chemokine (C-X-C motif) ligand 12 (stromal cell-derived factor 1)isoform beta

C Subfamily
CC Subfamily
CXC Subfamily
CX3C Subfamily

Chemokines

gp130 (IL6ST) shared
IL13RA1 shared
IL3RB (CSF2RB) shared
ILRG shared

interleukin 18
interleukin 18 proprotein
interleukin 1 alpha
interleukin 1, alpha proprotein
interleukin 1 beta
interleukin 1, beta proprotein

interleukin 17
interleukin 17b
interleukin 17E
interleukin 17E isoform 1

IL-1 Family /IL-17 Family

interleukin 10
interleukin 19
interleukin 19 isoform 2
interleukin 20
interleukin 22
interleukin 24
interleukin 24 isoform 1
interleukin 28A
interleukin 28B
interleukin 29

IL-10 Family

interferon alpha family, gene 1
interferon, alpha 1
interferon beta
interferon, beta 1
interferon epsilon 1
interferon, epsilon 1
interferon gamma
interferon, gamma
interferon kappa
interferon, kappa
interferon, omega 1

Interferon Family

CSF1 Egf Flt3l
FLT3LG HGF Kitl
KITLG Pdgfa PDGFB
PDGFC Pdgfd PLEKHQ1
VEGF Vegfa VEGFB
VEGFC

PDGF Family

AMH Bmp2 Bmp7
GDF5 Inhba INHBB
INHBC INHBE Tgfb1
TGFB2 TGFB3

TGF-β Family

CD40LG Eda Fasl
FASLG Lta LTB
TNF Tnfsf10 Tnfsf11
TNFSF12 Tnfsf13 TNFSF13B
Tnfsf14 TNFSF18 TNFSF4
TNFSF7 TNFSF8 TNFSF9

TNF Family

CHEMOKINE (C-X-C MOTIF) LIGAND 12 (STROMAL CELL-DERIVED FACTOR 1)ISOFORM BETA

LATEST LITERATURE

1: Annals of clinical and laboratory science, 2010 Summer, 40(3)
Stability of Human Stromal-Derived Factor-1{alpha} (CXCL12{alpha}) After Blood Sampling.

[Abstract]Stromal-derived factor 1-alpha (SDF-1alpha, or CXCL12alpha) is a major chemokine that controls adult stem cell trafficking. Little is known about its stability after blood sampling, but this is a crucial issue for clinical studies of this molecule. In a study of six subjects, we found total human plasma SDF-1alpha concentrations to be stable for 120 min when the blood is placed on ice immediately after sampling.

2: Current medicinal chemistry, 2010 Jul 14, 17(8)
CXCR4-CXCL12-Dependent Inflammatory Network and Endothelial Progenitors.

[Abstract]The endothelial progenitor cells (EPCs) are angiogenic cells having properties similar to those of embryonal angioblasts. The number and function of EPCs are affected by a variety of conditions, including cytokines and chemokines, which are pivotal inflammatory signaling molecules. The purpose of this paper is to review current knowledge about the role of these progenitor in different vascular diseases, emphasizing the important biological role played from the CXCR4-CXCL12 axis in the cellular trafficking. Indeed, as described in detail in this review, the CXCR4/CXCL12 interaction produces pleiotropic effects in stem cells and plays a pivotal role in several processes related to development, tissue regeneration and development/progression of malignancies.

3: Journal of immunology (Baltimore, Md. : 1950), 2010 Jun 28, 41(7)
Role of the CXCR4/CXCL12 Axis in Lymphangioleiomyomatosis and Angiomyolipoma.

[Abstract]Lymphangioleiomyomatosis (LAM) is a progressive disease caused by accumulation of metastatic (LAM) cells in the lungs, lymphatics, and the tumor angiomyolipoma (AML). LAM cells have biallelic loss of either tuberous sclerosis complex gene (but predominantly TSC-2) and resultant dysregulation of the mammalian target of rapamycin (mTOR) pathway. Chemokines are associated with neoplastic cell growth, survival, and homing to specific organs and may play similar roles in LAM. Our objective was to study comprehensively the expression and function of chemokine receptors and how their function interacts with dysregulation of the mTOR pathway in LAM and AML. We used RT-PCR and FACS to study receptor expression in primary AML cells and immunohistochemistry to investigate expression in tissues. Chemokine receptor function was analyzed in AML cells by Western blotting of signaling proteins and cell proliferation and apoptosis assays. Primary AML cells, LAM, and AML tissues expressed CCR3, CXCR4, CXCR6, and CXC3CR1. In AML cells, their ligands CXCL12 CX3CL1, CCL11, CCL24, and CCL28 caused robust phosphorylation of p42/44 MAPK and Akt. CXCL12 was expressed in type II pneumocytes covering LAM nodules and caused AML cell growth and protection from apoptosis, which was blocked by AMD3100, a CXCR4 inhibitor. The mTOR inhibitor rapamycin, but not AMD3100, inhibited growth of AML tumor xenografts. We conclude that the CXCL12/CXCR4 axis promotes, but is not absolutely required for, AML/LAM cell growth and survival.

4: Environmental toxicology, 2010 May 18, 285(21)
Development and validation of a test for environmental estrogens: Checking xeno-estrogen activity by CXCL12 secretion in breast cancer cell lines (CXCL-test).

[Abstract]Several methods have been developed to evaluate and quantify the effects of Endocrine disruptor chemicals (EDC). Nevertheless, most of these methods are time-consuming or not enough sensitive to detect EDC at the environmental range. To link the biological effect of tested EDC to natural protein secretion, we have developed a new screening method based on the secretion of the cytokine CXCL12 (or SDF-1, Stroma-cell Derived Factor 1), which plays a capital role in cell survival and migration. We have demonstrated that CXCL12 secretion is regulated by estrogenic compounds in a dose-dependent way in ER-positive breast cancer cell lines (MCF-7 and T47D). By combining cell culture and ELISA test, we used this up-regulation of CXCL12 secretion to test several major environmental contaminants. Our results showed that 17beta-estradiol (from 10(-11) M), 17alpha-ethynylestradiol (from 10(-12) M), genistein (from 10(-8) M) and bisphenol A (from 10(-6) M) dose-regulate CXCL12 secretion in T47D. In contrast, antiestrogens, raloxifen and 4-hydroxytamoxifen, had no effect on the CXCL12 secretion, but were able to inhibit E2 effect. Moreover, we used cell proliferation assays to evaluate the effect of these different compounds on the growth of T47D cells. We found strong correlation (P = 0.7) between proliferation and CXCL12 secretion. However CXCL12 secretion was as sensitive as cell proliferation assays but appeared more rapid. Thus, this bioassay named CXCL-test (for Checking Xeno-estrogen activity by CXCL12 secretion in breast cancer cell Lines) constitutes a fast and sensitive method for the detection of estrogenic compounds allowing in 14 h to achieve a detection limit of 10(-11) M of E2 (2.7 ng/L). (c) 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

5: Current molecular medicine, 2010 Jun 14,
Damage and Recovery of the Bone Marrow Microenvironment Induced by Cancer Chemotherapy - Potential Regulatory Role of Chemokine CXCL12/Receptor CXCR4 Signalling.

