Expression of chemokine receptor CXCR4 in nasopharyngeal carcinoma: pattern of expression and correlation with clinical outcome

Prognostic significance of SDF-1 chemokine and its receptors CXCR4 and CXCR7 involved in EMT of prostate cancer

Tendency to conversion from state of chronic inflammation to malignancy is a tumor characteristic trait, which encourages progression to its metastatic stage.. The inflammatory cells maintaining in the tumor inaugurate a communication with cancer cells and become tumor-fostering cells. Epithelial-mesenchymal transition (EMT) is a program supporting malignant cells during switch phenotype into metastatic form, providing looseness of cell-cell adherence and strengthens migratory or invasive features. EMT-undergone tumor cells become more aggressive and resistant to apoptosis. Additionally, malignant cells can be stimulated to manufacture proinflammatory factors throughout EMT program. Chronic inflammation is responsible for EMT induction in malignancies. Developed tumors induce inflammatory response through excretion of cytokines, chemokines and growth factors, which recruit populations of infiltrating immune cells straight to the tumor microenvironment. The inflammatory reaction potentially exerts tumor control, but instead it can be intercepted by the tumor to stimulate its own development in direction to metastatic form. Our study confirmed that SDF-1 chemokine and its receptors, CXCR4 and CXCR7 may participate in initiation of metastases formation and EMT process.

Epstein-Barr Virus-Associated Malignancies and Immune Escape: The Role of the Tumor Microenvironment and Tumor Cell Evasion Strategies

Simple Summary

The Epstein–Barr virus, also termed human herpes virus 4, is a human pathogenic double-stranded DNA virus. It is highly prevalent and has been linked to the development of 1–2% of cancers worldwide. EBV-associated malignancies encompass various structural and epigenetic alterations. In addition, EBV-encoded gene products and microRNAs interfere with innate and adaptive immunity and modulate the tumor microenvironment. This review provides an overview of the characteristic features of EBV with a focus on the intrinsic and extrinsic immune evasion strategies, which contribute to EBV-associated malignancies.

Abstract

The detailed mechanisms of Epstein–Barr virus (EBV) infection in the initiation and progression of EBV-associated malignancies are not yet completely understood. During the last years, new insights into the mechanisms of malignant transformation of EBV-infected cells including somatic mutations and epigenetic modifications, their impact on the microenvironment and resulting unique immune signatures related to immune system functional status and immune escape strategies have been reported. In this context, there exists increasing evidence that EBV-infected tumor cells can influence the tumor microenvironment to their own benefit by establishing an immune-suppressive surrounding. The identified mechanisms include EBV gene integration and latent expression of EBV-infection-triggered cytokines by tumor and/or bystander cells, e.g., cancer-associated fibroblasts with effects on the composition and spatial distribution of the immune cell subpopulations next to the infected cells, stroma constituents and extracellular vesicles. This review summarizes (i) the typical stages of the viral life cycle and EBV-associated transformation, (ii) strategies to detect EBV genome and activity and to differentiate various latency types, (iii) the role of the tumor microenvironment in EBV-associated malignancies, (iv) the different immune escape mechanisms and (v) their clinical relevance. This gained information will enhance the development of therapies against EBV-mediated diseases to improve patient outcome.

Insights into Nuclear G-Protein-Coupled Receptors as Therapeutic Targets in Non-Communicable Diseases

G-protein-coupled receptors (GPCRs) comprise a large protein superfamily divided into six classes, rhodopsin-like (A), secretin receptor family (B), metabotropic glutamate (C), fungal mating pheromone receptors (D), cyclic AMP receptors (E) and frizzled (F). Until recently, GPCRs signaling was thought to emanate exclusively from the plasma membrane as a response to extracellular stimuli but several studies have challenged this view demonstrating that GPCRs can be present in intracellular localizations, including in the nuclei. A renewed interest in GPCR receptors' superfamily emerged and intensive research occurred over recent decades, particularly regarding class A GPCRs, but some class B and C have also been explored. Nuclear GPCRs proved to be functional and capable of triggering identical and/or distinct signaling pathways associated with their counterparts on the cell surface bringing new insights into the relevance of nuclear GPCRs and highlighting the nucleus as an autonomous signaling organelle (triggered by GPCRs). Nuclear GPCRs are involved in physiological (namely cell proliferation, transcription, angiogenesis and survival) and disease processes (cancer, cardiovascular diseases, etc.). In this review we summarize emerging evidence on nuclear GPCRs expression/function (with some nuclear GPCRs evidencing atypical/disruptive signaling pathways) in non-communicable disease, thus, bringing nuclear GPCRs as targets to the forefront of debate.

Nonkeratinizing Nasopharyngeal Carcinoma, Undifferentiated Type With Trisomy 2: A Case Report and Short Review of Cytogenetic and Molecular Literature

Carcinoma originating from the surface epithelium of the nasopharynx is classified by the World Health Organization (WHO) as nasopharyngeal carcinoma (NPC) and has 3 main types: keratinizing squamous cell carcinoma (WHO type 1) and nonkeratinizing carcinoma, differentiated (WHO type II), and undifferentiated (WHO type III). Nonkeratinizing NPC is strongly associated with prior Epstein-Barr virus (EBV) infection. These tumors may be divided into differentiated and undifferentiated carcinoma. Histologically, the tumor is characterized by syncytia of large malignant cells with vesicular nuclei, conspicuous nucleoli, and easily observed mitotic figures. We report a case of a 14-year-old boy diagnosed with EBV and human papillomavirus (HPV)-positive NPC (WHO type 3) with cytogenetics showing the presence of mosaic trisomy 2. This case report brings to light a rare cytogenetic aberration to our knowledge only reported once before in the literature in a xenograft model.

Location Bias as Emerging Paradigm in GPCR Biology and Drug Discovery

GPCRs are the largest receptor family that are involved in virtually all biological processes. Pharmacologically, they are highly druggable targets, as they cover more than 40% of all drugs in the market. Our knowledge of biased signaling provided insight into pharmacology vastly improving drug design to avoid unwanted effects and achieve higher efficacy and selectivity. However, yet another feature of GPCR biology is left largely unexplored, location bias. Recent developments in this field show promising avenues for evolution of new class of pharmaceuticals with greater potential for higher level of precision medicine. Further consideration and understanding of this phenomenon with deep biochemical and molecular insights would pave the road to success. In this review, we critically analyze this perspective and discuss new avenues of investigation.

RTKs in pathobiology of head and neck cancers

Non-communicable diseases contribute to 71% of the deaths worldwide, of which cancers rank second after cardiovascular diseases. Among all the cancers, head and neck cancers (HNC) are consequential in augmenting the global cancer incidence as well as mortality. Receptor tyrosine kinases (RTKs) are emphatic for the matter that they serve as biomarkers aiding the analysis of tumor progression and metastasis as well as diagnosis, prognosis and therapeutic progression in the patients. The extensive researches on HNC have made significant furtherance in numerous targeted therapies, but for the escalating therapeutic resistance. This review explicates RTKs in HNC, their signaling pathways involved in tumorigenesis, metastasis and stemness induction, the association of non-coding RNAs with RTKs, an overview of RTK based therapy and associated resistance in HNC, as well as a sneak peek into the HPV positive HNC and its therapy. The review extrapolates the cardinal role of RTKs and RTK based therapy as superior to other existing therapeutic interventions for HNC.

