Vitamin D Regulates CXCL12/CXCR4 and Epithelial-to-Mesenchymal Transition in a Model of Breast Cancer Metastasis to Lung

Vitamin D deficiency is associated with poor cancer outcome in humans, and administration of vitamin D or its analogs decreases tumor progression and metastasis in animal models. Using the mouse mammary tumor virus-polyoma middle T antigen (MMTV-PyMT) model of mammary cancer, we previously demonstrated a significant acceleration of carcinogenesis in animals on a low vitamin D diet and a reduction in spontaneous lung metastases when mice received vitamin D through perfusion. We investigate here the action mechanism for vitamin D in lung metastasis in the same non-immunodeficient model and demonstrate that it involves the control of epithelial to mesenchymal transition as well as interactions between chemokine C-X-C motif chemokine 12 (CXCL12) and its receptor C-X-C chemokine receptor type 4 (CXCR4). In vitro, 10-9M vitamin D treatment modifies the phenotype of MMTV-PyMT primary mammary tumor cells and significantly decreases their invasiveness and mammosphere formation capacity by 40% and 50%, respectively. Vitamin D treatment also inhibits phospho-signal transducer and activator of transcription 3 (p-STAT3), zinc finger E-box-binding homeobox 1 (Zeb1), and vimentin by 52%, 75%, and 77%, respectively, and increases E-cadherin by 87%. In vivo, dietary vitamin D deficiency maintains high levels of Zeb1 and p-STAT3 in cells from primary mammary tumors and increases CXCL12 expression in lung stroma by 64%. In lung metastases, vitamin D deficiency increases CXCL12/CXCR4 co-localization by a factor of 2.5. These findings indicate an involvement of vitamin D in mammary cancer "seed" (primary tumor cell) and "soil" (metastatic site) and link vitamin D deficiency to epithelial-to-mesenchymal transition (EMT), CXCL12/CXCR4 signaling, and accelerated metastasis, suggesting vitamin D repleteness in breast cancer patients could enhance the efficacy of co-administered therapies in preventing spread to distant organs.

Assessment of endothelial progenitor cells, VEGF-A and SDF-1α in Hodgkin's lymphoma

Recently, there is great interest in vasculogenesis, a process of the formation of new blood vessels from progenitor cells or angioblasts, in the pathogenesis of cancer. To the best of our knowledge, the evaluation of endothelial progenitor cells (EPCs) in Hodgkin's lymphoma has not yet been reported. The aim of the present study was to assess the number of EPCs and selected cytokines, such as vascular endothelial growth factor (VEGF-A) and stromal cell-derived factor (SDF-1α) involved in vasculogenesis in Hodgkin's lymphoma patients. The study was conducted in a group of 42 patients with Hodgkin's lymphoma (eight patients with relapsed Hodgkin's lymphoma and 34 patients before the first treatment) and 30 healthy controls. The number of EPCs defined as CD31(+), CD34(+), CD45(-), CD133(+) was analysed on FacsCalibur flow cytometer and the concentration of VEGF-A and SDF-1α was assessed by ELISA. The study showed that there was a significantly higher EPCs number and VEGF-A concentration in the blood of Hodgkin's lymphoma patients compared to healthy individuals (8.20 vs. 0.55 cells/μl; P < 0.000001; 85.10 vs. 25.33 pg/ml, P = 0.000017; respectively). Detailed analysis revealed that there was elevated EPCs number in both study subgroups as compared to the control group. However, there was no difference in VEGF concentration between recurrent Hodgkin's lymphoma patients and the control group. A significant positive correlation was found between the number of EPCs and VEGF-A concentration (R = 0.31, P = 0.047). Significantly higher EPCs number combined with increased VEGF-A concentration, found in Hodgkin's lymphoma patients before the first treatment, suggest stimulation of new blood vessels formation, which may in turn contribute to tumour growth and metastasis in these patients.

Association of CXCR4 Expression and Clinical Outcome in Different Subsets of De Novo Acute Myeloid Leukemia Patients

BACKGROUND

Acute myeloid leukemia is a heterogeneous group of diseases characterized by the uncontrolled proliferation of hematopoietic stem cells (HSCs) and progenitor cells with a reduced capacity to differentiate into mature cells. CXC chemokine receptor (CXCR4) and its ligand stromal derived factor-1 (SDF-1/CXCL12) are important players involved in cross-talk between leukemia cells and the bone marrow (BM) microenvironment. The aim to study the association between the immunohistochemical CXCR4 expression and the clinical outcome of AML in adult Egyptian patients.

METHODS

Fifty-eight patients suffering from AML were recruited for this study, with an age range from 18 to 60 years and presenting from January 2013 to March 2017. All patients were subjected to complete blood count, BM aspiration, immunophenotyping, BM trephine biopsy, immunohistochemical staining with CXCR4 McAb and cytogenetics when feasible.

RESULTS

CXCR4 was widely expressed (55.2%) among the studied patients. There was a significant relationship between CXCR4 and patients' outcomes. Fifteen (71.4%) patients who died were CXCR4 positive. The estimated mean time until death among CXCR4 negative cases was 37.6 ± 4.04 months which was longer than that of CXCR4 positive cases who had mean of 20.04 ± 4.9 months p = 0.016. The risk for death among CXCR4 positive cases was higher than CXCR4 negative cases with hazard ratio (HR) = 2.147 (p = 0.048).

