Intratumoural level of SDF-1 correlates with survival in head and neck squamous cell carcinoma

Evaluation of the cancer stem cell marker DCLK1 in patients with lymph node metastases of head and neck cancer

BACKGROUND

Lymph node metastases are frequently detected in head and neck squamous cell carcinoma (HNSCC) patients. Little is known about biomarkers expressed in lymph node metastases or their influence on clinical outcome. Doublecortin-like kinase 1 (DCLK1) is one marker that might be associated with outcome, owing to its correlation with stem cell-like characteristics.

METHODS

We assessed the expression of DCLK1 in 74 postoperatively irradiated patients in histologically confirmed HNSCC lymph node metastases. Statistical analysis of the association with DCLK1 on clinical outcomes was performed.

RESULTS

DCLK1 was expressed in 63.5% of our patient cohort. DCLK1(+) HNSCC patients, compared with those without DCLK1 expression, showed a significantly poorer time to recurrence. Moreover, we observed a significantly poorer time to recurrence in HPV(-) HNSCC patients, and significantly shorter overall and disease-free survival rates in HPV(-) oropharyngeal cancer patients, compared with HPV(+) patients with these cancers. HPV(+) patients showed no significant differences in survival time according to DCLK1 expression. However, recurrent disease occurred in only DCLK1(+) patients. Mulitivariate analysis showed that DCLK1 expression in lymph node metastases is an independent marker for recurrence.

CONCLUSION

DCLK1 expression might be associated with poorer clinical outcomes in HNSCC patients, specifically in HPV(-) move patients. However, larger studies are required to verify our results.

CXCL12 is associated with FoxP3+ tumor-infiltrating lymphocytes and affects the survival of patients with oral squamous cell carcinoma

The role of tumor-infiltrating lymphocytes (TILs) suggests that cancer is a disease with not only a genetic, but also an immunological basis. Additionally, immune cell infiltration is an important feature of oral cancer. C-X-C motif chemokine ligand 12 (CXCL12) serves an important role in immune suppression in the tumor microenvironment. Therefore, the present study investigated how CXCL12 expression in oral squamous cell carcinoma (OSCC) was associated with clinicopathological parameters and TILs distribution. Complete CXCL12, TIL and clinical data were available for 45 patients with oral cancer treated by surgery. Expression levels of CXCL12, CD8⁺ TILs and forkhead box P3 (FoxP3⁺) TILs were assessed by immunohistochemistry in OSCC samples. CXCL12 expression in OSCC cells was observed in 32 (68.9%) cases and was associated with poor differentiation (P=0.045), advanced stages (P<0.001), tumor recurrence (P=0.011), poor overall survival (P=0.0476) and a higher density of FoxP3⁺ TILs (P<0.001). The CD8⁺/FoxP3⁺ ratio was lower in patients with poor differentiation (P=0.034), advanced stage tumors (P=0.015) and tumor recurrence (P=0.002). In addition, the ratio of CD8⁺/FoxP3⁺ TILs was significantly associated with the 5-year overall survival rate (P<0.001). The CD8⁺/FoxP3⁺ ratio was indicated to be a stronger prognostic indicator compared with the density of FoxP3⁺ TILs or CD8⁺ TILs. The present study identified an association between increased CXCL12 expression and FoxP3⁺ cell infiltration in OSCC. Targeting the CXCL12/C-X-C motif chemokine receptor 4 axis in OSCC may be employed as a novel strategy of tumor immunotherapy in the future.

Potential Role of CXCR4 Targeting in the Context of Radiotherapy and Immunotherapy of Cancer

Cancer immunotherapy has been established as standard of care in different tumor entities. After the first reports on synergistic effects with radiotherapy and the induction of abscopal effects-tumor shrinkage outside the irradiated volume attributed to immunological effects of radiotherapy-several treatment combinations have been evaluated. Different immunotherapy strategies (e.g., immune checkpoint inhibition, vaccination, cytokine based therapies) have been combined with local tumor irradiation in preclinical models. Clinical trials are ongoing in different cancer entities with a broad range of immunotherapeutics and radiation schedules. SDF-1 (CXCL12)/CXCR4 signaling has been described to play a major role in tumor biology, especially in hypoxia adaptation, metastasis and migration. Local tumor irradiation is a known inducer of SDF-1 expression and release. CXCR4 also plays a major role in immunological processes. CXCR4 antagonists have been approved for the use of hematopoietic stem cell mobilization from the bone marrow. In addition, several groups reported an influence of the SDF-1/CXCR4 axis on intratumoral immune cell subsets and anti-tumor immune response. The aim of this review is to merge the knowledge on the role of SDF-1/CXCR4 in tumor biology, radiotherapy and immunotherapy of cancer and in combinatorial approaches.