Cancer-Associated Fibroblasts in Undifferentiated Nasopharyngeal Carcinoma: A Putative Role for the EBV-Encoded Oncoprotein, LMP1

Undifferentiated nasopharyngeal carcinoma (NPC) is 100% associated with Epstein–Barr virus (EBV) infection, and biopsies display variable levels of expression of the viral oncoprotein, latent membrane protein 1 (LMP1). Emerging evidence suggests an important role for cancer-associated fibroblasts (CAFs) in the NPC tumour microenvironment, yet the interaction between the virus, its latent gene products and the recruitment and activation of CAFs in the NPC tumour stroma remains unclear. This short review will discuss the current evidence for the importance of CAFs in NPC pathogenesis and outline a putative role for the EBV-encoded oncoprotein, LMP1, in governing tumour–stromal interactions.

Antitumor activity of cell-penetrant kinin B1 receptor antagonists in human triple-negative breast cancer cells

High nuclear expression of G protein-coupled receptors, including kinin B1 receptors (B1R), has been observed in several human cancers, but the clinical significance of this is unknown. We put forward the hypothesis that these "nuclearized" kinin B1R contribute to tumorigenicity and can be a new target in anticancer strategies. Our initial immunostaining and ultrastructural electron microscopy analyses demonstrated high B1R expression predominantly located at internal/nuclear compartments in the MDA-MB-231 triple-negative breast cancer (TNBC) cell line as well as in clinical samples of patients with TNBC. On the basis of these findings, in the present study, we evaluated the anticancer therapeutic potential of newly identified, cell-permeable B1R antagonists in MDA-MB-231 cells (ligand-receptor binding/activity assays and LC-MS/MS analyses). We found that these compounds (SSR240612, NG67, and N2000) were more toxic to MDA-MB-231 cells in comparison with low- or non-B1R expressing MCF-10A normal human mammary epithelial cells and COS-1 cells, respectively (clonogenic, MTT proliferative/cytocidal assays, and fluorescence-activated cell-sorting (FACS)-based apoptosis analyses). By comparison, the peptide B1R antagonist R954 unable to cross cell membrane failed to produce anticancer effects. Furthermore, the putative mechanisms underlying the anticancer activities of cell-penetrant B1R antagonists were assessed by analyzing cell cycle regulation and signaling molecules related to cell survival and apoptosis (FACS and western blot). Finally, drug combination experiments showed that cell-penetrant B1R antagonists can cooperate with suboptimal doses of chemotherapeutic agents (doxorubicin and paclitaxel) to promote TNBC death. This study provides evidence on the potential value of internally acting kinin B1R antagonists in averting growth of breast cancer.

The Microenvironment in Epstein-Barr Virus-Associated Malignancies

The Epstein–Barr virus (EBV) can cause a wide variety of cancers upon infection of different cell types and induces a highly variable composition of the tumor microenvironment (TME). This TME consists of both innate and adaptive immune cells and is not merely an aspecific reaction to the tumor cells. In fact, latent EBV-infected tumor cells utilize several specific mechanisms to form and shape the TME to their own benefit. These mechanisms have been studied largely in the context of EBV+ Hodgkin lymphoma, undifferentiated nasopharyngeal carcinoma, and EBV+ gastric cancer. This review describes the composition, immune escape mechanisms, and tumor cell promoting properties of the TME in these three malignancies. Mechanisms of susceptibility which regularly involve genes related to immune system function are also discussed, as only a small proportion of EBV-infected individuals develops an EBV-associated malignancy.

CXCL12 gene silencing down-regulates metastatic potential via blockage of MAPK/PI3K/AP-1 signaling pathway in colon cancer

Background

To investigate the effect of CXCL12 gene silencing on proliferation,invasion, angiogenesis and the relationship of MAPK/PI3K/AP-1 signaling pathway in colon cancer cells.

Methods

RT-PCR and Western-blot were used to detect the expression of CXCL12 mRNA and protein in four colon cancer cell lines. Human colon cancer cells were transfected with CXCL12 siRNA carrying by Lipofectamine 2000. The expression of CXCL12 protein was confirmed by immunoblotting. WST-1, invasion and angiogenesis assay were used to examine the effect on proliferation, invasion and angiogenesis in colon cancer cells after CXCL12 siRNA silence, respectively. The phosphorylation of MAPK/PI3K/AP-1 protein levels was detected by Western blotting in CXCL12 siRNA suppression DLD-1 cell.

Results

CXCL12 mRNA and proteins were only expressed in DLD-1 colon cancer cell lines. CXCL12 siRNA were transfected into DLD-1 cells, the expression CXCL12 proteins was significantly inhibited (P < 0.01), and the proliferation, invasion and angiogenesis of DLD-1 cells were inhibited significantly (P < 0.01). CXCL12 gene silencing resulted in blockage of MAPK, PI3K and AP-1 phosphorylation by CXCL12-induced in DLD-1 colon cancer cell.

Conclusion

The silencing CXCL12 gene significantly inhibits the proliferation, invasion and angiogenesis ability of some types colon carcinoma cells through down-regulation of MAPK/PI3K/AP-1 signaling pathway.

Role of SDF-1α/CXCR4 signaling pathway in clinicopathological features and prognosis of patients with nasopharyngeal carcinoma

The present study aims to explore the role of stromal cell-derived factor-1α (SDF-1α)/stromal cell-derived factor receptor-4 (CXCR4) signaling pathway to the clinicopathological features and prognosis of patients with nasopharyngeal carcinoma (NPC). From January 2009 to December 2010, 102 patients with NPC and 80 patients with chronic nasopharyngitis were enrolled for the study. Immunohistochemical staining, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting were employed to determine the expressions of SDF-1α and CXCR4 proteins in NPC tissues and chronic nasopharyngitis tissues. Chi-square test was conducted to analyze the associations of the expressions of SDF-1α and CXCR4 proteins with the clinicopathological features of NPC patients. Spearman rank correlation analysis was used to analyze the correlation between the SDF-1α protein expression and CXCR4 protein expression. The mRNA and protein expressions of SDF-1α and CXCR4 in NPC tissues were significantly higher than those in chronic nasopharyngitis tissues. The expressions of SDF-1α and CXCR4 proteins showed associations with T staging, N staging, tumor node metastasis (TNM) staging, skull base invasion, and cervical lymph node metastasis of NPC patients. Compared with NPC patients showing negative expressions of SDF-1α and CXCR4 proteins, those with positive expressions of SDF-1α and CXCR4 proteins had a significantly shorter survival time. SDF-1α protein, CXCR4 protein, EBV-IgG status, T staging, N staging, TNM staging, skull base invasion, and cervical lymph node metastasis were independent risk factors for the prognosis of NPC. The findings indicated that SDF-1α/CXCR4 signaling pathway might be associated with the clinicopathological features and prognosis of patients with NPC.

