Interleukin-8 secreted by endothelial cells induces chemotaxis of melanoma cells through the chemokine receptor CXCR1

Self-assembled and perfusable microvasculature-on-chip for modeling leukocyte trafficking

Leukocyte recruitment from blood to tissue is a process that occurs at the level of capillary vessels during both physiological and pathological conditions. This process is also relevant for evaluating novel adoptive cell therapies, in which the trafficking of therapeutic cells such as chimeric antigen receptor (CAR)-T cells throughout the capillaries of solid tumors is important. Local variations in blood flow, mural cell concentration, and tissue stiffness contribute to the regulation of capillary vascular permeability and leukocyte trafficking throughout the capillary microvasculature. We developed a platform to mimic a biologically functional human arteriole-venule microcirculation system consisting of pericytes (PCs) and arterial and venous primary endothelial cells (ECs) embedded within a hydrogel, which self-assembles into a perfusable, heterogeneous microvasculature. Our device shows a preferential association of PCs with arterial ECs that drives the flow-dependent formation of microvasculature networks. We show that PCs stimulate basement membrane matrix synthesis, which affects both vessel diameter and permeability in a manner correlating with the ratio of ECs to PCs. Moreover, we demonstrate that hydrogel concentration can affect capillary morphology but has no observed effect on vascular permeability. The biological function of our capillary network was demonstrated using an inflammation model, where significantly higher expression of cytokines, chemokines, and adhesion molecules was observed after tumor necrosis factor-alpha (TNF-α) treatment. Accordingly, T cell adherence and transendothelial migration were significantly increased in the immune-activated state. Taken together, our platform allows the generation of a perfusable microvasculature that recapitulates the structure and function of an in vivo capillary bed that can be used as a model for developing potential immunotherapies.

A Narrative Review of Cytokine Networks: Pathophysiological and Therapeutic Implications for Inflammatory Bowel Disease Pathogenesis

Inflammatory bowel disease (IBD) is a lifelong inflammatory immune mediated disorder, encompassing Crohn's disease (CD) and ulcerative colitis (UC); however, the cause and specific pathogenesis of IBD is yet incompletely understood. Multiple cytokines produced by different immune cell types results in complex functional networks that constitute a highly regulated messaging network of signaling pathways. Applying biological mechanisms underlying IBD at the single omic level, technologies and genetic engineering enable the quantification of the pattern of released cytokines and new insights into the cytokine landscape of IBD. We focus on the existing literature dealing with the biology of pro- or anti-inflammatory cytokines and interactions that facilitate cell-based modulation of the immune system for IBD inflammation. We summarize the main roles of substantial cytokines in IBD related to homeostatic tissue functions and the remodeling of cytokine networks in IBD, which may be specifically valuable for successful cytokine-targeted therapies via marketed products. Cytokines and their receptors are validated targets for multiple therapeutic areas, we review the current strategies for therapeutic intervention and developing cytokine-targeted therapies. New biologics have shown efficacy in the last few decades for the management of IBD; unfortunately, many patients are nonresponsive or develop therapy resistance over time, creating a need for novel therapeutics. Thus, the treatment options for IBD beyond the immune-modifying anti-TNF agents or combination therapies are expanding rapidly. Further studies are needed to fully understand the immune response, networks of cytokines, and the direct pathogenetic relevance regarding individually tailored, safe and efficient targeted-biotherapeutics.

CXCR1: A Cancer Stem Cell Marker and Therapeutic Target in Solid Tumors

Therapy resistance is a significant concern while treating malignant disease. Accumulating evidence suggests that a subset of cancer cells potentiates tumor survival, therapy resistance, and relapse. Several different pathways regulate these purported cancer stem cells (CSCs). Evidence shows that the inflammatory tumor microenvironment plays a crucial role in maintaining the cancer stem cell pool. Typically, in the case of the tumor microenvironment, inflammatory pathways can be utilized by the tumor to aid in tumor progression; one such pathway is the CXCR1/2 pathway. The CXCR1 and CXCR2 receptors are intricately related, with CXCR1 binding two ligands that also bind CXCR2. They have the same downstream pathways but potentially separate roles in the tumor microenvironment. CXCR1 is becoming more well known for its role as a cancer stem cell identifier and therapeutic target. This review elucidates the role of the CXCR1 axis as a CSC marker in several solid tumors and discusses the utility of CXCR1 as a therapeutic target.

Induced pluripotent stem cell-derived astrocytes from patients with schizophrenia exhibit an inflammatory phenotype that affects vascularization

Molecular and functional abnormalities of astrocytes have been implicated in the etiology and pathogenesis of schizophrenia (SCZ). In this study, we examined the proteome, inflammatory responses, and secretome effects on vascularization of human induced pluripotent stem cell (hiPSC)-derived astrocytes from patients with SCZ. Proteomic analysis revealed alterations in proteins related to immune function and vascularization. Reduced expression of the nuclear factor kappa B (NF-κB) p65 subunit was observed in these astrocytes, with no incremental secretion of cytokines after tumor necrosis factor alpha (TNF-α) stimulation. Among inflammatory cytokines, secretion of interleukin (IL)-8 was particularly elevated in SCZ-patient-derived-astrocyte-conditioned medium (A_SCZCM). In a chicken chorioallantoic membrane (CAM) assay, A_SCZCM reduced the diameter of newly grown vessels. This effect could be mimicked with exogenous addition of IL-8. Taken together, our results suggest that SCZ astrocytes are immunologically dysfunctional and may consequently affect vascularization through secreted factors.

Interleukin-8 in Melanoma Pathogenesis, Prognosis and Therapy-An Integrated View into Other Neoplasms and Chemokine Networks

Cutaneous melanoma accounts for only about 7% of skin cancers but is causing almost 90% of deaths. Melanoma cells have a distinct repertoire of mutations from other cancers, a high plasticity and degree of mimicry toward vascular phenotype, stemness markers, versatility in evading and suppress host immune control. They exert a significant influence on immune, endothelial and various stromal cells which form tumor microenvironment. The metastatic stage, the leading cause of mortality in this neoplasm, is the outcome of a complex, still poorly understood, cross-talk between tumor and other cell phenotypes. There is accumulating evidence that Interleukin-8 (IL-8) is emblematic for advanced melanomas. This work aimed to present an updated status of IL-8 in melanoma tumor cellular complexity, through a comprehensive analysis including data from other chemokines and neoplasms. The multiple processes and mechanisms surveyed here demonstrate that IL-8 operates following orchestrated programs within signaling webs in melanoma, stromal and vascular cells. Importantly, the yet unknown molecularity regulating IL-8 impact on cells of the immune system could be exploited to overturn tumor fate. The molecular and cellular targets of IL-8 should be brought into the attention of even more intense scientific exploration and valorization in the therapeutical management of melanoma.

Novel diagnostic and prognostic biomarkers of colorectal cancer: Capable to overcome the heterogeneity-specific barrier and valid for global applications

Introduction

The heterogeneity-specific nature of the available colorectal cancer (CRC) biomarkers is significantly contributing to the cancer-associated high mortality rate worldwide. Hence, this study was initiated to investigate a system of novel CRC biomarkers that could commonly be employed to the CRC patients and helpful to overcome the heterogenetic-specific barrier.

Methods

Initially, CRC-related hub genes were extracted through PubMed based literature mining. A protein-protein interaction (PPI) network of the extracted hub genes was constructed and analyzed to identify few more closely CRC-related hub genes (real hub genes). Later, a comprehensive bioinformatics approach was applied to uncover the diagnostic and prognostic role of the identified real hub genes in CRC patients of various clinicopathological features.