[Abstract]The bone marrow microenvironment houses haematopoietic stem cells (HSC), mesenchymal stem cells (MSC) and their progeny, supports haematopoiesis, osteogenesis, osteoclastogenesis, and adipogenesis. It plays a key role in maintaining homeostatic production of erythroid, myeloid or lymphoid cells, appropriate bone mass and bone health throughout life. Through cell-cell adhesion and chemotactic axes, a reciprocal inter-dependent relationship exists between these two cell lineages. Following chemotherapy-induced myelosuppression observed in cancer patients, HSCs are induced to enter into the cell cycle in order to re-establish the damaged microenvironment. These cells not only have the capacity to mobilize to the peripheral blood, but the ability to repopulate the marrow cavity as required. However, depending on the dosage and length of chemotherapy treatment, complications in bone and bone marrow recovery occur. This may manifest as marrow haematopoietic depletion, high marrow fat content, reduced bone formation and aggravated osteoclastic bone resorption. Although the molecular and cellular mechanisms governing injured states of the marrow microenvironment are yet to be fully elucidated, many reports have demonstrated the CXCL12/CXCR4 axis plays an important role in regulating the two cell lineages. Their interaction maintains bone marrow homeostasis and orchestrates its regeneration following chemotherapy. This review explores movement of MSC and HSC, haematopoiesis, committment of osteoblasts, osteoclasts, and adipocytes, as well as the major signalling pathways that regulate these cellular processes under chemotherapy-treated conditions. This review also discusses molecular targets that are being used clinically or are currently under investigation for preserving the bone marrow microenvironment during or enhancing recovery after chemotherapy.

6: Proceedings of the National Academy of Sciences of the United States of America, 2010 Jun 1, 30(3)
Migration of engrafted neural stem cells is mediated by CXCL12 signaling through CXCR4 in a viral model of multiple sclerosis.

[Abstract]Multiple sclerosis (MS) is a human demyelinating disease characterized by multifocal regions of inflammation, progressive myelin loss within the central nervous system (CNS), and eventual failure to remyelinate damaged axons. These problems suggest deficiencies in recruiting and/or maturation of oligodendrocyte progentior cells (OPCs) and highlight cell replacement therapies to promote remyelination. We have used a model of viral-induced demyelination to characterize signaling cues associated with positional migration of transplanted remyelination-competent cells. Although successful transplantation of rodent-derived glial cell types into models of MS has been performed, the mechanisms by which these cells navigate within an inflammatory environment created by a persistent virus has not been defined. Infection of the mouse CNS with the neurotropic JHM strain of mouse hepatitis virus (JHMV) results in an immune-mediated demyelinating disease with clinical and histologic similarities to MS. Surgical engraftment of GFP+ neural stem cells (NSCs) into spinal cords of JHMV-infected mice with established demyelination results in migration, proliferation, and differentiation of the cells into OPCs and mature oligodendrocytes that is associated with increased axonal remyelination. Treatment with anti-CXCL12 [stromal derived factor-1alpha, (SDF-1alpha)] blocking serum resulted in a marked impairment in migration and proliferation of engrafted stem cells. Moreover, small molecule-mediated antagonism of CXCR4, but not CXCR7, impaired migration and proliferation, to an extent similar to that with anti-CXCL12 treatment. These data highlight the importance of the CXCL12:CXCR4 pathway in regulating homing of engrafted stem cells to sites of tissue damage within the CNS of mice persistently infected with a neurotropic virus undergoing immune-mediated demyelination.

7: Journal of leukocyte biology, 2010 May 25, 30(3)
The multiple faces of CXCL12 (SDF-1{alpha}) in the regulation of immunity during health and disease.

[Abstract]Chemokines are a group of small, structurally related molecules that regulate the trafficking of various types of leukocytes through interactions with a subset of 7-transmembrane G-protein-coupled receptors. As key chemoattractants of inflammatory leukocytes, chemokines have been marked as potential targets for neutralization in autoimmune diseases. Cancer cells also express chemokines, where they function as survival/growth factors and/or angiogenic factors that promote tumor development and angiogenesis. Accordingly, these functions make them attractive targets for therapy of these diseases. Recently, we reported that one of these chemokines CXCL12 (SDF-1alpha) functions as an anti-inflammatory chemokine during autoimmune inflammatory responses and explored the mechanistic basis of this function. As a pleiotropic chemokine, CXCL12 participates in the regulation of tissue homeostasis, immune surveillance, autoimmunity, and cancer. This chemokine is constitutively expressed in the BM and various tissues, which enables it to regulate the trafficking and localization of immature and maturing leukocytes, including BM stem cells, neutrophils, T cells, and monocytic cells. We have shown recently that CXCL12 increases immunological tolerance in autoimmune diseases by polarizing Tregs and by doing so, restrains the progression of these diseases. This finding suggests a possible use of stabilized rCXCL12 as a potential drug for therapy of these diseases and targeted neutralization of CXCL12 for therapy of cancer diseases. The current review explores the different biological properties of CXCL12 and discusses the implications of CXCL12-based therapies for autoimmunity and cancer diseases.

8: Haematologica, 2010 May 21, 30(3)
Cathepsin X is secreted by human osteoblasts, digests CXCL-12 and impairs adhesion of hematopoietic stem and progenitor cells to osteoblasts.

[Abstract]Background: Hematopoietic stem cells (HSC) are retained within discrete bone marrow niches through cell adhesion molecules and chemokine gradients. However, a small proportion of HSC can also be found trafficking in the peripheral blood. During induced stem cell mobilization a proteolytic microenvironment is generated, but whether proteases are also involved in physiological trafficking of HSC is not known. In the present study we examined the expression, secretion and function of the cysteine protease cathepsin X by cells of the human bone marrow. Design and methods: Human osteoblasts, bone marrow stromal cells and hematopoietic stem and progenitor cells (HSPC) were analyzed for the secretion of cathepsin X by Western blotting, active site labeling, immunofluorescence staining and activity assays. A possible involvement of cathepsin X on cell adhesion and CXCL-12-mediated cell migration was studied in functional assays. MALDI-TOF analysis revealed the digestion mechanism of CXCL-12 by cathepsin X. Results: Osteoblasts and stromal cells secrete cathepsin X, whereas HSPC do not. Using a cathepsin X-selective substrate, we detected the catalytic activity of cathepsin X in cell culture supernatants of osteoblasts. Activated cathepsin X is able to reduce cellular adhesive interactions between CD34+ HSPC and adherent osteoblasts. The chemokine CXCL-12, a highly potent chemoattractant for HSC secreted by osteoblasts, is readily digested by cathepsin X. Conclusions: The exo-peptidase cathepsin X has been identified as a new member of CXCL-12 degrading enzymes secreted by non-hematopoietic bone marrow cells. The functional data indicate that cathepsin X can influence HSPC trafficking in the bone marrow.