Serum CXCL12, but not CXCR4, Is Associated with Head and Neck Squamous Cell Carcinomas

Background: Squamous cell carcinoma (SCC) is the most frequent malignancy of the head and neck (HN) region. We here evaluated associations of stromal cell derived factor-1 (SDF-1or CXCL12) and its receptor, CXCR4, with HNSCCs. Materials and Methods: Sixty newly diagnosed HNSCC patients were enrolled in the patient group, and 28 healthy individuals in the control group. Plasma levels of CXCL12 and CXCR4 were measured using ELISA kits. Results: There was a significant difference in mean CXCL12, but not CXCR4, plasma levels between the patient and control groups (P=0.0001). No significant associations were found between mean plasma levels of either CXCL12 or CXCR4 with age, gender, tumor site, tumor size, lymph-node involvement or tumor stage. Conclusion: For the first time, our findings demonstrate a significant association between serum CXCL12 but not CXCR4 levels and HNSCCs.

SDF-1/CXCR4 expression is an independent negative prognostic biomarker in patients with head and neck cancer after primary radiochemotherapy

INTRODUCTION

Preclinical and clinical data suggest that the chemokine pathway governed by SDF-1 and CXCR4 contributes to a resistant phenotype. This retrospective biomarker study aims to explore the specific prognostic value of SDF-1 and CXCR4 expression in locally advanced head and neck squamous cell carcinomas (HNSCC) treated with primary radiochemotherapy (RT-CT).

MATERIAL AND METHODS

Biopsies from 141 HNSCC tumours of the oral cavity, oropharynx and hypopharynx were evaluated for SDF-1 and CXCR4 expression by immunofluorescence. SDF-1 and CXCR4 expression was correlated with clinico-pathological characteristics and outcome after RT-CT.

RESULTS

Patients with tumours exhibiting overexpression of intracellular SDF-1 and CXCR4 have a higher risk for loco-regional relapse and a worse overall survival after RT-CT (multivariate analysis, hazard ratio 2.33, CI [1.18-4.62], p = 0.02 and hazard ratio 2.02, CI [1.13-3.59], p = 0.02, respectively). Similar results were observed when only the subgroup of HPV DNA negative patients were analysed (hazard ratio 2.23 and 2.16, p = 0.02 and p = 0.01, respectively).

CONCLUSIONS

Our data support the importance of SDF-1 and CXCR4 expression for loco-regional control and overall survival in HNSCC after primary radiochemotherapy. Prospective multivariate validation and further studies into CXCR4 inhibition to overcome radiation resistance are warranted.

SDF-1/CXCR4 expression in head and neck cancer and outcome after postoperative radiochemotherapy

INTRODUCTION

Outcome after postoperative radiochemotherapy (RT-CT) for patients with advanced head and neck squamous cell carcinomas (HNSCC) remains unsatisfactory, especially among those with HPV negative tumours. Therefore, new biomarkers are needed to further define subgroups for individualised therapeutic approaches. Preclinical and first clinical observations showed that the chemokine receptor CXCR4 and its ligand SDF-1 (CXCL12) play an important role in tumour cell proliferation, survival, cancer progression, metastasis and treatment resistance. However, the data on the prognostic value of SDF-1/CXCR4 expression for HNSCC are conflicting. The aim of our hypothesis-generating study was to retrospectively explore the prognostic potential of SDF-1/CXCR4 in a well-defined cohort of HNSCC patients collected within the multicenter biomarker study of the German Cancer Consortium Radiation Oncology Group (DKTK-ROG).

MATERIAL AND METHODS

Patients with stage III and IVA HNSCC of the oral cavity, oropharynx and hypopharynx were treated with resection and adjuvant radiotherapy (RT) with ≥60 Gy and concurrent cisplatin-based chemotherapy (CT). Tissue micro-arrays (TMAs) from a total of 221 patients were generated from surgical specimens, 201 evaluated for the SDF-1 and CXCR4 expression by immunofluorescence and correlated with clinico-pathological and outcome data.

