cells by using transwell chamber and IBIDI(TM) Culture-Inserts and μ-slide plates. Transwell and horizontal migration/invasion assays and time-lapse microscopy were used to monitor and analyze the migration and invasion of EPCs induced by these HCC cells. A human cytokine antibody array was used to compare protein expression profiles in EPCs and HCC cells. Flow cytometry and electromobility shift analysis were used to detect nuclear factor-κB (NF-κB)-DNA binding activity and pro-inflammatory adhesion molecule expression in EPCs. Ectopic full-length CC chemokine receptor 6 (CCR6) plasmid was used to transfect into ECFCs to investigate the role of CCR6 in HCC-induced EPC migration and invasion. The results show that co-culture with Huh7 and Hep3B cells induces the expression of endothelial cell (EC) markers KDR, Flt1, CD31 and VE-cadherin in CFU-ECs, but down-regulates the expressions of CD31 and VE-cadherin in ECFCs. These HCC cells induce migration and invasion of CFU-ECs, but not ECFCs, and do not affect the cell cycle distribution in these EPCs. Cytokine protein array identifies macrophage inflammatory protein-3α (MIP-3α) produced by HCC cells as a critical factor responsible for the HCC-induced chemotaxis of CFU-ECs, which highly express the specific MIP-3α counterreceptor CCR6. Overexpressing CCR6 in ECFCs significantly increases their chemotaxis in response to HCC cells. Co-culturing EPCs with HCC cells results in decreases in NF-κB binding activity and hence intracellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin expressions in EPCs. Our results indicate that HCC cells exert differential effects on CFU-ECs and ECFCs, with increased chemotaxis for CFU-ECs, but not ECFCs. This HCC-induced chemotaxis of CFU-ECs is mediated by MIP-3α produced by HCC cells, which targets to CCR6 on CFU-ECs. Tumors may provide a humoral microenvironment to attenuate the pro-inflammatory activity of EPCs, which might be associated with the tumor escape mechanism.

miR-21 functionally interacts with the 3'UTR of chemokine CCL20 and down-regulates CCL20 expression in miR-21 transfected colorectal cancer cells

As deregulation of miRNAs and chemokine CCL20 was shown to play a role in colorectal cancer (CRC) pathogenesis, we analyzed the functional interactions of candidate miRNAs with CCL20 mRNA. After target prediction software programs indicated a role for miR-21 in CCL20 regulation, we applied the luciferase reporter assay system to demonstrate that miR-21 functionally interacts with the 3'UTR of CCL20 mRNA and down-regulates CCL20 in miR-21 mimic transfected CRC cell lines (Caco-2, SW480 and SW620). Thus, regulation of CCL20 expression by miR-21 might be a regulatory mechanism involved in progression of CRC.