CCR6/CCL20 chemokine expression profile in distinct colorectal malignancies

Altered expression of cytokines, chemokines, growth factors, and soluble receptors in patients with colorectal cancer, and correlation with treatment outcome

Insofar as they play an important role in the pathogenesis of colorectal cancer (CRC), this study analyzes the serum profile of cytokines, chemokines, growth factors, and soluble receptors in patients with CRC and cancer-free controls as possible CRC signatures. Serum levels of 65 analytes were measured in patients with CRC and age- and sex-matched cancer-free controls using the ProcartaPlex Human Immune Monitoring 65-Plex Panel. Of the 65 tested analytes, 8 cytokines (CSF-3, IFN-γ, IL-12p70, IL-18, IL-20, MIF, TNF-α and TSLP), 8 chemokines (fractalkine, MIP-1β, BLC, Eotaxin-1, Eotaxin-2, IP-10, MIP-1a, MIP-3a), 2 growth factors (FGF-2, MMP-1), and 4 soluble receptors (APRIL, CD30, TNFRII, and TWEAK), were differentially expressed in CRC. ROC analysis confirmed the high association of TNF-α, BLC, Eotaxin-1, APRIL, and Tweak with AUC > 0.70, suggesting theranostic application. The expression of IFN-γ, IL-18, MIF, BLC, Eotaxin-1, Eotaxin-2, IP-10, and MMP1 was lower in metastatic compared to non-metastatic CRC; only AUC of MIF and MIP-1β were > 0.7. Moreover, MDC, IL-7, MIF, IL-21, and TNF-α are positively associated with tolerance to CRC chemotherapy (CT) (AUC > 0.7), whereas IL-31, Fractalkine, Eotaxin-1, and Eotaxin-2 were positively associated with resistance to CT. TNF-α, BLC, Eotaxin-1, APRIL, and Tweak may be used as first-line early detection of CRC. The variable levels of MIF and MIP-1β between metastatic and non-metastatic cases assign prognostic nature to these factors in CRC progression. Regarding tolerance to CT, MDC, IL-7, MIF, IL-21, and TNF-α are key when down-regulated or resistant to treatment is observed.

SMAD4 Suppresses Colitis-associated Carcinoma Through Inhibition of CCL20/CCR6-mediated Inflammation

BACKGROUND & AIMS

We previously reported that colon epithelial cell silencing of Smad4 increased epithelial expression of inflammatory genes, including the chemokine c-c motif chemokine ligand 20 (CCL20), and increased susceptibility to colitis-associated cancer. Here, we examine the role of the chemokine/receptor pair CCL20/c-c motif chemokine receptor 6 (CCR6) in mediating colitis-associated colon carcinogenesis induced by SMAD4 loss.

METHODS

In silico analysis of SMAD4, CCL20, and CCR6 messenger RNA expression was performed on published transcriptomic data from human ulcerative colitis (UC), and colon and rectal cancer samples. Immunohistochemistry for CCL20 and CCR6 was performed on human tissue microarrays comprising human UC-associated cancer specimens, Mice with conditional, epithelial-specific Smad4 loss with and without germline deletion of the Ccr6 gene were subjected to colitis and followed for up to 3 months. Tumors were quantified histologically, and immune cell populations were analyzed by flow cytometry and immunostaining.

RESULTS

In human UC-associated cancers, loss of epithelial SMAD4 was associated with increased CCL20 expression and CCR6+ cells. SMAD4 loss in mouse colon epithelium led to enlarged gut-associated lymphoid tissues and recruitment of immune cells to the mouse colon epithelium and stroma, particularly T regulatory, Th17, and dendritic cells. Loss of CCR6 abrogated these immune responses and significantly reduced the incidence of colitis-associated tumors observed with loss of SMAD4 alone.

CONCLUSIONS

Regulation of mucosal inflammation is central to SMAD4 tumor suppressor function in the colon. A key downstream node in this regulation is suppression of epithelial CCL20 signaling to CCR6 in immune cells. Loss of SMAD4 in the colon epithelium increases CCL20 expression and chemoattraction of CCR6+ immune cells, contributing to greater susceptibility to colon cancer.

A comprehensive bioinformatics analysis to identify potential prognostic biomarkers among CC and CXC chemokines in breast cancer

Breast cancer (BC) is a major human health problem due to its increasing incidence and mortality rate. CC and CXC chemokines are associated with tumorigenesis and the progression of many cancers. Since the prognostic values of CC and CXC families' expression in various types of cancers are becoming increasingly evident, we aimed to conduct a comprehensive bioinformatics analysis elucidating the prognostic values of the CC and CXC families in BC. Therefore, TCGA, UALCAN, Kaplan–Meier plotter, bc-GenExMiner, cBioPortal, STRING, Enrichr, and TIMER were utilized for analysis. We found that high levels of CCL4/5/14/19/21/22 were associated with better OS and RFS, while elevated expression of CCL24 was correlated with shorter OS in BC patients. Also, high levels of CXCL9/13 indicated longer OS, and enhanced expression of CXCL12/14 was linked with better OS and RFS in BC patients. Meanwhile, increased transcription levels of CXCL8 were associated with worse OS and RFS in BC patients. In addition, our results showed that CCL5, CCL8, CCL14, CCL20, CCL27, CXCL4, and CXCL14 were notably correlated with the clinical outcomes of BC patients. Our findings provide a new point of view that may help the clinical application of CC and CXC chemokines as prognostic biomarkers in BC.