An investigation into the potential role of brain angiogenesis inhibitor protein 3 (BAI3) in the tumorigenesis of small-cell carcinoma: a review of the surrounding literature

Brain angiogenesis inhibitor protein 3 (BAI3) is from the adhesion group of seven-transmembrane spanning G protein-coupled receptors (GPCRs) and has been identified via gene expression profiling as being upregulated in small-cell lung cancer (SCLC) tumors. It has subsequently been validated as a sensitive and specific immunohistochemical marker for SCLC, helping to differentiate these tumors from morphologically similar large-cell neuroendocrine (LCNEC) malignancies. It is, however, still unclear as to the role BAI3 proteins might play in SCLC and indeed how they might contribute to tumorigenesis. Interestingly, the pattern of staining observed on immunohistochemistry was in fact nuclear as opposed to the membranous staining pattern expected of transmembrane-bound molecules. This fact has lead the authors to believe that the protein receptor is structurally altered in SCLC and that this modification may confer different behavioral properties that contribute toward tumorigenesis. Nuclear localization is not unique to BAI3 and has been reported in a number of GPCRs and frequently correlates with survival outcomes. BAI3 has the potential to act as target for pharmaceutical intervention inline with developing trends in molecular pathology aiming to provide personalized, treatment regimes based on tumor-specific mutation profiles. The adhesion group of the GPCR superfamily is still poorly understood. We present a review of the existing literature regarding the role they play in both physiological and disease states and the mechanisms by which they influence a range of cellular processes.

CXCR4 knockdown inhibits the growth and invasion of nasopharyngeal cancer stem cells

Nasopharyngeal cancer is a type of malignant tumor with a high rate of incidence. Cancer stem cells are regarded as one of the main causes for the formation and recurrence of nasopharyngeal cancer. CXC chemokine receptor type 4 (CXCR4) has been reported to perform an important role in cancer; however, the association between CXCR4 and nasopharyngeal cancer stem cells remains unclear. The present study explored the effect of CXCR4 on cellular viability, apoptosis and invasion of nasopharyngeal cancer stem cells. Results of the present study demonstrated that knockdown of CXCR4 inhibited the viability and invasion of nasopharyngeal cancer stem cells and promoted cellular apoptosis. Further studies have revealed that the anti-tumor effect of CXCR4 knockdown was associated with the inhibition of the protein kinase B signal. These results demonstrate that the knockdown of CXCR4 resulted in an anti-tumor effect in nasopharyngeal cancer stem cells. Therefore, CXCR4 may become a promising therapeutic target in the treatment of nasopharyngeal cancer.

CXCR4 and CCR7: Two eligible targets in targeted cancer therapy

Cancer is one of the most common cause of death in the world with high negative emotional, economic, and social impacts. Conventional therapeutic methods, including chemotherapy and radiotherapy, have not proven satisfactory and relapse is common in most cases. Recent studies have focused on targeted therapy with more precise identification and targeted attacks to the cancer cells. For this purpose, chemokine receptors are proper targets and among them, CXCR4 and CCR7, with a crucial role in cancer metastasis, are being considered as desired candidates for investigation. In this review paper, the most important experimental results are highlighted on the potential targeted therapies based on CXCR4 and CCR7 chemokine receptors.

Updated overview of current biomarkers in head and neck carcinoma

Squamous cell cancer is the most common type of malignancy arising from the epithelial cells of the head and neck region. Head and neck squamous cell carcinoma (HNSCC) is one of the predominant causes of cancer related casualties worldwide. Overall prognosis in this disease has improved to some extent with the advancements in therapeutic modalities but detection of primary tumor at its initial stage and prevention of relapse are the major targets to be achieved for further improvement in terms of survival rate of patients. Latest achievements in basic research regarding molecular characterization of the disease has helped in better perception of the molecular mechanisms involved in HNSCC progression and also in recognizing and targeting various molecular biomarkers associated with HNSCC. In the present article, we review the information regarding latest and potential biomarkers for the early detection of HNSCC. A detailed molecular characterization, ultimately, is likely to improve the development of new therapeutic strategies, potentially relevant to diagnosis and prognosis of head and neck cancers. The need for more accurate and timely disease prediction has generated enormous research interests in this field.

CXCR4 over-expression and survival in cancer: a system review and meta-analysis

C-X-C chemokine receptor 4 (CXCR4) is frequently over-expressed in various types of cancer; many agents against CXCR4 are in clinical development currently despite variable data for the prognostic impact of CXCR4 expression. Here eighty-five studies with a total of 11,032 subjects were included to explore the association between CXCR4 and progression-free survival (PFS) or overall survival (OS) in subjects with cancer. Pooled analysis shows that CXCR4 over-expression is significantly associated with poorer PFS (HR 2.04; 95% CI, 1.72-2.42) and OS (HR=1.94; 95% CI, 1.71-2.20) irrespective of cancer types. Subgroup analysis indicates significant association between CXCR4 and shorter PFS in hematological malignancy, breast cancer, colorectal cancer, esophageal cancer, renal cancer, gynecologic cancer, pancreatic cancer and liver cancer; the prognostic effects remained consistent across age, risk of bias, levels of adjustment, median follow-up period, geographical area, detection methods, publication year and size of studies. CXCR4 over-expression predicts unfavorable OS in hematological malignancy, breast cancer, colorectal cancer, esophageal cancer, head and neck cancer, renal cancer, lung cancer, gynecologic cancer, liver cancer, prostate cancer and gallbladder cancer; these effects were independence of age, levels of adjustment, publication year, detection methods and follow-up period. In conclusion, CXCR4 over-expression is associated with poor prognosis in cancer.

Inflammatory CXCL12-CXCR4/CXCR7 axis mediates G-protein signaling pathway to influence the invasion and migration of nasopharyngeal carcinoma cells

