High CXCL12 Expression Research Articles

1688PD - The Combined Expression of CXCR7 and its Ligand CXCL12 is a Marker for Unfavorable Prognosis in Gastric Cancer

ABSTRACT Background Chemokines and their receptors have been shown to play a critical role in cancer growth and metastasis. In particular, recent data have suggested that the chemokine CXCL12 and its receptor CXCR7 (also known as RDC1), which has been recently identified as a chemokine receptor, have key functions in promoting tumor development and progression. However, there is little information regarding their expression and clinical relevance in gastric cancer. Here we investigated for the first time the effects of combined CXCR7 and CXCL12 expression on the prognosis of patients with gastric cancer. Methods We studied CXCL12 and CXCR7 protein expression in 221 specimens of primary gastric cancer using immunohistochemistry, and investigated the relationaship between CXCL12/CXCR7 expression and clinicopathological features and clinical outcomes. Results Patients were categorized into four groups according to CXCR7 and CXCL12 expression: low CXCR7/low CXCL12, high CXCR7/low CXCL12, low CXCR7/high CXCL12, and high CXCR7/high CXCL12. No significant differences existed in age, gender, histology, tumor location, lymphovascular invasion among the four groups. However, high CXCR7/high CXCL12 expression in tumor cells was significantly associated with invasion depth of the tumor (T status; P 5 cm (P = 0.006) compared to tumors with low CXCR7/low CXCL12 expression or high CXCR7/low CXCL12–low CXCR7/high CXCL12 expression. Furthermore, patients with high CXCR7/high CXCL12 expression had the worst prognosis (5-year survival rate 30.6%; median, 2.3 years; range, 0.1 - 5.7 years) compared to those of other patient groups (5-year survival rate, 52.4%; median, not reached; log-rank test, P = 0.008) . Conclusions CXCR7 and CXCL12 are useful prognostic factors in gastric cancer, and the combination of high CXCR7 protein expression with high CXCL12 expression suggests a dismal prognosis. Disclosure All authors have declared no conflicts of interest.

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

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 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. 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). 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.

Improved Outcome of High-Risk Early HER2 Positive Breast Cancer With High CXCL13-CXCR5 Messenger RNA Expression

BackgroundChemokines are important in cell migration and are thought to play a key role in metastasis. We explored the prognostic significance of C-X-C ligand-motif (CXCL) 12, CXCL13, and receptor (CXCR) 5 on disease-free survival (DFS) and overall survival (OS) in early breast cancer. MethodsA total of 595 patients at high risk for early breast cancer were treated in a 2-arm trial (HE10/97) with dose-dense sequential epirubicin followed by cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) with or without paclitaxel. RNA was extracted from 321 formalin-fixed paraffin-embedded primary tumor tissue samples and quantitative reverse-transcriptase polymerase chain reaction was used to assess messenger RNA (mRNA) expression of CXCL12, CXCL13, and CXCR5; estrogen receptor; progesterone receptor (PgR); microtubule-associated protein tau and human epidermal growth factor receptor 2 (HER2). ResultsCXCL13 and CXCR5 were found to be negatively associated with estrogen receptor and microtubule-associated protein tau mRNA expression and with dense lymphocytic infiltration, and were positively associated with nuclear grade. Only CXCL13 was positively associated with HER2. Multivariate analysis revealed an association between high CXCL13 mRNA expression and improved DFS (hazard ratio [HR] 0.48 [95% CI, 0.25-0.90]; Wald, P = .023) but not OS; whereas high CXCL12 expression was significantly associated with increased OS (HR 0.53 [95% CI, 0.33-0.85]; Wald, P = .009). In the HER2 mRNA overexpressing subgroup, high CXCL13 mRNA expression was associated with improved DFS (P < .001), whereas high CXCR5 was associated with increased DFS and OS (P = .004 and P = .049, respectively). ConclusionsThe CXCL13-CXCR5 axis is associated with classic determinants of poor prognosis, such as high grade, hormone receptor negativity, and axillary node involvement. Interestingly, this chemokine axis seems to be strongly associated with improved outcome in patients with HER2+ disease.

