Differences in gene expression profiling and biomarkers between histological colorectal carcinoma subsets from the serrated pathway

AIMS

To discern the differences in expression profiling of two histological subtypes of colorectal carcinoma (CRC) arising from the serrated route (serrated adenocarcinoma (SAC) and CRC showing histological and molecular features of a high level of microsatellite instability (hmMSI-H) both sharing common features (female gender, right-sided location, mucinous histology, and altered CpG methylation), but dramatically differing in terms of prognosis, development of an immune response, and treatment options.

METHODS AND RESULTS

Molecular signatures of SAC and hmMSI-H were obtained by the use of transcriptomic arrays; quantitative polymerase chain reaction (qPCR) and immunohistochemistry (IHC) were used to validate differentially expressed genes. An over-representation of innate immunity functions (granulomonocytic recruitment, chemokine production, Toll-like receptor signalling, and antigen processing and presentation) was obtained from this comparison, and intercellular cell adhesion molecule-1 (ICAM1) was more highly expressed in hmMSI-H, whereas two genes [those encoding calcitonin gene-related peptide-receptor component protein and C-X-C motif chemokine ligand 14 (CXCL14)] were more highly expressed in SAC. These array results were subsequently validated by qPCR, and by IHC for CXCL14 and ICAM1. Information retrieved from public databanks confirmed our findings.

CONCLUSIONS

Our findings highlight specific functions and genes that provide a better understanding of the role of the immune response in the serrated pathological route and may be of help in identifying actionable molecules.

Distribution, nature, and origin of CXCL14-immunoreactive fibers in rat parotid gland

The distribution and nature of CXCL14-immunoreactive nerve fibers in salivary glands, especially the parotid gland was immunohistochemically investigated. Furthermore, the origin of parotid CXCL14-immunoreactive nerve fibers was determined by retrograde tracing experiments. CXCL14-immunoreactive nerve fibers were localized in the parotid, submandibular, and sublingual glands, particularly in the parotid gland. Double staining using identical sections revealed that a subpopulation of cells neuropeptide Y (NPY)-containing fibers was immunopositive for CXCL14 in the parotid gland. In the peripheral regions of acinar cells, CXCL14-immunoreactive fibers tended to coexist with NPY; however, perivascular NPY-immunoreactive fibers tended to be immunonegative for CXCL14. Parotid CXCL14-immunoreactive fibers were immunopositive for tyrosine hydroxylase (TH) but immunonegative for choline acetyltransferase and vasoactive intestinal peptide (VIP). After injection of horseradish peroxidase-labeled wheat germ agglutinin (WGA-HRP) in the parotid gland, retrogradely labeled neurons were seen in the superior cervical ganglion (SCG) and otic ganglion. Some of the WGA-immunoreactive somata in the SCG were immunopositive for CXCL14; however, no doubly-labeled somata were noted in the otic ganglion. These results indicate that CXCL14-immunoreactive nerve fibers originate in the SCG, and are sympathetic in nature. The coexistence of CXCL14 with NPY/TH suggests that CXCL14 may be associated with NPY/TH functions as a neuromodulatory chemokine in the parotid gland. The localization of CXCL14 nerve fibers around the acinar cells of the parotid gland indicates its involvement in acinar cell function, but not vasoconstriction.

The Expression of the Chemokine CXCL14 Correlates with Several Aggressive Aspects of Glioblastoma and Promotes Key Properties of Glioblastoma Cells

