Coexpression of interleukin-8 receptors in head and neck squamous cell carcinoma

Multifaceted role of chemokines in solid tumors: From biology to therapy

Chemokines are small secretory chemotactic cytokines that control the directed migration of immune cells. Chemokines are involved in both anti-and pro-tumorigenic immune responses. Accumulating evidence suggests that the balance between these responses is influenced by several factors such as the stage of tumorigenesis, immune cell activation, recruitment of immune activating or immunosuppressive cells in the tumor microenvironment (TME), and chemokine receptor expression on effector and regulatory target cells. Cancer cells engage in a complex network with their TME components via several factors including growth factors, cytokines and chemokines that are critical for the growth of primary tumor and metastasis. However, chemokines show a multifaceted role in tumor progression including maintenance of stem-like properties, tumor cell proliferation/survival/senescence, angiogenesis, and metastasis. The heterogeneity of solid tumors in primary and metastatic cancers presents a challenge to the development of successful cancer therapy. Despite extensive research on how solid tumors escape immune cell-mediated anti-tumor response, finding an effective therapy for metastatic cancer still remains a challenge. This review discusses the multifarious roles of chemokines in solid tumors including various chemokine signaling pathways such as CXCL8-CXCR1/2, CXCL9, 10, 11-CXCR3, CXCR4-CXCL12, CCL(X)-CCR(X) in primary and metastatic cancers. We further discuss the novel therapeutic approaches that have been developed by major breakthroughs in chemokine research to treat cancer patients by the strategic blockade/activation of these signaling axes alone or in combination with immunotherapies.

Expression of Interleukin-1ß and Interleukin-8 in Oral Potentially Malignant Disorders and Carcinomas

Objective: To evaluate interleukin-1ß (IL-1ß) and interleukin-8 (IL-8) epithelial expressions in potentially malignant disorders of the oral mucosa as malignant predictive markers. Study design: About 55 tissues embedded in paraffin, comprising 15 oral lichen planus (OLP) lesions, 15 leukoplakias, 15 oral squamous cell carcinomas (OSCC), and 10 samples of normal oral mucosa were included in the study. IL-1ß and 8 expressions were assessed by immunohistochemistry using antibodies antihuman IL-1ß human (sc-7884, Santa Cruz® H-153) and antihuman IL-8 (ab7747, abcam®). The number of positive cells was compared using Student's t-test. Any p-value < 0.05 was considered statistically significant. Results: Nuclear and cytoplasmatic keratinocyte staining were positive for both cytokines in all study groups. However, a statistically significant decrease was observed within all cases compared to normal mucosa, both staining for IL-1β and 8. Moreover, IL-8 showed significant differences between OLP and leukoplakia, and when compared to OSCC. Conclusions: Oral epithelial expression of IL-1β and 8 seems to decrease when the malignant transformation of the oral mucosa increases.

An overview of the role of interleukin-8 in colorectal cancer

Colorectal Cancer (CRC), a common malignancy, is developing globally among people. Mutagenic insults activate peripheral nucleated cells to secrete chemokines in order to cause an inflammatory state. Despite the presence of multi-retrieving factors, elevated production of minor cytokines may speed-up the sever stages of the baseline inflammation targeting normal compensatory mechanism. IL-8 is a pro-inflammatory cytokine that is believed to be up-regulated in CRC to proceed primary condition into tumor behavior via induction of proliferation, angiogenesis and metastasis. Here, we assess the role of IL-8 in every step of CRC from signaling pathway and formation to invasion and discuss around new perspective therapy that targets IL-8 to manage CRC worldwide incidence and survival rate, more precisely.

CXCR2 is a novel cancer stem-like cell marker for triple-negative breast cancer

Background

Breast cancer is the leading cause of mortality from cancer in women worldwide, and cancer stem-like cell (CSC) is responsible for failure treatment of breast cancer. It plays an important role in resistant disease and metastasis. CD44/CD24 and ALDH are well-accepted protein markers of breast CSC, and it was reported that distinct subtypes of breast CSC were identified by the 2 markers. It is possible that there are various kinds of breast CSC which could be identified by different markers, and CSC markers utilized at present are not enough to fully understand breast CSC. Finding out more novel CSC markers is necessary. CXCR2 is involved in breast cancer metastasis, treatment resistance, and recurrence and has positive cross-talk with known breast CSC protein markers. It can be concluded that CXCR2 is related to breast CSC, and further study is in need.

Results

In this study, we assessed expression of CXCR2 with immunohistochemistry in breast cancer tissues from 37 patients and discovered that level of CXCR2 was significantly lower in triple-negative breast cancer (TNBC) compared with non-TNBC. CXCR2 expression decreased in estrogen receptor-negative or HER2-negative breast cancer, but not progesterone receptor-negative counterparts. By immunofluorescence, we observed high coexpression rate of CXCR2 and CSC-related proteins, including NANOG and SOX2. To prove our speculation that CXCR2 was a novel CSC marker for TNBC, we used 4T1 cell, which is a TNBC cell line, to analyze CXCR2-positive subpopulations and observed that CXCR2-positive 4T1 cells showed characteristics of CSC, including resistance to cisplatinum, radiation, and hypoxia, low proportion (around 1%), much more tumor xenografts, tumor spherule formation, and higher levels of CSC-related mRNA compared with CXCR2-negative cells.

Conclusion

CXCR2 is an acceptable and newly discovered CSC marker for only TNBC.

Identification of genes and signaling pathways associated with squamous cell carcinoma by bioinformatics analysis

The present study aimed to investigate the genes and signaling pathways associated with squamous cell carcinoma (SCC) by bioinformatics analysis. For this purpose, the GSE2503 was downloaded from the Gene Expression Omnibus database, and the differentially expressed genes (DEGs) between 6 normal skin and 5 SCC samples were analyzed using the Linear Models for Microarray Data package. Gene Ontology (GO) and pathway enrichment analysis of DEGs were performed, followed by functional annotation and construction of a protein-protein interaction (PPI) network. Subnetwork modules were subsequently identified and analyzed. A total of 181 DEGs, including 95 upregulated and 86 downregulated DEGs, were identified, in addition to 20 GO biological processes terms enriched by upregulated DEGs and 14 enriched by downregulated DEGs. The upregulated DEGs were enriched in 18 pathways, and the downregulated DEGs were enriched in 7 pathways. Following functional annotation, three upregulated transcription factors (TFs), including hypoxia inducible factor 1, alpha subunit (HIF1A), and six downregulated TFs were identified. In the PPI network and subnetwork, matrix metallopeptidase 1 (MMP1), also known as interstitial collagenase, and interleukin 8 (IL8) were the hub genes with the highest degree of connectivity (degree =8). Integrin alpha (ITGA)6 and 2 were enriched in several pathways, including focal adhesion and extracellular matrix-receptor interaction. DEGs of SCC were primarily enriched in pathways associated with cancer and cell adhesion. Therefore, DEGs such as IL8, MMP1, HIF1A, ITGA6 and ITGA2 may be potential targets for the diagnosis and treatment of SCC.