Ibandronate arrests tumor cell proliferation by epigenetic mechanisms

It has been recently demonstrated that in colonic carcinoma, CXCL12 expression undergoes epigenetic regulation by methylation of cytosine in cytosine–guanosine (CpG) dinucleotides of the promoter sequence.Using lentiviral vectors, we generated stable RNA interference-mediated knockdown of DNMT1 and DNMT3B in MCF-7 breast cancer and AsPC1 pancreatic carcinoma cell lines. Employing reverse transcription real-time quantitative PCR and immunofluorescence analysis, we determined re-expression levels of CXCL12 transcript and protein in these cells. Bisulfite sequencing revealed that the level of promoter demethylation appeared more effective in cells expressing DNMT1 siRNA than in those expressing DNMT3B siRNA, and this correlated with higher expression of CXCL12. Moreover, the combined expression of DNMT1 and DNMT3B siRNAs enhanced promoter demethylation that was associated only with a slight increase of CXCL12 expression. However, the demethylating agent 5-Aza-2′-deoxycytidine exhibited the strongest effect on promoter demethylation, which correlated with the highest expression level of CXCL12 transcript and protein in MCF-7 and AsPC1 cells.Our findings suggest that DNMT1 plays a key role in maintenance of methylation, and DNMT3B may act as an accessory DNA methyltransferase to epigenetically silence CXCL12 expression in MCF-7 and AsPC1 cells.

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.

Emergence of Fibroblasts with a Proinflammatory Epigenetically Altered Phenotype in Severe Hypoxic Pulmonary Hypertension

Persistent accumulation of monocytes/macrophages in the pulmonary artery adventitial/perivascular areas of animals and humans with pulmonary hypertension has been documented. The cellular mechanisms contributing to chronic inflammatory responses remain unclear. We hypothesized that perivascular inflammation is perpetuated by activated adventitial fibroblasts, which, through sustained production of proinflammatory cytokines/chemokines and adhesion molecules, induce accumulation, retention, and activation of monocytes/macrophages. We further hypothesized that this proinflammatory phenotype is the result of the abnormal activity of histone-modifying enzymes, specifically, class I histone deacetylases (HDACs). Pulmonary adventitial fibroblasts from chronically hypoxic hypertensive calves (termed PH-Fibs) expressed a constitutive and persistent proinflammatory phenotype defined by high expression of IL-1β, IL-6, CCL2(MCP-1), CXCL12(SDF-1), CCL5(RANTES), CCR7, CXCR4, GM-CSF, CD40, CD40L, and VCAM-1. The proinflammatory phenotype of PH-Fibs was associated with epigenetic alterations as demonstrated by increased activity of HDACs and the findings that class I HDAC inhibitors markedly decreased cytokine/chemokine mRNA expression levels in these cells. PH-Fibs induced increased adhesion of THP-1 monocytes and produced soluble factors that induced increased migration of THP-1 and murine bone marrow-derived macrophages as well as activated monocytes/macrophages to express proinflammatory cytokines and profibrogenic mediators (TIMP1 and type I collagen) at the transcriptional level. Class I HDAC inhibitors markedly reduced the ability of PH-Fibs to induce monocyte migration and proinflammatory activation. The emergence of a distinct adventitial fibroblast population with an epigenetically altered proinflammatory phenotype capable of recruiting, retaining, and activating monocytes/macrophages characterizes pulmonary hypertension-associated vascular remodeling and thus could contribute significantly to chronic inflammatory processes in the pulmonary artery wall.

Expression of CXCR7 chemokine receptor in human meningioma cells and in intratumoral microvasculature

CXCR4 and CXCR7 chemokine receptors, and their ligands CXCL11 and CXCL12, have been often involved in tumor cell proliferation and survival. We report the expression pattern of these ligand/receptor pairs in 22 human meningiomas. High CXCR7 and CXCL12 expression was associated with high-proliferative tumors. CXCR7 levels were correlated to the content of both ligands, suggesting a possible autocrine regulation. CXCR4 and CXCL12 were homogeneously expressed within tumor cells, while CXCR7 was mainly detected in tumor endothelial cells and CXCL11 in pericytes. Our results highlight the preferential CXCR7 and CXCL12 expression within more aggressive tumors and the possible role of CXCR7 in meningioma vascularization.