RESULTS

In univariate and multivariate analyses intracellular SDF-1 expression was associated with lower loco-regional control (LRC) in the entire patient group as well as in the HPV16 DNA negative subgroup. CXCR4 expression showed a trend for lower LRC in the univariate analysis which was not confirmed in the multivariate analysis. Neither for SDF-1 nor CXCR4 expression associations with distant metastasis free or overall survival were found.

CONCLUSIONS

Our exploratory data support the hypothesis that overexpression of intracellular SDF-1 is an independent negative prognostic biomarker for LRC after postoperative RT-CT in high-risk HNSCC. Prospective validation is warranted and further exploration of SDF-1/CXCR4 as a potential therapeutic target to overcome treatment resistance in HNSCC appears promising.

Cytokine Regulation of Metastasis and Tumorigenicity

The human body combats infection and promotes wound healing through the remarkable process of inflammation. Inflammation is characterized by the recruitment of stromal cell activity including recruitment of immune cells and induction of angiogenesis. These cellular processes are regulated by a class of soluble molecules called cytokines. Based on function, cell target, and structure, cytokines are subdivided into several classes including: interleukins, chemokines, and lymphokines. While cytokines regulate normal physiological processes, chronic deregulation of cytokine expression and activity contributes to cancer in many ways. Gene polymorphisms of all types of cytokines are associated with risk of disease development. Deregulation RNA and protein expression of interleukins, chemokines, and lymphokines have been detected in many solid tumors and hematopoetic malignancies, correlating with poor patient prognosis. The current body of literature suggests that in some tumor types, interleukins and chemokines work against the human body by signaling to cancer cells and remodeling the local microenvironment to support the growth, survival, and invasion of primary tumors and enhance metastatic colonization. Some lymphokines are downregulated to suppress tumor progression by enhancing cytotoxic T cell activity and inhibiting tumor cell survival. In this review, we will describe the structure/function of several cytokine families and review our current understanding on the roles and mechanisms of cytokines in tumor progression. In addition, we will also discuss strategies for exploiting the expression and activity of cytokines in therapeutic intervention.

Expression of the CXCL12/CXCR4 chemokine axis predicts regional control in head and neck squamous cell carcinoma

Expression of the CXCL12/CXCR4 chemokine axis has been related with the appearance of metastatic recurrence survival, including regional and distant recurrence, in patients with head and neck squamous cell carcinoma (HNSCC). RT-PCR was used to determine mRNA expression levels of CXCL12 and CXCR4 in biopsy tumor samples in 111 patients with HNSCC. Five-year regional recurrence-free survival for patients with low CXCR4 expression (n = 39, 31.5 %) was 97.4 %, for patients with high CXCR4/high CXCL12 expression (n = 22, 19.8 %) it was 94.7 %, and for patients with high CXCR4/low CXCL12 expression (n = 50, 45.0 %) it was 63.3 %. We found significant differences in the regional recurrence-free survival according to CXCR4/CXCL12 expression values (P = 0.001). HNSCC patients with high CXCR4 and low CXCL12 expression values had a significantly higher risk of regional recurrence and could benefit from a more intense treatment of lymph node areas in the neck.

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.

Prognostic value of CXCL12 and CXCR4 in inoperable head and neck squamous cell carcinoma

OBJECTIVE

The chemokine CXCL12 and its receptor CXCR4 can affect tumor growth, recurrence, and metastasis. We tested the hypothesis that the CXCL12 and CXCR4 expression influences the prognosis of patients with inoperable head and neck cancer treated with definite radiotherapy or chemoradiotherapy.

METHODS

Formalin-fixed paraffin-embedded pretreatment tumor tissue from 233 patients with known HPV/p16(INK4A) status was analyzed. CXCL12 and CXCR4 expressions were correlated with pretreatment parameters and survival data by univariate and multivariate Cox regression.

RESULTS

CXCL12 was expressed in 43.3 % and CXCR4 in 66.1 % of the samples and both were correlated with HPV/p16(INK4A) positivity. A high CXCL12 expression was associated with increased overall survival (p = 0.036), while a high CXCR4 expression was associated with decreased metastasis-free survival (p = 0.034).