Trefoil Factor-3 (TFF3) Stimulates De Novo Angiogenesis in Mammary Carcinoma both Directly and Indirectly via IL-8/CXCR2

Mammary carcinoma cells produce pro-angiogenic factors to stimulate angiogenesis and tumor growth. Trefoil factor-3 (TFF3) is an oncogene secreted from mammary carcinoma cells and associated with poor prognosis. Herein, we demonstrate that TFF3 produced in mammary carcinoma cells functions as a promoter of tumor angiogenesis. Forced expression of TFF3 in mammary carcinoma cells promoted proliferation, survival, invasion and in vitro tubule formation of human umbilical vein endothelial cells (HUVEC). MCF7-TFF3 cells with forced expression of TFF3 generated tumors with enhanced microvessel density as compared to tumors formed by vector control cells. Depletion of TFF3 in mammary carcinoma cells by siRNA concordantly decreased the angiogenic behavior of HUVEC. Forced expression of TFF3 in mammary carcinoma cells stimulated IL-8 transcription and subsequently enhanced IL-8 expression in both mammary carcinoma cells and HUVEC. Depletion of IL-8 in mammary carcinoma cells with forced expression of TFF3, or antibody inhibition of IL-8, partially abrogated mammary carcinoma cell TFF3-stimulated HUVEC angiogenic behavior in vitro, as did inhibition of the IL-8 receptor, CXCR2. Depletion of STAT3 by siRNA in MCF-7 cells with forced expression of TFF3 partially diminished the angiogenic capability of TFF3 on stimulation of cellular processes of HUVEC. Exogenous recombinant hTFF3 also directly promoted the angiogenic behavior of HUVEC. Hence, TFF3 is a potent angiogenic factor and functions as a promoter of de novo angiogenesis in mammary carcinoma, which may co-coordinate with the growth promoting and metastatic actions of TFF3 in mammary carcinoma to enhance tumor progression.

The chemokine receptors CXCR1 and CXCR2 regulate oral cancer cell behaviour

BACKGROUND

Chemokines regulate physiological and pathological leucocyte trafficking, and chemokine receptors play a role in tumorigenesis. Expression of interleukin-8 (IL-8) receptors CXCR1 and CXCR2 has been shown in oral squamous cell carcinoma (OSCC) but remains poorly characterised. This aim of this study was to investigate CXCR1 and CXCR2 expression on normal oral keratinocytes (NOKs) and oral cancer cell lines (OCCL) and their relative response when exposed to IL-8 and growth-related oncogene-α (which selectively binds CXCR2).

METHODS

mRNA and protein expression was studied using RT-PCR, immunocytochemistry and flow cytometry. ELISAs were used to investigate ERK1/2 phosphorylation and MMP production, whereas a MTS-based assay was employed to study proliferation. Migration assays were carried out using modified Boyden chambers with a matrigel coating used for invasion assays.

RESULTS

mRNA expression of CXCR1 and CXCR2 was seen in both NOKs and OCCL with significantly higher protein expression in OCCL. Exposure to IL-8 and GROα increased intracellular ERK phosphorylation, proliferation, migration and invasion with OCCL showing a greater response than NOKs. These effects were mediated through CXCR1 and CXCR2 (for IL-8) and CXCR2 (for GROα) as receptor-blocking antibodies significantly inhibited the responses. IL-8 and GROα also increased MMP-9 release from NOKs and OCCL with significantly higher amounts released by OCCL. However, an increase in MMP-7 production was only seen in OCCL.

CONCLUSIONS

Functional CXCR1 and CXCR2 exist on normal and cancerous oral epithelial cells, and our data suggests a role for these receptors in oral cancer biology.

Targeting CXCR2 enhances chemotherapeutic response, inhibits mammary tumor growth, angiogenesis, and lung metastasis

Breast cancer is one of the leading causes of cancer deaths among females. Many challenges exist in the current management of advanced stage breast cancer as there are fewer recognized therapeutic strategies, often because of therapy resistance. How breast cancer cells evade chemotherapy and the underlying mechanism remains unclear. We and others have observed that malignant cells that survive initial chemo- and radiation therapy express higher levels of CXCR2 ligands, which may provide a survival benefit leading to therapy resistance. In this report, we test the hypothesis that CXCR2-dependent signaling in malignant cells may be critical for chemotherapy resistance and targeting this signaling axis may enhance the antitumor and antimetastatic activity of chemotherapeutic drugs and limit their toxicity. We used Cl66-wt, 4T1-wt, Cl66sh-CXCR2, and 4T1sh-CXCR2 cells expressing differential levels of the CXCR2 receptor to evaluate the role of targeting CXCR2 on chemotherapeutic responses. Knockdown of CXCR2 enhances paclitaxel and doxorubicin-mediated toxicity at suboptimal doses. Moreover, we observed an increase in the expression of CXCL1, a CXCR2 ligand in paclitaxel and doxorubicin-treated mammary tumor cells, which were inhibited following CXCR2 knockdown. Knockdown of CXCR2 enhanced antitumor activity of paclitaxel in an in vivo mammary tumor model. We observed significant inhibition of spontaneous lung metastases in animals bearing CXCR2 knockdown tumors and treated with paclitaxel as compared with the control group. Our data suggest the novel role of CXCR2 and its ligands in maintaining chemotherapy resistance and provide evidence that targeting CXCR2 signaling in an adjuvant setting will help circumvent chemotherapy resistance.

Role of NF-κB activation in matrix metalloproteinase 9, vascular endothelial growth factor and interleukin 8 expression and secretion in human breast cancer cells

The aims of this study were to assess the effects and potential mechanisms of parthenolide on the expression of vascular endothelial growth factor (VEGF), interleukin 8 (IL-8) and matrix metalloproteinase 9 (MMP-9) in human breast cancer cell line MDA-MB-231. After incubation with different concentrations of parthenolide for 24 h, MDA-MB-231 cells were collected, and the expressions of VEGF, IL-8 and MMP-9 were measured by real-time PCR and Western blot. The secretions of VEGF, IL-8 and MMP-9 in culture supernatant of MDA-MB-231 cells were then measured with ELISA assays. The NF-κB DNA-binding activity of breast cancer cells treated with parthenolide was analyzed using electrophoretic mobility assays. The real-time PCR and Western blot data showed that the expressions of VEGF, IL-8 and MMP-9 were significantly inhibited by parthenolide at both transcription level and protein level in MDA-MB-231 cells. ELISA results also confirmed these effects at a secretion level. The electrophoretic mobility assay results demonstrated that parthenolide can inhibit NF-κB DNA-binding activity of the breast cancer cells. Hence, the expression of VEGF, IL-8 and MMP-9 may be suppressed by parthenolide through the inhibition of NF-κB DNA-binding activity in MDA-MB-231 cells.