Chemokines and chemokine receptors in colorectal cancer; multifarious roles and clinical impact

Colorectal cancer (CRC) is considered the second cause of cancer death worldwide. The early diagnosis plays a key role in patient prognosis and subsequently overall survival. Similar to several types of cancer, colorectal cancer is also characterised by drug resistance and heterogeneity that contribute to its complexity -especially at advanced stages. However, despite the extensive research related to the identification of biomarkers associated to early diagnosis, accurate prognosis and the management of CRC patients, little progress has been made thus far. Therefore, the mortality rates, especially at advanced stages, remain high. A large family of chemoattractant cytokines called chemokines are known for their significant role in inflammation and immunity. Chemokines released by the different tumorous cells play a key role in increasing the complexity of the tumour's microenvironment. The current review investigates the role of chemokines and chemokine receptors in colorectal cancer and their potential as clinical molecular signatures that could be effectively used as a personalised therapeutic approach. We discussed how chemokine and chemokine receptors regulate the microenvironment and lead to heterogeneity in CRC. An important aspect of chemokines is their role in drug resistance which has been extensively discussed. This review also provides an overview of the current advances in the search for chemokines and chemokine receptors in CRC.

Targeting mTOR-CCL20 Signaling May Improve Response to Docetaxel in Head and Neck Squamous Cell Carcinoma

Patients with advanced head and neck squamous cell carcinoma (HNSCC) usually show a dismal prognosis. It is this worthwhile to develop new, effective therapeutic regimens for these patients, such as molecular targeted therapy, which is promising as an alternative or combination treatment for HNSCC. The mammalian target of rapamycin (mTOR) pathway, which plays an important role in the carcinogenesis of HNSCC, is the most frequently activated, and is thus worthy of further investigation. In this study, two human HNSCC cell lines, FaDu and SAS, were evaluated for cell growth with trypan blue staining and tumor growth using an orthotopic xenograft model. The immunohistochemical expression of mTOR in the subcutaneous xenograft model and the inhibitory effects of docetaxel on the growth and state of activation of the PI3K/mTOR pathway were also evaluated and examined by colony formation and Western blot, respectively. Cell proliferation and migration were measured by water-soluble tetrazolium salt (WST-1) and OrisTM cell migration assay, respectively. Furthermore, the effects of rapamycin and BEZ235, a phosphatidylinositol 3-kinases (PI3K) and mTOR inhibitor in combination with docetaxel or CCL20 were evaluated in the FaDu and SAS cells. The results showed that the expression of mTOR was significantly higher in the SAS and FaDu xenograft models than in the control. Docetaxel treatment significantly suppressed HNSCC cell proliferation and migration in vitro via the PI3K/mTOR/CCL-20 signaling pathway. Additionally, when administered in a dose-dependent fashion, mTOR inhibitors inhibited the growth and migration of the HNSCC cells. This combination was synergistic with docetaxel, resulting in almost complete cell growth and migration arrest. In conclusion, docetaxel significantly inhibited HNSCC cell proliferation and migration in vitro via the PI3K/mTOR/CCL-20 signaling pathway. The synergistic and additive activity of mTOR inhibitors combined with docetaxel shows potential as a new treatment strategy for HNSCC.

Salivary CCL20 Level as a Biomarker for Oral Squamous Cell Carcinoma

BACKGROUND/AIM

This study investigated the utility of C-C motif chemokine ligand 20 (CCL20) expression in saliva as a biomarker for oral squamous cell carcinoma (OSCC) and also examined the associated microbiome.

MATERIALS AND METHODS

The study group included patients with OSCC or oral potentially malignant disorder (OPMD), and healthy volunteers (HVs). microarray and qRT-PCR were used to compare salivary CCL20 expression levels among groups. Data on CCL20 levels in oral cancer tissues and normal tissues were retrieved from a public database and examined. Furthermore, next-generation sequencing was used to investigate the salivary microbiome.

RESULTS

A significant increase in the expression level of CCL20 was observed in both OSCC tissues and saliva from patients with oral cancer. Fusobacterium was identified as the predominant bacteria in OSCC and correlated with CCL20 expression level. OSCC screening based on salivary CCL20 expression enabled successful differentiation between patients with OSCC and HVs.

CONCLUSION

CCL20 expression may be a useful biomarker for OSCC.