9: Clinical cancer research : an official journal of the American Association for Cancer Research, 2010 May 18, 285(21)
CXCL12 (SDF-1)/CXCR4 Pathway in Cancer.

[Abstract]Chemokines, small proinflammatory chemoattractant cytokines that bind to specific G-protein-coupled seven-span transmembrane receptors, are major regulators of cell trafficking and adhesion. The chemokine CXCL12 [stromal cell-derived factor-1 (SDF-1)] binds primarily to CXC receptor 4 (CXCR4; CD184). The binding of CXCL12 to CXCR4 induces intracellular signaling through several divergent pathways initiating signals related to chemotaxis, cell survival and/or proliferation, increase in intracellular calcium, and gene transcription. CXCR4 is expressed on multiple cell types including lymphocytes, hematopoietic stem cells, endothelial and epithelial cells, and cancer cells. The CXCL12/CXCR4 axis is involved in tumor progression, angiogenesis, metastasis, and survival. This pathway is a target for therapeutics that can block the CXCL12/CXCR4 interaction or inhibit downstream intracellular signaling. Clin Cancer Res; 16(11); 2927-31. (c)2010 AACR.

10: The Journal of surgical research, 2010 Mar 26, 78(5)
The CXCR4-CXCL12 Pathway Facilitates the Progression of Pancreatic Cancer Via Induction of Angiogenesis and Lymphangiogenesis.

[Abstract]BACKGROUND: This study reports the influence of CXCL12 and its receptor CXCR4 on the progression of pancreatic cancer and illuminates the correlation between the CXCL12/CXCR4 axis and the angiogenesis and lymphangiogenesis of pancreatic adenocarcinoma (PAC). METHODS: A total of 30 patients with pancreatic cancer participated in the current study. The expression of CXCL12 and CXCR4 in cancerous tissues, paracancerous tissues, normal pancreas, and lymph nodes surrounding the pancreas were investigated using real-time PCR and immunohistochemistry, respectively. In addition, we assessed microvessel density (MVD) and microlymphatic vessel density (MLVD) in tumor tissues using immunohistochemistry. RESULTS: CXCL12 expression in tumor tissues was significantly lower than that of paracancerous tissues, normal pancreas, and lymph nodes. In contrast, CXCR4 expression in cancerous tissues was considerably higher than that of normal pancreas. Additionally, a significant correlation between the expression pattern of the CXCL12/CXCR4 axis and clinicopathologic features, such as lymph node metastasis, was identified. Furthermore, we found that CXCL12 expression was significantly associated with MVD but not significantly associated with MLVD, while CXCR4 expression was significantly associated with MLVD but not significantly associated with MVD. CONCLUSIONS: The chemotactic interaction between CXCR4 and its ligand CXCL12 may be a critical event during the progression of pancreatic cancer. The underlying mechanism may be the induction of angiogenesis and lymphangiogenesis regulated by the interaction of CXCL12 and CXCR4.

11: Journal of the American Chemical Society, 2010 May 11, 30(3)
Targeting SDF-1/CXCL12 with a Ligand That Prevents Activation of CXCR4 through Structure-Based Drug Design.

[Abstract]CXCL12 is an attractive target for clinical therapy because of its involvement in autoimmune diseases, cancer growth, metastasis, and neovascularization. Tyrosine sulfation at three positions in the CXCR4 N-terminus is crucial for specific, high-affinity CXCL12 binding. An NMR structure of the complex between the CXCL12 dimer and a sulfotyrosine-containing CXCR4 fragment enabled high-throughput in silico screening for inhibitors of the chemokine-receptor interface. A total of 1.4 million compounds from the ZINC database were docked into a cleft on the CXCL12 surface normally occupied by sulfotyrosine 21 (sY21), and five were selected for experimental screening. NMR titrations with CXCL12 revealed that four of the compounds occupy the sY21 site, one of which binds with a K(d) of 64 muM. This compound selectively inhibits SDF1-induced CXCR4 signaling in THP1 cells. Our results suggest that sulfotyrosine recognition sites can be targeted for the development of novel chemokine inhibitors.

12: Cancer research, 2010 Apr 15, 70(8)
The effect of CXCL12 processing on CD34+ cell migration in myeloproliferative neoplasms.

[Abstract]Primary myelofibrosis (PMF) and polycythemia vera (PV) are chronic myeloproliferative neoplasms. PMF and, to a lesser degree, PV are characterized by constitutive mobilization of hematopoietic stem cells (HSC) and progenitor cells (HPC) into the peripheral blood (PB). The interaction between the chemokine CXCL12 and its receptor CXCR4 plays a pivotal role in determining the trafficking of CD34(+) cells between the bone marrow (BM) and the PB. PMF, but not PV, is associated with downregulation of CXCR4 by CD34(+) cells due to epigenetic events. Both PV and PMF patients have elevated levels of immunoreactive forms of CXCL12 in the BM and PB. Using electrospray mass spectrometry, the PB and BM plasma of PV and PMF patients was shown to contain reduced amounts of intact CXCL12 but significant amounts of several truncated forms of CXCL12, which are lacking in normal PB and BM plasma. These truncated forms of CXCL12 are the product of the action of several serine proteases, including dipeptidyl peptidase-IV, neutrophil elastase, matrix metalloproteinase-2 (MMP-2), MMP-9, and cathepsin G. Unlike CXCL12, these truncates either lack the ability to act as a chemoattractant for CD34(+) cells and/or act as an antagonist to the action of CXCL12. These data suggest that proteolytic degradation of CXCL12 is characteristic of both PV and PMF and that the resulting truncated forms of CXCL12, in addition to the reduced expression of CXCR4 by CD34(+) cells, lead to a profound mobilization of HSC/HPC in PMF.

13: The Journal of biological chemistry, 2010 Mar 26, 78(5)
Calcium mobilization triggered by the chemokine CXCL12 regulates migration in wounded intestinal epithelial monolayers.

[Abstract]Restitution of intestinal epithelial barrier damage involves the coordinated remodeling of focal adhesions in actively migrating enterocytes. Defining the extracellular mediators and the intracellular signaling pathways regulating those dynamic processes is a key step in developing restitution-targeted therapies. Previously we have determined that activation of the chemokine receptor CXCR4 by the cognate ligand CXCL12 enhances intestinal epithelial restitution through reorganization of the actin cytoskeleton. The aim of these studies was to investigate the role of calcium effectors in CXCL12-mediated restitution. CXCL12 stimulated release of intracellular calcium in a dose-dependent manner. Inhibition of intracellular calcium flux impaired CXCL12-mediated migration of IEC-6 and CaCo2 cells. Pharmacological blockade and specific shRNA depletion of the phospholipase-C (PLCbeta3) isoform attenuated CXCL12 enhanced migration, linking receptor activation with intracellular calcium flux. Immunoblot analyses demonstrated CXCL12 activated the calcium regulated focal adhesion protein proline-rich tyrosine kinase-2 (Pyk2) and the effector proteins paxillin and p130Cas. Interruption of Pyk2 signaling potently blocked CXCL12-induced wound closure. CXCL12-stimulated epithelial cell migration was enhanced on laminin and abrogated by intracellular calcium chelation. These results suggest CXCL12 regulates restitution through calcium-activated Pyk2 localized to active focal adhesions. Calcium signaling pathways may therefore provide a novel avenue for enhancing barrier repair.