CXCL12-CXCR4 Axis in Angiogenesis, Metastasis and Stem Cell Mobilization

Chemokines are key players in the attraction and activation of leukocytes and are thus implicated in the recruitment of immune cells at sites of infection and/or inflammation. They exert their action by binding to seven-transmembrane G protein-coupled receptors. The chemokine stromal cell-derived factor-1 (SDF-1)/CXCL12 represents the single natural ligand for the chemokine receptor CXCR4. CXCL12 possesses angiogenic properties and is involved in the outgrowth and metastasis of CXCR4-expressing tumors and in certain inflammatory autoimmune disorders, such as rheumatoid arthritis. CXCR4 expression on tumor cells is upregulated by hypoxia and angiogenic factors, such as vascular endothelial growth factor (VEGF). CXCR4 also acts as a co-receptor for entry of human immunodeficiency virus (HIV) in CD4(+) T cells. Finally, CXCL12/CXCR4 interactions were shown to play an important role in the migration of hematopoietic stem cells and their progenitors from, and their retention within, the bone marrow, a site characterized by high CXCL12 expression. As such, CXCR4 inhibitors may be utilized to inhibit HIV-1 infection, tumor growth and metastasis and to mobilize hematopoietic stem cells from the bone marrow in the circulation, where they can be collected for autologous stem cell transplantation. Here, we discuss the different aspects of CXCL12/CXCR4 biology as well as the development and anti-cancer/stem cell mobilizing activity of CXCR4 antagonists.

Macrophages may promote cancer growth via a GM-CSF/HB-EGF paracrine loop that is enhanced by CXCL12

BackgroundIncreased numbers of tumour-associated macrophages correlate with shortened survival in some cancers. The molecular bases of this correlation are not thoroughly understood. Events triggered by CXCL12 may play a part, as CXCL12 drives the migration of both CXCR4-positive cancer cells and macrophages and may promote a molecular crosstalk between them.ResultsSamples of HER1-positive colon cancer metastases in liver, a tissue with high expression of CXCL12, were analysed by immunohistochemistry. In all of the patient biopsies, CD68-positive tumour-associated macrophages presented a mixed CXCL10 (M1)/CD163 (M2) pattern, expressed CXCR4, GM-CSF and HB-EGF, and some stained positive for CXCL12. Cancer cells stained positive for CXCR4, CXCL12, HER1, HER4 and GM-CSF. Regulatory interactions among these proteins were validated via experiments in vitro involving crosstalk between human mononuclear phagocytes and the cell lines DLD-1 (human colon adenocarcinoma) and HeLa (human cervical carcinoma), which express the above-mentioned ligand/receptor repertoire. CXCL12 induced mononuclear phagocytes to release HB-EGF, which activated HER1 and triggered anti-apoptotic and proliferative signals in cancer cells. The cancer cells then proliferated and released GM-CSF, which in turn activated mononuclear phagocytes and induced them to release more HB-EGF. Blockade of GM-CSF with neutralising antibodies or siRNA suppressed this loop.ConclusionsCXCL12-driven stimulation of cancer cells and macrophages may elicit and reinforce a GM-CSF/HB-EGF paracrine loop, whereby macrophages contribute to cancer survival and expansion. The involvement of mixed M1/M2 GM-CSF-stimulated macrophages in a tumour-promoting loop may challenge the paradigm of tumour-favouring macrophages as polarized M2 mononuclear phagocytes.

Neutralization of TGF-beta led to spontaneous elicitation of antitumor immune responses and elimination of tumors in mice administered of DNA encoding soluble TGF-beta receptor

CXCR4 and CXCR7 chemokine receptors, and their ligands CXCL11 and CXCL12, have been often involved in tumor cell proliferation and survival. We report the expression pattern of these ligand/receptor pairs in 22 human meningiomas. High CXCR7 and CXCL12 expression was associated with high-proliferative tumors. CXCR7 levels were correlated to the content of both ligands, suggesting a possible autocrine regulation. CXCR4 and CXCL12 were homogeneously expressed within tumor cells, while CXCR7 was mainly detected in tumor endothelial cells and CXCL11 in pericytes. Our results highlight the preferential CXCR7 and CXCL12 expression within more aggressive tumors and the possible role of CXCR7 in meningioma vascularization.