The role of CXC chemokines and their receptors in the progression and treatment of tumors

Chemokines are a class of functional chemotactic peptides that contribute to a number of tumor-related processes. They are functionally defined as soluble factors that are able to control the directional migration of leukocytes, in particular, during infection and inflammation. It appears, however, that the biological effects mediated by chemokines are far more complex, and virtually all cells, including many tumor cell types, can express chemokines and chemokine receptors. A growing body of evidence indicates that they also contribute to a number of tumor-related processes, such as tumor cell growth, angiogenesis/angiostasis, local invasion, and mediate organ-specific metastases of cancer. The CXC chemokine class is a subfamily of a large family of chemokines. During the occurrence and development of tumor cells, this chemokine class is often accompanied by a series of molecular and biological changes. The CXC chemokine subfamily is closely related to the body's immune response to tumors and biological behaviors of tumors. In this paper, CXC chemokines and their role in the progression and treatment of tumors will be reviewed.

Knockdown of aberrantly expressed nuclear localized decorin attenuates tumour angiogenesis related mediators in oral cancer progression model in vitro

Background

Oral cancer accounts for roughly 3% of cancer cases in the world with about 350,000 newly reported cases annually and a 5-year survival rate of only 50%. Majority of oral cancers are squamous cell carcinomas that originate in the oral mucosal epithelial linings. We have previously shown that in human malignant squamous cells carcinoma (SCC-25) as well as in dysplastic oral keratinocytes (DOK), a small leucine-rich multifunctional proteoglycan decorin is aberrantly expressed and localized in the nucleus where it interacts with nuclear epidermal growth factor receptor (EGFR). Post-transcriptional silencing of nuclear decorin significantly reduced IL-8 and IL8-dependent migration and invasion in these dysplastic and malignant oral epithelia. The objective of this study was to further examine the effects of nuclear decorin silencing on angiogenesis and angiogenesis related mediators in this oral cancer progression cell line model.

Methods

We have used multiplex PCR, western blotting, and in vitro endothelial tube formation assay to study angiogenesis and related pathways in nuclear decorin silenced (stable knockdown) DOK and SCC-25 cells.

Results

Nuclear decorin knockdown resulted in significant down regulation of IL-8 expression, however IL-10, and TGF-β expression was not affected in either DOK or SCC25 cells as measured by multiplex RT PCR. IL-8 receptor CXCR 1 and 2 expression was slightly lower in nuclear decorin silenced cells indicating a contributing mechanism in previously shown reduced IL-8 mediated migration and invasion phenotype in these cells. IL-8 is known to induce Matrix metalloproteinase 9 (MMP9) which not only plays a role in tumour migration and invasion but also induces angiogenic switch. We found MMP9 to be significantly reduced in nuclear decorin silenced dysplastic and malignant oral epithelia. Other potent angiogenic mediators, VEGF₁₈₉ and ANG-1 were either significantly reduced or completely abrogated in these cells. Angiogenesis as measured by endothelial tube-like formations of HUVEC cells was reduced by almost 50 percent when HUVECs were incubated in the presence of conditioned medium form nuclear decorin silenced dysplastic and malignant cell lines as compared to respective controls.

Conclusions

Together these results indicate that aberrantly expressed nuclear localized decorin strongly influences angiogenic potential of dysplastic and malignant oral epithelial cells.

Upregulation of C-X-C chemokine receptor type 1 expression is associated with late-stage gastric adenocarcinoma

Chemokine receptors play multiple roles in the development and progression of various tumor types. The aim of this study was to examine C-X-C chemokine receptor type 1 (CXCR1) protein expression in gastric adenocarcinoma and to investigate the clinical implications of CXCR1 upregulation. Expression of CXCR1 protein in 83 specimens of sporadic gastric adenocarcinoma and their corresponding non-neoplastic mucosa obtained by gastrectomy was assayed using immunohistochemistry. The intensity of immunostaining in tumor tissue was considered strong when tumor tissue staining was more intense than in the corresponding non-neoplastic mucosa; the intensity was null when staining was weaker in the tumor than in the corresponding non-neoplastic mucosa; and the intensity was weak when staining was similar in both tissues. Microvascular density in tumor tissue and its corresponding non-neoplastic mucosa was measured using monoclonal antibody against CD34. A strong correlation was observed between elevated CXCR1 protein expression and tumor stage (P<0.05). T stage, N stage and overall stage positively correlated with CXCR1 protein expression. Microvascular density was higher in tumors with strong CXCR1 protein expression, but the correlation with CXCR1 was not linear (P=0.07). Multiple logistic regression analyses showed that, compared to no or weak expression, overexpression of CXCR1 protein was a significant risk factor for high N stage (N2, N3). These results indicate that CXCR1 may be considered as a new and promising target for gastric adenocarcinoma therapy.

Salivary level of interleukin-8 in oral precancer and oral squamous cell carcinoma

BACKGROUND

Interleukin 8 (IL-8) is a pro-angiogenic, pro-inflammatory mediator that belongs to the family of chemokines. Due to its pro-angiogenic characteristic, it may play a vital role in tumour angiogenesis and progression.

OBJECTIVES

This study was designed to estimate the levels of salivary IL-8 in oral precancer and oral squamous cell carcinoma (OSCC) patients and compare them with healthy controls. The aim was to evaluate its efficacy as a potential biomarker for these diseases.

MATERIALS AND METHODS

Each group comprised 25 individuals. The salivary IL-8 levels were determined by enzyme-linked immunosorbent assay.

RESULTS

The levels of salivary IL-8 were found to be significantly elevated in patients with OSCC as compared to the precancer group (p < 0.0001) and healthy controls (p < 0.0001). However, the difference in salivary IL-8 concentrations among the precancer group and controls was statistically non-significant (p = 0.738).

CONCLUSIONS

Our results suggested that salivary IL-8 can be utilised as a potential biomarker for OSCC. Salivary IL-8 was found to be non-conclusive for oral premalignancy in this preliminary study. Hence, its possible role in transition from premalignancy to malignancy needs further research with larger sample sizes.

CLINICAL RELEVANCE

Saliva as a diagnostic biofluid offers a number of advantages over blood-based testing. The role of IL-8 in oral cancer if validated further by future research can provide an easy diagnostic test as well as a prognostic indicator for patients undergoing treatment. Therefore, if it's role in tumourigenesis can be sufficiently assessed, it could open up new avenues to find out novel treatment modalities for oral cancer.

High expression of CXCR2 is associated with tumorigenesis, progression, and prognosis of laryngeal squamous cell carcinoma

The laryngeal squamous cell carcinoma (LSCC) is one of the most common cancers threatening people's life. CXC-chemokine receptor type 2 (CXCR2) was reported to play critical roles in angiogenesis, tumorigenesis, and metastasis of several cancers such as colon cancer, melanoma, lung cancer, and so on. However, the expression of CXCR2 in LSCC and its association with clinical characters of LSCC remain unclear. Quantitative real-time reverse transcription-PCR and immunohistochemistry were used, respectively, to analyze the mRNA level and protein level of CXCR2 in 109 cases of LSCC tissues and 28 cases of tumor-adjacent normal tissues. The expression of CXCR2 in LSCC was significantly higher than that in tumor-adjacent tissues. Moreover, the expression level of CXCR2 protein in LSCC was significantly related to lymph node metastasis (P=.022), histopathological grade (P=.038), and 5 years' survival (P=.007). Cox regression analysis revealed that CXCR2 expression (P=.031), as well as lymphatic metastasis (P=.026) and TNM classification (P=.042), is an independent prognostic marker of LSCC. High expression of CXCR2 is also associated with short survival of LSCC patients. Our data indicate that the expression of CXCR2 is associated with the development and progression of LSCC. CXCR2 expression may serve as an independent prognostic marker for LSCC patients.