This study explored whether the migration, invasion, and apoptosis of nasopharyngeal carcinoma (NPC) cells were affected by the CXCR4/CXCR7-CXCL12 axis and if this mechanism was related to G-protein signaling pathway. A total of 72 NPC patients admitted in our hospital between April 2013 and February 2015 were incorporated in this study. Immunohistochemistry was performed to compare the expression levels of CXCR4, CXCR7, and CXCL12 between NPC tissues and adjacent normal tissues. Then, the correlation analysis was implemented to assess the association among CXCR4, CXCR7, and CXCL12 expressions. Jellyfish glow protein experiment was carried out after the cultivation of CNE-2Z cell lines in order to observe the intracellular calcium mobilization resulted from G-protein activation contributed by CXCR4/CXCR7-CXCL12 axis. The impact of CXCR4/CXCR7-CXCL12 axis on the migration and invasion of NPC cells was explored using transwell experiments. Finally, the anti-apoptosis effects of CXCR4/CXCR7-CXCL12 axis on NPC cells were investigated by the splicing of poly ADP-ribose polymerase (PARP). Compared to NPC patients with low-grade (stage I-II) tumor node metastasis (TNM) and those without lymph node metastasis, the expression of CXCR4, CXCR7, and CXCL12 were significantly higher in NPC patients with high-grade (stage III-IV) TNM and those with lymph node metastasis (P < 0.05). Moreover, there was significant positive correlation between the expression level of CXCL12 and CXCR7 (r s = 0.484, P < 0.001) as well as the expression level of CXCL12 and CXCR4 (r s = 0.414, P < 0.001). As suggested by cellular experiments using CNE-2Z, the calcium mobilization degree induced by CXCR4-CXCL12 axis in activating G proteins seemed to be slightly more effective than that induced by CXCR4/CXCR7-CXCL12 axis, while the CXCR7-CXCL12 axis could hardly activate calcium mobilization. Furthermore, the transwell experiment showed that CXCR4/CXCR7-CXCL12 axis could exacerbate the migration and invasion of NPC cells (P < 0.05). The transwell experiment also suggested that the CXCR4/CXCR7-CXCL12 axis was associated with the expression of matrix metallo proteinase 9 (MMP9) which is a substance in the downstream of G-protein pathways (P < 0.05). Results from PARP shear zone also indicated that the CXCR4/CXCR7-CXCL12 axis could suppress NPC cell apoptosis (P < 0.05). The expressional levels of CXCR4, CXCR7, and CXCL12 significantly varied with clinical stages and status of lymph node metastasis of NPC patients. This revealed potential indicators which can be used for NPC prognosis. Additionally, the CXCR4/CXCR7-CXCL12 axis may regulate the expression of downstream proteins (e.g., MMP-9) through the activation of G-protein signaling pathways. These conclusions may provide key evidence for NPC aetiology which can be further investigated to develop novel molecular targets for NPC treatments.

CXCR4 Expression is Associated with Poor Prognosis in Patients with Esophageal Squamous Cell Carcinoma

BACKGROUND

Chemokines and their receptors are known to play important roles in the tumorigenesis of many malignancies. The chemokine CXCL12 and its receptors CXCR4 and CXCR7 were suggested to be involved in cancer invasion and metastasis. The aim of this retrospective study was to evaluate the prognostic impact of the expressions of CXCL12, CXCR4 and CXCR7 in patients with esophageal squamous cell carcinoma (ESCC).

METHODS

We used immunohistochemistry (IHC) and reverse transcriptase-polymerase chain reaction (RT-PCR) to evaluate the expressions of CXCL12, CXCR4, and CXCR7 in ESCC patients' tumor biopsy specimens obtained during preoperative endoscopy or surgery. These results were compared with the patients' clinicopathological parameters and survival.

RESULTS

IHC was conducted for 172 patients. High expression of CXCR4 in the cytoplasm and nuclei and that of CXCR7 were associated with poor cause-specific survival (CSS) (P= .002 and .010, respectively). The specimens from 52 of the 172 patients were examined by RT-PCR and quantitative real-time PCR. The expression levels of messenger RNA (mRNA) of CXCR4 and CXCR7 were significantly increased in the tumors compared with normal esophageal mucosae (P < .0001). The expression level of mRNA of CXCR4 was associated with poor recurrence-free survival and CSS (P = .012 and .038, respectively).

CONCLUSIONS

CXCR4 expression is associated with poor prognosis in patients with ESCC.

CXCR7 expression in nasopharyngeal carcinoma tissues correlates with disease severity

The chemokine CXCL12 and its receptors, CXCR4 and CXCR7, are important contributors to the pathogenesis of multiple types of tumors. CXCL12/CXCR4 was previously demonstrated to be upregulated in nasopharyngeal carcinoma (NPC) tissues, but the status of CXCR7 in NPC remains unknown. Here, 62 nasopharyngeal carcinoma specimens were obtained from patients who received rhinitis biopsy in our hospital in 2012 and 2013. Another 30 samples were collected from patients with nasopharyngitis who did not have NPC, to serve as a control group. Expression of CXCR7 protein and mRNA in NPC and normal tissues was detected by immunohistochemistry and quantitative real-time polymerase chain reaction, respectively. CXCR7 protein was detected in just 7.1% (2/30) of normal nasopharyngeal samples, but 61.3% (38/62) of tumor tissues (P<0.05). The staining patterns (proportion of stained cells/sample as well as staining intensity) were correlated with lymph node metastasis, TNM staging, and disease severity (P<0.01). Thus, CXCR7 may promote disease progression in nasopharyngeal carcinoma, and may be useful as a predictor of metastasis and prognosis.

CXCL12 genetic variants as prognostic markers in nasopharyngeal carcinoma

The chemokine receptor 4/chemokine ligand 12 (CXCR4/CXCL12) axis plays an important role in tumorigenesis, metastasis, and recurrence of tumors. Its single nucleotide polymorphisms (SNPs) are associated with patient survival in several types of cancer. However, the prognostic value of SNPs in nasopharyngeal carcinoma (NPC) has not been fully investigated. This retrospective study assessed the relationships between CXCR4 rs2228014 and CXCL12 rs1801157 polymorphisms and patient outcome in 222 patients newly diagnosed with NPC. The analysis found no significant correlation between the presence of both SNPs and clinicopathological factors. However, univariate analysis showed that N classification, clinical stage, and the CXCL12 rs1801157 polymorphism were significantly associated with distant metastasis-free survival (P=0.018, 0.028, and 0.013, respectively) and progression-free survival (P=0.007, 0.046, and 0.021, respectively). After adjusting clinicopathological factors, multivariate analysis identified CXCL12 rs1801157 as an independent prognostic factor for distant metastasis-free survival and progression-free survival (hazard ratio: 3.332; 95% confidence interval: 1.597-6.949; P=0.001 and hazard ratio: 2.665 95% confidence interval: 1.387-5.119; P=0.003, respectively). Our results suggest that CXCL12 rs1801157 AA genotype might serve as a potential prognostic factor in patients with NPC.