CONCLUSIONS

These results suggest that CXCR4 was expressed in a subset of AML patients and was associated with poor prognosis. CXCR4 expression appears to be an independent prognostic factor for survival in a heterogeneous group of AML patients.

CXCR4 and its ligand CXCL12 display opposite expression profiles in feline mammary metastatic disease, with the exception of HER2-overexpressing tumors

BACKGROUND

The receptor CXCR4 and its ligand CXCL12 play crucial roles in breast cancer. Despite the fact that the spontaneous feline mammary carcinoma (FMC) is considered a suitable model for breast cancer studies, the importance of the CXCR4/CXCL12 axis in FMC is completely unknown. Therefore, this work aims to elucidate the role of CXCR4 and its ligand in the progression of FMC and metastatic disease.

METHODS

CXCR4 and CXCL12 expression was analyzed by immunohistochemistry and immunofluorescence on primary tumors (PT), regional and distant metastases of female cats with mammary carcinoma and correlated with serum CXCL12 levels, tumor molecular subtypes and clinicopathological features.

RESULTS

CXCR4 was more expressed in PT than in metastases (p = 0.0067), whereas CXCL12 was highly expressed in metastatic lesions located in liver and lung (p < 0.0001), as reported for human breast cancer. Moreover, cats with CXCR4 positive PT exhibited significantly lower serum CXCL12 levels than cats with CXCR4 negative mammary carcinomas (p = 0.0324). At metastatic lesions, HER2-overexpressing tumors presented higher CXCR4 expression than the other molecular tumor subtypes (p = 0.012) and significant differences in overall (p = 0.0147) and disease-free survival (p = 0.0279) curves between the cats with CXCL12 positive and CXCL12 negative tumors were found. Indeed, CXCL12 negative PT were associated with unfavorable prognosis in cats with HER2-overexpressing tumors.

CONCLUSIONS

This work exposes part of the complex interaction between CXCR4 and CXCL12 in PT, but also in metastases of a breast cancer model. These findings could uncover novel therapeutic tools to be used in cats and humans.

The different dosages of estrogen affect endometrial fibrosis and receptivity, but not SDF-1/CXCR4 axis in the treatment of intrauterine adhesions

OBJECTIVE

The study was to evaluate whether fibrotic markers, endometrial receptivity markers and SDF-1/CXCR4 had been changed in the treatment of intrauterine adhesions (IUAs) by different dosages of estrogen.

STUDY DESIGN

A total of 39 patients with IUAs were treated with EV 4 mg or 9 mg randomly post-surgery. TGF-β1/MMP-9, VEGF/αvβ3 and SDF-1/CXCR4 were detected in endometrial tissue before and after treatment by real-time PCR and Western blot.

RESULTS

TGF-β1 and MMP-9 expression significantly decreased after treatment for 3 months than before (p < .05), the falling range was larger with EV 4 mg than 9 mg in the mild-moderate degree IUAs (p < .05); Integrin avβ3 expression significantly increased after treatment for 3 months than before (p < .05), the variation range was larger with EV 4 mg than 9 mg (p < .05); CXCR4 expression had no significant change after treatment 3 months compared to that before treatment (p > .05). SDF-1 presented an upward tendency at early phase, and it came back to the level of pre-surgery. But there were no significant difference between treatment with 4 mg and 9 mg in the rate of menstrual restoration and pregnancy follow-up 3 months after the treatment.

CONCLUSIONS

Endometrium fibrosis may be inhibited and endometrium receptivity may be improved by estrogen with moderate dosage therapy. Compared to the large one, it seems to be advantageous.

Functional reprogramming of human prostate cancer to promote local attraction of effector CD8(+) T cells

BACKGROUND

Local infiltration of CD8(+) T cells (CTLs) in tumor lesions predicts overall clinical outcomes and the clinical benefit of cancer patients from immune checkpoint blockade. In the current study, we evaluated local production of different classes of chemokines in prostate cancer lesions, and the feasibility of their modulation to promote selective entry of CTLs into prostate tumors.

METHODS

Chemokine expression in prostate cancer lesion was analyzed by TaqMan-based quantitative PCR, confocal fluorescence microscopy and ELISA. For ex vivo chemokine modulation analysis, prostate tumor explants from patients undergoing primary prostate cancer resections were cultured for 24 hr, in the absence or presence of the combination of poly-I:C, IFNα, and celecoxib (PAC). The numbers of cells producing defined chemokines in the tissues were analyzed by confocal microscopy. Chemotaxis of effector CD8(+) T cells towards the untreated and PAC-treated tumor explant supernatants were evaluated in a standard in vitro migration assays, using 24 well trans-well plates. The number of effector cells that migrated was enumerated by flow cytometry. Pearson (r) correlation was used for analyzing correlations between chemokines and immune filtrate, while paired two tailed students t-test was used for comparison between treatment groups.

RESULTS

Prostate tumors showed uniformly low levels of CTL/NK/Th1-recruiting chemokines (CCL5, CXCL9, CXCL10) but expressed high levels of chemokines implicated in the attraction of myeloid derived suppressor cells (MDSC) and regulatory T cells (Treg ): CCL2, CCL22, and CXCL12. Strong positive correlations were observed between CXCL9 and CXCL10 and local CD8 expression. Tumor expression levels of CCL2, CCL22, and CXCL12 were correlated with intratumoral expression of MDSC/Treg markers: FOXP3, CD33, and NCF2. Treatment with PAC suppressed intratumoral production of the Treg -attractant CCL22 and Treg /MDSC-attractant, CXCL12, while increasing the production of the CTL attractant, CXCL10. These changes in local chemokine production were accompanied by the reduced ability of the ex vivo-treated tumors to attract CD4(+) FOXP3(+) Treg cells, and strongly enhanced attraction of the CD8(+) Granzyme B(+) CTLs.