Biased agonism at chemokine receptors

In the human chemokine system, interactions between the approximately 50 known endogenous chemokine ligands and 20 known chemokine receptors (CKRs) regulate a wide range of cellular functions and biological processes including immune cell activation and homeostasis, development, angiogenesis, and neuromodulation. CKRs are a family of G protein-coupled receptors (GPCR), which represent the most common and versatile class of receptors in the human genome and the targets of approximately one third of all Food and Drug Administration-approved drugs. Chemokines and CKRs bind with significant promiscuity, as most CKRs can be activated by multiple chemokines and most chemokines can activate multiple CKRs. While these ligand-receptor interactions were previously regarded as redundant, it is now appreciated that many chemokine:CKR interactions display biased agonism, the phenomenon in which different ligands binding to the same receptor signal through different pathways with different efficacies, leading to distinct biological effects. Notably, these biased responses can be modulated through changes in ligand, receptor, and or the specific cellular context (system). In this review, we explore the biochemical mechanisms, functional consequences, and therapeutic potential of biased agonism in the chemokine system. An enhanced understanding of biased agonism in the chemokine system may prove transformative in the understanding of the mechanisms and consequences of biased signaling across all GPCR subtypes and aid in the development of biased pharmaceuticals with increased therapeutic efficacy and safer side effect profiles.

Chemokines-What Is Their Role in Colorectal Cancer?

Colorectal cancer (CRC) is one of the leading causes of cancer-related death. It is the second most frequently diagnosed malignancy in Europe and third worldwide. Colorectal malignancies diagnosed at an early stage offer a promising survival rate. However, advanced tumors often present distant metastases even after the complete resection of a primary tumor. Therefore, novel biomarkers of CRC are sorely needed in the diagnosis and prognosis of this common malignancy. A family of chemokines are composed of small, secreted proteins. They are best known for their ability to stimulate the migration of several cell types. Some investigations have indicated that chemokines are involved in cancer development, including CRC. This article presents current knowledge regarding chemokines and their specific receptors in CRC progression. Moreover, the prime aim of this review is to summarize the potential role of these proteins as biomarkers in the diagnosis and prognosis of CRC.

Synergistic association of FOXP3+ tumor infiltrating lymphocytes with CCL20 expressions with poor prognosis of primary breast cancer: A retrospective cohort study

Studies have shown that forkhead/winged helix transcription factor P3 (FOXP3) tumor infiltrating lymphocytes (TILs) are intimately associated with invasion and survival of many invasive tumors. The inflammatory chemokine ligand 20 (CCL20) and its receptor CCR6 were found to be associated with tumor prognosis in some studies. Although increases in FOXP3 TILs infiltration and CCL20 expression have been revealed in several malignancies, their correlation in human breast tumors is as yet unclear.Surgically resected samples from 156 patients with invasive breast cancer (BC) were assessed for the expression of FOXP3 and CCL20 by immunohistochemistry. Correlation between their expressions and the association with clinicopathological characteristics and patient's prognosis were studied. Forty pairs of fresh BC and their nontumor adjacent tissues (NATs) in BC were carried out by real-time quantitative PCR (qRT-PCR) to evaluate the correlation between FOXP3 and CCL20 mRNA expression.CCL20 and FOXP3 TILs mRNA expression in tumor tissue demonstrated a high correlation (rs = 0.359, P < .001) in this cohort of breast cancer patients. Both elevated CCL20 expression and FOXP3 TILs infiltration were significantly correlated with high histological grade, positive human epidermal growth factor receptor-2 (HER2), high Ki67 index, and axillary lymph node metastases. Tumors with concomitant high expressions of both markers had the worst prognosis. Multivariate analysis showed that these 2 markers were independent predictors of overall survival. The patients with axillary lymph node metastases with the concomitant CCL20 high expression and increased FOXP3 TILs infiltration had the worst overall survival (OS) (P < .001), In lymph node-negative breast cancer patients, the status of CCL20 and FOXP3 was not related to OS (P = .22).The results suggest that CCL20 and FOXP3 TILs may have synergistic effects, and their upregulated expressions may lead to immune evasion in breast cancer. Combinatorial immunotherapeutic approaches aiming at blocking CCL20 and depleting FOXP3 might improve therapeutic efficacy in breast cancer patients.

The Four Horsemen in Colon Cancer

Worldwide, neoplasms of the gastrointestinal tract have a very high incidence and mortality. Among these, colorectal cancer, which includes colon and rectum malignancies, representing both highest incidence and mortality. While gallbladder cancer, another neoplasm associated to gastrointestinal tract occurs less frequently. Genetic factors, inflammation and nutrition are important risk factors associated with colorectal cancer development. Likewise, pathogenic microorganisms inducing intestinal dysbiosis have become an important scope to determine the role of bacterial infection on tumorigenesis. Interestingly, in human biopsies of different types of gastrointestinal tract cancer, the presence of different bacterial strains, such as Fusobacterium nucleatum, Escherichia coli, Bacteroides fragilis and Salmonella enterica have been detected, and it has been considered as a high-risk factor to cancer development. Therefore, pathogens infection could contribute to neoplastic development through different mechanisms; including intestinal dysbiosis, inflammation, evasion of tumoral immune response and activation of pro-tumoral signaling pathways, such as β catenin. Here, we have reviewed the suggested bacterial molecular mechanisms and their possible role on development and progression of gastrointestinal neoplasms, focusing mainly on colon neoplasms, where the bacteria Fusobacterium nucleatum, Escherichia coli, Bacteroides fragilis and Salmonella enterica infect.