14: Human pathology, 2010 Mar 22, 78(5)
Expression of angiostatic platelet factor-4var/CXCL4L1 counterbalances angiogenic impulses of vascular endothelial growth factor, interleukin-8/CXCL8, and stromal cell-derived factor 1/CXCL12 in esophageal and colorectal cancer.

[Abstract]Chemokines influence tumor progression through regulation of leukocyte chemotaxis, angiogenesis, and metastasis. In this study, the regulated expression of angiogenic (stromal cell-derived factor [SDF]-1/CXCL12 and interleukin [IL]-8/CXCL8) and angiostatic (platelet factor [PF]-4var/CXCL4L1 and inducible protein [IP-10]/CXCL10) chemokines was examined in human colorectal and esophageal cancer. In HCT 116 and HCT-8 colorectal adenocarcinoma cells, the production of IL-8 immunoreactivity was up-regulated by IL-1beta, tumor necrosis factor (TNF)-alpha, the toll-like receptor (TLR) ligands double-stranded RNA and peptidoglycan and phorbol ester. Increased PF-4 and synergistic IL-8 and IP-10 induction in carcinoma cells after stimulation with IL-1beta plus TNF-alpha or interferon-gamma was demonstrated by enzyme-linked immunosorbent assay, quantitative reverse transcriptase polymerase chain reaction, or immunocytochemistry. In addition, IL-8 from HT-29 colorectal adenocarcinoma cells was molecularly identified as intact chemokine, as well as NH(2)-terminally truncated, more active IL-8(6-77). The presence of PF-4var, SDF-1, and vascular endothelial growth factor (VEGF) was evidenced by immunohistochemistry in surgical samples from 51 patients operated on for colon adenocarcinoma (AC), esophageal AC, or esophageal squamous cell carcinoma (SCC). PF-4var was strongly detected in colorectal cancer, whereas its expression in esophageal cancer was rather weak. Staining for SDF-1 was almost negative in esophageal SCC, whereas a more intense and frequent staining was observed in AC of the esophagus and colon. Staining for VEGF was moderately to strongly positive in all 3 types of cancer, although less prominent in esophageal AC. The heterogenous expression of angiogenic (IL-8, SDF-1) as well as angiostatic (IP-10, PF-4var) chemokines not only within the tumor and between the different cases but also between the different tumor cell types may indicate a distinct role of the various chemokines in the complex process of tumor development.

15: Immunology, 2010 Mar 17, 5(3)
Characterization of the migration of lung and blood T cells in response CXCL12 in a three-dimensional matrix.

[Abstract]Summary The ability of T cells to microlocalize within tissues, such as the lung, is crucial for immune surveillance and increased T-cell infiltration is a feature of many inflammatory lung conditions. T-cell migration has mainly been studied in two-dimensional assays. Using three-dimensional collagen gels to mimic the extracellular matrix of lung tissue, we have characterized the migration of T lymphocytes isolated from peripheral blood (PBT) and lung (LT) in response to interleukin-2 (IL-2) and CXCL12. Freshly isolated PBT and LT showed a low degree of migration (blood 4.0 +/- 1.3% and lung 4.1 +/- 1.7%). Twenty-four hours of culture increased the percentage of migrating PBT and LT (blood 17.5 +/- 2.9% and lung 17.7 +/- 3.8%). The IL-2 stimulation modestly increased migration of PBT after 6 days (32.3 +/- 6.0%), but had no effect on the migration of LT (25.5 +/- 3.2%). Twenty-four hours of stimulation with anti-CD3/CD28 caused a small but significant increase in the migration of PBT (to 36.4 +/- 5.8%). In a directional three-dimensional assay, CXCL12 failed to induce migration of fresh PBT or LT. Twenty-four hours of culture, which increased CXCR4 expression of PBT 3.6-fold, significantly increased the migration of PBT in response to CXCL12. Migration of PBT to CXCL12 was blocked by pertussis toxin, but not by the phosphoinositide 3-kinase inhibitor wortmannin. Twenty-four-hour cultured LT did not respond to CXCL12. CD3/CD28-stimulation inhibited CXCL12-mediated migration of PBT. These results suggest that the migration pattern of PBT is distinct from that of LT.

16: Haematologica, 2010 Feb 23, 396(3)
Bone marrow mesenchymal stromal cells non-selectively protect chronic myeloid leukemia cells from imatinib-induced apoptosis via the CXCR4/CXCL12 axis.

[Abstract]Background Residual disease of chronic myeloid leukaemia (CML) following imatinib treatment has been attributed to the presence of a quiescent leukaemic stem cell intrinsically resistant to imatinib. Mesenchymal stromal cells (MSC) in the bone marrow may favour leukemia persistence and progression by preserving proliferation and self-renewal of malignant progenitors. DESIGN AND METHODS: BV173 or primary CML cells were cocultured with human MSC and imatinib cell death was then measured. The role of pro-and anti-apoptotic proteins as well as of the chemokine CXCL12 have been evaluated in this context. We also studied the ability of BV173 cells to repopulate NOD/SCID mice following in-vitro exposure to imatinib and MCS. RESULTS: Whilst imatinib induced dose-dependent apoptosis of BV173 cells and CML primary cells, the co-culture with MSC protected both CML cell types. Molecular analysis indicated that MSC reduced caspase-3 activation and modulated the expression of the anti-apoptotic protein Bcl-XL. Furthermore, the exposure of CML cells to imatinib in the presence of MSC preserved the ability of the leukemia to engraft into NOD/SCID mice. We observed that CML cells and MSC express functional levels of CXCR4 and CXCL12, respectively. Finally, the CXCR4 antagonist, AMD3100 restored apoptosis by imatinib and the susceptibility of the SCID leukemia repopulating cells to the TK inhibitor. Conclusions Human MSC mediate protection of CML cells from imatinib-induced apoptosis. Disruption of CXCL12/CXCR4 axis at least in part restores sensitivity to imatinib. The combination of anti-CXCR4 antagonists with TK inhibitors may represent a powerful approach in the treatment of CML.

17: Neuroimmunomodulation, 2010, 17(3)
The CXCL12/CXCR4 Pair in Aged Human Thymus.

[Abstract]CXCL12 is an important CXC chemokine involved in numerous biological processes. We had previously demonstrated the synergistic participation of CXCL12 and IL-7 in the control of both survival and proliferation of CD34(+) human thymic lymphoid progenitors. On this basis, we hypothesize a presumptive role for CXCL12 and its receptor, CXCR4, in the thymus involution. In this respect, in the current report we describe the expression of both molecules in the human thymus during aging. Our results demonstrate that, despite the profound alterations observed in the thymic epithelial microenvironment of aged thymuses, the proportions of different CD4/CD8 thymocyte subsets do not undergo significant variations. Remarkably, a strong CXCL12 expression was found in older thymuses, which appeared in the same locations as in younger thymuses: the subcapsulary and medullary areas. The proportions of CXCR4(+) cells, most of them belonging to the CD3(-) compartment, showed no important variations in the older thymuses. However, within the CD34(+) cell population, a significant reduction in the expression of CXCR4 molecules was observed.