Results

Out of 210 collected hub genes, in total 6 genes (CXCL12, CXCL8, AGT, GNB1, GNG4, and CXCL1) were identified as the real hub genes. We further revealed that all the six real hub genes were significantly dysregulated in colon adenocarcinoma (COAD) patients of various clinicopathological features including different races, cancer stages, genders, age groups, and body weights. Additionally, the dysregulation of real hub genes has shown different abnormal correlations with many other parameters including promoter methylation, overall survival (OS), genetic alterations and copy number variations (CNVs), and CD8+T immune cells level. Finally, we identified a potential miRNA and various chemotherapeutic drugs via miRNA, and real hub genes drug interaction network that could be used in the treatment of CRC by regulating the expression of real hub genes.

Conclusion

In conclusion, we have identified six real hub genes as potential biomarkers of CRC patients that could help to overcome the heterogenetic-specific barrier across different clinicopathological features.

Exosomes of adult human fibroblasts cultured on 3D silk fibroin nonwovens intensely stimulate neoangiogenesis

Background

Bombyx mori silk fibroin is a biomacromolecule that allows the assembly of scaffolds for tissue engineering and regeneration purposes due to its cellular adhesiveness, high biocompatibility and low immunogenicity. Earlier work showed that two types of 3D silk fibroin nonwovens (3D-SFnws) implanted into mouse subcutaneous tissue were promptly vascularized via undefined molecular mechanisms. The present study used nontumorigenic adult human dermal fibroblasts (HDFs) adhering to a third type of 3D-SFnws to assess whether HDFs release exosomes whose contents promote neoangiogenesis.

Methods

Electron microscopy imaging and physical tests defined the features of the novel carded/hydroentangled 3D-SFnws. HDFs were cultured on 3D-SFnws and polystyrene plates in an exosome-depleted medium. DNA amounts and D-glucose consumption revealed the growth and metabolic activities of HDFs on 3D-SFnws. CD9-expressing total exosome fractions were from conditioned media of 3D-SFnws and 2D polystyrene plates HDF cultures. Angiogenic growth factors (AGFs) in equal amounts of the two groups of exosomal proteins were analysed via double-antibody arrays. A tube formation assay using human dermal microvascular endothelial cells (HDMVECs) was used to evaluate the exosomes’ angiogenic power.

Results

The novel features of the 3D-SFnws met the biomechanical requirements typical of human soft tissues. By experimental day 15, 3D-SFnws-adhering HDFs had increased 4.5-fold in numbers and metabolized 5.4-fold more D-glucose than at day 3 in vitro. Compared to polystyrene-stuck HDFs, exosomes from 3D-SFnws-adhering HDFs carried significantly higher amounts of AGFs, such as interleukin (IL)-1α, IL-4 and IL-8; angiopoietin-1 and angiopoietin-2; angiopoietin-1 receptor (or Tie-2); growth-regulated oncogene (GRO)-α, GRO-β and GRO-γ; matrix metalloproteinase-1; tissue inhibitor metalloproteinase-1; and urokinase-type plasminogen activator surface receptor, but lesser amounts of anti-angiogenic tissue inhibitor metalloproteinase-2 and pro-inflammatory monocyte chemoattractant protein-1. At concentrations from 0.62 to 10 μg/ml, the exosomes from 3D-SFnws-cultured HDFs proved their angiogenic power by inducing HDMVECs to form significant amounts of tubes in vitro.

Conclusions

The structural and mechanical properties of carded/hydroentangled 3D-SFnws proved their suitability for tissue engineering and regeneration applications. Consistent with our hypothesis, 3D-SFnws-adhering HDFs released exosomes carrying several AGFs that induced HDMVECs to promptly assemble vascular tubes in vitro. Hence, we posit that once implanted in vivo, the 3D-SFnws/HDFs interactions could promote the vascularization and repair of extended skin wounds due to burns or other noxious agents in human and veterinary clinical settings.

Adult astrocytes from reptiles are resistant to proinflammatory activation via sustaining Vav1 expression

Adult mammalian astrocytes are sensitive to inflammatory stimuli in the context of neuropathology or mechanical injury, thereby affecting functional outcomes of the central nervous system (CNS). In contrast, glial cells residing in the spinal cord of regenerative vertebrates exhibit a weak astroglial reaction similar to those of mammals in embryonic stages. Macrophage migration inhibitory factor (MIF) participates in multiple neurological disorders by activation of glial and immune cells. However, the mechanism of astrocytes from regenerative species, such as gecko astrocytes (gAS), in resistance to MIF-mediated inflammation in the severed cords remains unclear. Here, we compared neural stem cell markers among gAS, as well as adult (rAS) and embryonic (eAS) rat astrocytes. We observed that gAS retained an immature phenotype resembling rat eAS. Proinflammatory activation of gAS with gecko (gMIF) or rat (rMIF) recombinant protein was unable to induce the production of inflammatory cytokines, despite its interaction with membrane CD74 receptor. Using cross-species screening of inflammation-related mediators from models of gMIF- and rMIF-induced gAS and rAS, we identified Vav1 as a key regulator in suppressing the inflammatory activation of gAS. The gAS with Vav1 deficiency displayed significantly restored sensitivity to inflammatory stimuli. Meanwhile, gMIF acts to promote the migration of gAS through regulation of CXCL8 following cord lesion. Taken together, our results suggest that Vav1 contributes to the regulation of astrocyte-mediated inflammation, which might be beneficial for the therapeutic development of neurological diseases.

miRNA and mRNA expression profiling reveals potential biomarkers for metastatic cutaneous melanoma

Purpose: This study aims to uncover potential biomarkers associated with cutaneous melanoma (CM) metastasis.Methods: The mRNA and microRNA (miRNA) expression data from the metastatic CM and non-metastatic CM population were obtained from The Cancer Genome Atlas database. Functional analysis, protein-protein interaction (PPI), and survival analysis were performed for differentially expressed mRNAs (DEmRNAs) and miRNAs (DEmiRNAs). The interaction between DEmRNAs and DEmiRNAs was analyzed. The expression of several key DEmRNAs and DEmiRNAs was validated by Gene Expression Omnibus datasets.Results: Overall, 1172 DEmRNAs and 26 DEmiRNAs were identified from metastatic and non-metastatic CM. Cytokine-cytokine receptor interaction and chemokine signaling pathway were key pathways. CXCR1, CXCR2, CXCR4, CCR1, CCR2, and CCR5 were hub genes in the PPI network. Among these, miR-29 c-3p, miR-100-5p, miR-150-5p, and miR-150-3p were not only diagnostic biomarkers but also related to survival time. miR-203a-3p interacted with CCR5 and LIFR, while miR-224-5p was strongly associated with CXCR4. LIFR, CXCR1, CXCR2, CXCR4, CCR1, CCR2, and CCR5 were enriched in the cytokine-cytokine receptor interaction pathway. The levels of seven DEmRNAs (CXCR1, CXCR2, CXCR4, CCR1, CCR2, CCR5, and LIFR) and two DEmiRNAs (miR-203a-3p and miR-224-5p) were validated using the GSE65568 and GSE109244 datasets, respectively.Conclusion: Our findings may provide novel biomarkers for CM metastasis.[Formula: see text].

Cytokines in Inflammatory Disease

This review aims to briefly discuss a short list of a broad variety of inflammatory cytokines. Numerous studies have implicated that inflammatory cytokines exert important effects with regard to various inflammatory diseases, yet the reports on their specific roles are not always consistent. They can be used as biomarkers to indicate or monitor disease or its progress, and also may serve as clinically applicable parameters for therapies. Yet, their precise role is not always clearly defined. Thus, in this review, we focus on the existing literature dealing with the biology of cytokines interleukin (IL)-6, IL-1, IL-33, tumor necrosis factor-alpha (TNF-α), IL-10, and IL-8. We will briefly focus on the correlations and role of these inflammatory mediators in the genesis of inflammatory impacts (e.g., shock, trauma, immune dysregulation, osteoporosis, and/or critical illness).