Relationships of alpha-SMA-positive fibroblasts and SDF-1-positive tumor cells with neoangiogenesis in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is one of the most prevalent malignant tumors with poor prognosis in Southern China and Southeast Asia. Angiogenesis-related molecules can be promising therapeutic targets in NPC. To investigate the relationships of cancer-associated fibroblasts (CAFs) and chemokine-related molecules with neoangiogenesis, we compared immunohistochemical analyses of alpha-smooth-muscle actin (α-SMA), stroma-derived factor-1 (SDF-1), and its receptor CXCR4 in primary NPC specimens and chronic nasopharyngitis tissues. In addition, we examined the expression of vascular endothelial growth factor (VEGF-A), and CD133- and VEGF- receptor-2 (VEGFR-2) double positive cells, as endothelial progenitor cells (EPCs). We also assessed CD34-positive microvessels. Significantly higher expression of α-SMA was observed in fibroblasts in NPC stroma. The immunoreactive intensities of SDF-1 and CXCR4 were significantly higher in NPC cells. CXCR4-positive cells and CD133/VEGFR-2- double positive cells were observed in the stroma surrounding cancer nests, and VEGF was detected in both cancer and stromal cells. Microvessel density was significantly higher in the stroma of NPC tissues compared to chronic nasopharyngitis tissues. Our data suggest that CAFs and NPC tumor cells may enhance neoangiogenesis in a VEGF- and SDF-1-dependent manner by recruiting EPCs from the bone marrow into tumor stroma.

miR-9 targets CXCR4 and functions as a potential tumor suppressor in nasopharyngeal carcinoma

MicroRNA deregulation and pathway alterations have been implicated in nasopharyngeal carcinoma (NPC), a highly invasive and metastatic cancer widely prevalent in Southern China. In this study, we report that miR-9 is commonly downregulated in NPC specimens and NPC cell lines with important functional consequences. The reduced expression of miR-9 was inversely correlated with clinical stages and marked the progression from locoregional to metastatic tumors. The CpG island hypermethylation contributed to miR-9 silencing in NPC cell lines and tissues. Ectopic expression of miR-9 dramatically inhibited the proliferative, migratory and invasive capacities of NPC cells in vitro and in vivo. We found that miR-9 strongly reduced the expression of CXCR4 in NPC cells. Luciferase assay demonstrated that miR-9 could directly bind to the 3' untranslated region of CXCR4. Similar to the restoring miR-9 expression, CXCR4 downregulation inhibited cell growth, migration and invasion, whereas CXCR4 overexpression rescued the suppressive effect of miR-9. Mechanistic investigations revealed that CXCR4 functionally mediated the SDF-1-stimulated activation of p38 mitogen-activated protein kinase pathway in NPC cells with miR-9 downregulation or CXCR4 overexpression. In clinical specimens, CXCR4 and phospho-p38 were widely overexpressed, and the levels increased with the progression from locoregional to metastatic tumors in NPC tissues. The levels of CXCR4 were inversely correlated with miR-9 or phospho-p38 expression. Taken together, our results indicate that miR-9 functions as a tumor-suppressive microRNA in NPC, and that its suppressive effects are mediated chiefly by repressing CXCR4 expression.

The independent, unfavorable prognostic factors endothelin A receptor and chemokine receptor 4 have a close relationship in promoting the motility of nasopharyngeal carcinoma cells via the activation of AKT and MAPK pathways

Background

Recent studies have indicated that the expression of endothelin A receptor (ETAR) and chemokine receptor 4 (CXCR4) could be used as an indicator of the metastatic potential of nasopharyngeal carcinoma (NPC). The aim of this study was to determine the prognostic value of ETAR and CXCR4 in NPC patients and to reveal the interplay of the endothelin-1 (ET-1)/ETAR and stromal-derived factor-1(SDF-1)/CXCR4 pathways in promoting NPC cell motility.

Methods

Survival analysis was used to analyze the prognostic value of ETAR and CXCR4 expression in 153 cases of NPC. Chemotaxis assays were used to evaluate alterations in the migration ability of non-metastatic 6-10B and metastatic 5-8F NPC cells. Real-time PCR, immunoblotting, and flow cytometric analyses were used to evaluate changes in the expression levels of CXCR4 mRNA and protein induced by ET-1.

Results

The expression levels of ETAR and CXCR4 were closely related to each other and both correlated with a poor prognosis. A multivariate analysis showed that the expression levels of both ETAR and CXCR4 were independent prognostic factors for overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival (DMFS). The migration of 6-10B and 5-8F cells was elevated by ET-1 in combination with SDF-1α. The knockdown of ETAR protein expression by siRNA reduced CXCR4 protein expression in addition to ETAR protein expression, leading to a decrease in the metastatic potential of the 5-8F cells. ET-1 induced CXCR4 mRNA and protein expression in the 6-10B NPC cells in a time- and concentration-dependent fashion and was inhibited by an ETAR antagonist and PI3K/AKT/mTOR and MAPK/ERK1/2 pathway inhibitors.

Conclusions

ETAR and CXCR4 expression levels are potential prognostic biomarkers in NPC patients. ETAR activation partially promoted NPC cell migration via a mechanism that enhanced functional CXCR4 expression.

TNF-α up-regulates cellular inhibitor of apoptosis protein 2 (c-IAP2) via c-Jun N-terminal kinase (JNK) pathway in nasopharyngeal carcinoma

Inhibitor of apoptosis proteins (IAPs) contribute to both tumor progression and tumor metastasis. Here, we show that pro-inflammatory cytokine TNF-α induced the up-regulation of c-IAP2 in the potential metastatic nasopharyngeal carcinoma (NPC) cells in a dose- and time-dependent manner. This up-regulation is tolerant, as the pre-treatment of NPC cells with TNF-α reversed the up-regulation of c-IAP2 induced by TNF-α re-stimulation. TNF-α activated MAKP signals, including ERK, JNK and p38, and NF-κB signal, but only inhibition of JNK signal transduction reversed the induction of c-IAP2, suggesting that JNK signaling contributed to the c-IAP2 induction. The results from in vitro scratch wound-healing assays showed that TNF-α promoted cell invasion, which was reversed by the inhibition of JNK signaling. Taken together, these studies suggested that pro-inflammation cytokine TNF-α may be a promoter for NPC metastasis, and the anti-inflammatory therapy may be of benefit to the prevention of NPC metastasis.

Cysteine (C)-x-C receptor 4 undergoes transportin 1-dependent nuclear localization and remains functional at the nucleus of metastatic prostate cancer cells

The G-protein coupled receptor (GPCR), Cysteine (C)-X-C Receptor 4 (CXCR4), plays an important role in prostate cancer metastasis. CXCR4 is generally regarded as a plasma membrane receptor where it transmits signals that support transformation, progression and eventual metastasis. Due to the central role of CXCR4 in tumorigenesis, therapeutics approaches such as antagonist and monoclonal antibodies have focused on receptors that exist on the plasma membrane. An emerging concept for G-protein coupled receptors is that they may localize to and associate with the nucleus where they retain function and mediate nuclear signaling. Herein, we demonstrate that CXCR4 associated with the nucleus of malignant prostate cancer tissues. Likewise, expression of CXCR4 was detected in nuclear fractions among several prostate cancer cell lines, compared to normal prostate epithelial cells. Our studies identified a nuclear pool of CXCR4 and we defined a nuclear transport pathway for CXCR4. We reveal a putative nuclear localization sequence (NLS), ‘RPRK’, within CXCR4 that contributed to nuclear localization. Additionally, nuclear CXCR4 interacted with Transportinβ1 and Transportinβ1-binding to CXCR4 promoted its nuclear translocation. Importantly, G_αi immunoprecipitation and calcium mobilization studies indicated that nuclear CXCR4 was functional and participated in G-protein signaling, revealing that the nuclear pool of CXCR4 retained function. Given the suggestion that functional, nuclear CXCR4 may be a mechanism underlying prostate cancer recurrence, increased metastatic ability and poorer prognosis after tumors have been treated with therapy that targets plasma membrane CXCR4, these studies addresses a novel mechanism of nuclear signaling for CXCR4, a novel mechanism of clinical targeting, and demonstrate an active nuclear pool that provides important new information to illuminate what has been primarily clinical reports of nuclear CXCR4.