Glioblastoma (GBM) is a primary brain tumor whose prognosis is inevitably dismal, leading patients to death in about 15 months from diagnosis. Tumor cells in the mass of the neoplasm are in continuous exchange with cells of the stromal microenvironment, through the production of soluble molecules, among which chemokines play prominent roles. CXCL14 is a chemokine with a pro-tumor role in breast and prostate carcinoma, where it is secreted by cancer associated fibroblasts, and contributes to tumor growth and invasion. We previously observed that CXCL14 expression is higher in GBM tissues than in healthy white matter. Here, we study the effects of exogenously supplemented CXCL14 on key tumorigenic properties of human GBM cell lines. We show that CXCL14 enhances the migration ability and the proliferation of U87MG and LN229 GBM cell lines. None of these effects was affected by the use of AMD3100, an inhibitor of CXCR4 receptor, suggesting that the observed CXCL14 effects are not mediated by this receptor. We also provide evidence that CXCL14 enhances the sphere-forming ability of glioblastoma stem cells, considered the initiating cells, and is responsible for tumor onset, growth and recurrence. In support of our in vitro results, we present data from several GBM expression datasets, demonstrating that CXCL14 expression is inversely correlated with overall survival, that it is enriched at the leading edge of the tumors and in infiltrating tumor areas, and it characterizes mesenchymal and NON G-CIMP tumors, known to have a particularly bad prognosis. Overall, our results point to CXCL14 as a protumorigenic chemokine in GBM.

Possible association of decreased serum CXCL14 levels with digital ulcers in patients with systemic sclerosis

CXCL14 serves as a chemoattractant for activated macrophages, immature dendritic cells and natural killer cells, as well as an antiangiogenic factor by preventing the migration of endothelial cells. CXCL14 also exerts an inhibitory effect on the CXCL12/CXCR4 signaling pathway, which is involved in the maintenance of T-helper (Th)2 bias, and promotes Th1 immune response under the physiological and pathological conditions. Because CXCL14-mediated biological processes seem to be involved in the development of systemic sclerosis (SSc), which is characterized by Th2/Th17-skewed immune polarization and impaired neovascularization, we investigated the clinical correlation of serum CXCL14 levels in patients with this disease. Serum CXCL14 levels were significantly decreased in SSc patients compared with healthy individuals and in diffuse cutaneous SSc patients relative to limited cutaneous SSc patients. SSc patients with digital ulcers had serum CXCL14 levels significantly lower than those without. Furthermore, i.v. cyclophosphamide pulse significantly increased serum CXCL14 levels as compared with the baseline in SSc patients with interstitial lung disease successfully treated with this therapy. These results indicate that decreased CXCL14 expression may contribute to the maintenance of Th2-skewed immune polarization and dysregulated neovascularization, both of which underlie the developmental process of SSc.

CXCL14 Inhibits Insulin Secretion Independently of CXCR4 or CXCR7 Receptor Activation or cAMP Inhibition

BACKGROUND/AIMS

CXCL14, a secreted chemokine peptide that promotes obesity-induced insulin resistance, is expressed by islets, but its effects on islet function are unknown. The aim of this study was to determine the role of CXCL14 in β-cells and investigate how it transduces these effects.

METHODS

Cxcl14 and Cxc-receptor mRNA expression was quantified by qPCR and CXCL14 expression in the pancreas was determined by immunohistochemistry. The putative function of CXCL14 at CXCR4 and CXCR7 receptors was determined by β-arrestin recruitment assays. The effects of CXCL14 on glucose-stimulated insulin secretion, cAMP production, glucose-6-phosphate accumulation, ATP generation, apoptosis and proliferation were determined using standard techniques.

RESULTS

CXCL14 was present in mouse islets, where it was mainly localised to islet δ-cells. Cxc-receptor mRNA profiling indicated that Cxcr4 and Cxcr7 are the most abundant family members in islets, but CXCL14 did not promote β-arrestin recruitment at CXCR4 or CXCR7 or antagonise CXCL12 activation of these receptors. CXCL14 induced a concentration-dependent inhibition of glucose-stimulated insulin secretion, which was not coupled to G_αi signalling. However, CXCL14 inhibited glucose-6-phosphate generation and ATP production in mouse islets.