The Crucial Role of CXCL8 and Its Receptors in Colorectal Liver Metastasis

CXCL8 (also known as IL-8) can produce different biological effects by binding to its receptors: CXCR1, CXCR2, and the Duffy antigen receptor for chemokines (DARC). CXCL8 and its receptors are associated with the development of various tumor types, especially colorectal cancer and its liver metastases. In addition to promoting angiogenesis, proliferation, invasion, migration, and the survival of colorectal cancer (CRC) cells, CXCL8 and its receptors have also been known to induce the epithelial-mesenchymal transition (EMT) of CRC cells, to help them to escape host immunosurveillance as well as to enhance resistance to anoikis, which promotes the formation of circulating tumor cells (CTCs) and their colonization of distant organs. In this paper, we will review the established roles of CXCL8 signaling in CRC and discuss the possible strategies of targeting CXCL8 signaling for overcoming CRC drug resistance and cancer progression, including direct targeting of CXCL8/CXCR1/2 or indirect targeting through the inhibition of CXCL8-CXCR1/2 signaling.

Adipocytes Promote Early Steps of Breast Cancer Cell Dissemination via Interleukin-8

Fat is a major tissue component in human breast cancer (BC). Whether breast adipocytes (BAd) affect early stages of BC metastasis is yet unknown. BC progression is dependent on angiogenesis and inflammation, and interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF) are key regulators of these events. Here, we show that BAd increased the dissemination of estrogen receptor positive BC cells (BCC) in vivo in the zebrafish model of metastasis, while dissemination of the more aggressive and metastatic BCC such as estrogen receptor negative was unaffected. While anti-VEGF and anti-IL-8 exhibited equal inhibition of angiogenesis at the primary tumor site, anti-IL-8 reduced BCC dissemination whereas anti-VEGF had minor effects on this early metastatic event. Mechanistically, overexpression of cell-adhesion molecules in BCC and neutrophils via IL-8 increased the dissemination of BCC. Importantly, the extracellular in vivo levels of IL-8 were 40-fold higher than those of VEGF in human BC. Our results suggest that IL-8 is a clinical relevant and promising therapeutic target for human BC.

The CXCL8-CXCR1/2 pathways in cancer

Persistent infection or chronic inflammation contributes significantly to tumourigenesis and tumour progression. C-X-C motif ligand 8 (CXCL8) is a chemokine that acts as an important multifunctional cytokine to modulate tumour proliferation, invasion and migration in an autocrine or paracrine manner. Studies have suggested that CXCL8 and its cognate receptors, C-X-C chemokine receptor 1 (CXCR1) and CX-C chemokine receptor 2 (CXCR2), mediate the initiation and development of various cancers including breast cancer, prostate cancer, lung cancer, colorectal carcinoma and melanoma. CXCL8 also integrates with multiple intracellular signalling pathways to produce coordinated effects. Neovascularisation, which provides a basis for fostering tumour growth and metastasis, is now recognised as a critical function of CXCL8 in the tumour microenvironment. In this review, we summarize the biological functions and ficlinical significance of the CXCL8 signalling axis in cancer. We also propose that CXCL8 may be a potential therapeutic target for cancer treatment

Significant hepatic expression of IL-2 and IL-8 in biliary atresia compared with other neonatal cholestatic disorders

OBJECTIVES

Although the exact etiology of biliary atresia (BA) is still elusive, inflammation plays a key role. Release of proinflammatory cytokines from activated immune cells perpetuates the injury and causes biliary destruction. We aimed to study interleukin (IL)-2 and IL-8 expression in liver tissue of BA patients compared with other neonatal cholestatic disorders.

METHODS

The study included 59 infants with neonatal cholestasis in two groups; BA group (n=31) and non-BA group (n=28) with cholestatic disorders other than BA as controls. Demographic, clinical, laboratory, and histopathological parameters were collected. IL-2 and IL-8 immunostaining was performed. Immunostaining in portal cellular infiltrate was scored as positive or negative and expressed as the mean cell count in three portal tracts.

RESULTS

The mean value of IL-2 and IL-8 positive inflammatory cells was significantly higher in BA than in non-BA group (P-values of 0.004 and 0.002 respectively). IL-2 correlated significantly with IL-8 immunostaining in both BA and non-BA group (P<0.0001 for both). Furthermore, both cytokines in both groups correlated significantly with inflammatory activity in liver biopsy while there was no significant correlation with the other studied parameters. Yet, there was a trend of increased expression of IL-2 and IL-8 with increasing stage of fibrosis in BA group. This trend was not observed in non-BA group.

CONCLUSION

The significantly higher expression of IL-2 and IL-8 in patients with BA compared to non-BA suggests a potential role for these cytokines in the pathogenesis in therapy of this devastating neonatal hepatic disorder.

Mechanobiology of cell migration in the context of dynamic two-way cell-matrix interactions

Migration of cells is integral in various physiological processes in all facets of life. These range from embryonic development, morphogenesis, and wound healing, to disease pathology such as cancer metastasis. While cell migratory behavior has been traditionally studied using simple assays on culture dishes, in recent years it has been increasingly realized that the physical, mechanical, and chemical aspects of the matrix are key determinants of the migration mechanism. In this paper, we will describe the mechanobiological changes that accompany the dynamic cell-matrix interactions during cell migration. Furthermore, we will review what is to date known about how these changes feed back to the dynamics and biomechanical properties of the cell and the matrix. Elucidating the role of these intimate cell-matrix interactions will provide not only a better multi-scale understanding of cell motility in its physiological context, but also a more holistic perspective for designing approaches to regulate cell behavior.

Melanoma stem cells and metastasis: mimicking hematopoietic cell trafficking?

Malignant melanoma is a highly metastatic cancer that bears responsibility for the majority of skin cancer-related deaths. Amidst the research efforts to better understand melanoma progression, there has been increasing evidence that hints at a role for a subpopulation of virulent cancer cells, termed malignant melanoma stem or initiating cells (MMICs), in metastasis formation. MMICs are characterized by their preferential ability to initiate and propagate tumor growth and their selective capacity for self-renewal and differentiation into less tumorigenic melanoma cells. The frequency of MMICs has been shown to correlate with poor clinical prognosis in melanoma. In addition, MMICs are enriched among circulating tumor cells in the peripheral blood of cancer patients, suggesting that MMICs may be a critical factor in the metastatic cascade. Although these links exist between MMICs and metastatic disease, the mechanisms by which MMICs may advance metastatic progression are only beginning to be elucidated. Recent studies have shown that MMICs express molecules critical for hematopoietic cell maintenance and trafficking, providing a possible explanation for how circulating MMICs could drive melanoma dissemination. We therefore propose that MMICs might fuel melanoma metastasis by exploiting homing mechanisms commonly utilized by hematopoietic cells. Here we review the biological properties of MMICs and the existing literature on their metastatic potential. We will discuss possible mechanisms by which MMICs might initiate metastases in the context of established knowledge of cancer stem cells in other cancers and of hematopoietic homing molecules, with a particular focus on selectins, integrins, chemokines and chemokine receptors known to be expressed by melanoma cells. Biological understanding of how these molecules might be utilized by MMICs to propel the metastatic cascade could critically impact the development of more effective therapies for advanced disease.

One cell, multiple roles: contribution of mesenchymal stem cells to tumor development in tumor microenvironment

The discovery of tissue reparative and immunosuppressive abilities of mesenchymal stem cells (MSCs) has drawn more attention to tumor microenvironment and its role in providing the soil for the tumor cell growth. MSCs are recruited to tumor which is referred as the never healing wound and altered by the inflammation environment, thereby helping to construct the tumor microenvironment. The environment orchestrated by MSCs and other factors can be associated with angiogenesis, immunosuppression, inhibition of apoptosis, epithelial-mesenchymal transition (EMT), survival of cancer stem cells, which all contribute to tumor growth and progression. In this review, we will discuss how MSCs are recruited to the tumor microenvironment and what effects they have on tumor progression.