Prognostic value of the chemokine receptor CXCR4 and epithelial-to-mesenchymal transition in patients with squamous cell carcinoma of the mobile tongue

OBJECTIVE

The aim of this study was to evaluate the expression and the prognostic value of chemokine receptor 4 (CXCR4), its cognate ligand the CXCL12, and markers of epithelial-to-mesenchymal transition (EMT) in squamous cell carcinoma (SCC) of the mobile tongue.

PATIENTS AND METHODS

Patients with primary SCC of the mobile tongue who underwent surgery in our center were screened retrospectively. Patients without prior treatment, who had pre-surgery TNM staging and available tumor samples, were eligible. Protein expression of CXCL12, CXCR4, CA9, E-cadherin, and vimentin was determined by immunohistochemical staining, scored, and correlated with clinical and pathological parameters and overall survival. Multivariate and Cox proportional hazards analyses were performed.

RESULTS

Among 160 patients treated and screened, 47 were analyzed. CXCR4 and CXCL12 expression was high in tumor cells. CXCR4 expression in primary tumor samples was significantly higher in patients with high-grade tumors, lymph node metastases, and microscopic nerve invasion (p ≤ 0.05). There was a non-significant trend towards a correlation between high CXCL12 expression and pathologic tumor stage (p=0.07). Tumors with high CXCR4 expression correlated with poor overall survival (hazard ratio=3.6, 95% confidence interval 1.3-9.7; p=0.011), notably in the CXCR4(high)/vimentin-positive subgroup. Vimentin-positive tumors, characterizing EMT, were associated with lower survival (hazard ratio=4.5, 95% confidence interval 1.6-12.3; p=0.0086). Multivariate analysis confirmed vimentin (but not CXCR4) expression as an independent prognostic factor of poor overall survival (p=0.016).

CONCLUSION

Our results suggest that CXCR4 is a marker of tumor aggressiveness and vimentin is an important and independent prognostic factor in patients with SCC of the mobile tongue.

The chemokine, CXCL12, is an independent predictor of poor survival in ovarian cancer

BACKGROUND

The chemokine CXCL12 and its cognate receptor, CXCR4, have been implicated in numerous tumour types where expression promotes tumour growth, angiogenesis, metastasis and suppresses tumour immunity.

METHODS

Using a tissue microarray of 289 primary ovarian cancers coupled to a comprehensive database of clinicopathological variables, the expression of CXCL12 and CXCR4 was assessed by immunohistochemistry and its impact in terms of survival and clinicopathological variables was determined.

RESULTS

Patients whose tumours expressed high levels of CXCL12 had significantly poorer survival (P=0.026) than patients whose tumours failed to produce this chemokine. Lack of CXCL12 expression within tumours was associated with a 51-month survival advantage for patients when compared with patients whose tumours expressed high levels of CXCL12. FIGO stage, adjuvant chemotherapy and the absence of macroscopic disease after surgery were all shown to predict prognosis independently of each other in this cohort of patients. CXCL12 was independently predictive of prognosis on multivariate analysis (P=0.016). There was no correlation between CXCL12 and any clinicopathological variable.

CONCLUSION

The chemokine CXCL12 is an independent predictor of poor survival in ovarian cancer. High expression of CXCL12 was seen in only 20% of the tumours, suggesting a role for anti-CXCL12/CXCR4 therapy in the management of these patients.

High expression of CXCR4 and CXCR7 predicts poor survival in gallbladder cancer

Chemokine receptors play a prominent role in cancer progression and metastasis. This study investigated whether the expression of CXC chemokine receptor types 4 and 7 (CXCR4 and CXCR7, respectively), determined immunohistochemically, was associated with clinicopathological characteristics and postoperative survival in gallbladder cancer specimens from 72 patients. CXCR4 was detected in the cytoplasm and/or nucleus of gallbladder cancer cells, but CXCR7 was detected only in the cytoplasm. Expression of either CXCR7 or CXCR4 in the cytoplasm was associated with tumour stage. Expression of nuclear CXCR4 was associated with lymph node metastases and lymphatic invasion. Cytoplasmic expression of CXCR4 and CXCR7 were each independent risk factors for worse postoperative survival. Further research is required to clarify the mechanisms involved in these associations and to determine their potential prognostic and therapeutic implications.

Host-tumor interactions in nasopharyngeal carcinomas

Like other human solid tumors, nasopharyngeal carcinoma (NPC) is a tissue and a systemic disease as much as a cell disease. Tumor cell population in NPC is highly heterogeneous. Heavy infiltration by non-malignant leucocytes results at least in part from the production of abundant inflammatory cytokines by the malignant epithelial cells. There is indirect evidence that interactions between stromal and malignant cells contribute to tumor development. Peripheral blood samples collected from NPC patients contain multiple products derived from the tumor, including cytokines, non-cytokine tumor proteins, tumor exosomes and viral nucleic acids. These products represent a potential source of biomarkers for assessment of tumor aggressiveness, indirect exploration of cellular interactions and monitoring of tumor response to therapeutic agents. Most NPC patients are immunocompetent with evidence of active humoral and cellular immune responses against EBV-antigens at the systemic level. Tumor development is facilitated by local immunosuppressive factors which are not fully understood. Local accumulation of regulatory T-cells is probably one important factor. At least two NPC tumor products are suspected to contribute to their expansion, the cytokine CCL20 and the tumor exosomes carrying galectin 9. In the future, new therapeutic modalities will probably aim at breaking immune tolerance or at blocking cellular interactions critical for tumor growth.

The expression of the hypoxia markers CA9 and CXCR4 is correlated with survival in patients with neuroendocrine tumours of the ileum

BACKGROUND/AIM

The hypoxia-inducible factor pathway regulates the expression of a diverse group of molecules such as CA9 and CXCR4. Our aim was to investigate the expression of these markers in a series of patients with an ileal neuroendocrine tumour (IET) at various stages of tumorigenesis.

METHODS

The immunohistochemical expression of CA9 and CXCR4 was examined in 51 patients with a resected IET. A 'hypoxic score' was calculated, integrating the expression of both CA9 and CXCR4 (hypoxic score 0: absence of expression of both molecules; hypoxic score 1: expression of CXCR4 and/or CA9). Results were compared to histoprognostic factors (including tumour size, stage and grade, WHO and TNM classifications, presence of vascular or perineural invasion, presence of a fibrotic stroma and microvascular density) and to survival.