The Diagnostic Value of Chemokine/Chemokine Receptor Pairs in Hepatocellular Carcinoma and Colorectal Liver Metastasis

Chemokines and their receptors have been proposed to play important roles in tumor progression and metastasis. To investigate their roles in the progression of primary and metastatic malignant liver tumors and their prognosis, we compared expression profiles of CXCL12/CXCR4, CCL20/CCR6, and CCL21/CCR7 in hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLM). Immunohistochemistry was used to analyze the expression levels of the chemokine/chemokine receptor pairs in 29 HCC and 11 CRLM specimens and adjacent non-cancerous tissues, and correlations with clinicopathological variables and overall survival were determined. CCL20/CCR6 expression was higher in HCC than in adjacent non-cancerous tissues. High CCR6 expression in HCC was negatively associated with 5-year survival rate and was an independent prognostic factor for overall survival of HCC patients, whereas differences were not observed between CRLM and adjacent tissues. Furthermore, significantly higher expression of CCL21/CCR7 was found in CRLM than in HCC. In summary, the CCL20/CCR6 axis was elevated in HCC but not in CRLM, whereas the CCL21/CCR7 axis was elevated in CRLM but not in HCC.

CCR6–CCL20 Axis in IBD: What Have We Learnt in the Last 20 Years?

CC chemokine receptor 6 (CCR6) and its specific partner CC chemokine ligand 20 (CCL20) are known to play a pivotal role in intestinal inflammation. CCR6-associated inflammatory bowel disease (IBD) is already at the forefront of experimental inflammatory disease models, being the subject of numerous analytical studies. IBD is associated with two sub phenotypes, Crohn’s disease (CD) and ulcerative colitis (UC). Both these disease entities produce potent immune dysregulation followed by intense tissue damage within the gut mucosal system, initiating symptoms that are severely debilitating. Multiple causative factors are said to be responsible for IBD, but direct immune dysfunction is kindled by overplay of innate and adaptive immune responses produced against the luminal contents through the weakened or leaky gut epithelial barrier. Once immune homeostasis is not achieved by endogenous protective mechanisms, the self-assertive adaptive immunity mobilizes its various T and B cell cohorts, initializing their immune mechanisms by deploying the immune cells towards the site of infection. CCR6 and its unique solitary ligand CCL20 are small protein molecules that are abundantly expressed by T and B lymphocytes and act as chemotactic immune-modulatory envoys that help in the deployment of the effector lymphocyte arm of the immune system and produce two directly opposing outcomes in IBD. This dichotomous immunity consists of either immune tolerance or inflammation which then develops into a chronic state, remaining unresponsive to inherent immunity or targeted clinical therapy. In this review, we have identified large numbers of experimental studies that have employed both mouse models and clinical subjects spanning a period of nearly two decades and we have clustered these into 13 different groups. This review will provide greater understanding of the CCR6–CCL20 axis in IBD and identify gaps in the literature that can be filled in the future.

Epithelial Smad4 Deletion Up-Regulates Inflammation and Promotes Inflammation-Associated Cancer

Background & Aims

Chronic inflammation is a predisposing condition for colorectal cancer. Many studies to date have focused on proinflammatory signaling pathways in the colon. Understanding the mechanisms that suppress inflammation, particularly in epithelial cells, is critical for developing therapeutic interventions. Here, we explored the roles of transforming growth factor β (TGFβ) family signaling through SMAD4 in colonic epithelial cells.

Methods

The Smad4 gene was deleted specifically in adult murine intestinal epithelium. Colitis was induced by 3 rounds of dextran sodium sulfate in drinking water, after which mice were observed for up to 3 months. Nontransformed mouse colonocyte cell lines and colonoid cultures and human colorectal cancer cell lines were analyzed for responses to TGFβ1 and bone morphogenetic protein 2.

Results

Dextran sodium sulfate treatment was sufficient to drive carcinogenesis in mice lacking colonic Smad4 expression, with resulting tumors bearing striking resemblance to human colitis-associated carcinoma. Loss of SMAD4 protein was observed in 48% of human colitis-associated carcinoma samples as compared with 19% of sporadic colorectal carcinomas. Loss of Smad4 increased the expression of inflammatory mediators within nontransformed mouse colon epithelial cells in vivo. In vitro analysis of mouse and human colonic epithelial cell lines and organoids indicated that much of this regulation was cell autonomous. Furthermore, TGFβ signaling inhibited the epithelial inflammatory response to proinflammatory cytokines.

Conclusions

TGFβ suppresses the expression of proinflammatory genes in the colon epithelium, and loss of its downstream mediator, SMAD4, is sufficient to initiate inflammation-driven colon cancer. Transcript profiling: GSE100082.