Chemotaxis in cancer

Chemotaxis of tumour cells and stromal cells in the surrounding microenvironment is an essential component of tumour dissemination during progression and metastasis. This Review summarizes how chemotaxis directs the different behaviours of tumour cells and stromal cells in vivo, how molecular pathways regulate chemotaxis in tumour cells and how chemotaxis choreographs cell behaviour to shape the tumour microenvironment and to determine metastatic spread. The central importance of chemotaxis in cancer progression is highlighted by discussion of the use of chemotaxis as a prognostic marker, a treatment end point and a target of therapeutic intervention.

CXCR1 and CXCR2 silencing modulates CXCL8-dependent endothelial cell proliferation, migration and capillary-like structure formation

CXCR1 and CXCR2 are receptors for angiogenic ELR+CXC chemokines and are differentially expressed on endothelial cells; however, their functional significance in angiogenesis remains unclear. In this study, we determined the functional significance of these receptors in modulating endothelial cell phenotype by knocking-down the expression of CXCR1 and/or CXCR2 in human microvascular endothelial cells (HMEC-1) using short-hairpin RNA (shRNA). Cell proliferation, migration, invasion and capillary-like structure (CLS) formation were analyzed. Our data demonstrate that knock-down of CXCR1 and/or CXCR2 expression inhibited endothelial cell proliferation, survival, migration, invasion and CLS formation. Additionally, we examined the mechanism of CXCL8-dependent CXCR1 and/or CXCR2 mediated phenotypic changes by evaluating ERK phosphorylation and cytoskeletal rearrangement and observed inhibition of ERK phosphorylation and cytoskeletal rearrangement in HMEC-1-shCXCR1, HMEC-1-shCXCR2 and HMEC-1-shCXCR1/2 cells. Together, these data demonstrate that CXCR1 and CXCR2 expression plays a critical role in regulating multiple biological activities in human microvascular endothelial cells.

CXCL8 enhances the angiogenic activity of umbilical cord blood-derived outgrowth endothelial cells in vitro

OECs (outgrowth endothelial cells), also known as late-EPCs (late-endothelial progenitor cells), have a high proliferation potential in addition to in vitro tube formation capability. In ischaemic animal models, injected OECs were integrated into regenerating blood vessels and improved neovascularization. Previous reports have demonstrated the expression of CXCL8 to be up-regulated in ischaemic tissues. It has also been documented that CXCL8 stimulates the angiogenic activity of mature ECs (endothelial cells). Therefore, it has been suggested that CXCL8 plays an important role in neovascularization in ischaemic tissues. However, it is still uncertain whether CXCL8 also stimulates the angiogenic activity of OECs. This study evaluated the effects of CXCL8 on the angiogenic activity of OECs in vitro. OECs were isolated from human UCB (umbilical cord blood)-derived mononuclear cells. Phenotypes of the OECs were assessed by flow cytometry, immunostaining, and real-time RT (reverse transcription)-PCR. The effects of CXCL8 on OECs were investigated by transwell migration assay and capillary tube formation assay on Matrigel. The OEC clones isolated from UCB expressed OEC phenotypes. In addition, CXCL8 receptors (CXCR1 and CXCR2) were expressed on these OEC clones. CXCL8 significantly stimulated the transwell migration and capillary tube formation of OECs. Neutralizing antibody against CXCR2, but not CXCR1, abolished a transwell migration of OECs induced by CXCL8, suggesting the involvement of CXCL8/CXCR2 axis in transwell migration. These results demonstrate that CXCL8 stimulates the angiogenic activity of UCB-derived OECs in vitro.

CXCL9 induces chemotaxis, chemorepulsion and endothelial barrier disruption through CXCR3-mediated activation of melanoma cells

Background:

Metastasis is associated with poor prognosis for melanoma. The formation of metastases is a multi-step process, in which cancer cells can subsequently acquire the potential to intravasate into the blood or lymph vessels, disseminate through the circulation, extravasate through the endothelium and invade the connective tissue. There is increasing evidence that chemokines have a pivotal role in the dissemination and establishment of melanoma metastasis.

Methods:

We isolated melanoma cells from melanoma metastasis and performed different migration assays and transendothelial resistance measurements of endothelial monolayers co-cultured with melanoma cells, in order to monitor barrier function and diapedesis and confirmed these results by confocal microscopy.

Results:

We observed that tumour endothelial cells (ECs) secrete high levels of CXCL9 in all, and CXCL10 in most melanoma metastases. Migration studies revealed that low concentrations of these chemokines induce chemotaxis, whereas high concentrations induce spontaneous migration of melanoma cells (chemokinesis/chemorepulsion) and the disruption of the endothelial barrier, resulting in an accelerated transendothelial migration (TEM). Addition of anti-CXCL9 or anti-CXCR3 antibodies to the co-cultures delayed the TEM of melanoma cells.

Conclusion:

Our data represent novel mechanisms by which tumour cells in melanoma metastases might use the chemokine-expressing endothelium to leave the tumour and eventually to form additional metastases at distinct sites.

Small molecule antagonists for CXCR2 and CXCR1 inhibit human colon cancer liver metastases

CXCR1 and CXCR2 are G-protein coupled receptors, that have been shown to play important role in tumor growth and metastasis, and are prime targets for the development of novel therapeutics. Here, we report that targeting CXCR2 and CXCR1 activity using orally active small molecule antagonist (SCH-527123, SCH-479833) inhibits human colon cancer liver metastasis mediated by decreased neovascularization and enhanced malignant cell apoptosis. There were no differences in primary tumor growth. These studies demonstrate the important role of CXCR2/1 in colon cancer metastasis and that inhibition of CXCR2 and CXCR1, small molecule antagonists provides a novel therapeutic strategy.

Interleukin-1β regulates the migratory potential of MDAMB231 breast cancer cells through the hypoxia-inducible factor-1α

The casual relationship between inflammation and tumour progression has been widely accepted and the etiology of breast cancer has been associated with inflammatory processes. Interleukin (IL)-1β, besides its central role in inflammation, has also been recognised as a powerful player in tumour progression, angiogenesis and invasiveness. Recently, there has been considerable interest in understanding the non-hypoxic upregulation of the hypoxia-inducible factor (HIF)-1α by IL-1 in neoplastic cells since aberrant expression of HIF-1α correlates with tumour progression. Here, using the highly invasive human breast cancer cell line MDAMB231, we studied the effect of IL-1β on tumour cell migration along with HIF-1α accumulation. We observed that non-hypoxic induction of HIF-1α by IL-1β in MDAMB231 was associated with increased cell migration, paralleled by upregulation of p38 MAPK phosphorylation and CXCL8/CXCR1 expression. Inhibition of HIF-1α by siRNA resulted in a significant reduction of CXCR1 expression and IL-1β-induced cell migration in MDAMB231 cells, thus confirming a role of HIF-1α in the non-hypoxic-IL-1β-dependent induction of migratory potentials. Our observation that IL-1 induces HIF-1α accumulation in MDAMB231 cells was confirmed in tumour cells growing in vivo using an experimental approach, mimicking the endogenous release of IL-1 in mice bearing MDAMB231 xenografts. Our in vivo data, along with the fact that inhibition of HIF-1α resulted in the decrease of IL-1β-promoted cell migration, further support the link between inflammation and cancer. The overall results may have important implications in those therapeutic approaches aimed to inhibit IL-1-mediated activities in tumour cells, specifically in breast cancer.

Targeting CXCR1/CXCR2 receptor antagonism in malignant melanoma

IMPORTANCE OF THE FIELD

The incidence of malignant melanoma is increasing throughout the world and is currently rising faster than any other cancer in men and second only to lung cancer in women. Current strategies focused on systemic therapy for treatment of melanoma have shown no effect on survival. Therefore there is a pressing need for developing novel targeted therapeutics.

AREAS COVERED IN THIS REVIEW

Our goal is to provide an overview regarding targeting CXCR1/2 in malignant melanoma, the rationale behind these approaches and the future perspective.