Role of chemokine receptor CXCR2 expression in mammary tumor growth, angiogenesis and metastasis

BACKGROUND

Chemokines and their receptors have long been known to regulate metastasis in various cancers. Previous studies have shown that CXCR2 expression is upregulated in malignant breast cancer tissues but not in benign ductal epithelial samples. The functional role of CXCR2 in the metastatic phenotype of breast cancer still remains unclear. We hypothesize that the chemokine receptor, CXCR2, mediates tumor cell invasion and migration and promotes metastasis in breast cancer. The objective of this study is to investigate the potential role of CXCR2 in the metastatic phenotype of mouse mammary tumor cells.

MATERIALS AND METHODS

We evaluated the functional role of CXCR2 in breast cancer by stably downregulating the expression of CXCR2 in metastatic mammary tumor cell lines Cl66 and 4T1, using short hairpin RNA (shRNA). The effects of CXCR2 downregulation on tumor growth, invasion and metastatic potential were analyzed in vitro and in vivo.

RESULTS

We demonstrated knock down of CXCR2 in Cl66 and 4T1 cells (Cl66-shCXCR2 and 4T1-shCXCR2) cells by reverse transcriptase polymerase chain reaction (RT-PCR) at the transcriptional level and by immunohistochemistry at the protein level. We did not observe a significant difference in in vitro cell proliferation between vector control and CXCR2 knock-down Cl66 or 4T1 cells. Next, we examined the invasive potential of Cl66-shCXCR2 cells by in vitro Matrigel invasion assay. We observed a significantly lower number (52 ± 5) of Cl66-shCXCR2 cells invading through Matrigel compared to control cells (Cl66-control) (182 ± 3) (P < 0.05). We analyzed the in vivo metastatic potential of Cl66-shCXCR2 using a spontaneous metastasis model by orthotopically implanting cells into the mammary fat pad of female BALB/c mice. Animals were sacrificed 12 weeks post tumor implantation and tissue samples were analyzed for metastatic nodules. CXCR2 downregulation significantly inhibited tumor cell metastasis. All the mice (n = 10) implanted with control Cl66 cells spontaneously developed lung metastasis, whereas a significantly lower number of mice (40%) implanted with Cl66-shCXCR2 cells exhibited lung metastases.

CONCLUSIONS

Together, these results suggest that CXCR2 may play a critical role in breast cancer invasion and metastasis.

The role of chemokines and their receptors in angiogenesis

Chemokines are a vertebrate-specific group of small molecules that regulate cell migration and behaviour in diverse contexts. So far, around 50 chemokines have been identified in humans, which bind to 18 different chemokine receptors. These are members of the seven-transmembrane receptor family. Initially, chemokines were identified as modulators of the immune response. Subsequently, they were also shown to regulate cell migration during embryonic development. Here, we discuss the influence of chemokines and their receptors on angiogenesis, or the formation of new blood vessels. We highlight recent advances in our understanding of how chemokine signalling might directly influence endothelial cell migration. We furthermore examine the contributions of chemokine signalling in immune cells during this process. Finally, we explore possible implications for disease settings, such as chronic inflammation and tumour progression.

CXC chemokines in cancer angiogenesis and metastases

The tumor microenvironment is extremely complex that depends on tumor cell interaction with the responding host cells. Angiogenesis, or new blood vessel growth from preexisting vasculature, is a preeminent feature of successful tumor growth of all solid tumors. While a number of factors produced by both the tumor cells and host responding cells have been discovered that regulate angiogenesis, increasing evidence is growing to support the important role of CXC chemokines in this process. As a family of cytokines, the CXC chemokines are pleiotropic in their ability to regulate tumor-associated angiogenesis, as well as cancer cell metastases. In this chapter, we will discuss the disparate activity that CXC chemokines play in regulating cancer-associated angiogenesis and metastases.

Immunohistochemical expression of interleukin-4, -6, -8, and -12 in inflammatory cells in surrounding invasive front of oral squamous cell carcinoma

BACKGROUND

Cytokines play important roles in the diverse interactions between tumor microenvironment and malignant cells. This study evaluated the association of interleukin (IL)-4, -6, -8, and -12 expressions and clinicopathologic parameters of 35 primary oral squamous cell carcinomas (OSCCs).

METHODS

Patients were staged according to the TNM clinical staging. Malignancy grading of invasive front was evaluated in hematoxylin-eosin (H&E)-stained slides. Immunohistochemical technique was performed on frozen tissue sections. Association between clinicopathologic parameters and IL expression were analyzed using nonparametric Kruskal-Wallis (alpha = 0.05) and Mann-Whitney U tests, with Bonferroni correction. Correlations between interleukins were analyzed by the Spearman coefficient.

RESULTS

Expression of ILs was verified in all samples; however, this finding was not related to clinicopathologic parameters. It was not the observed correlation between ILs.

CONCLUSIONS

Expression of IL-4, -6, -8, and -12 in the invasive front of OSCC is not involved with the clinicopathologic parameters of the disease.

Chemokines as mediators of neovascularization

Chemokines are a superfamily of homologous heparin-binding proteins, first described for their role in recruiting leukocytes to sites of inflammation. Chemokines have since been recognized as key factors mediating both physiological and pathological neovascularization in such diverse clinical settings as malignancy, wound repair, chronic fibroproliferative disorders, myocardial ischemia, and atherosclerosis. Members of the CXC chemokine family, structurally defined as containing the ELR amino acid motif, are potent inducers of angiogenesis, whereas another subset of the CXC chemokines inhibits angiogenesis. In addition, CCL2, a CC chemokine ligand, has been implicated in arteriogenesis. In this article, we review the current literature on the role of chemokines as mediators of neovascularization.

Molecular pathogenesis of oral squamous cell carcinoma: implications for therapy

The development of oral squamous cell carcinoma (OSCC) is a multistep process requiring the accumulation of multiple genetic alterations, influenced by a patient's genetic predisposition as well as by environmental influences, including tobacco, alcohol, chronic inflammation, and viral infection. Tumorigenic genetic alterations consist of two major types: tumor suppressor genes, which promote tumor development when inactivated; and oncogenes, which promote tumor development when activated. Tumor suppressor genes can be inactivated through genetic events such as mutation, loss of heterozygosity, or deletion, or by epigenetic modifications such as DNA methylation or chromatin remodeling. Oncogenes can be activated through overexpression due to gene amplification, increased transcription, or changes in structure due to mutations that lead to increased transforming activity. This review focuses on the molecular mechanisms of oral carcinogenesis and the use of biologic therapy to specifically target molecules altered in OSCC. The rapid progress that has been made in our understanding of the molecular alterations contributing to the development of OSCC is leading to improvements in the early diagnosis of tumors and the refinement of biologic treatments individualized to the specific characteristics of a patient's tumor.