RNA interference-mediated knockdown of DNMT1 and DNMT3B induces CXCL12 expression in MCF-7 breast cancer and AsPC1 pancreatic carcinoma cell lines

It has been recently demonstrated that in colonic carcinoma, CXCL12 expression undergoes epigenetic regulation by methylation of cytosine in cytosine–guanosine (CpG) dinucleotides of the promoter sequence. Using lentiviral vectors, we generated stable RNA interference-mediated knockdown of DNMT1 and DNMT3B in MCF-7 breast cancer and AsPC1 pancreatic carcinoma cell lines. Employing reverse transcription real-time quantitative PCR and immunofluorescence analysis, we determined re-expression levels of CXCL12 transcript and protein in these cells. Bisulfite sequencing revealed that the level of promoter demethylation appeared more effective in cells expressing DNMT1 siRNA than in those expressing DNMT3B siRNA, and this correlated with higher expression of CXCL12. Moreover, the combined expression of DNMT1 and DNMT3B siRNAs enhanced promoter demethylation that was associated only with a slight increase of CXCL12 expression. However, the demethylating agent 5-Aza-2′-deoxycytidine exhibited the strongest effect on promoter demethylation, which correlated with the highest expression level of CXCL12 transcript and protein in MCF-7 and AsPC1 cells. Our findings suggest that DNMT1 plays a key role in maintenance of methylation, and DNMT3B may act as an accessory DNA methyltransferase to epigenetically silence CXCL12 expression in MCF-7 and AsPC1 cells.

Prognostic Value of Tumor Architecture, Tumor-Associated Vascular Characteristics, and Expression of Angiogenic Molecules in Pancreatic Endocrine Tumors

It is difficult to predict the biological behavior of pancreatic endocrine tumors (PETs). Our aim was to evaluate the prognostic significance of certain variables in PETs. The following variables were examined in 37 patients with PETs and then compared with other clinicopathologic characteristics: histologic tumor structure; microvessel density (MVD) measured by three different methods, including a unique method involving calculation of solid area MVD; endothelial proliferation; and the immunohistochemical expression of vascular endothelial growth factor-A and CXC chemokine CXCL-12. Intratumoral vascular structures were analyzed by double immunofluorescence using 30-microm-thick sections. The presence of focal and intensive solid growth of tumor cells (large solid nests; P = 0.003), low solid area MVD (P = 0.002), a high endothelial cell proliferation index (EPI; P = 0.005), and high expression of CXCL-12 in PET cells (P = 0.018) were significant unfavorable prognostic indicators. The predominant structure of the overall tumor histology and the expression of vascular endothelial growth factor-A did not separate aggressive PETs. In areas of focal solid growth, tumor-associated blood vessels had obviously low MVD and high EPI, and their structures were poorly formed with highly abnormal features, in comparison with other areas. High expression of CXCL-12 in tumor cells was significantly associated with variables representing tumor growth, hematogenous tumor spread, low MVD, high EPI, and the presence of large solid nests. This study has provided novel findings on the prognostic features of tumor architecture and tumor-associated angiogenesis in PETs. CXCL-12 is the first candidate molecule in association with neoangiogenesis in PETs.

CD4+CXCR4highCD69+ T Cells Accumulate in Lung Adenocarcinoma

The chemokine receptor CXCR4 is involved in the growth and metastasis of tumor cells. However, the expression of its ligand, the chemokine CXCL12, in tumors and its role in regulating the accumulation of immune cells within the tumors is not clear. Using ELISA and immunohistochemistry we found that CXCL12 is expressed in the majority of nonsmall cell lung cancer tissue sections obtained from stage IA to IIB nonsmall cell lung cancer patients undergoing operation. Histopathologic examination of these sections indicated that high CXCL12 expression correlated with increased tumor inflammation. In addition, disease recurrence rates in a subgroup of adenocarcinoma patients showed a tendency to correlate with high CXCL12 expression in the tumor. Isolation of adenocarcinoma-infiltrating immune cells demonstrated an increase in the percentage of CD4+CD69+CXCR4+ T cells as compared with normal lung tissue. About 30% of these cells expressed the regulatory T cell markers CD25high and FoxP3. The percentage of CD8 T cells within the tumor did not change, however; the percentage of NK and NK T cells was significantly reduced. In correlation with CXCR4 expression, CD4 T cells showed increased migration in response to CXCL12 compared with CD8 T cells and NK cells. Overall, these observations suggest that CXCL12 expression may influence tumor progression by shaping the immune cell population infiltrating lung adenocarcinoma tumors.