WHAT THE READER WILL GAIN

This review illustrates our current understanding of CXCR1/2 receptor in melanoma progression and metastasis. We describe approaches that are being developed to block CXCR1/2 activation, including low-molecular-weight antagonists, modified chemokines and antibodies directed against ligands and receptors.

TAKE HOME MESSAGE

The chemokine receptors CXCR1 and CXCR2 and their ligands play an important role in the pathogenesis of malignant melanoma. Recent reports demonstrated that CXCR1 is constitutively expressed in all melanoma cases irrespective of stage and grade, however, CXCR2 expression was restricted to aggressive melanoma tumors,. Furthermore, modulation of CXCR1/2 expression and/or activity has been shown to regulate malignant melanoma growth, angiogenesis and metastasis, suggesting CXCR1/2 targeting as a novel therapeutic approach for malignant melanoma.

Small interfering RNA-mediated CXCR1 or CXCR2 knock-down inhibits melanoma tumor growth and invasion

CXCR1 and CXCR2 are receptors for CXCL-8 and are differentially expressed on melanoma and endothelial cells. In this study, we determined the functional role of these receptors in melanoma progression. We stably knock-down the expression of CXCR1 and/or CXCR2 in A375-SM (SM; high metastatic) human melanoma cells by short-hairpin RNA transfection. Cell proliferation, migration, invasion, ERK phosphorlyation and cytoskeletal rearrangements were carried out in vitro. In vivo growth was evaluated using murine subcutaneous xenograft model. Our data demonstrate that knock-down of CXCR1 and/or CXCR2 expression, inhibited melanoma cell proliferation, survival, migration and invasive potential in vitro. Moreover, we also observed inhibition of ERK phosphorylation and cytoskeltal rearrangement in SM-shCXCR1, SM-shCXCR2 and SM-shCXCR1/2 cells. Furthermore, when SM-shCXCR1 or SM-shCXCR2 cells implanted in nude mice, tumor growth, proliferation and microvessel density was significantly inhibited as compared to SM-control cells. In addition, we observed a significant increase in melanoma cell apoptosis in SM-shCXCR1 and SM-shCXCR2 tumors compared to SM-control tumors. Together, these data demonstrate that CXCR1 and CXCR2 expression play a critical role in human melanoma tumor progression and, functional blockade of CXCR1 and CXCR2 could be potentially used for future therapeutic intervention in malignant melanoma.

Functional activity of CXCL8 receptors, CXCR1 and CXCR2, on human malignant melanoma progression

We examined the autocrine/paracrine role of interleukin-8 (CXCL8) and the functional significance of CXCL8 receptors, CXCR1 and CXCR2, in human malignant melanoma proliferation, migration, invasion and angiogenesis. We found that a panel of seven cell lines, even though at different extent, secreted CXCL8 protein, and expressed CXCR1 and CXCR2 independently from the CXCL8 expression, but depending on the oxygen level. In fact, hypoxic exposure increases the expression of CXCR1 and CXCR2. The cell proliferation of both M20 and A375SM lines, expressing similar levels of both CXCR1 and CXCR2 but secreting low and high amounts of CXCL8, respectively, was significantly enhanced by CXCL8 exposure and reduced by CXCL8, CXCR1 and CXCR2 neutralising antibodies, indicating the autocrine/paracrine role of CXCL8 in melanoma cell proliferation. Moreover, an increased invasion and migration in response to CXCL8 was observed in several cell lines, and a further enhancement evidenced under hypoxic conditions. A CXCL8-dependent in vivo vessel formation, evaluated through a matrigel assay, was also demonstrated. Furthermore, when neutralising antibodies against CXCR1 or CXCR2 were used, only the involvement of CXCR2, but not CXCR1 was observed on cell migration and invasion, while both receptors played a role in angiogenesis. In summary, our data demonstrate that CXCL8 induces cell proliferation and angiogenesis through both receptors and that CXCR2 plays an important role in regulating the CXCL8-mediated invasive and migratory behaviour of human melanoma cells. Thus, blocking the CXCL8 signalling axis promises an improvement for the therapy of cancer and, in particular, of metastatic melanoma.

CXCR1 and CXCR2 enhances human melanoma tumourigenesis, growth and invasion

The aggressiveness of malignant melanoma is associated with differential expression of CXCL-8 and its receptors, CXCR1 and CXCR2. However, the precise functional role of these receptors in melanoma progression remains unclear. In this study, we investigate the precise functional role of CXCR1 and CXCR2 in melanoma progression. CXCR1 or CXCR2 were stably overexpressed in human melanoma cell lines, SBC-2 (non-tumourigenic) and A375P (low-tumourigenic) exhibiting low endogenous expression of receptors. Functional assays were performed to study the resulting changes in cell proliferation, motility and invasion, and in vivo tumour growth using a mouse xenograft model. Our data demonstrated that CXCR1- or CXCR2-overexpressing SBC-2 and A375P melanoma cells had enhanced proliferation, chemotaxis and invasiveness in vitro. Interestingly, CXCR1 or CXCR2 overexpression in SBC-2 cells induced tumourigenicity, and A375P cells significantly enhanced tumour growth as examined in vivo. Immunohistochemical analyses showed significantly increased tumour cell proliferation and microvessel density and reduced apoptosis in tumours generated from CXCR1- or CXCR2-overexpressing melanoma cells. CXCR1- or CXCR2-induced modulation of melanoma cell proliferation and migration was observed to be mediated through the activation of ERK1/2 phosphorylation. Together, these studies demonstrate that CXCR1 and CXCR2 play essential role in growth, survival, motility and invasion of human melanoma.

Glioma-associated endothelial cells are chemoresistant to temozolomide

Temozolomide is considered the standard of care and drug of choice for the treatment of initially diagnosed malignant gliomas. Although well tolerated, temozolomide still has limited clinical efficacy. Following drug treatment, patient prognosis still remains poor; tumor recurrence is almost universal. We hypothesized that this lack of effectiveness with temozolomide is because this drug does not target the glioma microenvironment, which is highly vascular in malignant gliomas. To test this hypothesis we analyzed the effects of temozolomide on the tumor vasculature in vitro and in vivo. We found that this drug did not affect the viability or proliferation rate of endothelial cells isolated from human glioma specimens, although temozolomide was highly cytotoxic to the glioma cell lines U87MG and U251. Furthermore, temozolomide did not inhibit the migration of these glioma-associated endothelial cells, a key mechanism responsible for tumor angiogenesis. In in vivo studies, using the intracranial glioma mouse model, temozolomide did not cause a pronounced effect on microvessel density. Our findings show that temozolomide has no apparent effect on the glioma vascular microenvironment. Thus combination therapy with anti-vascular agents may enhance temozolomide effectiveness as glioma therapeutic protocol.

Small-molecule antagonists for CXCR2 and CXCR1 inhibit human melanoma growth by decreasing tumor cell proliferation, survival, and angiogenesis

PURPOSE

Melanoma, the most aggressive form of skin cancer, accounts for 75% of all skin cancer-related deaths and current therapeutic strategies are not effective in advanced disease. In the current study, we have investigated the efficacy of orally active small-molecule antagonist targeting CXCR2/CXCR1.

EXPERIMENTAL DESIGN

Human A375SM melanoma cells were treated with SCH-479833 or SCH-527123, and their effect on proliferation, motility, and invasion was evaluated in vitro. We examined the downstream signaling events in the cells following treatment with antagonists. For in vivo studies, A375SM cells were implanted subcutaneously into athymic nude mice followed by administration of SCH-479833, SCH-527123, or hydroxypropyl-beta-cyclodextrin (20%) orally for 21 days and their effect on tumor growth and angiogenesis was evaluated.