A single nucleotide polymorphism in the matrix metalloproteinase-1 and interleukin-8 gene promoter predicts poor prognosis in tongue cancer

OBJECTIVE

Matrix metalloproteinase-1 (MMP-1) and interleukin-8 (IL-8) play an important role in cancer development and metastasis. There is a single nucleotide polymorphism (SNP) located in the promoter region of MMP-1 and IL-8 that regulates gene expression. MMP-1 -1607 2G/2G and IL-8 -251 A/A genotypes enhance transcriptional activity and may be associated with increased risk in malignant tumors. We therefore evaluated the impact of these SNPs in tongue squamous cell carcinoma (SCC).

METHODS

In this study, we genotyped 69 tongue SCC patients. The expression of MMP-1 and IL-8 in tongue SCC patients was analyzed by immunohistochemistry.

RESULTS

We found a significant difference in IL-8 A/A genotypes with nodal recurrence (P=0.0068). An analysis of disease-free survival rates showed that the presence of both MMP-1 2G/2G and IL-8 A/A genotypes was associated with a particularly poor prognosis (P=0.0032) and was an independent prognostic factor (P=0.001). The expression of MMP-1 was significantly correlated with the frequency of MMP-1 2G/2G genotypes (P=0.049).

CONCLUSION

These results suggest that SNP in the promoter region of MMP-1 and IL-8 plays an important role in tumor progression and recurrence through its expression in tongue SCC.

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.

Design of Noncompetitive Interleukin-8 Inhibitors Acting on CXCR1 and CXCR2

Chemokines CXCL8 and CXCL1 play a key role in the recruitment of neutrophils at the site of inflammation. CXCL8 binds two membrane receptors, CXCR1 and CXCR2, whereas CXCL1 is a selective agonist for CXCR2. In the past decade, the physiopathological role of CXCL8 and CXCL1 has been investigated. A novel class of small molecular weight allosteric CXCR1 inhibitors was identified, and reparixin, the first drug candidate, is currently under clinical investigation in the prevention of ischemia/reperfusion injury in organ transplantation. Reparixin binding mode to CXCR1 has been studied and used for a computer-assisted design program of dual allosteric CXCR1 and CXCR2 inhibitors. In this paper, the results of modeling-driven SAR studies for the identification of potent dual inhibitors are discussed, and three new compounds (56, 67, and 79) sharing a common triflate moiety have been selected as potential leads with optimized pharmacokinetic characteristics.

Differential regulation of CXC ligand 1 transcription in melanoma cell lines by poly(ADP-ribose) polymerase-1

The continuous production of the CXC ligand 1 (CXCL1) chemokine by melanoma cells is a major effector of tumor growth. We have previously shown that the constitutive expression of this chemokine is dependent upon transcription factors nuclear factor-kappa B (NF-kappaB), stimulating protein-1 (SP1), high-mobility group-I/Y (HMGI/Y), CAAT displacement protein (CDP) and poly(ADP-ribose) polymerase-1 (PARP-1). In this study, we demonstrate for the first time the mechanism of transcriptional regulation of CXCL1 through PARP-1 in melanoma cells. In its inactive state, PARP-1 binds to the CXCL1 promoter in a sequence-specific manner and prevents binding of NF-kappaB (p65/p50) to its element. However, activation of the PARP-1 enzymatic activity enhances CXCL1 expression, owing to the loss of PARP-1 binding to the CXCL1 promoter, accompanied by enhanced binding of p65 to the promoter. The delineation of the role of NF-kappaB-interacting factors in the putative CXCL1 enhanceosome will provide key information in developing strategies to block constitutive expression of this and other chemokines in cancer and to develop targeted therapy.

ELR+ CXC chemokines and their receptors (CXC chemokine receptor 1 and CXC chemokine receptor 2) as new therapeutic targets

ELR+ CXC chemokines, by direct interaction with their cell surface receptors CXC chemokine receptor 1 (CXCR1) and CXC chemokine receptor 2 (CXCR2), are believed to be crucially involved in the direct migration and activation of leukocytes. ELR+ CXC chemokines are supposed to play a key role in several inflammatory diseases and this makes ELR+ CXC chemokines and their receptors attractive therapeutic targets. The first aim of this review is to discuss the potential pathological role of ELR+ CXC chemokines in different pathologies, including ulcerative colitis (UC), ischaemia/reperfusion injury (RI), bronchiolitis obliterans syndrome (BOS) and tumor progression. Moreover, the most recently described inhibitors of ELR+ CXC chemokines and their therapeutic indications will be reviewed. Finally, the mode of action and the potential therapeutical use of reparixin, a new potent and selective inhibitor of CXCR1/2 activity, and its chemical derivatives are also discussed.

Genetic variation in IL-8 associated with increased risk and poor prognosis of breast carcinoma

Interleukin-8 (IL-8), a potent chemoattractant, has been demonstrated to contribute to human cancer progression through its potential functions as a mitogenic, angiogenic, and motogenic factor. We designed a broad study to investigate whether genetic variation in IL-8 has implications for susceptibility to and prognosis in breast carcinoma. We used the allele-specific polymerase chain reaction to characterize the variation of the IL-8 promoter region for 308 unrelated Tunisian patients with breast carcinoma and 236 healthy control subjects. Associations of the clinicopathologic parameters and the genetic marker with the rates of the breast carcinoma-specific overall survival and the disease-free survival were assessed using univariate and multivariate analyses. A significantly increased risk of breast carcinoma was associated with heterozygous IL-8 (-251) TA (OR=1.58, p=0.02) and homozygous IL-8 (-251) AA (OR=1.76, p=0.01) variants. A significant association between the IL-8 (-251) AA homozygous genotype and the aggressive phenotype of breast carcinoma as defined by the high histological grade, auxiliary's lymph node metastasis, and large tumor size was found. The IL-8 (-251) A allele manifested a significant association with decreased overall survival and disease-free survival for breast carcinoma patients. The polymorphism in the promoter region of the IL-8 gene may not only represent a marker for the increased risk of breast carcinoma but also predict the clinical outcome.

Cancer CXC chemokine networks and tumour angiogenesis

Chemokines have pleiotropic effects in regulating immunity, angiogenesis, stem cell trafficking, and mediating organ-specific metastases of cancer. In the context of angiogenesis, the CXC chemokine family is a unique group of cytokines known for their ability to behave in a disparate manner in the regulation of angiogenesis. The glutamic acid-leucine-arginine (ELR+) CXC chemokines are potent promoters of angiogenesis, and mediate their angiogenic activity via signal-coupling of CXCR2 on endothelium. By contrast, members of the CXC chemokine family, such as platelet factor-4 (PF4; CXCL4) and interferon-inducible CXC chemokines are potent inhibitors of angiogenesis, and use CXCR3 on endothelium to mediate their angiostatic activity. This review will discuss the biology of CXC chemokines in the context of angiogenesis related to cancer.