18: The Journal of biological chemistry, 2010 Feb 2,
Interactions between chemokines: Regulation of fractalkine/CX3CL1 homeostasis by SDF/CXCL12 in cortical neurons.

[Abstract]The soluble form of the chemokine fractalkine/CX3CL1 regulates microglia activation in the central nervous system (CNS), ultimately affecting neuronal survival. This study aims to determine whether CXCL12, another chemokine constitutively expressed in the CNS (known as stromal cell-derived factor 1; SDF-1), regulates cleavage of fractalkine from neurons. To this end, ELISA was used to measure protein levels of soluble fractalkine in the medium of rat neuronal cultures exposed to SDF-1. Gene arrays, quantitative RT-PCR, and Western blot were used to measure overall fractalkine expression in neurons. The data show that the rate of fractalkine shedding in healthy cultures positively correlates with in vitro differentiation and survival. In analogy to non-neuronal cells, metalloproteinases (ADAM10/17) are involved in cleavage of neuronal fractalkine as indicated by studies with pharmacologic inhibitors. Moreover, treatment of the neuronal cultures with SDF-1 stimulates expression of the inducible metalloproteinase ADAM17 and increases soluble fractalkine content in culture media. The effect of SDF-1 is blocked by an inhibitor of both ADAM10 and 17, but only partially affected by a more specific inhibitor of ADAM10. In addition, SDF-1 also up-regulates expression of the fractalkine gene. Conversely, exposure of neurons to an excitotoxic stimulus (i.e. NMDA) inhibits alpha-secretase activity and markedly diminishes soluble fractalkine levels, leading to cell death. These results, along with previous findings on the neuroprotective role of both SDF-1 and fractalkine, suggest that this novel interaction between the two chemokines may contribute to in vivo regulation of neuronal survival by modulating microglial neurotoxic properties.

19: European journal of haematology, 2010 Jan 19,
Effective ex vivo expansion of hematopoietic stem cells using osteoblast-differentiated mesenchymal stem cells is CXCL12 dependent.

[Abstract]ABSTRACT Effective ex vivo expansion of hematopoietic stem cells (HSCs) is a prerequisite for HSC transplantation. Growth and maintenance of HSC is dependent on cytokine and niche factors. We investigated whether mesenchymal stem cells (MSCs) or osteogenic cytokine-differentiated MSCs play a role in HSC expansion. We used the human HM3.B10 (B10) MSC cell line and the osteoblast-differentiated B10 (Ost-B10) as a feeder layer and examined ex vivo expansion of CD34(+)CD38(-) HSCs obtained from peripheral blood (PB) and cord blood (CB) with or without several growth cytokines. Both undifferentiated B10 and Ost-B10 cells exhibited similar effects on total HSC expansion; however, Ost-B10 demonstrated a higher potency in CD34(+)CD38(-) cell- specific proliferation in the presence of cytokines compared to undifferentiated B10 HSCs. Colony forming cell assay and long-term culture initiating cell assay revealed that Ost-B10 displayed multipotent differentiation and enabled long-term ex vivo culture of HSCs. We next examined the relationship between HSC expansion and the presence of various chemokines. CXCL4 and CXCL12 expression were increased in Ost-B10 cells compared with the B10 cells. CD34(+)CD38(-) cells were significantly increased with CXCL12, but not CXCL4 treatment. siRNA inhibition of CXCL12 decreased CXCL12 secretion in both B10 and Ost-B10, whereas expansion of CD34(+)CD38(-) cells was decreased in Ost-B10 alone. These results demonstrated that ex vivo expansion of HSCs may be highly effective through osteoblast-differentiated MSCs acting as a feeder layer, and likely operates through the CXCL12 chemokines signaling pathway.

20: PloS one, 2010, 5(1)
Stromal cell-derived factor-1/CXCL12 contributes to MMTV-Wnt1 tumor growth involving Gr1+CD11b+ cells.

[Abstract]BACKGROUND: Histological examinations of MMTV-Wnt1 tumors reveal drastic differences in the tumor vasculature when compared to MMTV-Her2 tumors. However, these differences have not been formally described, nor have any angiogenic factors been implicated to be involved in the Wnt1 tumors. METHODOLOGY/PRINCIPAL FINDINGS: Here, we show that MMTV-Wnt1 tumors were more vascularized than MMTV-Her2 tumors, and this correlated with significantly higher expression of a CXC chemokine, stromal cell-derived factor-1 (SDF1/CXCL12) but not with VEGFA. Isolation of various cell types from Wnt1 tumors revealed that SDF1 was produced by both tumor myoepithelial cells and stromal cells, whereas Her2 tumors lacked myoepithelial cells and contained significantly less stroma. The growth of Wnt1 tumors, but not Her2 tumors, was inhibited by a neutralizing antibody to SDF1, but not by neutralization of VEGFA. Anti-SDF1 treatment decreased the proportion of infiltrating Gr1(+) myeloid cells in the Wnt1 tumors, which correlated with a decrease in the percentage of endothelial cells. The involvement of Gr1(+) cells was evident from the retardation of Wnt1 tumor growth following in vivo depletion of these cells with an anti-Gr1-specific antibody. This degree of inhibition on Wnt1 tumor growth was comparable, but not additive, to the effect observed with anti-SDF1, indicative of overlapping mechanisms of inhibition. In contrast, Her2 tumors were not affected by the depletion of Gr1(+) cells. CONCLUSIONS/SIGNIFICANCE: We demonstrated that SDF1 is important for Wnt1, but not for HER2, in inducing murine mammary tumor and the role of SDF1 in tumorigenesis involves Gr1(+) myeloid cells to facilitate growth and/or angiogenesis.

21: Proteins, 2009 Dec 1, 35(6)
Heterologous quaternary structure of CXCL12 and its relationship to the CC chemokine family.

[Abstract]AIMS: It has been shown that neural stem cells (NSCs) migrate towards areas of brain injury or brain tumours and that NSCs have the capacity to track infiltrating tumour cells. The possible mechanism behind the migratory behaviour of NSCs is not yet completely understood. As chemokines are involved in the migration of immune cells in the injured brain, they may also be involved in chemoattraction of NSCs towards a brain tumour. METHODS: The expression profile of various chemokine receptors in NSCs, harvested from the subventricular zone of adult mice, was investigated by reverse transcriptase- polymerase chain reaction analysis. Furthermore, the functionality of the chemokine receptors was assessed in in vitro chemotaxis assays and calcium signalling experiments. To test the in vivo migration of NSCs, a syngeneic mouse model was developed, whereby a B16F10 melanoma cell line was grafted into one hemisphere and later NSCs were grafted in the contralateral hemisphere. Furthermore, the expression of chemokines in this melanoma cell line was investigated. RESULTS AND CONCLUSIONS: Adult mouse NSCs functionally express various chemokine receptors of which CXC chemokine receptor (CXCR)4 shows the highest mRNA levels and most pronounced functional responses in vitro. CXC chemokine ligand (CXCL)12, the ligand for CXCR4, is expressed by the melanoma cell line. In this mouse model for metastatic brain tumours, it is shown that NSCs express CXCR4 at their cell membranes while they migrate towards the tumour, which produces CXCL12. It is therefore suggested that the CXCR4/CXCL12 pathway plays a role in the mechanism underlying tumour-mediated attraction of NSCs.