CONCLUSION

CXCL14 is expressed by islet δ-cells where it may have paracrine effects to inhibit insulin secretion in a CXCR4/CXCR7-independent manner through reductions in β-cell ATP levels. These observations, together with the previously reported association of CXCL14 with obesity and impaired glucose homeostasis, suggest that inhibition of CXCL14 signalling could be explored to treat type 2 diabetes.

Effects of Notch signalling on the expression of SEMA3C, HMGA2, CXCL14, CXCR7, and CCL20 in breast cancer

Metastasis is the main reason for death in breast cancer. Understanding the molecular players in metastasis is crucial for diagnostic and therapeutic purposes. Notch signalling plays an oncogenic role in breast tumorigenesis and is involved in metastasis. Downstream mediators of Notch signalling in prometastatic processes are not yet fully discovered. Here we aimed to investigate whether Notch signalling regulates the expression of SEMA3C, HMGA2, CXCL14, CXCR7, and CCL20, which are involved in prometastatic processes, in breast cell lines. To this end, expression of the selected genes was analysed following Notch activation by overexpression of the Notch1 intracellular domain in the normal breast epithelial cell line MCF10A, and inhibition by silencing of the Notch transcriptional mediator RBPjκ in the breast cancer cell line MDA MB 231. SEMA3C and HMGA2 mRNA were decreased, while CXCL14 and CXCR7 mRNA were increased significantly in response to Notch activation in MCF10A cells. Notch inhibition in MDA MB 231 cells significantly decreased HMGA2 and CCL20 mRNA. Protein levels were not significantly altered by Notch modulation. In conclusion, we showed that Notch signalling regulates expression of SEMA3C, CXCL14, CCL20, CXCR7, and HMGA2, which are prominent candidate genes that might function downstream of Notch to induce prometastatic processes.

Heterogeneous Expression of SDF1 Retains Actively Proliferating Neural Progenitors in the Capillary Compartment of the Niche

The vascular compartment of the adult brain ventricular-subventricular zone (V-SVZ) is a critical regulator of neural stem cell and progenitor function. Blood enters the V-SVZ via arteries and arterioles to capillaries that then connect with venules and veins to return blood to the heart. We found that stromal cell-derived factor 1 (SDF1) is expressed by a subpopulation of V-SVZ vessels, the capillaries, and that actively proliferating neural stem cells (NSCs) and progenitors are preferentially associated with these SDF1-positive vessels. In contrast, slowly dividing or quiescent NSCs are most prevalent near SDF1-negative vessels. By conditional knockout, we found that loss of SDF1 signaling in NSCs stimulates lineage progression and NSC displacement from the vessel niche. With aging, SDF1/CXCR4 signaling is dysregulated, coincident with reduced proliferation and increased displacement of dividing cells from the vasculature. Our findings demonstrate SDF1-based vascular heterogeneity in the niche and suggest that reduced SDF1 signaling contributes to age-related declines in adult neurogenesis.

miR-17-5p-CXCL14 axis related transcriptome profile and clinical outcome in diffuse gliomas

GBM tissues are comprised of not only tumor cells but also tumor-associated nontumor cells, such as stromal cells and immune cells, which dilute the purity of glioma cells and function in glioma biology. However, the roles of miRNAs in modulating glioma purity are not clarified. In total, 838 glioma samples with transcriptome data, including 537 RNAseq data from TCGA project and 301 microarray data from Chinese Glioma Genome Atlas (CGGA project), were recruited into our investigation. Tumor purity, molecular subtypes and IDH status were also available. R language was employed as the main tool for statistical analysis and graphical work. Screening miRNA profiling and paired TCGA samples' transcriptome data demonstrates that miR-17-5p expression harbors the most significant positive correlation with glioma purity among all miRNAs. CXCL14 shows robust negative correlation with miR-17-5p expression in TCGA and CGGA dataset. miR-17-5p directly targets CXCL14 and functions as a tumor-suppressor of GBM. CXCL14 showed lower expression in proneural subtype and may contribute as a potential marker for proneural subtype in glioma. Genes markedly correlated with CXCL14 are involved in essential functions associated with anti-tumor immune process. CXCL14 has a strong correlation with immune(T cells, Monocytic lineage and Neutrophils) and Fibroblasts within glioma environment. miR-17-5p and CXCL14 exhibited predictive values for high-grade glioma(HGG) patients: Higher miR-17-5p indicated significantly longer survival while lower CXCL14 indicated longer survival. Our results highlight the importance of the miR-17-5p-CXCL14 axis in regulating key steps of anti-tumor immune process and may serve as potential targets of immune treatments for gliomas.