CONCLUSION

A high CXCR4 expression could be regarded as a negative prognostic factor in head and neck cancer because it may foster metastatic spread. This may recommend CXCR4 as therapeutic target for combating head and neck cancer metastasis.

CXCL12 and CXCR4, but not CXCR7, are primarily expressed by the stroma in head and neck squamous cell carcinoma

The CXCL12/CXCR4 axis is involved in numerous models of metastatic dissemination, including head and neck squamous cell carcinoma (HNSCC). We assessed the relative expressions of CXCL12, CXCR4 and CXCR7 in the stroma and the tumour of HNSCC, and evaluated the methylation status of the CXCL12 promoter.Snap-frozen, HPV negative HNSCC samples were micro-dissected to isolate the tumoural and stromal compartments. The expression levels of CXCL12, CXCR4 and CXCR7 were assessed by qRT-PCR, and the methylation level of the CXCL12 promoter was evaluated by pyrosequencing.In total, 23 matched tumour/stroma samples were analysed. Higher expressions of CXCR4 and CXCL12 were observed in the stroma (p = 0.012 and p < 0.0001, respectively). No significant difference in expression was observed for CXCR7. A high methylation level (>40%) of the CXCL12 promoter was observed in only a few tumoural samples (5/23) and was associated with a lower expression of the gene (p = 0.03).Stromal cells, rather than the tumour itself, are mainly responsible for the expression of both CXCL12 and CXCR4 expression in HNSCC. CXCR7 expression did not differ between the two compartments and was not related to CXCL12 or CXCR4 expression. Finally, the methylation of the CXCL12 promoter could only explain the low intra-tumoural expression of this gene in 20% of cases.

Postoperative interstitial brachytherapy for resectable squamous cell carcinoma of the tongue

PURPOSE

To evaluate the efficiency and toxicity of postoperative brachytherapy (POBT) in the treatment of resectable mobile tongue squamous cell carcinoma.

PATIENTS AND METHODS

This was a retrospective single-center study of patients with SSC of the mobile tongue who were treated between August 1992 and June 2013 by glossectomy and neck dissection followed by (192)Ir interstitial brachytherapy of the tumor bed. Endpoints were local control, cancer-specific survival (CSS), overall survival (OS), and morbidity. Independent prognostic factors were analyzed in a Cox regression model.

RESULTS

A total of 112 patients were identified (median age, 55 years [range, 15-84]; 76% male). Patient and tumor characteristics were: T1T2N0 (85%), pN+ (13%), positive surgical margins (14%), negative margins <5 mm (29%), dysplasic margins (14%), lymphatic vessel invasion (5%), and perineural spread (5%). Median followup was 6.7 years (1.5 months to 17.7 years). Local control, CSS, and OS rates at 2 years were 79%, 81%, and 72%, respectively. The corresponding 5-year rates were 76%, 67%, and 56%, respectively. After POBT, 22% of patients presented grade ≥2 necrosis and 8% experienced chronic pain. Independent prognostic factors were positive surgical margins for poor local control and tumor recurrence and lymphatic vessel invasion for poor OS.

CONCLUSION

POBT provided good local control and better CSS and OS than reported for surgery alone. Morbidity was higher than that reported for brachytherapy alone but may be considered acceptable in a well-selected patient population at high risk of local recurrence.

CXCL12 chemokine expression suppresses human pancreatic cancer growth and metastasis

Pancreatic ductal adenocarcinoma is an unsolved health problem with nearly 75% of patients diagnosed with advanced disease and an overall 5-year survival rate near 5%. Despite the strong link between mortality and malignancy, the mechanisms behind pancreatic cancer dissemination and metastasis are poorly understood. Correlative pathological and cell culture analyses suggest the chemokine receptor CXCR4 plays a biological role in pancreatic cancer progression. In vivo roles for the CXCR4 ligand CXCL12 in pancreatic cancer malignancy were investigated. CXCR4 and CXCR7 were consistently expressed in normal and cancerous pancreatic ductal epithelium, established cell lines, and patient-derived primary cancer cells. Relative to healthy exocrine ducts, CXCL12 expression was pathologically repressed in pancreatic cancer tissue specimens and patient-derived cell lines. To test the functional consequences of CXCL12 silencing, pancreatic cancer cell lines stably expressingthe chemokine were engineered. Consistent with a role for CXCL12 as a tumor suppressor, cells producing the chemokine wereincreasingly adherent and migration deficient in vitro and poorly metastatic in vivo, compared to control cells. Further, CXCL12 reintroduction significantly reduced tumor growth in vitro, with significantly smaller tumors in vivo, leading to a pronounced survival advantage in a preclinical model. Together, these data demonstrate a functional tumor suppressive role for the normal expression of CXCL12 in pancreatic ducts, regulating both tumor growth andcellulardissemination to metastatic sites.