Gene polymorphisms of epidermal growth factor receptor and its downstream effector, interleukin-8, predict oxaliplatin efficacy in patients with advanced colorectal cancer

BACKGROUND

Researchers have recently reported an association between the epidermal growth factor receptor (EGFR) pathway and platinum-chemotherapy sensitivity in cancer patients. The (CA)(n) repeat polymorphism in intron 1 of the EGFR gene has been identified and found to alter EGFR expression in vitro as well as in vivo. A higher number of these CA repeats is associated with lower EGFR levels, whereas a low number of repeats is associated with higher EGFR levels. A second key polymorphism within the EGFR pathway (HER1 R497K) is a single nucleotide change (G-A) in codon 497 of the EGFR gene, which leads to an arginine-lysine substitution in the extracellular domain of subdomain IV. Furthermore, interleukin-8 (IL-8), recently identified as an EGFR downstream effector, plays a vital role in tumor angiogenesis and progression. Three other polymorphisms, each related to the IL-8 gene, have also been identified as playing a pivotal role in the EGFR pathway: T-251A in the promoter region of the IL-8 gene, G+2607C in exon 2 of the IL-8 receptor CXCR1 gene, and C+785T in exon 11 of the IL-8 receptor CXCR2 gene.

PATIENTS AND METHODS

In this study, we employed a 5'-end 33P-gATP-labeled polymerase chain reaction (PCR) protocol as well as the PCR-restriction fragment length polymorphism method in order to determine the genotypes for the previously mentioned polymorphisms in 105 patients with metastatic colorectal cancer. Tests were conducted to establish whether these polymorphisms could predict clinical outcome to 5-flourouracil/oxaliplatin chemotherapy.

RESULTS

Among all patients assessed, those possessing < 20 EGFR CA repeats were more likely to show disease progression than were patients with >or= 20 CA repeats (P = 0.019; log-rank test). Also, patients with the CXCR1 GC genotype were found to have an increased relative risk of time to tumor progression that was 1.55 (95% CI, 0.8-3.0) times that of patients with the homozygous GG genotype (P = 0.17; log-rank test).

CONCLUSION

Overall, our data suggest that gene polymorphisms active in the EGFR pathway may be associated with the sensitivity of colorectal cancer patients to platinum-based chemotherapy.

CXC chemokines in angiogenesis

CXC chemokines display pleiotropic effects in immunity, regulating angiogenesis, and mediating organ-specific metastases of cancer. In the context of angiogenesis, CXC chemokines are a unique family of cytokines, known for their ability to behave in a disparate manner in the regulation of angiogenesis. Members that contain the 'ELR' motif are potent promoters of angiogenesis, and mediate their angiogenic activity via binding and activating CXCR2 on endothelium. In contrast, members, in general, those are inducible by interferons and lack the ELR motif (ELR-) are potent inhibitors of angiogenesis, and bind to CXCR3 on endothelium. This review will discuss the biology of these angiogenic and angiostatic CXC chemokines and discuss their disparate angiogenic activity in the context of a variety of disorders.

Role of CXCR2/CXCR2 ligands in vascular remodeling during bronchiolitis obliterans syndrome

Angiogenesis and vascular remodeling support fibroproliferative processes; however, no study has addressed the importance of angiogenesis during fibro-obliteration of the allograft airway during bronchiolitis obliterans syndrome (BOS) that occurs after lung transplantation. The ELR(+) CXC chemokines both mediate neutrophil recruitment and promote angiogenesis. Their shared endothelial cell receptor is the G-coupled protein receptor CXC chemokine receptor 2 (CXCR2). We found that elevated levels of multiple ELR(+) CXC chemokines correlated with the presence of BOS. Proof-of-concept studies using a murine model of BOS not only demonstrated an early neutrophil infiltration but also marked vascular remodeling in the tracheal allografts. In addition, tracheal allograft ELR(+) CXC chemokines were persistently expressed even in the absence of significant neutrophil infiltration and were temporally associated with vascular remodeling during fibro-obliteration of the tracheal allograft. Furthermore, in neutralizing studies, treatment with anti-CXCR2 Abs inhibited early neutrophil infiltration and later vascular remodeling, which resulted in the attenuation of murine BOS. A more profound attenuation of fibro-obliteration was seen when CXCR2(-/-) mice received cyclosporin A. This supports the notion that the CXCR2/CXCR2 ligand biological axis has a bimodal function during the course of BOS: early, it is important for neutrophil recruitment and later, during fibro-obliteration, it is important for vascular remodeling independent of neutrophil recruitment.

Expression of interleukin-8 receptor A predicts poor outcome in patients with nasopharyngeal carcinoma

OBJECTIVES/HYPOTHESIS

The authors recently demonstrated that interleukin-8 (IL-8) is induced by Epstein-Barr virus encoding latent membrane protein 1 and that IL-8 is overexpressed in tumor cells and correlates significantly with angiogenesis in nasopharyngeal carcinoma. The present objective was to investigate the expressions and the roles of IL-8 receptors in nasopharyngeal carcinoma.

STUDY DESIGN

Retrospective patient file review and immunohistochemical study of tissues of patients with nasopharyngeal carcinoma.

METHODS

The authors examined the expressions of two high-affinity IL-8 receptors, IL-8 receptor A (IL8RA) and IL-8 receptor B (IL8RB), in 30 patients with nasopharyngeal carcinoma by immunohistochemical analysis.

RESULTS

As expected, both IL-8 receptors were expressed on microvessels in tumor nests and surrounding stroma. Interestingly, they were also abundantly expressed on tumor cells. The expressions of IL8RA and IL8RB had no associations with gender, metastasis, or clinical stage. However, the expression of IL8RA in tumors significantly correlated with a shorter overall survival rate (P = .0045). Although the estimated 5-year overall survival rate for IL8RA-negative patients was 68.2%, that in IL8RA-positive patients was only 33.3%.

CONCLUSION

The study results suggest that the expression of IL8RA in tumor cells becomes an important indicator of poor prognosis in nasopharyngeal carcinoma.

Revisiting immunosurveillance and immunostimulation: Implications for cancer immunotherapy

Experimental and clinical experience demonstrates that the resolution of a pathogenic challenge depends not only on the presence or absence of an immune reaction, but also on the initiation of the proper type of immune reaction. The initiation of a non-protective type of immune reaction will not only result in a lack of protection, but may also exacerbate the underlying condition. For example, in cancer, constituents of the immune system have been shown to augment tumor proliferation, angiogenesis, and metastases. This review discusses the duality of the role of the immune system in cancer, from the theories of immunosurveillance and immunostimulation to current studies, which illustrate that the immune system has both a protective role and a tumor-promoting role in neoplasia. The potential of using chemotherapy to inhibit a tumor-promoting immune reaction is also discussed.