RESULTS

Our data show that SCH-479833 or SCH-527123 inhibited the melanoma cell proliferation, chemotaxis, and invasive potential in vitro. Treatment of melanoma cells with SCH-479833 or SCH-527123 also inhibited tumor growth. Histologic and histochemical analyses showed significant (P < 0.05) decreases in tumor cell proliferation and microvessel density in tumors. Moreover, we observed a significant increase in melanoma cell apoptosis in SCH-479833- or SCH-527123-treated animals compared with controls.

CONCLUSION

Together, these studies show that selectively targeting CXCR2/CXCR1 with orally active small-molecule inhibitors is a promising therapeutic approach for inhibiting melanoma growth and angiogenesis.

Developmental changes in circulating IL-8/CXCL8 isoforms in neonates

Interleukin-8 (IL-8/CXCL8) is widely expressed in fetal tissues although inflammatory changes are not seen. Circulating IL-8 is comprised of an endothelial-derived [ala-IL-8](77) isoform and another, more potent [ser-IL-8](72) secreted by most other cells; [ala-IL-8](77) can be converted into [ser-IL-8](72) by proteolytic removal of an N-terminal pentapeptide from [ala-IL-8](77). In this study, we show [ala-IL-8](77) is the predominant circulating isoform of IL-8 in premature neonates but not in term neonates/adults, who have [ser-IL-8](72) as the major isoform. This isoform switch from the less potent [ala-IL-8](77) to [ser-IL-8](72) correlates with a maturational increase in the neutrophil chemotactic potency of plasma IL-8. The emergence of [ser-IL-8](72) as the major isoform is likely due to increased plasma [ala-IL-8](77)-convertase activity and/or changes in the cellular sources of IL-8. Developmental changes in IL-8 isoforms may serve to minimize its inflammatory effects in the fetus and also provide a mechanism to restore its full activity after birth.

The good and the bad of chemokines/chemokine receptors in melanoma

Chemokine ligand/receptor interactions affect melanoma cell growth, stimulate or inhibit angiogenesis, recruit leukocytes, promote metastasis, and alter the gene expression profile of the melanoma associated fibroblasts. Chemokine/chemokine receptor interactions can protect against tumor development/growth or can stimulate melanoma tumor progression, tumor growth and metastasis. Metastatic melanoma cells express chemokine receptors that play a major role in the specifying the organ site for metastasis, based upon receptor detection of the chemokine gradient elaborated by a specific organ/tissue. A therapeutic approach that utilizes the protective benefit of chemokines involves delivery of angiostatic chemokines or chemokines that stimulate the infiltration of cytotoxic T cells and natural killer T cells into the tumor microenvironment. An alternative approach that tackles the tumorigenic property of chemokines uses chemokine antibodies or chemokine receptor antagonists to target the growth and metastatic properties of these interactions. Based upon our current understanding of the role of chemokine-mediated inflammation in cancer, it is important that we learn to appropriately regulate the chemokine contribution to the tumorigenic 'cytokine/chemokine storm', and to metastasis.

Chemokines and the microenvironment in neuroectodermal tumor-host interaction

Chemokines and chemokine receptors play an important role in immune homeostasis and surveillance. Altered or defective expression of chemokines and/or chemokine receptors could lead to a disease state including autoimmune disorder or cancer. Tumors from glioblastoma, melanoma, and neuroblastoma secrete high levels of chemokines that can promote tumor growth and progression or induce stromal cells present in the tumor microenvironment to produce cytokines or chemokines which, in turn, can regulate angiogenesis, tumor growth, and metastasis. On the other hand, chemokines secreted by tumor or stromal cells can also attract leukocytes such as dendritic cells, macrophages, neutrophils, and lymphocytes which may downmodulate tumor growth. New therapies that are aimed at limiting tumor growth and progression by attracting immune effector cells to the tumor site with chemokines may hold the key to the successful treatment of cancer, although this approach may be hampered by possible tumor growth-stimulating effects of chemokines.

Melanoma and innate immunity--aActive inflammation or just erroneous attraction? Melanoma as the source of leukocyte-attracting chemokines

Unwanted growth breeds response--in the garden as well as in the tumor microenvironment. Innate immune cells mediate the earliest responses against melanoma or its precursors. However, the actual benefit by those cellular efforts is questionable. Why can early melanoma lesions actually develop in the face of rapid innate responses, and why is neutrophil- and macrophage-attracting chemokine secretion observed in melanoma? A surprisingly similar choice of chemokine receptors and chemokines are present in both innate immune cells and melanoma. Here we focus on analogies and differences between the two. Melanoma cell clusters show active chemokine signalling, with mostly tumor growth-enhancing and leukocyte-attracting effects. However, infiltrating leukocytes have only weak tumoricidal effects. Therefore, the observed leukocyte infiltration in melanoma might be at least in part an epiphenomenon of neoplastic self-stimulation rather than a full-fledged innate anti-tumor immune response.

Angiotensin and NMDA receptors in the median preoptic nucleus mediate hemodynamic response patterns to stress

The brain renin-angiotensin system plays an important role in the regulation of arterial pressure in response to stress, in part due to activation of AT1 receptors in the hypothalamic median preoptic nucleus (MnPO) by endogenous angiotensin II (ANG II). N-methyl-d-aspartate (NMDA) receptors are also involved in the angiotensinergic signaling pathway through the MnPO. We investigated whether AT1 and NMDA receptors in the MnPO are responsible for variable hemodynamic response patterns to stress. Cocaine or startle with cold water evoked a pressor response in Sprague-Dawley rats due, in some rats [vascular responders (VR)], to a large increase in systemic vascular resistance (SVR) and, in other rats [mixed responders (MR)], to small increases in SVR and cardiac output (CO). Microinjection of the GABAA agonist muscimol into the MnPO to block synaptic transmission attenuated the cocaine- or stress-induced increase in SVR and the decrease in CO seen in VR without altering either response in MR. Likewise, administration of either an AT1 receptor antagonist, losartan, or an NMDA receptor antagonist, MK-801, attenuated the increase in SVR and the decrease in CO in VR in response to either cocaine (losartan and MK-801) or startle with cold water (losartan) without altering either response in MR. We propose that the MnPO is responsible for greater SVR responses in VR and that AT1 and NMDA receptors play an important role in greater SVR responses in VR. These data provide additional support for the critical role of the MnPO in cardiovascular responses to stress.

The tumor suppressor semaphorin 3B triggers a prometastatic program mediated by interleukin 8 and the tumor microenvironment

Semaphorins are a large family of evolutionarily conserved morphogenetic molecules originally identified for their repelling role in axonal guidance. Intriguingly, semaphorins have recently been implicated in cancer progression (Neufeld, G., T. Lange, A. Varshavsky, and O. Kessler. 2007. Adv. Exp. Med. Biol. 600:118-131). In particular, semaphorin 3B (SEMA3B) is considered a putative tumor suppressor, and yet we found that it is expressed at high levels in many invasive and metastatic human cancers. By investigating experimental tumor models, we confirmed that SEMA3B expression inhibited tumor growth, whereas metastatic dissemination was surprisingly increased. We found that SEMA3B induced the production of interleukin (IL) 8 by tumor cells by activating the p38-mitogen-activated protein kinase pathway in a neuropilin 1-dependent manner. Silencing the expression of endogenous SEMA3B in tumor cells impaired IL-8 transcription. The release of IL-8, in turn, induced the recruitment of tumor-associated macrophages and metastatic dissemination to the lung, which could be rescued by blocking IL-8 with neutralizing antibodies. In conclusion, we report that SEMA3B exerts unexpected functions in cancer progression by fostering a prometastatic environment through elevated IL-8 secretion and recruitment of macrophages coupled to the suppression of tumor growth.