Down-regulation of miR-29b in carcinoma associated fibroblasts promotes cell growth and metastasis of breast cancer

Carcinoma associated fibroblasts (CAFs) play important roles in breast cancer development and progression. Recent studies show that microRNAs (miRNAs) are the main regulators in CAFs. MiR-29b is one of the significant down-regulated miRNAs in CAFs from the miRNA screening. The role of miR-29b in the interaction between CAFs and breast cancer is still unclear. In the present study, we investigated the effects of CAFs on breast cancer cell proliferation and metastasis regulated by miR-29b. We found that fibroblasts activated by co-cultured breast cancer cells produced higher levels of some chemokines like CCL11, CXCL14, which accelerated breast cancer cell growth and induced drug resistance and metastasis. Increased miR-29b expression in activated fibroblasts could suppress the activating p38-STAT1 signal pathway in breast cancer cells. We also found that the expression of CCL11 and CXCL14 could be regulated by miR-29b in CAFs. Our results illustrate that down-regulation of miR-29b in CAFs plays an important role in tumor stroma by activating p38-STAT1 in breast cancer cells. The study indicates that cancer cells and fibroblasts interaction promotes breast cancer cell growth, drug resistance, migration and invasion due to the lack of miR-29b expression in CAFs.

Mucosal Chemokines

Several chemokines have important functions in mucosal immunity. While there are many chemokines, 4 of them (CCL25, CCL28, CXCL14, and CXCL17) are especially important in mucosal immunity because they are homeostatically expressed in mucosal tissues. Of these, only CCL25 and CCL28 have been widely recognized as mucosal chemokines. In this study, we review the physiology of these chemokines with specific emphasis on their function in mucosal immunity. CCL25 recruits certain important subsets of T cells that express CCR9 to the small intestine. These CCR9⁺ T cells also express the integrin α4β7 and have been shown to play important roles in the control of intestinal inflammation. CCL28 recruits CCR10⁺ IgA plasmablasts to the lactating mammary gland. The role of CXCL14 in mucosal immunity is less well defined, but a Cxcl14^-/- mouse exhibits significant metabolic abnormalities. Finally, CXCL17 was the last chemokine to be described and signals through a new chemokine receptor (GPR35/CXCR8), which is expressed in a subset of macrophages that are recruited to mucosal tissues by this chemokine. We conclude that these 4 chemokines play very important roles in mucosal immunity and their continued functional characterization will likely identify novel therapeutic targets.

CXCL14-like Immunoreactivity Exists in Somatostatin-containing Endocrine Cells, and in the Lamina Propria and Submucosal Somatostatinergic Nervous System of Mouse Alimentary Tract

In the present study, we investigated the distribution of CXCL14 immunoreactive endocrine cells and neurons in mouse alimentary tract by immunohistochemistry. CXCL14 immunoreactive endocrine cells were found as closed-type cells in the stomach and open-type cells in the small intestine. The immunostaining of these endocrine cells corresponded with that of the somatostatin-containing endocrine cells. Only a few CXCL14 immunoreactive endocrine cells were seen in the large intestine. CXCL14 immunoreactive fibers were observed in the muscular layer from the stomach to the rectum with most abundance in the rectum. Many CXCL14 immunoreactive fibers were observed in the lamina propria and submucosal layer from the duodenum to the rectum with most abundance in the rectum; these fibers corresponded to the somatostatin-containing nerve fibers. Some CXCL14 immunoreactive neuronal somata that were also immuno-positive for somatostatin, were noted in the submucosal layer of the rectum. However, the remaining parts of the alimentary tract presented with almost negligible immunoreactive somata. The co-localization of CXCL14 and somatostatin suggests that CXCL14 contributes to the function of somatostatin, which include the inhibition of other endocrine and exocrine cells and the enteric nervous systems.