CONCLUSIONS

Our data demonstrate that the chemokine environment in prostate cancer can be reprogrammed to selectively enhance the attraction of type-1 effector immune cells and reduce local attraction of MDSCs and Tregs . Prostate 76:1095-1105, 2016. © 2016 Wiley Periodicals, Inc.

Effects of PB-EPCs on Homing Ability of Rabbit BMSCs via Endogenous SDF-1 and MCP-1

Traumas, infections, tumors, and some congenital malformations can lead to bone defects or even bone loss. The goal of the present study was to investigate whether inclusion of endothelial progenitor cells derived from peripheral blood (PB–EPCs) in cell-seeded partially deproteinized bone (PDPB) implants would stimulate recruitment of systemically injected bone marrow stromal cells (BMSCs) to the implant. Methods: BMSCs were injected intravenously with lentiviral expression vector expressing enhanced green fluorescent protein (eGFP) for tracing. Recruitment of eGFP-positive BMSCs was tested for the following implant configurations: 1) seeded with both BMSC and PB-EPC, 2) BMSC alone, 3) PB-EPC alone, and 4) unseeded PDPB. Protein and mRNA levels of endogenous stromal-derived factor-1 (SDF-1) and its receptor CXCR4, as well as monocyte chemotactic protein-1 (MCP-1) and its receptor CCR2, were evaluated on the 8th week. Immunohistochemical staining was performed to determine eGFP-positive areas at the defective sites. Masson’s trichrome staining was conducted to observe the distribution of collagen deposition and evaluate the extent of osteogenesis. Results: The mRNA and protein levels of SDF-1 and CXCR4 in the co-culture group were higher than those in other groups (p < 0.05) 8 weeks after the surgery. MCP-1 mRNA level in the co-culture group was also higher than that in the other groups (p < 0.05). Immunohistochemical assays revealed that the area covered by eGFP-positive cells was larger in the co-culture group than in the other groups (p < 0.05) after 4 weeks. Masson’s trichrome staining revealed better osteogenic potential of the co-culture group compared to the other groups (p < 0.05). Conclusion: These experiments demonstrate an association between PB-EPC and BMSC recruitment mediated by the SDF-1/CXCR4 axis that can enhance repair of bone defects.

[Buyang Huanwu decoction promotes neuroblast migration from subventricular zone via inducing angiogenesis after ischemia]

OBJECTIVE

To study the effect of Buyang Huanwu decoction (BYHWD) inducing angiogenesis on the neuroblast migration from the subventricular zone and its mechanisms after focal cerebral ischemia.

METHOD

The middle cerebral artery occlusion (MCAO) was performed to mice for 30 minutes to establish the model. The rats were divided into sham group, model group, BYHWD group and endostatin group. BYHWD (20 g x kg(-1), ig) and endostatin (10 μg, sc) were administered 24 h after ischemia once a day for consecutively 14 days. At 14 d after ischemia, the density of micro-vessel and the number of neuroblasts in the ischemia border zone were determined by immunofluorescence staining. The mRNA and protein expression of cell-derived factor-1 (SDF-1) and brain-derived neurotrophic (BDNF) were examined by real-time PCR and Western blot.

RESULT

Compared with the model group, BYHWD significantly increased the density of micro-vessel and the number of DCX positive cells in the ischemia border zone (P < 0.01), and significantly increased the SDF-1 and BDNF mRNA and protein expression (P < 0.01). Compared with BYHWD group, endostatin significantly reduced the density of micro-vessel and the number of DCX positive cells in the ischemia border zone (P < 0.01), as well as the SDF-1, BDNF mRNA and protein expression (P < 0.01).

CONCLUSION

BYHWD could promote the neuroblast migration from the subventricular zone via inducing angiogenesis after cerebral ischemia, the mechanism may be correlated with up-regulating the expression of SDF-1 and BDNF.

Molecular imaging, biodistribution and efficacy of mesenchymal bone marrow cell therapy in a mouse model of Chagas disease

Chagasic cardiomyopathy, resulting from infection with the parasite Trypanosoma cruzi, was discovered more than a century ago and remains an incurable disease. Due to the unique properties of mesenchymal stem cells (MSC) we hypothesized that these cells could have therapeutic potential for chagasic cardiomyopathy. Recently, our group pioneered use of nanoparticle-labeled MSC to correlate migration with its effect in an acute Chagas disease model. We expanded our investigation into a chronic model and performed more comprehensive assays. Infected mice were treated with nanoparticle-labeled MSC and their migration was correlated with alterations in heart morphology, metalloproteinase activity, and expression of several proteins. The vast majority of labeled MSC migrated to liver, lungs and spleen whereas a small number of cells migrated to chagasic hearts. Magnetic resonance imaging demonstrated that MSC therapy reduced heart dilatation. Additionally metalloproteinase activity was higher in heart and other organs of infected mice. Protein expression analyses revealed that connexin 43, laminin γ1, IL-10 and INF-γ were affected by the disease and recovered after cell therapy. Interestingly, MSC therapy led to upregulation of SDF-1 and c-kit in the hearts. The beneficial effect of MSC therapy in Chagas disease is likely due to an indirect action of the cells of the heart, rather than the incorporation of large numbers of stem cells into working myocardium.