Histone deacetylase inhibitors inhibit metastasis by restoring a tumor suppressive microRNA-150 in advanced cutaneous T-cell lymphoma

Tumor suppressive microRNA (miR)-150 inhibits metastasis by combining with the C-C chemokine receptor 6 (CCR6) “seed sequence” mRNA of the 3′-untranslated region (3′-UTR) in advanced cutaneous T-cell lymphoma (CTCL). Because the histone deacetylase inhibitor (HDACI) vorinostat showed excellent outcomes for treating advanced CTCL, HDACIs may reduce the metastasis of CTCL by targeting miR-150 and/ or CCR6. To examine whether these candidate molecules are essential HDACI targets in advanced CTCL, we used the My-La, HH, and HUT78 CTCL cell lines for functional analysis because we previously demonstrated that their xenografts in NOD/Shi-scid IL-2γnul mice (CTCL mice) induced multiple metastases. We found that pan- HDACIs (vorinostat and panobinostat) inhibited the migration of CTCL cells and downregulated CCR6. The miRNA microarray analysis against CTCL cell lines demonstrated that these pan-HDACIs commonly upregulated 161 miRNAs, including 34 known tumor suppressive miRNAs such as miR-150. Although 35 miRNAs possessing the CCR6 “seed sequence” were included in these 161 miRNAs, miR-150 and miR-185-5p were downregulated in CTCL cells compared to in normal CD4+ T-cells. The transduction of 12 candidate miRNAs against CTCL cells revealed that miR-150 most efficiently inhibited their migration capabilities and downregulated CCR6. Quantitative reverse transcriptase-polymerase chain reaction demonstrated that miR-150 was downregulated in advanced but not early CTCL primary cases. Finally, we injected miR-150 or siCCR6 into CTCL mice and found that mouse survival was significantly prolonged. These results indicate that miR-150 and its target, CCR6, are essential therapeutic targets of pan-HDACIs in advanced CTCL with metastatic potential.

Chemokines and receptors in intestinal B lymphocytes

Recent studies indicate that chemoattractant cytokines (chemokines) and their receptors modulate intestinal B lymphocytes in different ways, including regulating their maturity and differentiation in the bone marrow and homing to intestinal target tissues. Here, we review several important chemokine/chemokine receptor axes that guide intestinal B cells, focusing on the homing and migration of IgA antibody-secreting cells (IgA-ASCs) to intestinal-associated lymphoid tissues. We describe the selective regulation of these chemokine axes in coordinating the IgA-ASC trafficking in intestinal diseases. Finally, we discuss the role of B cells as chemokine producers serving dual roles in regulating the mucosal immune microenvironment.

Rediscovery of NF-κB signaling in nasopharyngeal carcinoma: How genetic defects of NF-κB pathway interplay with EBV in driving oncogenesis?

Nasopharyngeal carcinoma (NPC) is a unique EBV-associated subtype of head and neck cancer, which has the highest incidence in Southern China and eastern South Asia. The interaction between genetic risk factors and environmental challenge, have been considered to contribute to the development of nasopharyngeal carcinogenesis. Constitutive activation of NF-κB signaling has been seen in NPC tissues and is associated with unfavorable prognosis. Recently, several whole exome sequencing study consistently revealed that high frequency mutations of NF-κB pathway negative regulators is common in nasopharyngeal carcinoma, which reinforce the importance of NF-κB driving oncogenesis. This review focuses on the current state of research in role of NF-κB in NPC carcinogenesis. We summarized the newly identified loss of function (LOF) mutations on NF-κB negative regulators leading to it's activation bypass LMP-1 stimulation. We discussed the critical role of NF-κB activation in immortalization and transformation of nasopharygeal epithelium. We also depicted how NF-κB signaling mediated chronic inflammation contribute to persistent EBV infection, immune evasion of EBV infected cells, metabolic reprogramming, and cancer stem cells (CSCs) formation in NPC. Lastly, we discussed the clinical resonance of targeting NF-κB for NPC precise therapy.

Disruption of CCL20-CCR6 interaction inhibits metastasis of advanced cutaneous T-cell lymphoma

We recently demonstrated that upregulation of a chemokine receptor CCR6 and its ligand CCL20 led to metastasis of advanced cutaneous T-cell lymphoma (CTCL) cells, suggesting the involvement of CCL20-CCR6 interaction in initiating CTCL cell metastasis. In this study, we determined whether this interaction is functional in metastatic CTCL cells. We first demonstrated increased STAT3 expression during the progression of primary CTCL. STAT3 was spontaneously activated and mediated the transcription of CCL20 in CTCL cell lines. Next, to determine whether the transient knockdown of STAT3, CCL20, or CCR6 or treatment with neutralizing antibody against CCL20 (neutralizing CCL20 antibody) could reduce the migration ability of CTCL cells, we conducted an in vitro migration assay. All treatments reduced the nutrition-dependent migration activity of CTCL cells. Notably, treatment with neutralizing CCL20 antibody reduced the migration ability of the cells without decreasing the expression of CCL20 and CCR6. This demonstrated that the CCL20-CCR6 interaction is actually functional in metastatic CTCL cells. Finally, to examine the in vivo effect of neutralizing CCL20 antibody, we used NOD/Shi-scid IL-2γnul mice inoculated with CTCL cells. These mice were expected to die due to metastasis of CTCL cells into multiple organs. However, administration of neutralizing CCL20 antibody significantly prolonged the survival of the xenografted mice. These findings suggested that automatic activation of the STAT3/CCL20/CCR6 cascade was involved in CTCL lymphomagenesis and that disruption of CCL20-CCR6 interaction could be a key therapeutic strategy against advanced CTCL.