The gene expression profile of inflammatory, hypoxic and metabolic genes predicts the metastatic spread of human head and neck squamous cell carcinoma

OBJECTIVES

To assess the prognostic value of the expression profile of the main genes implicated in hypoxia, glucose and lactate metabolism, inflammation, angiogenesis and extracellular matrix interactions for the metastatic spread of head and neck squamous cell carcinoma.

PATIENTS AND METHODS

Using a high-throughput qRT-PCR, we performed an unsupervised clustering analysis based on the expression of 42 genes for 61 patients. Usual prognostic factors and clustering analysis results were related to metastasis free survival.

RESULTS

With a median follow-up of 48months, 19 patients died from a metastatic evolution of their head and neck squamous cell carcinoma and one from a local recurrence. The unsupervised clustering analysis distinguished two groups of genes that were related to metastatic evolution. A capsular rupture (p=0.005) and the "cluster CXCL12 low" (p=0.002) were found to be independent prognostic factors for metastasis free survival. Using a Linear Predictive Score methodology, we established a 9-gene model (VHL, PTGER4, HK1, SLC16A4, DLL4, CXCL12, CXCR4, PTGER3 and CA9) that was capable of classifying the samples into the 2 clusters with 90% accuracy.

CONCLUSION

In this cohort, our clustering analysis underlined the independent prognostic value of the expression of a panel of genes involved in hypoxia and tumor environment. It allowed us to define a 9-gene model which can be applied routinely to classify newly diagnosed head and neck squamous cell carcinoma. If confirmed by an independent prospective study, this approach may help future clinical management of these aggressive tumors.

Chemokines and cytokines as salivary biomarkers for the early diagnosis of oral cancer

Chemokines have been shown to be important in both inflammation and carcinogenesis and are able to be measured in saliva with relatively robust methods including enzyme-linked immunosorbent assays (ELISA). Thus it has been hypothesized that patients with oral cancer and oral potentially malignant lesions will have elevated levels of specific chemokines in oral fluids and that this may be used as a marker of both the early detection of malignant disease and progression to malignancy. The concept that salivary biomarkers can be easily measured and indicate disease states has profound consequences for clinical practice and may open up new strategies for the diagnosis, prognosis, and potential therapy of oral squamous cell carcinoma (OSCC). This review focuses on our understanding of cytokines and chemokines and the potential role that they may have in clinical practice.

Interaction of a CD44+ head and neck squamous cell carcinoma cell line with a stromal cell-derived factor-1-expressing supportive niche: An in vitro model

The cancer stem cell (CSC) theory implies that CSCs are surrounded by supportive stromal cells, which are known as the CSC niche. Stromal cell-derived factor-1 (SDF-1) shows a multitude of functional effects in head and neck squamous cell carcinoma (HNSCC) cells, including migration and polarization. Therefore, the SDF-1-CXCR4 axis may be involved in the pathophysiology of the progression, recurrence and metastasis of malignant diseases of the head and neck. In the present study, the CD44⁺ HNSCC UM-SCC-11A cell line was used as a model for CSCs. The interaction between the UM-SCC-11A cells and the supportive microenvironmental cells, including fibrocytes, human umbilical vein endothelial cells (HUVECs) and human microvascular vein endothelial cells (HMVECs) was evaluated. All the cell types that were tested were shown to secrete different concentrations of SDF-1 into the surrounding culture medium [mean (m)_fibro, 1243.3±156.2 pg/ml; m_HMVEC, 1061.4±23.2 pg/ml; m_HUVEC, 849.6±110.9 pg/ml]. The migration of the UM-SCC-11A cells towards the supportive cells was increased by a higher supply of SDF-1 (contr_fibro, 315.23±61.55 μm; m_fibro, 477.73±143.7 μm; P_fibro=0.003; contr_HMVEC, 123.41±66.68 μm; m_HMVEC, 249.04±111.95 μm; P_HMVEC=0.004; contr_HUVEC, 189.7±93.26 μm; m_HUVEC, 260.82±161.58 μm). The amount of the UM-SCC-11A cells that migrated towards the differentiated fibrocytes was significantly higher than that which migrated towards the HMVECs or HUVECs (P_fibro/HMVEC=2.12E-11; P_fibro/HUVEC=2.28E-5). Cell-cell interaction by podia formation of the UM-SCC-11A cells was observed in all the supportive cell types that were tested. Broadly based cell-cell contacts were observed. By contrast, digitiform podia formations presented by the UM-SCC-11A cells were determined using fluorescence microscopy. The SDF-1-CXCR4 axis is postulated to be a crucial pathway in the interaction between CSCs and their surrounding supportive cells. Understanding the cell-cell interactions in the CSC niche using in vitro models may aid in gaining further insight into these mechanisms and finding new strategies of therapy in this field.