Expression of SNCG, MAP2, SDF-1 and CXCR4 in gastric adenocarcinoma and their clinical significance

OBJECTIVES

The purpose of the study was to detect the expression of SNCG, MAP2, SDF-1 and CXCR4 in gastric adenocarcinoma, and to evaluate their roles in the carcinogenesis of gastric adenocarcinoma, development, invasion and metastasis as well as their clinical significance.

METHODS

The expression of SNCG, MAP2, SDF-1 and CXCR4 was detected by SP immunohistochemical method in 225 cases of gastric adenocarcinoma and 105 cases of nonneoplastic adjacent gastric tissue. The expression of SNCG, MAP2, SDF-1 and CXCR4 mRNA was also detected by RT-PCR method in 50 cases of gastric adenocarcinoma and 30 cases of nonneoplastic adjacent gastric tissue.

RESULTS

The expression of SNCG, MAP2, SDF-1 and CXCR4 in the gastric adenocarcinoma was remarkably higher than those in the nonneoplastic adjacent gastric tissue (P < 0.01); The positive expression of SNCG and MAP2 was correlated with the depth of tumor invasion and the metastasis of lymph nodes (P < 0.05), and that of SDF-1 and CXCR4 was correlated with the metastasis of lymph nodes (P < 0.05).

CONCLUSIONS

SNCG, MAP2, SDF-1 and CXCR4 may play an important role in the carcinogenesis, progression, invasion and metastasis of gastric adenocarcinoma. However, it still needs more exploration whether they can serve as promising therapeutic targets of gastric adenocarcinoma.

Can expression of CXCL12 and CXCR4 be used to predict survival of gastric cancer patients?

BACKGROUND

Currently, there is no effective therapy for advanced gastric cancer. In this study, we investigated whether protein expression of CXCL12 and/or its receptor CXCR4 is associated with clinicopathological features and/or survival of gastric cancer.

MATERIALS AND METHODS

Primary tumor specimens from patients (n=137) with pathologically-confirmed gastric cancer, collected between 2001 and 2009, were analyzed by immunohistochemistry using anti-CXCL12 and anti-CXCR4 antibodies.

RESULTS

Expression of CXCL12 was directly associated with tumor differentiation (p=0.0143) but inversely associated with depth of invasion (p=0.0255), lymphatic invasion (p=0.0173), venous invasion (p=0.0022) and stage (p=0.049). Expression of CXCR4 was associated with depth of invasion (p=0.005) and stage (p=0.028). Increased CXCR4 expression, but not CXCL12 expression, was associated with 5-year cancer-specific survival (p=0.0079).

CONCLUSION

CXCL12 was not associated with survival. Positive CXCR4 expression in gastric carcinoma was significantly associated with poor survival and, therefore, may be a potential biomarker for predicting poor survival.

CXC chemokine ligand 12 (CXCL12) and its receptor CXCR4

Chemokines were recognized originally for their ability to dictate the migration and activation of leukocytes. However, CXC chemokine ligand 12 (CXCL12, also known as stromal cell-derived factor-1) and its receptor CXCR4 are the first chemokine and receptor that have been shown to be critical for developmental processes, including homing and maintenance of hematopoietic stem cells (HSCs), production of immune cells, homing of primordial germ cells (PGCs), cardiogenesis, arterial vessel branching in some organs, and appropriate assemblies of particular types of neurons. This review focuses on the pathophysiological relevance of CXCL12-CXCR4 signaling in mammals.

Inhibition of angiogenesis, fibrosis and thrombosis by tetramethylpyrazine: mechanisms contributing to the SDF-1/CXCR4 axis

BACKGROUND

Tetramethylpyrazine (TMP) is one of the active ingredients extracted from the Chinese herb Chuanxiong, which has been used to treat cerebrovascular and cardiovascular diseases, pulmonary diseases and cancer. However, the molecular mechanisms underlying the actions of TMP have not been fully elucidated. In a previous study we showed that TMP-mediated glioma suppression and neural protection involves the inhibition of CXCR4 expression. The SDF-1/CXCR4 axis plays a fundamental role in many physiological and pathological processes. In this study, we further investigated whether the regulation of the SDF-1/CXCR4 pathway is also involved in the TMP-mediated inhibition of neovascularization or fibrosis and improvement of microcirculation.

METHODOLOGY/PRINCIPAL FINDINGS

Using a scratch-wound assay, we demonstrated that TMP significantly suppressed the migration and tubule formation of the human umbilical vein endothelial cell line ECV304 in vitro. The expression of CXCR4 in ECV304 cells is notably down-regulated after TMP treatment. In addition, TMP significantly suppresses corneal neovascularization in a rat model of corneal alkali burn injury. The expression of CXCR4 on days 1, 3 and 7 post-injury was determined through RT-PCR analysis. Consistent with our hypotheses, the expression of CXCR4 in the rat cornea is significantly increased with alkali burn and dramatically down-regulated with TMP treatment. Moreover, TMP treatment significantly attenuates bleomycin-induced rat pulmonary fibrosis, while immunofluorescence shows a notably decreased amount of CXCR4-positive cells in the TMP-treated group. Furthermore, TMP significantly down-regulates the expression of CXCR4 in platelets, lymphocytes and red blood cells. Whole-blood viscosity and platelet aggregation in rats are significantly decreased by TMP treatment.