Cysteine-rich 61 (CCN1) enhances chemotactic migration, transendothelial cell migration, and intravasation by concomitantly up-regulating chemokine receptor 1 and 2

Cysteine-rich 61 (Cyr61; CCN1) plays an important role in tumor development and progression in many kinds of human malignancies. Here, we further show the enforced expression of the Cyr61 gene or treatment with recombinant Cyr61 protein enhanced expression of chemokine receptors CXCR1 and CXCR2 in gastric cancer AGS cells. Attenuation of Cyr61 levels in MKN-45 cells by transfecting with antisense Cyr61 significantly reduced the level of CXCR1 and CXCR2. It is suggested that Cyr61 tightly regulates the downstream genes CXCR1 and CXCR2 in gastric cancer cells. Supportively, reverse transcription-PCR and immunohistochemical analysis of human gastric adenocarcinoma showed that there was a high correlation between the expression level of Cyr61 and CXCR1/CXCR2. The up-regulated functionality of CXCR1 andCXCR2 in Cyr61-overexpressing AGS cells could facilitate their chemotactic migration toward interleukin-8, a physiologic ligand of CXCR1 and CXCR2. In addition, the Cyr61-mediated up-regulation of CXCR1/CXCR2 also contributed to transendothelial migration, as well as intravasation in a chick embryo model. Pharmacologic and genetic approaches revealed that phosphoinositide 3-kinase (PI3K)/Akt, but not extracellular signal-regulated kinase 1/2 or p38, signaling pathway is requisite for the up-regulation of CXCR1/CXCR2 mRNA and protein induced by Cyr61. Function-neutralizing antibody to integrin alphavbeta3, but not alpha(2)beta(1), effectively abolished Cyr61-elicited Src activation and the subsequent PI3K/Akt pathway. Antagonists toward integrin alphavbeta3, Src kinase, and PI3K/Akt not only suppressed CXCR1/CXCR2 elevation but also blocked chemotactic migration induced by Cyr61. In conclusion, we suggest that Cyr61 promotes interleukin-8-dependent chemotaxis, transendothelial migration, and intravasation by induction of CXCR1/CXCR2 through integrin alphavbeta3/Src/PI3K/Akt-dependent pathway.

Chemokines: novel targets for breast cancer metastasis

Recent studies have highlighted the possible involvement of chemokines and their receptors in breast cancer progression and metastasis. Chemokines and their receptors constitute a superfamily of signalling factors whose prognosis value in breast cancer progression remains unclear. We will examine here the expression pattern of chemokines and their receptors in mammary gland physiology and carcinogenesis. The nature of the cells producing chemokines or harboring chemokine receptors appears to be crucial in certain conditions for example, the infiltration of the primary tumor by leukocytes and angiogenesis. In addition, chemokines, their receptors and the interaction with glycosaminoglycan (GAGs) are key players in the homing of cancer cells to distant metastasis sites. Several lines of evidence, including in vitro and in vivo models, suggest that the mechanism of action of chemokines in cancer development involves the modulation of proliferation, apoptosis, invasion, leukocyte recruitment or angiogenesis. Furthermore, we will discuss the regulation of chemokine network in tumor neovascularity by decoy receptors. The reasons accounting for the deregulation of chemokines and chemokine receptors expression in breast cancer are certainly crucial for the comprehension of chemokine role in breast cancer and are in several cases linked to estrogen receptor status. The targeting of chemokines and chemokine receptors by antibodies, small molecule antagonists, viral chemokine binding proteins and heparins appears as promising tracks to develop therapeutic strategies. Thus there is significant interest in developing strategies to antagonize the chemokine function, and an opportunity to interfere with metastasis, the leading cause of death in most patients.

Overexpression of cyclin B1 in human esophageal squamous cell carcinoma cells induces tumor cell invasive growth and metastasis

Cyclin B1, a key component in the control of cell cycle progression from G(2) to M phase, has been implicated in tumorigenesis and the development of malignancy. However, the underlying mechanism by which cyclin B1 acts as an important oncogenic molecule remains largely unknown. Here we show that ectopic expression of cyclin B1 promotes cell proliferation, enhances cell motility and migration and results in increased ability of cells extravasating through the capillary endothelium. Interestingly, isogenic esophageal squamous cell carcinoma (ESCC) cells overexpressing cyclin B1 reveal strong invasive growth and high potential of metastasis to lung in xenograft mice. Suppression of cyclin B1 expression via small interfering RNA approach in high-metastatic esophagus carcinoma cells specifically inhibits their ability to metastasize from the primary ESCC to lung. Notably, altered expression of epithelial markers and mesenchymal markers were observed in the cells overexpressing cyclin B1, suggesting that cyclin B1 contributes to metastasis probably by promoting an epithelial-mesenchymal transition. These results establish a mechanistic link between cyclin B1 and ESCC metastasis and provide novel insight into understanding of cyclin B1 in the development of ESCC malignancy.

Expression profiling reveals genes associated with transendothelial migration of tumor cells: a functional role for alphavbeta3 integrin

Transendothelial migration is a key step in the extravasation of tumor cells during metastasis formation. Here, we have classified 45 human tumor cell lines derived from various tissues according to their capacity for transendothelial migration in vitro. We could distinguish cell lines showing strong transmigration (TEM+ cell lines) from others that did not transmigrate (TEM- cell lines). By DNA microarray analysis we could cluster TEM+ and TEM- cell lines according to their gene expression pattern and identify genes differentially expressed between the 2 groups. Among these we found the integrin beta3 subunit to be highly expressed in TEM+ cell lines as compared to TEM- cell lines. Cell surface localization of alphavbeta3 integrin receptors was exclusively found in TEM+ cell lines. Transendothelial migration of TEM+ cells but not their adhesion to the endothelial cells, or invasion into collagen gels could be blocked with an antibody against alphavbeta3 integrin and by RNAi mediated knock-down of the integrin beta3 subunit. These data establishes alphavbeta3 integrin as one key component of the transendothelial migration process of tumor cells, and as a potential target for anti-metastatic therapy. Our gene expression analysis of a defined collection of tumor cell lines can be used as a starting point to identify further genes functionally involved in transendothelial migration.

Tumor cell transendothelial passage in the absorbing lymphatic vessel of transgenic adenocarcinoma mouse prostate

The distribution and fine structure of the tumor-associated absorbing lymphatic vessel in the tumor mass of prostate adenocarcinoma and of seminal vesicle metastasis in transgenic mice was studied for the purpose of understanding the modality of tumor cell transendothelial passage from the extravasal matrix into the lymphatic vessel. In the tumor mass, two main cell populations were identified: stromal tumor cells and the invasive phenotype tumor (IPT) cells, having characteristics such as a highly electron-dense matrix rich in small granules lacking a dense core and massed nuclear chromatin, which is positive to immunostaining with anti-SV40 large T antigen antibody. Based on the ultrastructural pictures of different moments of the IPT cell transendothelial passage by ultrathin serial sections of the tumor-associated absorbing lymphatic vessel, the manner of its transendothelial passage through the intraendothelial channel, without involving intercellular contacts, was demonstrated. The presence of IPT cells in the parenchyma of satellite lymph node highlights its significant role in metastatic diffusion. The intraendothelial channel is the reply to the lack of knowledge regarding the intravasation of the tumor cell into the lymphatic circulation. The lymphatic endothelium would organize this channel on the basis of tumor cell-endothelial cell-extravasal matrix molecular interactions, which are as yet unidentified.

Elastin-elastases and inflamm-aging

Degradation of elastin, the main amorphous component of elastic fibers, by elastases belonging to the serine, metallo, or cysteine families leads to the generation of elastin fragments, designated as elastokines in keeping with their cytokine-like properties. Generation of elastokines from one of the longest lived protein in human might represent a strong tissue repair signal. Indeed, they (1) exhibit potent chemotactic activity for leukocytes, (2) stimulate fibroblast and smooth muscle cell proliferation, and (3) display proangiogenic activity as potent as VEGF. However, continuous exposure of cells to these matrikines, through increased elastase(s) expression with age, can contribute to the formation of a chronic inflammatory state, that is, inflamm-aging. Importantly, binding of elastokines to S-Gal, their cognate receptor, proved to stimulate matrix metalloproteinase expression in normal and cancer cells. Besides, these elastin fragments can polarize lymphocytes toward a Th-1 response or induce an osteogenic response in smooth muscle cells, and arterial wall calcification. In this chapter, emphasis will be made on the contribution of elastokines on the genesis of age-related arterial wall diseases, particularly abdominal aortic aneurysms (AAAs). An elastokine theory of AAAs progression will be proposed. Age is one main risk factor of cancer incidence and development. The myriad of biological effects exerted by elastokines on stromal and inflammatory cells led us to hypothesize that they might be main actors in elaborating a favorable cancerization field in melanoma; for instance these peptides could catalyze the vertical growth phase transition in melanoma through increased expression of gelatinase A and membrane-type 1 matrix metalloproteinase.