22: Connective tissue research, 2010, 51(1)
Expression Analysis of Angiogenic Growth Factors and Biological Axis CXCL12/CXCR4 Axis in Idiopathic Pulmonary Fibrosis.

[Abstract]Idiopathic pulmonary fibrosis (IPF) is associated with aberrant repair, persistence of collagen deposition, and the development of vascular remodeling. However, the role of angiogenesis in the pathogenesis of IPF is still undetermined. The aim of this study was to evaluate the combined mRNA expression of vascular endothelial growth factor A (VEGFA), fibroblast growth factor 2 (FGF2), insulin-like growth factor 1 (IGF1) epidermal growth factor (EGF), and its receptor (EGFR) in lung tissue obtained from IPF patients. We have also investigated the expression of chemokine CXCL12/stromal cell-derived factor-1 (SDF-1) and its receptor, CXCR4, to identify alterations that maybe implicated in the pathogenesis of IPF. The subjects studied consisted of two distinct groups: patients with IPF (n = 25) and subjects (control) undergoing thoracic surgery for reasons other than interstitial lung disease (n = 10). Expression analysis of the aforementioned growth factors and biological axis CXCL12/CXR4 analysis were performed using real-time RT-PCR. IGF-1, EGF, and FGF2 mRNA levels are significantly decreased in the patients compared to the controls (p = 0.028, p = 0.023 and p = 0.009, respectively). SDF1-TR1 and SDF1-TR2 transcript levels were significantly lower in patients compared to controls (p = 0.017 and p = 0.001). Significant coexpression of VEGF mRNA with IGF mRNA was observed in the group of the patients (p = 0.017). An additional coexpression of VEGF mRNA with SDF1-TR1 mRNA was demonstrated(p = 0.030). Our results show a downregulation in angiogenetic mechanisms in IPF. However, our results should be further verified by measuring other angiogenetic pathways in more samples.

23: Acta biochimica et biophysica Sinica, 2010 Jan, 42(1)
c-myb activates CXCL12 transcription in T47D and MCF7 breast cancer cells.

[Abstract]Chemokine C-X-C motif ligand 12 (CXCL12) is a potent chemotactic and angiogenic factor that has been proposed to play a role in organ-specific metastasis and angiogenic activity in several malignancies. In this study, we found that the overexpression of c-myb could elevate CXCL12 mRNA level and CXCL12 promoter activity in human T47D and MCF-7 breast cancer cells. Chromatin immunoprecipitation assay demonstrated that c-myb could bind to the CXCL12 promoter in the cells transfected with cmyb expression vector. c-myb siRNA attenuated CXCL12 promoter activity and the binding of c-myb to the CXCL12 promoter in T47D and MCF-7 cells. These results indicated that c-myb could activate CXCL12 promoter transcription.

24: American journal of physiology. Renal physiology, 2009 Dec 23, 58(1)
Expression and Function of CXCL12/ CXCR4 in Rat Urinary Bladder with Cyclophosphamide (CYP) - Induced Cystitis.

[Abstract]Chemokines, otherwise known as chemotactic cytokines, are pro-inflammatory mediators of the immune response and have been implicated in altered sensory processing, hyperalgesia and central sensitization following tissue injury or inflammation. To address the role of CXCL12/CXCR4 signaling in normal micturition and inflammation-induced bladder hyperreflexia, bladder inflammation in adult female Wistar rats (175-250g) was induced by injecting CYP intraperitoneally at acute (150 mg/kg; 4 hr), intermediate (150 mg/kg; 48 hr) and chronic (75 mg/kg; every third day for 10 days) time points. CXCL12, and its receptor, CXCR4, were examined in the whole urinary bladder of control and CYP-treated rats using enzyme-linked immunosorbent assays (ELISAs), quantitative PCR (qRT-PCR) and immunostaining techniques. ELISAs, qRT-PCR and immunostaining experiments revealed a significant (p 25: Molecular pharmacology, 2009 Dec 17, 58(1)
P-Rex1, a guanine nucleotide exchange factor for Rac, mediates angiogenic responses to SDF-1/CXCL-12 linked to Rac activation, endothelial cell migration and in vitro angiogenesis.

[Abstract]Stromal cell-derived Factor-1 (SDF-1/CXCL-12) and Vascular Endothelial Growth Factor (VEGF), which can be secreted by hypoxic tumors, promote the generation of new blood vessels. These potent angiogenic factors stimulate endothelial cell migration via the activation of Rho GTPases and the PI3K/AKT signaling pathway. Thus characterization of guanine nucleotide exchange factors critical in the angiogenic signaling cascades offers the possibility of identifying novel molecular targets. We previously demonstrated that mTOR, an important effector and regulator of PI3K/AKT, activates P-Rex1, a Rac guanine nucleotide exchange factor identified as a target of Gbetagamma and PI3K, via direct interactions. In this study we tested the hypothesis that P-Rex1 is involved in the angiogenic responses elicited by SDF-1 and VEGF. Using a knockdown approach, we demonstrate that P-Rex1 is indeed required for SDF-1 promoted signaling pathway, as there is decreased Rac activation, cell migration and in vitro angiogenesis in P-Rex1 knockdown cells stimulated with SDF-1. In contrast P-Rex1 knockdown does not affect responses to VEGF nor is signaling to ERK in response to either angiogenic factor sensitive to P-Rex1 knockdown. We also demonstrate that in endothelial cells, VEGF promotes an increase in the expression of endogenous P-Rex1 as well as the SDF-1 receptor CXCR4; in addition, VEGF-pretreated cells show an increased migratory and angiogenic response to SDF-1, suggesting that VEGF stimulation can complement SDF-1/CXCR4 signaling to induce angiogenesis. We conclude that P-Rex1 is a key element in SDF-1-induced angiogenic responses and a potential target for therapeutic intervention.

26: Journal of virology, 2009 Dec 16, 58(1)
The Potent Anti-HIV Activity of CXCL12{gamma} Correlates with Efficient CXCR4 Binding and Internalization.