CONCLUSIONS

These results show that TMP exerts potent effects in inhibiting neovascularization, fibrosis and thrombosis under pathological conditions; thus, the underlying mechanism of TMP might partially contribute to the down-regulation of CXCR4.

Micro-volume wall-less immunoassays using patterned planar plates

Miniaturization of immunoassays has numerous potential advantages over traditional ELISAs. Here we present a novel approach using patterned planar plates (PPPs). These 'wall-less' plates consist of a 16 × 24 array of 2 mm diameter hydrophilic regions surrounded by a hydrophobic polytetrafluoroethylene (PTFE) coating. Assays are performed by adding 2 μL droplets to the hydrophilic areas. These droplets are overlaid with an immiscible mixture of perfluorocarbon liquid (PFCL) that essentially eliminates evaporation. During wash steps, a thin film of PFCL covers the hydrophobic coating and prevents its wetting by wash buffer; as a result, the hydrophilic wells remain intact and inter-well cross-contamination is prevented. We compared the performance of three immunoassays using PPPs versus traditional 384-well ELISA plates. These included assays for soluble FcRH5 in human serum, SDF-1 in mouse serum, and human IgG in mouse plasma. The results show that the PPP assays were closely comparable to the ELISAs in terms of sensitivity, linearity of dilution, and sample quantitation. Moreover, the PPP assays were rapid to perform, easily adapted from ELISA protocols, and used 10- to 50-fold less sample and reagent volume as compared to 384- or 96-well plate ELISAs. As an additional advantage, PPPs conform to established microplate dimensional standards making them compatible with pre-existing equipment and workflows. PPPs therefore represent an attractive and broadly applicable approach to flexible miniaturization of plate-based immunochemical assays.

A kinetic study of SDF-1, VEGF and MCP-1 blood and tissue levels after aortic transplantation in mice

Vascular rejection is characterized by intimal proliferation and perivascular inflammation. We hypothesize that recipient stem cell therapy could prevent or ameliorate the development of the obliterative lesion. We studied the kinetic expression of three cytokines (SDF-1, MCP-1, VEGF) implicated in mobilization, homing and differentiation of progenitor cells during vascular aggression. An aortic allograft mouse model was used (BALBc donor-C57BL6/j recipient). Ten mice were sacrificed at Day 0, D1, D3, D6, D9, D12, and D20. Cytokine rates were measured in blood and in graft tissue by an ELISA technique. Results showed that in the allograft, SDF-1 and VEGF tissue levels were significantly increased at D12 as compared to the isograft (SDF-1: 22.16 ng/mg vs. 5.69 ng/mg, t=3.38; VEGF: 28.3 pg/mg vs. 9.3 pg/mg, t=3.06). In allografted and isografted groups, MCP-1 tissue levels were higher at D0 as compared to the other time points, without any difference between the two groups. These results prompt us to consider cell therapy at D0 and D12 in this mouse model of aortic graft.

Clinical analysis of systemic and adipose tissue levels of selected hormones/adipokines and stromal-derived factor-1

Recent studies demonstrated that selected hormones/adipokines may be involved into the regulation of bone metabolism and bone marrow-derived hematopoietic stem/progenitor cells (HSPCs) mobilization in humans. Interestingly, in obese individuals significantly higher numbers of spontaneously circulating stem cells are also observed. Therefore in this study we comprehensively examined plasma and AT (subcutaneous and visceral/omental) levels of hormones/adipokines involved in HSPCs mobilization in lean, overweight and obese individuals as well as verified their potential associations with concentrations of HSPCs chemoattractant, stromal-derived factor-1 (SDF-1). Blood and AT samples (35 subcutaneous and 35 omental) were obtained from individuals undergoing elective surgery. Plasma and AT-derived interstitial fluid levels of resistin, visfatin, osteocalcin and SDF-1 were measured using ELISA. In our study obese patients had almost significantly (P&#60;0.06) higher plasma visfatin and resistin levels as well as lower osteocalcin concentrations (P&#60;0.04) than lean individuals. Osteocalcin and resistin concentrations were strongly associated with levels of SDF-1 and metalloproteinases (MMP 2 and 9). AT levels of all examined substances were significantly lower than the corresponding levels in the plasma (in all cases at least P&#60;0.05), and depot-specific differences in the concentrations of these factors were found only in terms of osteocalcin and SDF-1. In addition, subcutaneous and visceral/omental concentrations of osteocalcin and visfatin, but not of resistin, were associated with values of such parameters as age, body mass or adiposity indexes (BMI and BAI, respectively) and/or waist-to-hip ratio (WHR). In summary, our study showed that in obese individuals the biochemical constellation of adipokines/hormones involved in the process of HSPCs mobilization resembles this observed during pharmacological HSPCs mobilization. Moreover, our study offers further indirect translational evidence for existence of a biochemical cross-talk between bone and AT metabolism (so called - bone-fat- axis) in humans.

Expression of platelet-bound stromal cell-derived factor-1 in patients with non-valvular atrial fibrillation and ischemic heart disease

AIMS

Blood cell infiltration and inflammation are involved in atrial remodelling during atrial fibrillation (AF) although the exact mechanisms of inflammatory cell recruitment remain poorly understood. Platelet-bound stromal cell-derived factor-1 (SDF-1) is increased in cases of ischemic myocardium and regulates recruitment of CXCR4(+) cells on the vascular wall. Whether platelet-bound SDF-1 expression is differentially influenced by non-valvular paroxysmal or permanent atrial fibrillation (AF) in patients with stable angina pectoris (SAP) or acute coronary syndrome (ACS) has not been reported so far.