Chemokine receptor expression profiles in nasopharyngeal carcinoma and their association with metastasis and radiotherapy

Nasopharyngeal carcinoma (NPC) is an epithelial cancer that metastasizes predictably to cervical lymph nodes or distant organs. To assess whether the chemokine receptors of NPC cells play important roles in metastasis and are associated with radiotherapy history, the significance of various chemokine receptors (CCR1-10, CXCR1-6, XCR1, and CX3CR1) in NPC cell lines (TW01, TW04, HONE1, BM1, and AS1) and 52 NPC tumour biopsies from 48 patients with NPC was evaluated by mRNA and cytometric analyses, chemotaxis and actin polymerization assays, and immunohistochemical staining. Quantitative real-time reverse transcription-polymerase chain reaction revealed substantial expression of CCR7, CCR9, CXCR4, and CXCR6 mRNA in all the NPC cell lines. Of these, however, only CCR7, CXCR4, and CXCR6 were functional in NPC cells. Negative immunoreactivity for CCR7, CXCR4, and CXCR6 was demonstrated in almost all nasopharyngeal (NP) specimens from patients with primary NPC (n = 12) and in those with regional metastatic NPC (n = 15). However, expression of two or three of these chemokine receptors was demonstrated in NP specimens from patients with liver metastasis. Strong positivity was demonstrated for all three of these chemokine receptors in almost all of the regional and distant metastasis specimens. Significant differences in the expression of CCR7, CXCR4, and CXCR6 were found between primary tumours and metastases (p < 0.001, p < 0.001, and p < 0.002, respectively). This observation was further confirmed by laser capture microdissection of freshly frozen tumours from primary (n = 5) and metastatic (n = 8) NPC sites (p = 0.04, 0.03, and 0.03 for CCR7, CXCR4, and CXCR6, respectively). Finally, significant differences in CXCR4 expression were demonstrated between de novo and post-radiotherapy groups (1/22 vs. 5/8; p < 0.003). It appears reasonable to conclude, therefore, that CCR7, CXCR4, and CXCR6 are expressed and active in human NPC metastases, while CXCR4 expression is associated with radiotherapy history.

On the transendothelial passage of tumor cell from extravasal matrix into the lumen of absorbing lymphatic vessel

The aim of the research is the study of ultrastructural characteristics of the absorbing lymphatic vessel and of tumor cell passage through the endothelial lymphatic wall in (a) subcutaneous xenografts of T84 colon adenocarcinoma and B16 melanoma cell lines in nude mice and (b) human colorectal cancer. It was found that the tumor-associated absorbing lymphatic (TAAL) vessel has the same ultrastructural characteristics as the absorbing lymphatic vessel in normal organs, and it is provided with an endothelial wall wholly lacking a continuous basement membrane, pores, fenestrations, and open junctions. The TAAL vessel is always missing in the studied tumor masses as far as the central stroma is concerned, whereas it is always present in the peripheral area of the tumor and in the peritumoral connective tissue. The factors of extravasal matrix that play an active role in migration process of invasive phenotype tumor (IPT) cell after its detachment from tumor mass, as well as the role of cytoplasmic protrusions (pseudopod-like) in lymphatic recognition, were considered. For the first time, this study demonstrated the transendothelial passage of IPT cell inside the TAAL vessel lumen, which takes place by means of the intraendothelial channel (approximately 1.8-2.1 mum in diameter and 6.8-7.2 microm in length). This channel is to be considered a transient morphological entity organized by TAAL vessel endothelium by means of still unidentified molecular mechanisms. Therefore, it appears to be ascertained that the intraendothelial channel represents a step forward in the knowledge of the drainage into lymphatic circulation of interstitial fluid and the answer to the lack of knowledge expressed till today by researchers concerning the modality of passage of the tumor cell through the endothelial wall of the TAAL vessel.

Production and upregulation of granulocyte chemotactic protein-2/CXCL6 by IL-1beta and hypoxia in small cell lung cancer

Small cell lung cancer (SCLC) is characterised by early and widespread metastasis. However, SCLC cells have so far been found to produce low levels of known pro-angiogenic factors. We speculated that SCLC cells might produce alternative pro-angiogenic factors. Here, we report that a panel of SCLC cell lines constitutively secrete granulocyte chemotactic protein-2 (GCP-2)/CXCL6, a CXC ELR+ chemokine. In contrast, none of the three tested NSCLC cell lines secreted GCP-2. Production of GCP-2 in vivo was also confirmed in seven out of nine specimens with SCLC. We demonstrate that expression of GCP-2 is mediated by NF-kappaB as ALLN, an NF-kappaB pathway inhibitor, almost completely abolished GCP-2 production in SCLC cell lines. We also demonstrate that GCP-2 can be significantly upregulated by IL-1beta and hypoxia in SCLC cell lines. This result suggests a role for GCP-2 in promoting tumour progression in vivo under unfavourable conditions such as oxygen deprivation. As SCLC cells express both GCP-2 and its receptors CXCR1 and CXCR2, their biological significance in SCLC progression was further studied. We demonstrate that GCP-2 is an autocrine growth factor. Cell proliferation was significantly inhibited by anti-GCP-2 neutralising antibody in two high-GCP-2-producing cell lines. In addition, expression of the proliferation marker PCNA was upregulated by exogenous GCP-2 in two low-GCP-2-producing cell lines. Taken together, these results suggest an important role for GCP-2 as an autocrine mitogen in the growth and metastasis of SCLC.

Does glycosylation of melanoma cells influence their interactions with fibronectin?

Cell surface integrins, especially those binding to fibronectin (FN), participate in processes of tumor cell invasion and metastasis. Changes in glycosylation of cell surface adhesion proteins are often associated with malignant transformation of cells. In this study we examined the influence of swainsonine (SW) on adhesion, wound healing and haptotactic migration on FN, comparing the responses of different human melanoma cell lines: primary WM35 and metastatic WM9, WM239 and A375. We also examined the role of alpha subunits in adhesion to FN. All of the antibodies inhibited adhesion to FN but with different efficiencies depending on the cell line. Adhesion was mediated mainly by integrin alpha(5)beta(1) (WM9, A375), alpha(3)beta(1) (WM35, A375, WM239). Scratch wound repair was significantly faster on FN-coated wells than on plastic for all cells except for WM9. A375 and WM9 had the greatest migration ability, both expressing the highest level of alpha(5)beta(1) integrin. It seems very likely that adhesion to FN can be accomplished by many different integrins, but for effective migration alpha(5)beta(1) integrin is responsible. Only A375 and WM239 cell lines reacted to SW treatment. In the presence of SW WM239 and A375 cells had 70% and 40% increased adhesion to FN, and their migration was decreased 40% and 50%, respectively. Interestingly, although most of the cell lines share a common profile of integrins, each line interacted with FN differently. They differed mainly in the repertoire of integrins used for adhesion, and in the manner in which glycosylation affected these processes. The influence of SW was observed in two metastatic cell lines indicating the contribution of glycosylation status to the progression of melanoma. The lack of reaction to SW in WM9 cells may suggest that there is a threshold in the expression level of the highly branched N-glycans that may influence the adhesion and migration properties of the cell.