CXCL14 Acts as a Specific Carrier of CpG DNA into Dendritic Cells and Activates Toll-like Receptor 9-mediated Adaptive Immunity

CXCL14 is a primordial chemokine that plays multiple roles in tumor suppression, autoimmune arthritis, and obesity-associated insulin resistance. However, the underlying molecular mechanisms are unclear. Here, we show that CXCL14 transports various types of CpG oligodeoxynucleotide (ODN) into the endosomes and lysosomes of bone marrow-derived dendritic cells (DCs), thereby activating Toll-like receptor 9 (TLR9). A combination of CpG ODN (ODN2395) plus CXCL14 induced robust production of IL-12 p40 by wild-type, but not Tlr9-knockout, DCs. Consistent with this, ODN2395-mediated activation of DCs was significantly attenuated in Cxcl14-knockout mice. CXCL14 bound CpG ODN with high affinity at pH 7.5, but not at pH 6.0, thereby enabling efficient delivery of CpG ODN to TLR9 in the endosome/lysosome. Furthermore, the CXCL14-CpG ODN complex specifically bound to high affinity CXCL14 receptors on DCs. Thus, CXCL14 serves as a specific carrier of CpG DNA to sensitize TLR9-mediated immunosurveillance.

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CXCL14 specifically binds CpG DNA with high affinity.

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CXCL14/CpG DNA complex is efficiently transported into dendritic cells.

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CXCL14/CpG DNA induces cytokine production via Toll-like receptor 9.

We discovered that CXCL14 specifically binds CpG DNAs with high affinity and transports them into the endosomes and lysosomes of dendritic cells (DCs). Consequently, Toll-like receptor 9 (Tlr9) in DCs was activated, thereby leading to robust production of IL-12 p40 and IL-6. These activities of CXCL14 were not observed in Tlr9-deficient DCs. Moreover, CpG DNA (ODN2395)-mediated activation of DCs was significantly attenuated in Cxcl14-knockout mice. Therefore, CXCL14 plays an important role in the Tlr9-mediated immunosurveillance against pathogens and cancers. From the clinical point of view, CXCL14/CpG DNA could be useful as a new type of vaccine adjuvant.

The epigenetic regulation of CXCL14 plays a role in the pathobiology of oral cancers

Background: Chemokines selectively attract and activate leukocytes and play roles in a variety of homeostatic and disease processes. Explore the biological properties of CXCL14 seems complicated due to unknown functional characteristics of CXCL14 in cancer. Methods: To study the multistep process of oral cancer development, we analyzed oral samples spanning normalcy, dysplasia and cancer from multiple perspectives, revealing a cascade of progressive changes. Results: CXCL14 protein was expressed in the cytoplasm adjacent to tumors. T classification (P<0.001), clinical stage (P=0.0013) and nodal metastasis (P=0.0035) were significantly associated with CXCL14 in relationships between CXCL14 expression levels and tumor and patient characteristics. Compared with non-tumor tissue, expression of the epidermal growth factor receptor (EGFR) gene was increased in dysplasia and was further sustained in cancer. Our data show an inverse relationship between CXCL14 and EGFR expression levels in tumor cells indicating that CXCL14 expression is beneficial for tumor suppression. To explore epigenetic regulation and the impact of CXCL14 on oral cancer, analysis of CpG islands methylation in the CXCL14 promoter region indicated that the abnormal hypermethylation of that promoter region in tumor cells and tissues is one of the mechanisms causing the reduced expression. Restoration of CXCL14 expression was induced by treatment with 5-aza-2'-deoxycytidine. Using in vivo mouse models, we demonstrate that the restoration of CXCL14 expression in irradiation-induced oral carcinoma cells induces the expression of Late Cornified Envelope (LCE) genes. Conclusions: Our data suggest that LCE genes are a novel target of CXCL14 and are likely to have a tumor suppressor function through the modulation of CXCL14 expression. In conclusion, CXCL14 might play a pivotal role in the pathobiology of oral cancer, probably by regulating DNA methylation and leukocyte migration. The level of CXCL14 expression may be a valuable adjuvant parameter to predict the prognosis of patients with oral carcinoma and may be a potential therapeutic target.