METHODS AND RESULTS

A total of 1291 consecutive patients with coronary artery disease (CAD) undergoing coronary angiography were recruited. Among the patients with SAP, platelet-bound-SDF-1 is increased in patients with paroxysmal AF compared with SR or to persistent/permanent AF (P < 0.05 for both). Platelet-bound SDF-1 correlated with plasma SDF-1 (r = 0.488, P = 0.013) in patients with AF and ACS, which was more pronounced among patients with persistent AF (r = 0.842, P = 0.009). Plasma SDF-1 was increased in persistent/permanent AF compared with SR. Patients with ACS presented with enhanced platelet-bound-SDF-1 compared with SAP. Interestingly, among patients with ACS, patients with paroxysmal or persistent/permanent AF presented with an impaired platelet-bound SDF-1 expression compared with patients with SR.

CONCLUSIONS

Differential expression of platelet-bound and plasma SDF-1 was observed in patients with AF compared with SR which may be involved in progenitor cell mobilization and inflammatory cell recruitment in patients with AF and ischemic heart disease. Further in vivo studies are required to elucidate the role of SDF-1 in atrial remodeling and the atrial fibrillation course.

Heterogeneity in SDF-1 expression defines the vasculogenic potential of adult cardiac progenitor cells

Rationale

The adult myocardium has been reported to harbor several classes of multipotent progenitor cells (CPCs) with tri-lineage differentiation potential. It is not clear whether c-kit+CPCs represent a uniform precursor population or a more complex mixture of cell types.

Objective

To characterize and understand vasculogenic heterogeneity within c-kit+presumptive cardiac progenitor cell populations.

Methods and Results

c-kit+, sca-1+ CPCs obtained from adult mouse left ventricle expressed stem cell-associated genes, including Oct-4 and Myc, and were self-renewing, pluripotent and clonogenic. Detailed single cell clonal analysis of 17 clones revealed that most (14/17) exhibited trilineage differentiation potential. However, striking morphological differences were observed among clones that were heritable and stable in long-term culture. 3 major groups were identified: round (7/17), flat or spindle-shaped (5/17) and stellate (5/17). Stellate morphology was predictive of vasculogenic differentiation in Matrigel. Genome-wide expression studies and bioinformatic analysis revealed clonally stable, heritable differences in stromal cell-derived factor-1 (SDF-1) expression that correlated strongly with stellate morphology and vasculogenic capacity. Endogenous SDF-1 production contributed directly to vasculogenic differentiation: both shRNA-mediated knockdown of SDF-1 and AMD3100, an antagonist of the SDF-1 receptor CXC chemokine Receptor-4 (CXCR4), reduced tube-forming capacity, while exogenous SDF-1 induced tube formation by 2 non-vasculogenic clones. CPCs producing SDF-1 were able to vascularize Matrigel dermal implants in vivo, while CPCs with low SDF-1 production were not.

Conclusions

Clonogenic c-kit+, sca-1+ CPCs are heterogeneous in morphology, gene expression patterns and differentiation potential. Clone-specific levels of SDF-1 expression both predict and promote development of a vasculogenic phenotype via a previously unreported autocrine mechanism.

[Expression of SDF-1 in lung tissues and intervention of AMD3100 in asthmatic rats]

OBJECTIVE

To study the expression of stromal cell derived factor-1(SDF-1) in the airway and to investigate the role of SDF-1 receptor antagonist AMD3100 intervention in rats with asthma.

METHODS

Thirty Sprague-Dawley rats were randomly divided into three groups: normal control and asthma with and without AMD3100 intervention. The rat model of asthma was prepared by aerosolized ovalbum (OVA) challenge. The AMD3100 intervention group was administered with AMD3100 of 50 μg 30 minutes before challenge every other day, for 10 times. The characteristic airway inflammation and alterations of airway structures were observed by hemetoxylin and eosin staining. The levels of interleukin 4 and interleukin 5 in whole lung homogenates were measured using ELISA. RT-PCR was used to evaluate the expression of SDF-1 mRNA in the lung.

RESULTS

The airway wall thickness in the untreated asthma group was greater than that in the control and the AMD3100 intervention groups (P<0.05). The levels of interleukin 4 and interleukin 5 in whole lung homogenates in the AMD3100 intervention group were lower than those in the untreated asthma group (P<0.05). The expression of SDF-1 mRNA in the untreated asthma group was higher than that in the control and the AMD3100 intervention groups (P<0.05).

CONCLUSIONS

SDF-1 may be associated with airway inflammation and remodeling in rats with asthma. AMD3100 may reduce the airway inflammation and improve airway remodeling by inhibiting the bioactivity of SDF-1.

SDF1/CXCL12 is involved in recruitment of stem-like progenitor cells to orthotopic murine malignant mesothelioma spheroids

BACKGROUND/AIM

Tumor progression is influenced by the microenvironment. We found stem cells are recruited to malignant mesothelioma spheroids. We aimed to determine if stem cell recruitment depends on the chemokine SDF1, and if inhibition of the cognate receptor CXCR4 affects tumor growth.

MATERIALS AND METHODS

The kinetics of stem cell recruitment was determined using immunofluorescence staining, BrdU incorporation and eGFP transgenic mice. Chemokines were identified using PCR array. Inhibitors of CXCR4 were used to determine the effect on cell migration and tumor progression.