The Role of Chemokines in Thyroid Carcinoma

The global incidence of thyroid cancer is increasing, and metastatic spread to the lymph nodes is common in papillary thyroid carcinoma. The metastatic course of thyroid carcinoma is an intricate process involving invasion, angiogenesis, cell trafficking, extravasation, organ specific homing, and growth. A key aspect in this process involves a multitude of interactions between chemokines and their receptors. Chemokines are a group of small proteins, which act to elicit normal physiologic and immune responses principally through recruitment of specific cell populations to the site of infection or malignancy. Thyroid cancer cells, like other tumors, possess the ability to corrupt the chemokine system to their advantage by altering cell movement into the tumor microenvironment and affecting all aspects of thyroid cancer progression.

CCR6 promotes tumor angiogenesis via the AKT/NF-κB/VEGF pathway in colorectal cancer

Chemokines and chemokine receptors play an important role in tumorigenesis. Angiogenesis is a vital part of the occurrence, development and metastasis of cancer. CCR6 is an important factor during tumor progression; however, its function in tumor angiogenesis is not fully understood. In our study, we found that CCR6 was significantly overexpressed in colorectal cancer (CRC) tissues and predicted a poor prognosis in CRC patients. We then verified the function of CCR6 on tumor angiogenesis in vivo and in vitro. We observed that silencing CCR6 could decrease angiogenesis by inhibiting the proliferation and migration of human umbilical vein endothelial cells (HUVECs), whereas overexpression of CCR6 can promote angiogenesis. Additionally, we investigated the molecular mechanisms and demonstrated that activation of the AKT/NF-κB pathway maybe involved in CCR6-mediated tumor angiogenesis, which was able to promote the secretion of vascular endothelial growth factor A (VEGF-A). In conclusion, CCR6 facilitates tumor angiogenesis via the AKT/NF-κB/VEGF pathway in colorectal cancer. CCR6 inhibition may be a novel option for anti-vascular treatment in CRC.

CCL20 secreted from IgA1-stimulated human mesangial cells recruits inflammatory Th17 cells in IgA nephropathy

IgA nephropathy (IgAN) is the most common primary glomerulonephritis characterized by human mesangial cells (HMC) proliferation and extracellular matrix expansion associated with immune deposits consisting of galactose-deficient IgA1. However, how IgA1 contributes to IgAN has yet to be completely elucidated. In this study, the expression profile of chemokines was more altered in IgA1-treated HMC than in the control group. CCL20 was significantly higher either in the serum of IgAN patients or in IgA1-treated HMC. Further experiments demonstrated that CCR6, the only receptor of CCL20, was highly expressed in activated T cells. Intracellular staining assay and cytokine expression profile implied that CCR6⁺ T cells produced high IL-17 levels. Transwell experiment immunohistochemistry and immunofluorescence experiments extensively demonstrated that CCL20 could recruit inflammatory Th17 cells to the kidneys. These phenomena caused a series of immune inflammatory responses and further damaged the kidneys. Therefore, HMC stimulated by IgA1 could produce CCL20 and consequently recruit inflammatory Th17 cells to the kidneys to induce further lesion in IgA nephropathy.

Fusobacterium Nucleatum Subspecies Animalis Influences Proinflammatory Cytokine Expression and Monocyte Activation in Human Colorectal Tumors

Chronic infection and associated inflammation have long been suspected to promote human carcinogenesis. Recently, certain gut bacteria, including some in the Fusobacterium genus, have been implicated in playing a role in human colorectal cancer development. However, the Fusobacterium species and subspecies involved and their oncogenic mechanisms remain to be determined. We sought to identify the specific Fusobacterium spp. and ssp. in clinical colorectal cancer specimens by targeted sequencing of Fusobacterium 16S ribosomal RNA gene. Five Fusobacterium spp. were identified in clinical colorectal cancer specimens. Additional analyses confirmed that Fusobacterium nucleatum ssp. animalis was the most prevalent F. nucleatum subspecies in human colorectal cancers. We also assessed inflammatory cytokines in colorectal cancer specimens using immunoassays and found that expression of the cytokines IL17A and TNFα was markedly increased but IL21 decreased in the colorectal tumors. Furthermore, the chemokine (C-C motif) ligand 20 was differentially expressed in colorectal tumors at all stages. In in vitro co-culture assays, F. nucleatum ssp. animalis induced CCL20 protein expression in colorectal cancer cells and monocytes. It also stimulated the monocyte/macrophage activation and migration. Our observations suggested that infection with F. nucleatum ssp. animalis in colorectal tissue could induce inflammatory response and promote colorectal cancer development. Further studies are warranted to determine if F. nucleatum ssp. animalis could be a novel target for colorectal cancer prevention and treatment. Cancer Prev Res; 10(7); 398-409. ©2017 AACR.