RESULTS

All tumours were well differentiated. 69% of tumours were less than 25 mm. 46% of tumours largely infiltrated the intestinal wall (≥T3, subserosa and serosa) and 90% were classified as N1 and/or 63% as M1. 57% of tumours were of grade G1, 43% of grade G2. Grade G2 (p=0.004) and larger tumour infiltration (≥T4; p=0.03) correlated with lower survival. Hypoxic score 1 correlated with a greater tumour size (p=0.034), larger tumour infiltration (T3 or T4; p=0.001), grade G2 (p=0.046), presence of lymph node metastasis (p=0.0066) and with lower survival of patients (p=0.03).

CONCLUSION

The hypoxia-inducible factors CA9 and CXCR4 were found associated to the malignant progression of neuroendocrine tumours of the ileum. Their expression may reflect higher tumour aggressivity.

Analysis of chemokine and chemokine receptor expression in squamous cell carcinoma of the head and neck (SCCHN) cell lines

The purpose of this work was to analyze chemokine and chemokine receptor expression in untreated and in irradiated squamous cell carcinoma of the head and neck (SCCHN) tumor cell lines, aiming at the establishment of assays to test for the relevance of chemokine and chemokine receptor expression in the response of SCCHN to radiotherapy and radiochemotherapy. Five low passage and 10 established SCCHN lines, as well as two normal cell lines, were irradiated at 2 Gy or sham-irradiated, and harvested between 1 and 48 h after treatment. For chemokines with CC and CXC structural motifs and their receptors, transcript levels of target and reference genes were quantified relatively by real-time PCR. In addition, CXCL1 and CXCL12 protein expression was analyzed by ELISA. A substantial variation in chemokine and chemokine receptor expression between SCCHN was detected. Practically, all cell lines expressed CCL5 and CCL20, while CCL2 was expressed in normal cells and in some of the tumor cell lines. CXCL1, CXCL2, CXCL3, CXCL10, and CXCL11 were expressed in the vast majority of the cell lines, while the expression of CXCL9 and CXCL12 was restricted to fibroblasts and few tumor cell lines. None of the analyzed cell lines expressed the chemokines CCL3, CCL4, or CCL19. Of the receptors, transcript expression of CCR1, CCR2, CCR3, CCR5, CCR7, CCXR2, and CCXR3 was not detected, and CCR6, CXCR1, and CXCR4 expression was restricted to few tumor cells. Radiation caused up- and down-regulation with respect to chemokine expressions, while for chemokine receptor expressions down-regulations were prevailing. CXCL1 and CXCL12 protein expression corresponded well with the mRNA expression. We conclude that the substantial variation in chemokine and chemokine receptor expression between SCCHN offer opportunities for the establishment of assays to test for the relevance of chemokine and chemokine receptor expression in the response of SCCHN to radiotherapy and radiochemotherapy.

Nuclear expression of CXCR4 is associated with advanced colorectal cancer

BACKGROUND AND OBJECTIVES

CXCR4 and its ligand, SDF-1alpha, play an important role in the targeted metastasis of colon cancer. In this study, we analyzed an expression of CXCR4 in clinical samples and showed that SDF-1alpha affected the expression of CXCR4 in colon cancer cells.

MATERIALS AND METHODS

A total of 388 patients with colorectal cancer (CRC) who underwent surgery in Taipei Veterans General Hospital from 2000 to 2004 were included. The expression of CXCR4 in CRC was visualized by immunohistochemistry (anti-CXCR4 mAb, R&D 12G5). HCT116, SW480, and SW620 cells were treated with SDF-1alpha in vitro and the CXCR4 proteins located in the cytoplasmic and nuclear compartments were separated and analyzed with western blotting.

RESULTS

The frequency of cytoplasmic and nuclear expression of CXCR4 in colorectal cancers was 35.6% and 36.9%, respectively. Nuclear but not cytoplasmic expression of CXCR4 was associated with advanced CRC (p < 0.001) and lymphovascular invasion. However, in multivariate analysis, nuclear expression of CXCR4 did not correlate with patients' outcome. In the in vitro study, SDF-1alpha, stimulation of three colorectal carcinoma lines enhanced the CXCR4 nuclear expression.

CONCLUSION

Expression of the CXCR4 plays a role in CRC progression and may be associated with SDF-1alpha stimulation.

Immunohistochemical expression of CXCR4 in thyroid carcinomas and thyroid benign lesions

In different tumor entities, expression of the chemokine receptor 4 (CXCR4) has been linked to tumor dissemination and poor prognosis. The aim of this study was to examine the immunohistochemical expression of CXCR4 in thyroid carcinomas and thyroid benign lesions. Using monoclonal anti-CXCR4 antibody, we performed immunohistochemical staining on tissue sections from 134 cases obtained from Ruijin Hospital affiliated with Shanghai Jiaotong University School of Medicine (Shanghai, China) between 2000 and 2007. In our study, the CXCR4 expression of the thyroid carcinoma group (including 16 papillary thyroid carcinomas, 18 follicular thyroid carcinomas, 9 poorly differentiated thyroid carcinomas, and 7 medullary thyroid carcinomas) was found to be higher than in the benign lesion group (including 19 cases of Hashimoto's thyroiditis, 15 nodular goiters, and 50 follicular adenomas) (p<0.0001). Within the carcinoma group, the more malignant thyroid carcinoma group (including 9 poorly differentiated thyroid carcinomas and 7 medullary thyroid carcinomas) showed a higher ratio of CXCR4 positivity compared to the less malignant thyroid carcinoma group (including 16 papillary thyroid carcinomas and 18 follicular thyroid carcinomas) (p<0.0001). Our study suggests that CXCR4 expression might be a frequent and cancer-specific event in thyroid carcinoma, and it might be involved in malignancy transformation during the progression of thyroid carcinoma.

Nuclear localization of CXCR4 determines prognosis for colorectal cancer patients

Chemokines and their receptors are implicated in formation of colorectal cancer metastases. Especially CXCR4 is an important factor, determining migration, invasiveness, metastasis and proliferation of colorectal cancer cells. Object of this study was to determine expression of CXCR4 in tumor tissue of colorectal cancer patients and associate CXCR4 expression levels to clinicopathological parameters. Levels of CXCR4 expression of a random cohort of patients, who underwent primary curative resection of a colorectal carcinoma, were retrospectively determined by quantitative real-time RT-PCR and semi-quantitative analyses of immunohistochemical stained paraffin sections. Expression levels were associated to clinicopathological parameters. Using RT-PCR we found that a high expression of CXCR4 in the primary tumor was an independent prognostic factor for a poor disease free survival (p = 0.03, HR: 2.0, CI = 1.1-3.7). Immunohistochemical staining showed that nuclear distribution of CXCR4 in the tumor cells was inversely associated with disease free and overall survival (p = 0.04, HR: 2.6, CI = 1.0-6.2), while expression in the cytoplasm was not associated with prognosis. In conclusion, our study showed that a high expression of nuclear localized CXCR4 in tumor cells is an independent predictor for poor survival for colorectal cancer patients.