RESULTS

The increasing number of stem cells found in tumor spheroids over time is attributed to cell recruitment. Stem cell migration in vitro was enhanced by exogenous SDF1 and abrogated by CXCR4 inhibition and. CXCR4 inhibition reduced tumor burden in vivo.

CONCLUSION

SDF1 is a candidate chemokine for recruitment of stem cells to malignant peritoneal mesothelioma and a potential target for therapy.

Vascular CXCR4 expression - a novel antiangiogenic target in gastric cancer?

BACKGROUND

G-protein-coupled receptors (GPCRs) are prime candidates for novel cancer prevention and treatment strategies. We searched for differentially expressed GPCRs in node positive gastric carcinomas.

METHODOLOGY/PRINCIPAL FINDINGS

Differential expression of GPCRs in three node positive vs. three node negative intestinal type gastric carcinomas was analyzed by gene array technology. The candidate genes CXCL12 and its receptor CXCR4 were validated by real-time reverse-transcription polymerase chain reaction in an independent set of 37 gastric carcinomas. Translation was studied by immunohistochemistry in 347 gastric carcinomas using tissue microarrays as well as in 61 matching lymph node metastases. Protein expression was correlated with clinicopathological patient characteristics and survival. 52 GPCRs and GPCR-related genes were up- or down-regulated in node positive gastric cancer, including CXCL12. Differential expression of CXCL12 was confirmed by RT-PCR and correlated with local tumour growth. CXCL12 immunopositivity was negatively associated with distant metastases and tumour grade. Only 17% of gastric carcinomas showed CXCR4 immunopositive tumour cells, which was associated with higher local tumour extent. 29% of gastric carcinomas showed CXCR4 positive tumour microvessels. Vascular CXCR4 expression was significantly associated with higher local tumour extent as well as higher UICC-stages. When expressing both, CXCL12 in tumour cells and CXCR4 in tumour microvessels, these tumours also were highly significantly associated with higher T- and UICC-stages. Three lymph node metastases revealed vascular CXCR4 expression while tumour cells completely lacked CXCR4 in all cases. The expression of CXCL12 and CXCR4 had no impact on patient survival.

CONCLUSIONS/SIGNIFICANCE

Our results substantiate the significance of GPCRs on the biology of gastric carcinomas and provide evidence that the CXCL12-CXCR4 pathway might be a novel promising antiangiogenic target for the treatment of gastric carcinomas.

[Expression of stromal cell derived factor-1 and CXC chemokine receptor 4 and the effects of budesonide on their expression in mice with asthma]

OBJECTIVE

To study the expression of stromal cell derived factor-1(SDF-1) and CXC chemokine receptor 4 (CXCR4) in the airway and the effect of budesonide on their expression in mice with asthma.

METHODS

Thirty BALB/c male mices were randomly divided into three groups: placebo control, untreated asthma, and budesonide-treated asthma. The asthma group were induced by intraperitoneal injection of 10% ovalbumin (OVA ) on days 1, 8 and 15, and then from days 22 to 34, challenged by inhalation of 2% OVA aerosol every other day. The budesonide-treated asthma group received an inhalation of budesonide (1 mg ) before OVA challenge. The pathological changes of the airway were assessed by hematoxylin and eosin staining. The immunohistochemistry was used to estimate the expression of SDF-1 in the lung. RT-PCR was used to evaluate the expression of CXCR4 in the lung.

RESULTS

Compared with the control group, SDF-1 and CXCR4 expression in the lung in the untreated asthma group increased significantly (p<0.05). The budesonide-treated asthma group demonstrated significantly decreased SDF-1 (0.426+/-0.052 vs 0.361+/-0.065; p<0.05) and CXCR4 (0.829+/-0.027 vs 0.723+/-0.094; p<0.05) expression in the lung as compared with the untreated asthma group. Both SDF-1 (r=0.744, p<0.01) and CXCR4 (r=0.553, p<0.01)were positively correlated with the thickness of the airway wall.

CONCLUSIONS

SDF-1 and CXCR4 may be associated with airway remodeling in mice with asthma. Budesonide can improve airway remodeling, possibly by decreasing the expression of SDF-1 and CXCR4.

Elevated amniotic fluid stromal cell-derived factor-1alpha (SDF-1alpha) concentration in mid-gestation as a predictor of adverse birth outcomes

BACKGROUND

This study aimed to predict maternal and neonatal outcomes by measuring mid-trimester amniotic fluid stromal cell-derived factor-1alpha (SDF-1alpha) concentration in healthy women.

METHODS

Mid-trimester amniotic fluid samples from healthy women with a singleton pregnancy were obtained at the time of genetic amniocenteses. SDF-1alpha concentrations were determined by enzyme-linked immunosorbent assay. Maternal and neonatal characteristics were recorded.

RESULTS

A total of 210 samples were collected. According to the SDF-1alpha cutoff value established by the receiver operating characteristic curve analysis (< 6.42 vs. > or = 6.42 pg/mL), there was a trend toward higher preterm birth rate, lower birth weight and lower 1-minute and 5-minute Apgar scores when SDF-1alpha levels increased (p < 0.05). The pair comparison between normal and selected pregnancy disorders (gestational diabetes, pre-eclampsia, and abnormal placentation) showed no statistical significance (p > 0.05). Pearson's correlations of SDF-1alpha to gestational age at delivery (r = -0.151) and birth weight (r = -0.194) were significant (p < 0.05). In the multivariate analysis on mid-trimester SDF-1alpha levels, maternal age at sampling (regression coefficient = -0.163) and 1-minute Apgar score (< 7 vs. > or = 7, regression coefficient = 2.028) were both significant (p < 0.05).