Tumor-associated macrophage-derived CCL20 enhances the growth and metastasis of pancreatic cancer

Pancreatic cancer is an aggressive malignancy with a high metastatic potential that results in a high mortality rate worldwide. Although macrophages have the potential to kill tumor cells and elicit immune responses against tumors, there is evidence that tumor-associated macrophages (TAMs) promote tumor progression and suppress T-cell responses. CC-chemokine ligand 20 (CCL20) and its unique receptor CC-chemokine receptor 6 (CCR6) are exploited by cancer cells for migration and metastasis and play important roles in the development and progression of cancer. Recent studies have shown that the expression of CCL20 is upregulated in pancreatic cancer; however, the mechanism of action of CCL20 remains to be fully elucidated. In this study, the aberrant expression of CCL20 in TAMs of pancreatic cancer tissue, including metastatic pancreatic cancer tissue, was detected. CCL20 expression was considerably higher in macrophages than in pancreatic cancer cell lines, particularly in interleukin-4-treated (M2) macrophages. Using Boyden chamber assays of pancreatic cancer cells, we found that CCL20 secreted by M2 macrophages promoted the migration, epithelial-mesenchymal transition, and invasion of pancreatic cancer cells. RNA interference results showed that CCR6 is a receptor for CCL20 in pancreatic cancer cells, mediating the increased invasive properties of these cells promoted by CCL20. Using a mouse model, we confirmed the roles of CCR6/CCL20 in promoting pancreatic cancer growth and liver metastasis in vivo Our findings provide insight into the important role of macrophage-secreted CCL20 in pancreatic cancer and implicate CCR6/CCL20 as potential therapeutic targets.

NF-κB-Mediated CCL20 Reigns Dominantly in CXCR2-Driven Ovarian Cancer Progression

Ovarian cancer is an inflammation-associated malignancy with a high mortality rate. CXCR2 expressing ovarian cancers are aggressive with poorer outcomes. We previously demonstrated that CXCR2-driven ovarian cancer progression potentiated NF-κB activation through EGFR-transactivated Akt. Here, we identified the chemokine signature involved in CXCR2-driven ovarian cancer progression using a mouse peritoneal xenograft model for ovarian cancer spreading with CXCR2-negative (SKA) and positive (SKCXCR2) cells generated previously from parental SKOV-3 cells. Compared to SKA bearing mice, SKCXCR2 bearing mice had the following characteristics: 1) shorter survival time, 2) greater tumor spreading in the peritoneal cavity and 3) higher tumor weight in the omentum and pelvic site. Particularly, SKCXCR2-derived tumor tissues induced higher activation of the NF-κB signaling pathway, while having no change in EGFR-activated signaling such as Raf, MEK, Akt, mTOR and Erk compared to SKA-derived tumors. Chemokine PCR array revealed that CCL20 mRNA levels were significantly increased in SKCXCR2-derived tumor tissues. The CCL20 promoter activity was regulated by NF-κB dependent pathways. Interestingly, all three κB-like sites in the CCL20 promoter were involved in regulating CCL20 and the proximal region between -92 and -83 was the most critical κB-like site. In addition, SKCXCR2-derived tumor tissues maintained high CCL20 mRNA expression and induced greater CCL24 and CXCR4 compared to SKCXCR2 cells, indicating the shift of chemokine network during the peritoneal spreading of tumor cells via interaction with other cell types in tumor microenvironment. Furthermore, we compared expression profiling array between human ovarian cancer cell lines and tumor tissues based on GEO datasets. The expression profiles in comparison with cell lines revealed that dominant chemokines expressed in ovarian tumor tissues are likely shifted from CXCL1-3 and 8 to CCL20. Taken together, the progression of ovarian cancer in the peritoneal cavity involves NF-κB-mediated CCL20 as a main chemokine network, which is potentiated by CXCR2 expression.

Stromal CCR6 drives tumor growth in a murine transplantable colon cancer through recruitment of tumor-promoting macrophages

Interactions between the inflammatory chemokine CCL20 and its receptor CCR6 have been implicated in promoting colon cancer; however, the mechanisms behind this effect are poorly understood. We have previously demonstrated that deficiency of CCR6 is associated with decreased tumor macrophage accumulation in a model of sporadic intestinal tumorigenesis. In this study, we aimed to determine the role of stromal CCR6 expression in a murine syngeneic transplantable colon cancer model. We show that deficiency of host CCR6 is associated with decreased growth of syngeneic CCR6-expressing colon cancers. Colon cancers adoptively transplanted into CCR6-deficient mice have decreased tumor-associated macrophages without alterations in the number of monocytes in blood or bone marrow. CCL20, the unique ligand for CCR6, promotes migration of monocytes in vitro and promotes accumulation of macrophages in vivo. Depletion of tumor-associated macrophages decreases the growth of tumors in the transplantable tumor model. Macrophages infiltrating the colon cancers in this model secrete the inflammatory mediators CCL2, IL-1α, IL-6 and TNFα. Ccl2, Il1α and Il6 are consequently downregulated in tumors from CCR6-deficient mice. CCL2, IL-1α and IL-6 also promote proliferation of colon cancer cells, linking the decreased macrophage migration into tumors mediated by CCL20-CCR6 interactions to the delay in tumor growth in CCR6-deficient hosts. The relevance of these findings in human colon cancer is demonstrated through correlation of CCR6 expression with that of the macrophage marker CD163 as well as that of CCL2, IL1α and TNFα. Our findings support the exploration of targeting the CCL20-CCR6 pathway for the treatment of colon cancer.