Nuclear expression of CXCR4 in tumor cells of non-small cell lung cancer is correlated with lymph node metastasis

The stromal-derived factor 1alpha (CXCL12)/chemokine receptor CXCR4 system plays an important role in the metastatic process of a variety of cancers, with CXCR4 frequently expressed by tumor cells homing to CXCL12-rich compartments. The current study evaluated a possible association of CXCR4 expression with lymph node metastasis in primary non-small cell lung cancer. CXCR4 expression levels were evaluated using immunohistology in 46 non-small cell lung cancer specimens of patients without or with lymph node involvement (N0 = 24, N1/N2/N3 = 22). Evaluation of immunostaining was performed semiquantitatively by visual assessment. Statistical analyses with multiple testing adjustments for confirmatory comparisons were performed to assess relevant parameters associated with lymph node metastases. In all samples of non-small cell lung cancer, tumor cells stained positively for cytoplasmic CXCR4. The intensity of the CXCR4 staining varied considerably between specimens: 2 (4%) tumors demonstrated weak cytoplasmic CXCR4, 22 (48%) intermediate, and 22 (48%) strong staining. Membranous staining was absent; however, nuclear staining of CXCR4 was observed in 5 non-small cell lung cancer samples. Statistical analyses of the association between presence of lymph node metastases and CXCR4 expression levels revealed that cytoplasmic CXCR4 expression was not associated with the presence of lymph node metastases. However, nuclear CXCR4 was significantly correlated with increasing lymph node stage (P = .008), linear-to-linear association. The association between aberrant expression of CXCR4 in the nucleus of non-small cell lung cancer and metastasis to lymph nodes points toward a potential tumor metastasis promoting function of nuclear CXCR4.

Expression of SDF-1 alpha and nuclear CXCR4 predicts lymph node metastasis in colorectal cancer

Although stromal cell-derived factor (SDF)-1 alpha and its receptor CXCR4 are experimentally suggested to be involved in tumorigenicity, the clinicopathological significance of their expression in human disease is not fully understood. We examined SDF-1 alpha and CXCR4 expression in colorectal cancers (CRCs) and their related lymph nodes (LNs), and investigated its relationship to clinicopathological features. Specimens of 60 primary CRCs and 27 related LNs were examined immunohistochemically for not only positivity but also immunostaining patterns for SDF-1 alpha and CXCR4. The relationships between clinicopathological features and SDF-1 alpha or CXCR4 expression were then analysed. Stromal cell-derived factor-1 alpha and CXCR4 expression were significantly associated with LN metastasis, tumour stage, and survival of CRC patients. Twenty-nine of 47 CXCR4-positive CRCs (61.7%) showed clear CXCR4 immunoreactivity in the nucleus and a weak signal in the cytoplasm (nuclear type), whereas others showed no nuclear immunoreactivity but a diffuse signal in the cytoplasm and at the plasma membrane (cytomembrane type). Colorectal cancer patients with nuclear CXCR4 expression showed significantly more frequent LN metastasis than did those with cytomembrane expression. Colorectal cancer patients with nuclear CXCR4 expression in the primary lesion frequently had cytomembrane CXCR4-positive tumours in their LNs. In conclusion, expression of SDF-1 alpha and nuclear CXCR4 predicts LN metastasis in CRCs.

CXCR4 membrane expression in node-negative breast cancer

CXC chemokine receptor 4 (CXCR4) has been reported to be involved in organ-specific homing of breast cancer-derived metastasis. We investigated CXCR4 expression by immunohistochemistry as a possible new prognostic factor for primary breast cancer. Two groups of women treated for breast cancer in 1991 at the Centre for the fight against cancer of Upper Normandy-France (Centre de Lutte contre le Cancer de Haute Normandie) were assessed retrospectively. CXCR4 expression was evaluated using standard immunohistochemistry. Usual prognostic factors were recorded in the computer database. Final date of follow-up was December 31, 2001. Tissues were available for 110 node-positive and 84 node-negative breast cancer patients treated in 1991. CXCR4 membrane staining was considered a strong prognostic factor for both 10-year metastasis-free- (p < 0.0001) and overall survival (p < 0.0001) in node-negative but not in node-positive breast cancer patients. CXCR4 cytoplasmic staining was not considered a significant prognostic factor. Our results suggest that CXCR4 membrane staining could be considered a new prognostic factor. Moreover, targeting CXCR4 in primary breast cancer patients may be a new therapeutic concept. However, these results warrant further investigation.

Association of CXCR4 and CCR7 chemokine receptor expression and lymph node metastasis in human cervical cancer

BACKGROUND

The chemokine receptors CXCR4 and CCR7 have been suggested to play an important role in cancer invasion and metastasis. The expression of these receptors in human cervical cancer, however, has seldom been characterized.

PATIENTS AND METHODS

We investigated the expression of CXCR4 and CCR7 in cervical cancer specimens and determined the association between their expression and the clinicopathological features observed, including patient outcome.

RESULTS

CXCR4 expression was significantly higher in elderly patients (P=0.025); it was also significantly increased in patients with cancers displaying large tumor size (P=0.010), deep stromal invasion (P=0.0004), lymph-vascular space involvement (P=0.0002), or lymph node metastasis (P<0.0001). CCR7 expression was significantly higher in cases of squamous cell carcinomas (P=0.010) and in patients with cancers showing large tumor size (P<0.0001), deep stromal invasion (P<0.0001), vaginal invasion (P=0.047), lymph-vascular space involvement (P=0.012), or lymph node metastasis (P<0.0001). Logistic regression analysis revealed that deep stromal invasion (P=0.017) and CXCR4 (P=0.016) and CCR7 (P=0.022) expression were independent factors that influenced pelvic lymph node metastasis. The disease-free survival and overall survival (OS) rates of patients exhibiting both CXCR4 and CCR7 expression were significantly reduced (P<0.0001). In addition, the expression of both CXCR4 and CCR7 was an independent prognostic factor for OS (95% confidence interval=1.03-17.86; P=0.046).

CONCLUSIONS

CXCR4 and CCR7 expression may be associated with lymph node metastasis; moreover, the expression of these receptors can serve as an indicator of poor prognosis in patients with cervical cancer.

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.

Stroma-derived factor (SDF-1/CXCL12) and human tumor pathogenesis

The chemokine stroma-derived factor (SDF-1/CXCL12) plays multiple roles in tumor pathogenesis. It has been demonstrated that CXCL12 promotes tumor growth and malignancy, enhances tumor angiogenesis, participates in tumor metastasis, and contributes to immunosuppressive networks within the tumor microenvironment. Therefore, it stands to reason that the CXCL12/CXCR4 pathway is an important target for the development of novel anti-cancer therapies. In this review, we consider the pathological nature and characteristics of the CXCL12/CXCR4 pathway in the tumor microenvironment. Strategies for therapeutically targeting the CXCL12/CXCR4 axis also are discussed.