KSHV-GPCR and CXCR2 transforming capacity and angiogenic responses are mediated through a JAK2-STAT3-dependent pathway

The Kaposi's sarcoma herpesvirus encodes a G-protein-coupled chemokine receptor termed KSHV-GPCR. Expression of this constitutively active GPCR leads to cell transformation and vascular overgrowth characteristic of Kaposi's sarcoma. Previously, we have shown that CXCR2, the closest human homolog, is similarly able to transform cells if continuously stimulated or constitutively activated by amino-acid exchange D138V of the DRY sequence. Here, we demonstrate that STAT3 activation is a prerequisite for transformation in KSHV-GPCR and CXCR2 transfected NIH 3T3 cells. In KSHV-GPCR and D138V transfected cells, STAT-3 is constitutively phosphorylated on Tyr705. In CXCR2 transfected NIH 3T3 cells and human microvascular endothelial cells (HMEC), which express the CXCR2 constitutively, STAT3 is phosphorylated upon stimulation with IL-8 (CXCL8). Focus formation in NIH 3T3 cells transfected with the KSHV-GPCR, CXCR2, or the D138V mutant, was blocked by the specific JAK2 inhibitor AG490. Typical functions of the CXCR2 including actin stress fiber formation, haptotaxis, and the angiogenic response in HMEC shown by tube formation in Matrigel were blocked by AG490. These data suggest that the transforming capacity and migratory responses that are involved in tumor development, metastasis, and angiogenesis in KSHV or CXCR2-expressing cells is at least partially mediated through a JAK2-STAT3 dependent pathway.

Serum concentrations of interleukin-8, vascular endothelial growth factor, and epidermal growth factor receptor in patients with squamous cell cancer of the head and neck

Squamous cell cancer of the head and neck (SCCHN) is associated with production of pro-inflammatory and pro-angiogenic cytokines. We hypothesized that cytokine serum levels will correlate with tumor volume and aggressiveness. We investigated interleukin-8 (IL-8), vascular endothelial growth factor (VEGF), and epidermal growth factor receptor (EGFR) in SCCHN. The patient population consisted of normal and irradiated controls: patients with newly diagnosed SCCHN, and patients with recurrent or metastatic disease. Pretreatment sera were studied by ELISA. Serum IL-8 levels, as opposed to VEGF or EGFR, were consistently elevated in patients with recurrent or metastatic disease. The differences in mean serum IL-8, compared to controls, were significant (p=0.02). Serum levels of IL-8 are consistently elevated in patients with recurrent or metastatic SCCHN and elevated levels may correlate with advanced or aggressive disease. Further, more intensive, study of IL-8 as a biomarker in SCCHN is warranted.

Identification of a gene expression signature associated with recurrent disease in squamous cell carcinoma of the head and neck

Molecular studies of squamous cell carcinoma of the head and neck (HNSCC) have demonstrated multiple genetic abnormalities such as activation of various oncogenes (Ras, Myc, epidermal growth factor receptor, and cyclin D1), tumor suppressor gene inactivation (TP53 and p16), and loss of heterozygosity at numerous chromosomal locations. Despite these observations, accurate and reliable biomarkers that predict patients at highest risk for local recurrence have yet to be defined. In an effort to identify gene expression signatures that may serve as biomarkers, we studied 41 squamous cell carcinoma tumors (25 primary and 16 locally recurrent) from various anatomical sites and 13 normal oral mucosal biopsy samples from healthy volunteers with microarray analysis using Affymetrix U133A GeneChip arrays. Differentially expressed genes were identified by calculating generalized t tests (P < 0.001) and applying a series of filtering criteria to yield a highly discriminant list of 2890 genes. Hierarchical clustering and image generation using standard software were used to visualize gene expression signatures. Several gene expression signatures were readily identifiable in the HNSCC tumors, including signatures associated with proliferation, extracellular matrix production, cytokine/chemokine expression, and immune response. Of particular interest was the association of a gene expression signature enriched for genes involved in tumor invasion and metastasis with patients experiencing locally recurrent disease. Notably, these tumors also demonstrated a marked absence of an immune response signature suggesting that modulation of tumor-specific immune responses may play a role in local treatment failure. These data provide evidence for a new gene expression-based biomarker of local treatment failure in HNSCC.

Potential for TRAIL as a Therapeutic Agent in Ovarian Cancer

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is known to induce apoptosis, otherwise known as programmed cell death, in many malignant cells without any known detrimental effects to normal cells. These aspects of TRAIL indicate the potential of TRAIL as a therapeutic agent in cancer. Ovarian cancer remains the deadliest gynecologic malignancy and is the fourth leading cause of death due to cancer in women. However, it has been shown in studies that ovarian cancer cells are sensitive to TRAIL-induced cell death when treated with TRAIL alone or in combination with chemotherapeutic agents. TRAIL signals through two death receptors, TRAIL-R1 and TRAIL-R2, to induce apoptosis. TRAIL also binds to two other cell surface receptors, TRAIL-R3 and TRAIL-R4, which do not have intracellular death domains and therefore do not transmit the apoptotic signal upon ligation with TRAIL. It has been shown that a chemokine, interleukin-8 (IL-8), may play a role in ovarian tumor progression due to its elevated presence in the fluid surrounding ovarian cancer tissues. Possible roles for IL-8 in ovarian tumorigenesis include angiogenesis and metastasis. Because the mechanism of regulation for TRAIL-induced apoptosis needs to be clarified, the role of IL-8 in TRAIL-induced apoptosis of ovarian cancer cells was studied. Results showed that the presence of IL-8 regulates cell-surface expression of TRAIL receptors in ovarian cancer cell lines in vitro. There may be a role for the p38 mitogen-activated protein kinase (MAPK) pathway in TRAIL-induced apoptosis of ovarian cancer cell.

Association of fibrin and interleukin 8 in human oral squamous cell carcinoma

OBJECTIVE

We have recently demonstrated that fibrin induces a specific, dose- and time-dependent upregulation of the angiogenic factor interleukin 8 (IL-8) from human oral squamous cell carcinoma (OSCC) cells in vitro. In this study we begin to test the hypothesis that fibrin induces IL-8 expression from tumor cells in vivo by studying their in vivo association in OSCC.

STUDY DESIGN

The presence of fibrin(ogen) was initially evaluated in 20 archival human OSCCs by means of immunohistochemistry with a polyclonal antibody. The presence of fibrin and IL-8 was then studied in 19 sections from 8 different patients' head and neck tumors (including 6 OSCCs) by means of immunohistochemistry with a monoclonal antibody against fibrin. These 8 tumors had been treated with inhibitors of new fibrin formation and degradation immediately after surgical removal.

RESULTS

Fibrin staining was found in 100% of the tumor sections tested. IL-8 staining was found in the cytoplasm of tumor cells in 100% of the studied tumors, including areas adjacent to fibrin.

CONCLUSIONS

These data demonstrate an in vivo association between fibrin and IL-8 in OSCC. These studies support our hypothesis that fibrin induces expression of protumorigenic factors such as IL-8 from tumor cells in vivo.