CCR6 expression in colon cancer is associated with advanced disease and supports epithelial-to-mesenchymal transition

Background:

Adjuvant chemotherapy offered to treat colon cancer is based on the TNM staging system, which often fails due to molecular heterogeneity and undefined molecular mechanisms independent of TNM. Therefore, identification of markers to better predict therapeutic option and outcome is needed. In this study we have characterised the clinical association of CCR6 with colon cancer and defined CCR6-mediated molecular pathway.

Methods:

Immunohistochemistry, RT-qPCR, western blot and FACS were used to determine expression of CCR6 and/or EMT markers in colon tissues/cells. BrdU assay and trans-well system were used to determine cell proliferation, migration and invasion in response to CCL20.

Results:

CCR6 was higher in cancer cases compared to normal adjacent tissue and expression was associated with nodal status and distant metastasis. Similarly, CCR6 expression was higher in cells derived from node-positive cases and highest expression was in cells derived from metastatic cases. Significant changes in EMT markers, that is, E-cadherin, vimentin, β-catenin, N-cadherin, α-SMA, SNAILl and ZEB1 were observed in response to CCL20 along with decreased proliferation, increased migratory and invasive potential.

Conclusions:

Results suggest CCR6 as a potential therapeutic target as well as biomarker in addition to nodal status for predicting therapeutic option.

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.

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.

The role of CCL20/CCR6 axis in recruiting Treg cells to tumor sites of NSCLC patients

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.

CCL20/CCR6 promotes the invasion and migration of thyroid cancer cells via NF-kappa B signaling-induced MMP-3 production

CCL20, an important member of the CC-chemokine family, is the only ligand that activates CCR6. The levels of CCL20 and CCR6 are elevated in many human cancers, and CCL20/CCR6 interaction participates in the development and progression of cancer. In this present study, we found that CCR6 was overexpressed in thyroid cancer cells. Activation of CCR6 by CCL20 promoted the invasion and migration of human thyroid cancer SW1736 cells, while knockdown of CCR6 repressed the effect of CCL20. Furthermore, CCL20/CCR6 interaction induced the activation of NF-κB, and stimulated the expression and secretion of MMP-3. In addition, BAY117082, a special inhibitor of NF-κB, suppressed the expression and secretion of MMP-3 stimulated by CCL20/CCR6. Together, these results suggest that CCL20/CCR6 enhances thyroid cancer cell invasion and migration. The possible molecular mechanisms involved NF-κB activation and NF-κB-dependent MMP-3 upregulation. Thus, molecular therapies that aim at CCL20 and CCR6 may offer promising intervention strategies for thyroid cancer.

CCR6, the sole receptor for the chemokine CCL20, promotes spontaneous intestinal tumorigenesis

Interactions between the inflammatory chemokine CCL20 and its receptor CCR6 have been associated with colorectal cancer growth and metastasis, however, a causal role for CCL20 signaling through CCR6 in promoting intestinal carcinogenesis has not been demonstrated in vivo. In this study, we aimed to determine the role of CCL20-CCR6 interactions in spontaneous intestinal tumorigenesis. CCR6-deficient mice were crossed with mice heterozygous for a mutation in the adenomatous polyposis coli (APC) gene (APC^MIN/+ mice) to generate APC^MIN/+ mice with CCR6 knocked out (CCR6KO-APC^MIN/+ mice). CCR6KO-APC^MIN/+ mice had diminished spontaneous intestinal tumorigenesis. CCR6KO-APC^MIN/+ also had normal sized spleens as compared to the enlarged spleens found in APC^MIN/+ mice. Decreased macrophage infiltration into intestinal adenomas and non-tumor epithelium was observed in CCR6KO-APC^MIN/+ as compared to APC^MIN/+ mice. CCL20 signaling through CCR6 caused increased production of CCL20 by colorectal cancer cell lines. Furthermore, CCL20 had a direct mitogenic effect on colorectal cancer cells. Thus, interactions between CCL20 and CCR6 promote intestinal carcinogenesis. Our results suggest that the intestinal tumorigenesis driven by CCL20-CCR6 interactions may be driven by macrophage recruitment into the intestine as well as proliferation of neoplastic epithelial cells. This interaction could be targeted for the treatment or prevention of malignancy.

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.