Chemokines, chemokine receptors and the gastrointestinal system

The biological properties of tumor cells are known to be regulated by a multitude of cytokines and growth factors, which include epidermal growth factor receptor agonists and members of the transforming growth factor β family. Furthermore, the recent explosion of research in the field of chemokine function as mediators of tumor progression has led to the possibility that these small, immunomodulatory proteins also play key roles in carcinogenesis and may, therefore, be potential targets for novel therapeutic approaches. In this review, we will summarize recently reported findings in chemokine biology with a focus on the gastrointestinal tract.

Focus on the role of the CXCL12/CXCR4 chemokine axis in head and neck squamous cell carcinoma

The human chemokine system includes approximately 48 chemokines and 19 chemokine receptors. The CXCL12/CXCR4 system is one of the most frequently studied that is also found overexpressed in a large variety of tumors. The CXCL12/CXCR4 axis has been increasingly identified as an important target in cancer growth, metastasis, relapse, and resistance to therapy. In this review, we highlight current knowledge of the molecular mechanisms involving chemokines CXCL12/CXCR4 and their consequences in head and neck squamous cell carcinoma (HNSCC). Overexpression of CXCL12/CXCR4 in HNSCC appears to activate cellular functions, including motility, invasion, and metastatic processes. Current findings suggest that CXCR4 and epithelial-mesenchymal transition markers are associated with tumor aggressiveness and a poor prognosis, and may be suitable biomarkers for head and neck tumors with high metastatic potential. Furthermore, knowledge of the role of CXCR4 in HNSCC could influence the development of new targeted therapies for treatment, aimed at improving the prognosis of this disease.

An infernal trio: the chemokine CXCL12 and its receptors CXCR4 and CXCR7 in tumor biology

Chemokines are small peptide mediators that play a role in many physiological and pathological processes. Apart from their initially discovered function in trafficking of leukocytes, they also influence migration, proliferation, survival and gene expression of a variety of cell types in their respective microenvironment. Chemokines can exert these effects via their respective G protein-coupled receptor. Over the recent decade, the involvement of chemokines and their respective receptors in tumor biology has been successively elucidated. This review will focus on the signaling and effects of the widespread chemokine CXCL12 and its long known G protein-coupled receptor CXCR4 and the recently discovered non-G protein-coupled receptor CXCR7 with a detailed reflection on glioma biology.

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.

Expressions of CXCL12/CXCR4 in oral premalignant and malignant lesions

OBJECTIVE

The chemokine receptor CXCR4 and its ligand CXCL12 have been suggested to play important roles in the initiation or progression of cancers. The goal of the present study was to investigate alterations of CXCL12/CXCR4 in oral premalignant lesions and oral squamous cell carcinoma (OSCC).

METHODS

In 13 normal oral epithelia, 24 dysplastic oral leukoplakia (OLK), and 40 OSCC specimens, expressions of CXCL12 and CXCR4 were evaluated by immunohistochemistry.

RESULTS

CXCR4 was expressed in 37.5% of OLK and 60% of OSCC. CXCL12 was detected in 50% of OLK and 62.5% of OSCC. In OLK, CXCR4 positive ratio showed no significant difference from normal epithelia, but the CXCL12 positive ratio was significantly higher. Significant relationship between CXCL12 and CXCR4 was found both in OLK and OSCC.

CONCLUSION

Our results indicated that CXCL12/CXCR4 axis may play roles from early steps of oral malignant transformation and contribute to the progress of oral carcinogenesis.