[Expression and its promoter methylation of chemokine CXC ligand 14 in peripheral blood mononuclear cells from patients with lupus]

OBJECTIVE

To analyze the expression and its promoter methylation of chemokine CXC ligand 14 (CXCL14) in peripheral blood mononuclear cells (PBMCs) from patients with systemic lupus erythematosus (SLE).

METHODS

The RNAs of PBMCs from 28 SLE patients and 20 healthy controls were isolated and reversely transcribed into cDNAs. Using GAPDH as the internal reference, the levels of CXCL14 ex-pression were detected by real-time polymerase chain reaction (PCR). The correlation between CXCL14 expression and the clinic pathological fe atures of SLE were further analyzed. DNA methylation was analyzed by bisulfite sequencing PCR (BSP).

RESULTS

Our data indicated that the level of CXCL14 in the PBMC of SLE patients was statistically lower than that in healthy controls (P < 0.05). Further analysis showed that CXCL14 expression was negatively correlated with anti-Sj gren syndrome B antibody(anti-SSB antibody, P < 0.01) and albuminuria(P < 0.05). However, CXCL14 expression was not significantly correlated with the indexes of SLE activity, renal damage, the level of anti-ds-DNA antibodies, complement C3 and C-reactive protein. In addition, we further demonstrated that the CXCL14 promoter hypermethylation expres-sion was significant higher than healthy controls.

CONCLUSIONS

Down-regulated of CXCL14 expression in PBMC maybe involved in the occur-rence or development of SLE disease. The loss of CXCL14 expression was regulated by promoter hypermethylation.

The Expression of HSPD1, SCUBE3, CXCL14 and Its Relations with the Prognosis in Osteosarcoma

The aim of the study was to explore the expression of three genes, HSPD1, SCUBE3, and CXCL14, in osteosarcoma cells and tissue, as well as their association with the prognosis of patients with osteosarcoma. The expression of HSPD1, SCUBE3, and CXCL14 in osteosarcoma cells was detected by using Western blotting method. siRNA was used to knockdown the expression of the three genes. CCK8 cell proliferation assay was used to observe the effect of siRNA interference on U2OS cell proliferation. The expression of the three genes in osteosarcoma tissue was detected employing immunohistochemical method. Kaplan-Meier survival analysis was used to compare the relations between the expression of the three genes and prognosis. The Western blotting results showed that the expression of Hsp70, SCUBE3 protein, and CXCL14 chemotactic factor in osteosarcoma cells was significantly higher than that in normal osteocytes (p < 0.05). After the three genes were interfered by siRNA, the mRNA and protein expression levels of these genes in osteosarcoma cells were significantly decreased (p < 0.05). The growth rate of U2OS cell after the siRNA interference was significantly lower than that before interference and that in the control group transfected with negative control siRNA (p < 0.05). The result of immunohistochemistry demonstrated that the expression of Hsp70, SCUBE3 protein, and CXCL14 chemotactic factor in osteosarcoma tissues was significantly higher than that in adjacent muscle tissue (p < 0.05). Kaplan-Meier survival analysis indicated that the survival rate of the patients with high expression of those three kinds of genes was obviously lower than that of other patients (p < 0.05). There was no significant difference between the survival rates of patients with high or low expression of two genes (p > 0.05). The expression of HSPD1, SCUBE3, and CXCL14 was all high in osteosarcoma tissues and cells; moreover, the three kinds of genes had close correlations with the prognosis of the patients. Targeted inhibition of these three genes could inhibit the proliferation of the tumor, which may become a new therapeutic target.