CONCLUSION

Increased SDF-1alpha levels in mid-trimester amniotic fluid suggest a possible role in predicting pregnant women at risk of adverse neonatal outcomes including higher preterm birth rate, lower birth weight, and lower Apgar scores.

Nestin, PDGFRbeta, CXCL12 and VEGF in glioma patients: different profiles of (pro-angiogenic) molecule expression are related with tumor grade and may provide prognostic information

Angiogenesis is a key event in the natural progression of gliomas. Nestin, a marker for multipotential neuroepithelial stem cells, is detected in neuroepithelial tumors and in proliferating endothelial cells (ECs) and is involved in the early stages of lineage commitment, proliferation and differentiation. Nestin expression is correlated with proangiogenic chemokines (CXCL12 and its receptor CXCR4) and growth factors (VEGF, PDGF-B and its receptor PDGFRbeta). VEGF expression upregulates CXCR4 on endothelial cells, binding the chemokine SDF1/CXCL12 (Stromal Derived Factor) that has a role on angiogenesis and chemotaxis of endothelial cells; PDGF (platelet-derived growth factor) and PDGFRbeta are also crucial by increasing the expression of VEGF. We performed a retrospective study on the presence and role of nestin-expressing cells in 102 patients with glioma, relating the findings to VEGF, CXCL12, PDGFRbeta expression and to clinical outcome (time to tumor progression-TTP and survival time-ST). Our results suggest that in gliomas the detection of proliferating ECs expressing nestin correlates to histological malignancy grade and clinical outcome. Also, the expression of CXCL12 in low-grade gliomas was the only factor associated with a significantly shorter TTP, suggesting a role of this chemokine in angiogenic shift and/or disease progression.

CXCL12 and CXCR4 in adenocarcinoma of the lung: association with metastasis and survival

OBJECTIVES

Although the chemokine CXCL12 and its receptor CXCR4 have been implicated in metastasis of non-small cell lung carcinoma, the prognostic significance of these molecules is poorly defined. This study aimed to determine whether expression of these molecules is associated with clinicopathologic features and disease-free survival in non-small cell lung carcinoma.

METHODS

Immunohistochemical staining for CXCL12 and CXCR4 was performed on 154 primary non-small cell lung carcinomas. Staining intensity was compared with tumor histotype, TNM stage, and disease-free survival; correlation was assessed by using the Fisher's exact test, and Kaplan-Meier and Cox multivariate proportional hazards regression analysis.

RESULTS

Intense CXCL12 immunostaining was associated with nodal metastasis, although no difference in survival was observed. The prognostic relevance of CXCR4 was dependent on its subcellular location: in univariate analysis intense nuclear staining was significantly associated with lower T classification and improved disease-free survival in patients with adenocarcinoma, whereas cytomembranous staining was associated with distant metastasis and decreased disease-free survival. On multivariate analysis, cytomembranous CXCR4 expression conferred a significantly worse disease-free survival (relative risk, 2.8; 95% confidence interval, 1.4-5.7; P = .004).

CONCLUSIONS

Cytomembranous expression of the chemokine receptor CXCR4 in adenocarcinoma of the lung is an independent risk factor associated with worse disease-free survival, whereas nuclear staining confers a survival benefit. These findings are consistent with a model in which CXCR4 promotes tumor cell proliferation and metastasis when present in the cytoplasm or cell membrane, whereas localization of this molecule in the nucleus prevents it from exerting these effects.

Aberrant methylation of CXCL12 in non-small cell lung cancer is associated with an unfavorable prognosis

Chemokines play an important role in the pathogenesis of non-small cell lung cancer (NSCLC). However, aberrant methylation of CXCL12 has not been examined in NSCLC. CXCL12 mRNA expression and methylation were examined in 17 NSCLC cell lines by RT-PCR and methylation-specific PCR (MSP). MSP was performed on 236 tumor specimens from NSCLC patients who received curative intent surgery. CXCL12 and CXCR4 protein expression was examined in 90 of the 236 NSCLC specimens by immunohistochemistry. Down-regulation of CXCL12 expression was found in 10 of 17 (59%) NSCLC cell lines compared with normal bronchial cells. Treatment of 8 expression-negative cell lines with a demethylating agent restored expression in all cases. Twelve cell lines (71%) showed aberrant methylation, and good concordance between methylation and expression was present. Aberrant methylation occurred in 85 out of 236 (36%) primary NSCLCs in a tumor-specific manner. In multivariate analysis, CXCL12 methylation correlated strongly and independently with prognosis both in all patients with NSCLCs and in those with stage I NSCLCs (hazard ratio=1.68, P=0.015 and hazard ratio=3.58, P=0.017). Secreted protein CXCL12 and its receptor CXCR4 were abundant in NSCLC cells (72 out of 90, 80%; 57 out of 90, 63%) and correlated with the progression of NSCLCs. In conclusion, epigenetic silencing of CXCL12 is a frequent event in NSCLCs, and could be an independent and powerful prognostic marker in patients with NSCLCs and those with stage I disease. Analysis for CXCL12 may provide novel opportunities for prognosis and therapy of resected NSCLCs.