Identification of a region of the fibrin molecule involved in upregulation of interleukin-8 expression from human oral squamous cell carcinoma cells

A number of studies have implicated the fibrin-coagulation-fibrinolysis system in human tumour progression. Interleukin-8 (IL-8) mediates most of the angiogenic activity induced by human oral squamous cell carcinoma (OSCC) cells. We have recently demonstrated that: (1) fibrin is present in association with IL-8 expressing human OSCC cells in vivo and (2) in situ fibrin polymerisation induces a specific, dose and time-dependent upregulation of IL-8 expression from human OSCC cells in vitro. Our present studies extend this observation by demonstrating that in addition to fibrin formed in situ, both fibrin-derived liquid expressates (soluble fibrin) and preformed fibrin clots induced an over eight-fold stimulation of IL-8 expression from human OSCC cells as compared to media controls. IL-8 upregulation by soluble fibrin was dose-dependent. A monoclonal antibody against the N terminal region of the beta chain of human fibrin (Bbeta15-42) inhibited 67% of soluble fibrin-induced IL-8 expression from human OSCC cells. A peptide (GHRP), representing the sequence at the N terminus of this region, induced a dose-dependent stimulation of IL-8 expression, further confirming the role of this region. These studies directly support our hypothesis that fibrin induces protumourigenic factor expression from tumour cells, thus promoting tumour progression. Future studies to further characterise the role of the Bbeta15-42 region in tumour cell activation may lead to the design of peptide antagonists with important therapeutic potential.

Genomic dissection for characterization of cancerous oral epithelium tissues using transcription profiling

Genome-wide and high-throughput functional genomic tools offer the potential of identifying disease-associated genes and dissecting disease regulatory patterns. There is a need for a set of systematic bioinformatic tools that handles efficiently a large number of variables for extracting biological meaning from experimental outputs. We present well-characterized statistical tools to discover genes that are differentially expressed between malignant oral epithelial and normal tissues in microarray experiments and to construct a robust classifier using the identified discriminatory genes. Those tools include Wilks' lambda score, error rate estimated from leave-one out cross-validation (LOOCV) and Fisher Discriminant Analysis (FDA). High Density DNA microarrays and Real Time Quantitative PCR were employed for the generation and validation of the transcription profile of the oral cancer and normal samples. We identified 45 genes that are strongly correlated with malignancy. Of the 45 genes identified, six have been previously implicated in the disease, and two are uncharacterized clones.

Analysis of the role of chemokines in angiogenesis

Chemokines, a large family of inflammatory cytokines, have been shown to play a critical role in the regulation of angiogenesis during several pathophysiologic processes, such as tumor growth, wound healing and ischemia. Semiquantitative or quantitative angiogenesis assays are commonly utilized to screen the angiogenic or angiostatic activity of chemokines. These include in vitro endothelial cell activation assays and ex vivo or in vivo models of neovascularization. Chemokines may exert their regulatory activity on angiogenesis directly or as a consequence of leukocyte infiltration and/or the induction of growth factor expression. The effect of chemokines on endothelium can be assessed by performing in vitro assays on purified endothelial cell populations or by in vivo assays. Nevertheless, each model used to evaluate the angiogenic or angiostatic activity of a discrete factor has advantages and limitations. Thus, in order to avoid under- or overestimating the regulatory effect of chemokines on angiogenesis and to evaluate all aspects of the angiogenic process, multiple assays are usually performed. This review summarizes past and recent studies on chemokines as modulators of angiogenesis with particular emphasis on the methods currently used for the assessment of chemokine-mediated angiogenic or angiostatic responses.

Chemokines: key players in cancer

Chemokines are a family of low molecular weight (8-10 kDa) pro-inflammatory cytokines, which bind to G-protein coupled receptors. Their primary function is chemoattraction and activation of specific leucocytes in various immuno-inflammatory responses. However, new research suggests that they are key players in cancer being involved in the neoplastic transformation of cells, promotion of aberrant angiogenesis, tumour clonal expansion and growth, passage through the extracellular matrix (ECM), intravasation into blood vessels or lymphatics and the non-random homing of tumour metastasis to specific sites. In view of the increasing significance of chemokines and their receptors in cancers of a variety of types, manipulation of this signalling pathway may be important in the development of new anticancer agents. This review provides an overview of recent research advances in this field and examines the potential therapeutic benefits future developments may bring.

Fine tuning the transcriptional regulation of the CXCL1 chemokine

Constitutive activation of the transcription factor nuclear factor-κB (NF-κB) plays a major role in inflammatory diseases as well as cancer by inducing the endogenous expression of many proinflammatory proteins such as chemokines, and facilitating escape from apoptosis. The constitutive expression of chemokines such as CXCL1 has been correlated with growth, angiogenesis, and metastasis of cancers such as melanoma. The transcription of CXCL1 is regulated through interactions of NF-κB with other transcriptional regulatory molecules such as poly(ADP-ribose) polymerase-1 (PARP-1) and cAMP response element binding protein (CREB)-binding protein (CBP). It has been proposed that these two proteins interact with NF-κB and other enhancers to form an enhanceosome at the promoter region of CXCL1 and modulate CXCL1 transcription. In addition to these positive cofactors, a negative regulator, CAAT displacement protein (CDP), may also be involved in the transcriptional regulation of CXCL1. It has been postulated that the elevated expression of CXCL1 in melanomas is due to altered interaction between these molecules. CDP interaction with the promoter down-regulates transcription, whereas PARP and/or CBP interactions enhance transcription. Thus, elucidation of the interplay between components of the enhanceosome of this gene is important in finding more efficient and new therapies for conditions such as cancer as well as acute and chronic inflammatory diseases.

Role of interleukin-8 secreted from human oral squamous cell carcinoma cell lines

Interleukin-8 (IL-8) is an important cytokine involved in tumor growth and angiogenesis in a variety of malignancies. Furthermore, matrix metalloptoteinases (MMPs) also play important roles in the invasion and metastasis of carcinomas including oral squamous cell carcinoma (OSCC). We studied whether IL-8 and MMPs participate in tumorigenesis and metastasis of OSCC. First, we investigated the gene and protein expressions of IL-8 and IL-8 receptor (IL-8R), and the effect of IL-8 on proliferation, migration and invasion of OSCC. Second, we thus also investigated the effect of IL-8 on MMP release in OSCC cells. OSCC cell lines NA and HSC-4 constitutively expressed IL-8 mRNA and secreted its protein in vitro. The production of IL-8 was significantly enhanced by the addition of tumor necrosis factor (TNF)-alpha and IL-beta, but not interferon (IFN)-gamma, granulocyte-macrophage colony-stimulating factor (GM-CSF) or IL-2. Flow cytometric analysis revealed the constitutive expression of both receptors of IL-8, IL-8RA and IL-8RB, in OSCC cell lines. The expression of IL-8 receptors in HSC-4 cells was stronger than that in NA cells. The intensity of IL-8RA expression was stronger than that of IL-8RB expression in each cell line. The expression of IL-8 receptors was not altered by the addition of cytokines such as TNF-alpha and IL-1beta. The conditioned medium containing IL-8 from OSCC cell lines induced migration and invasion of OSCC cells, but did not change cell proliferation. The differences in migrational and invasive ability between NA cells and HSC-4 cells were correlated with the expression intensity of IL-8 receptors in each cell line. Neutralizing antibodies to IL-8, IL-8RA and IL-8RB partially inhibited the chemotactic activity induced by conditioned medium. The expression of MMP-2, -7 and -9 was detected in culture supernatants from these OSCC cell lines. The expressions of MMP-7 protein and mRNA were enhanced by the addition of rIL-8, but that of other MMPs was not observed in a similar manner. These results suggest that IL-8 secreted from OSCC may contribute to the invasion of OSCC through the regulation of MMP-7 expression.