Knockdown of CXCL14 disrupts neurovascular patterning during ocular development

The C-X-C motif ligand 14 (CXCL14) is a recently discovered chemokine that is highly conserved in vertebrates and expressed in various embryonic and adult tissues. CXCL14 signaling has been implicated to function as an antiangiogenic and anticancer agent in adults. However, its function during development is unknown. We previously identified novel expression of CXCL14 mRNA in various ocular tissues during development. Here, we show that CXCL14 protein is expressed in the anterior eye at a critical time during neurovascular development and in the retina during neurogenesis. We report that RCAS-mediated knockdown of CXCL14 causes severe neural defects in the eye including precocious and excessive innervation of the cornea and iris. Absence of CXCL14 results in the malformation of the neural retina and misprojection of the retinal ganglion neurons. The ocular neural defects may be due to loss of CXCL12 modulation since recombinant CXCL14 diminishes CXCL12-induced axon growth in vitro. Furthermore, we show that knockdown of CXCL14 causes neovascularization of the cornea. Altogether, our results show for the first time that CXCL14 plays a critical role in modulating neurogenesis and inhibiting ectopic vascularization of the cornea during ocular development.

Elevated S100A6 (Calcyclin) enhances tumorigenesis and suppresses CXCL14-induced apoptosis in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is often resistant to existing therapy. We found elevated S100A6 levels in ccRCC tissues, associated with higher grade pathological features and clinical stages in ccRCC patients. Knockdown of S100A6 inhibited cell proliferation in vitro and tumor growth in vivo. Gene expression profiling suggests a novel function of S100A6 in suppressing apoptosis, as well as a relationship between S100A6 and CXCL14, a pro-inflammatory chemokine. We suggest that the S100A6/CXCL14 signaling pathway is a potential therapeutic target in ccRCC.

CXCL14 as an emerging immune and inflammatory modulator

CXCL14, a relatively novel chemokine, is a non-ELR (glutamic acid-leucine-arginine) chemokine with a broad spectrum of biological activities. CXCL14 mainly contributes to the regulation of immune cell migration, also executes antimicrobial immunity. The identity of the receptor for CXCL14 still remains obscure and therefore the intracellular signaling pathway is not entirely delineated. The present review summarizes the contribution of CXCL14 in these two aspects and discusses the biological mechanisms regulating CXCL14 expression and potential CXCL14 mediated functional implications in a variety of cells.

CXCL14-Like Immunoreactivity Exists in Somatostatin-Containing Cells of Mouse Pancreas

Immunohistochemical techniques were employed to investigate the distribution of the chemokine CXCL14, in the mouse pancreas. CXCL14-immunoreactive cells were detected in the peripheral region of the pancreatic islets and were immunoreactive for somatostatin, but not for glucagon, insulin, and pancreatic polypeptide. Immunoelectron microscopy indicated that the CXCL14-like peptide and somatostatin co-existed in the secretory granules. CXCL14, secreted from somatostatin-containing cells, may modulate insulin secretion in a paracrine fashion, and play a novel role in glucose homeostasis in addition to its well-known chemotactic activities.