[Abstract]We have previously demonstrated that the naturally occurring splice variant of Stromal Cell-Derived factor-1gamma/CXCL12gamma is the most potent CXCL12 isoform in blocking X4 HIV-1 with weak chemotactic activity. A conserved BBXB domain (B for basic and X for any residue) located in the N-terminus ((24)KHLK(27)) is found in all six isoforms of CXCL12. To determine whether the potent antiviral activity of CXCL12gamma is due to the presence of the extra C-terminal BBXB domains, we have mutated each domain individually as well as in combination. Although binding of CXCL12gamma to heparan sulfate proteoglycan (HSPG) was ten-fold higher than that observed with CXCL12alpha, the results did not demonstrate a direct correlation between HSPG binding and the potent antiviral activity. CXCL12gamma mutants lacking the conserved BBXB domain (designated gammaB1) showed increased binding to HSPG but reduced anti-HIV activity. In contrast, the mutants lacking the C-terminal second and/or third BBXB domain but retaining the conserved domain (designated B2, B3, and B23) showed decreased binding to HSPG but increased anti-HIV activity. The B2, B3 or B23 mutants were associated with enhanced CXCR4 binding, receptor internalization, and restored chemotaxis. Internalization of CXCR4 was more potent with CXCL12gamma than CXCL12alpha and was significantly reduced when the conserved BBXB domain was mutated. We concluded that the observed potent anti-HIV-1 activity of CXCL12gamma is due to increased affinity to CXCR4 and efficient receptor internalization.

27: Haematologica, 2009 Dec 16, 58(1)
The HIF-2 transcription factor is a novel regulator of aberrant CXCL12 expression in multiple myeloma plasma cells.

[Abstract]Background Multiple myeloma (MM) is an incurable malignancy of bone marrow (BM) plasma cells (PCs). MM disease progression is accompanied by an increase in BM angiogenesis. Studies from our laboratory suggest a role for the CXCL12 chemokine in this process, with circulating levels of CXCL12 correlating with BM angiogenesis in MM patients. While the mechanisms responsible for aberrant PC expression of CXCL12 remain to be determined, studies in other systems suggest a role for hypoxia and hypoxia-inducible transcription factors (HIFs). DESIGN AND METHODS: HIF protein expression was examined in patient BM biopsy specimens using immunohistochemistry. The hypoxic regulation of CXCL12 was examined in MM PC lines using PCR and Western blotting. The role of HIF-1 and HIF-2 in the regulation of CXCL12 expression was examined using over-expression and shRNA knockdown constructs, EMSA and ChIP. The contribution of CXCL12 to hypoxia-induced angiogenesis was examined in vivo using a subcutaneous murine model of neovascularisation. RESULTS: Strong HIF-2 protein expression was detected in CD138(+) MM PCs in patient biopsy specimens. Prolonged hypoxic exposure strongly up-regulated CXCL12 expression in MM PCs and HIF-2 was found to play a key role in this response. Promoter analyses revealed increased HIF-2 binding to the CXCL12 promoter under hypoxic conditions. Over-expression of HIF in MM PCs strongly induced in vivo angiogenesis, and administration of a CXCL12 antagonist decreased HIF-induced angiogenesis. Conclusions HIF-2 is a novel regulator of CXCL12 expression in MM PCs and a major contributor to MM PC-induced angiogenesis. Targeting the hypoxic niche, and more specifically HIF-2, may represent a viable strategy to inhibit MM angiogenesis and disease progression.

28: Journal of endodontics, 2010 Jan, 36(1)
Heat-killed Enterococcus faecalis Alters Nitric Oxide and CXCL12 Production but not CXCL8 and CCL3 Production by Cultured Human Dental Pulp Fibroblasts.

[Abstract]INTRODUCTION: Fibroblasts are the most abundant cells in dental pulp. To investigate their capacity to produce the chemokines CCL3, CXCL8, and CXCL12 as well as nitric oxide (NO), we evaluated the production of these mediators in supernatants of cultured human dental pulp fibroblasts (HDPF) stimulated by heat-killed Enterococcus faecalis (HKEF). METHODS: Primary cultures of HDPF were stimulated with medium alone or HKEF (1:1, 10:1, or 100:1 bacteria:fibroblast) for 1, 6, and 24 hours. Chemokines and NO were assessed through enzyme-linked immunosorbent assay and Griess reaction, respectively. Statistical analysis was performed by using analysis of variance and Tukey post test. RESULTS: CCL3 was not detected, whereas constitutive CXCL8 was not affected. Production of CXCL12 was increased at 1 and 6 hours, and NO was increased at the concentration of 1:1 bacteria:fibroblast at 24 hours. Viability and proliferation assays did not reveal cell number differences. CONCLUSIONS: These findings demonstrate that heat-killed E. faecalis is able to increase production of CXCL12 and NO by HDPF.

29: Cancer biology & therapy, 2010 Jan 17, 9(1)
CXCL12/CXCR4 promotes motility and proliferation of glioma cells.

[Abstract]Glioblastoma (GBM) is the most aggressive and malignant brain tumor. Recent studies indicated that glioma samples are characterized by increased expression of CXCR4, the CXCL12/SDF-1 chemokine receptor. To better understand the role of CXCR4 in GBM biology we performed an integrated study where we simultaneously evaluate the contribution of the CXCR4/CXCL12 signaling pathway to the proliferation, survival and motility of a human GBM cell line. Our results indicated that CXCR4/CXCL12 axis induced an increase in cell proliferation and in cell motility. The blockage of CXCR4 induced a significant increase of apoptosis. Together, our results indicated that CXCR4/CXCL12 signalling pathway may contribute to GBM development and emphasize the therapeutic potential of this pathway in patients with GBM.

30: Zhonghua wei chang wai ke za zhi = Chinese journal of gastrointestinal surgery, 2009 Nov, 12(6)
[Shikonin down-regulates CXCR4 expression and inhibits CXCL12-induced migratory responses in colorectal carcinoma cell line SW480.]

[Abstract]OBJECTIVE: To investigate the effects of shikonin on the proliferation, expression of CXCR4 and the migratory responses to CXCL12 in colorectal carcinoma cell line SW480. METHODS: The proliferation of SW480 cells was assessed by MTT assay. Cell surface expression of CXCR4 was determined by flow cytometry. The migratory ability was determined by Transwell. RESULTS: Shikonin inhibited the proliferation of SW480 cells in time- and concentration-dependent manner. The expression rate of CXCR4 in SW480 cells was 99.1%. After application of shikonin 0.01 mumol/L,0.1 mumol/L and 1.0 mumol/L for 24 h, the expression rate of CXCR4 decreased to 76.0%, 59.1% and 35.5% respectively(F=1098.041, P <0.001), and the CXCL12-induced SW480 cell migratory inhibition rate was 25.2%, 38.5% and 55.7% respectively(F=48.970, P <0.001). CONCLUSION: Besides having inhibiting tumor cell proliferation effect, Shikonin may also paly a role in anti-metastasis via down-regulating the expression of CXCR4 and reducing the CXCL12-induced migratory response in colorectal carcinoma cell.

31: Journal of immunology (Baltimore, Md. : 1950), 2009 Dec 1, 183(11)
CCR5 Ligands Modulate CXCL12-Induced Chemotaxis, Adhesion, and Akt Phosphorylation of Human Cord Blood CD34+ Cells.