Efficient one-pot synthesis of CXCL14 and its derivative using an N-sulfanylethylanilide peptide as a peptide thioester equivalent and their biological evaluation

CXCL14 is a CXC-type chemokine that exhibits chemotactic activity for immature dendritic cells, activated macrophages, and activated natural killer cells. However, its specific receptor and signaling pathway remain obscure. Recently, it was reported that CXCL14 binds to CXCR4 with high affinity and inhibits CXCL12-mediated chemotaxis. Furthermore, the CXCL14 C-terminal α-helical region is important for binding to its receptor. In this context, we chemically synthesized CXCL14 and its derivative with a one-pot method using N-sulfanylethylanilide peptide as a thioester equivalent. The synthetic CXCL14 proteins possessed inhibitory activities to CXCL12-mediated chemotaxis comparable with that of recombinant CXCL14. Moreover, we proved that chemically biotinylated CXCL14 binds to CXCR4 on cells by flow cytometry analysis.

Phenotypic and Functional Characterization of Ductal Carcinoma In Situ-Associated Myoepithelial Cells

BACKGROUND

Ductal carcinoma in situ (DCIS) is contained by myoepithelial cells that are morphologically similar to normal breast tissue myoepithelial cells. However, phenotypic and functional characteristics of DCIS-associated myoepithelial cells are not known. In this study, we aimed to assess the characteristics of DCIS-associated myoepithelial cells.

MATERIALS AND METHODS

Immunophenotypic and functional characteristics of myoepithelial cells of pure DCIS, the DCIS component of infiltrating duct carcinoma (IDC), and the adjacent normal breast tissue of both groups (30 cases in each group) was assessed using phenotypic (CK5/6, CK14, p63, and calponin) and functional markers (maspin and CXCL14).

RESULTS

There was a decrease in expression of CK14, p63, and calponin in pure DCIS-associated myoepithelial cells compared with normal breast tissue myoepithelial cells (43.3% vs. 80.3%, 3.3% vs. 70%, 46.6 vs. 93.3%, respectively) and in the DCIS component of IDC compared with normal breast tissue myoepithelial cells (56.6% vs. 100%, 3.3% vs. 73.3%, 56.6% vs. 96.6%, respectively). CK5/6 expression was low to absent in myoepithelial cells of pure DCIS and the DCIS component of IDC as well as normal breast tissue myoepithelial cells. Maspin was expressed in all samples of normal breast tissue; however, 20% of pure DCIS and 26.6% of the DCIS component of IDC showed decreased expression. CXCL14 expression was greater in pure DCIS compared with adjacent normal breast tissue and the DCIS component of IDC.

CONCLUSION

Decreased expression of myoepithelial cell markers in DCIS suggests that DCIS-associated myoepithelial cells are phenotypically different from their normal counterparts. Two or more markers, preferably p63 and calponin, should be used to distinguish in situ from invasive breast carcinomas.

Type 2 diabetes: a protective factor for prostate cancer? An overview of proposed mechanisms

Diabetes mellitus and prostate cancer are 2 of the most important public health concerns, especially in the elderly population. Although diabetes has been recognized as a potent risk factor for many types of cancers, there is a large amount of evidence that shows that it has a protective role against prostate cancer. The underlying cause of this protective role is not fully understood, however, some mechanisms have been proposed in this area. In the present study we have reviewed these mechanisms and some new mechanisms are also proposed.

Dimeric peptides of the C-terminal region of CXCL14 function as CXCL12 inhibitors

We recently reported that CXCL14 binds to CXCR4 with high affinity and inhibits CXCL12-mediated chemotaxis. Here we found that the C-terminal 51-77 amino acid residues of CXCL14 are responsible for CXCR4 binding. A disulfide dimer peptide of CXCL14(51-77) bound to CXCR4 with comparable affinity to full length CXCL14, and exhibited CXCL12 inhibitor activity. CXCR4 was efficiently internalized upon binding of dimeric CXCL14(51-77), thereby being reduced on the cell surface. Substitution of 5 amino acid residues in combination with the use of an oxime linker for dimerization increased the solubility and chemical stability of the dimeric CXCL14(51-77).