[Abstract]CXCL12 and its receptor CXCR4 play an important role in hematopoietic stem/progenitor cell (HSPC) migration from and retention within the bone marrow. HSPCs are very selective in their chemotactic response and undergo chemotaxis only in response to CXCL12. In addition to CXCR4, HSPCs express receptors for various other chemokines; however, the role of these receptors is not well understood. Freshly isolated CD34(+) cells (highly enriched for HSPCs) from cord blood (CB) express low levels of CCR5; however, if the cells were washed with acidic buffer before Ab staining to remove any ligand bound to CCR5, then nearly 80% of CD34(+) CB cells were found to express CCR5 on the cell surface. Although none of the CCR5 ligands investigated in this study (CCL3, CCL4, and CCL5) induced chemotaxis, at relatively high concentrations they transiently enhanced CXCL12-mediated chemotaxis of CD34(+) CB cells. In contrast, CXCL12-mediated adhesion of cells to VCAM-1-coated surfaces was reduced if CD34(+) CB cells were pretreated with these CCR5 ligands for 15 min. The effect of these chemokines on CXCL12-mediated responses was not at the level of CXCR4 expression, but on downstream signaling pathways elicited by CXCL12. Pretreatment with CCR5 chemokines enhanced CXCL12-mediated Akt phosphorylation, but down-modulated calcium flux in CD34(+) CB cells. Modulation of CXCL12-mediated responses of CD34(+) cells by CCR5 chemokines provides a possible mechanism that underlies movement of HSPCs during inflammation.

32: PloS one, 2009, 4(10)
A Chemokine Targets the Nucleus: Cxcl12-Gamma Isoform Localizes to the Nucleolus in Adult Mouse Heart.

[Abstract]Chemokines are extracellular mediators of complex regulatory circuits involved principally in cell-to-cell communication. Most studies to date of the essential chemokine Cxcl12 (Sdf-1) have focused on the ubiquitously expressed secreted isoforms alpha and beta. Here we show that, unlike these isoforms and all other known chemokines, the alternatively transcribed gamma isoform is an intracellular protein that localizes to the nucleolus in differentiated mouse Cardiac tissue. Our results demonstrate that nucleolar transportation is encoded by a nucleolar-localization signal in the unique carboxy-terminal region of Sdf-1gamma, and is competent both in vivo and in vitro. The molecular mechanism underlying these unusual chemokine properties involves cardiac-specific transcription of an mRNA containing a unique short-leader sequence lacking the signal peptide and translation from a non-canonical CUG codon. Our results provide an example of genome economy even for essential and highly conserved genes such as Cxcl12, and suggest that chemokines can exert tissue specific functions unrelated to cell-to-cell communication.

33: The American journal of pathology, 2009 Oct, 175(4)
Correlation of CXCL12 expression and FoxP3+ cell infiltration with human papillomavirus infection and clinicopathological progression of cervical cancer.

[Abstract]Human cervical cancer is an immunogenic tumor with a defined pattern of histopathological and clinical progression. Tumor-infiltrating T cells contribute to immune control of this tumor; however, cervical cancer dysregulates this immune response both through its association with human papillomavirus (HPV) infection and by producing cytokines and chemokines. Animal tumor models have revealed associations between overproduction of the chemokine stromal cell-derived factor-1 (SDF-1 or CXCL12) and dysregulation of tumor-specific immunity. We therefore proposed that CXCL12 expression by cervical precancerous and cancerous lesions correlates with histopathological progression, loss of immune control of the tumor, and HPV infection. We found a significant association between cancer stage and CXCL12 expression for squamous and glandular lesions as well as with the HPV16+ (high-risk) status of the neoplastic lesions. Cancer progression was correlated with increasing levels of FoxP3 T-cell infiltration in the tumor. FoxP3 and CXCL12 expression significantly correlated for squamous and glandular neoplastic lesions. These observations were supported by enzyme-linked immunosorbent assay and Western blotting. In addition, we demonstrated CXCL12 expression by dyskaryotic cells in ThinPrep cervical smears. This study robustly links increased CXCL12 expression and FoxP3(+)-cell infiltration to HPV infection and progression of cervical cancer. It supports the detection of CXCL12 in cervical smears and biopsies as an additional biomarker for this disease.

34: Clinical cancer research : an official journal of the American Association for Cancer Research, 2009 Oct 1, 15(19)
CXCL13 and CXCL12 in central nervous system lymphoma patients.

[Abstract]PURPOSE: Homing of malignant lymphocytes to the central nervous system (CNS) may play a role in the pathogenesis of CNS lymphoma. In this study, we evaluated the chemokines CXCL12 and CXCL13 in the cerebrospinal fluid (CSF) and serum of patients with CNS lymphoma. EXPERIMENTAL DESIGN: Samples from 30 patients with CNS lymphoma (23 with primary and 7 with secondary CNS lymphoma; all B-cell lymphoma) and 40 controls (10 patients with other CNS malignancies and 30 without a malignant CNS disease) were examined. CXCL12 and CXCL13 concentrations were measured using enzyme-linked immunosorbent assays. The grade of blood-brain barrier disruption was estimated by the CSF/serum albumin ratio. RESULTS: CNS lymphoma patients and controls did not differ in CXCL12 serum and CSF levels. Serum levels of CXCL13 were generally low. CXCL13 CSF levels, however, were significantly higher in CNS lymphoma patients as compared with controls (P < 0.0001). Chemokine levels in CSF and serum did not correlate. In CNS lymphoma, CXCL13 concentration in CSF correlated with the degree of blood-brain barrier disruption (R = 0.66; P = 0.003). Elevated CSF levels of CXCL12 and CXCL13 measured in seven CNS lymphoma patients during therapy decreased in five patients who responded to chemotherapy and increased in two with lymphoma progression. CONCLUSIONS: Our results suggest a production of CXCL13 within the CNS of CNS lymphoma patients, which decreases with response to therapy. Thus, CXCL13 may represent a marker for further diagnostic and prognostic studies.

35: Journal of neuroimmunology, 2009 Oct 30, 215(1-2)
Regulation of CXCL12 and CXCR4 expression by human brain endothelial cells and their role in CD4+ and CD8+ T cell adhesion and transendothelial migration.

[Abstract]Chemokines have emerged as important mediators of leukocyte recruitment to the CNS across the normally restrictive blood-brain barrier (BBB). In the present study we investigated the regulation of CXCL12 and its receptor, CXCR4, expression in human brain microvessel endothelial cells (HBMEC) and the effects of CXCL12 on the adhesion and migration of CD4+ and CD8+ T lymphocytes across HBMEC monolayers. Resting HBMEC constitutively expressed CXCL12 and CXCR4. Treatment with TNF-alpha, IFN-gamma, IL-1beta and LPS downregulated CXCL12 and CXCR4 expression and CXCL12 ligation induced internalization of CXCR4. The minimal adhesion and migration of CD4+ and CD8+ T lymphocytes across resting HBMEC were increased following cytokine treatment of HBMEC. CXCL12 gradients further enhanced adhesion of both T cell subsets to activated HBMEC and migration across resting monolayers. A greater number of CD8+ T lymphocytes adhered and migrated across activated HBMEC compared to CD4+ T cells. These studies provide insight into the regulation of CXCL12 and CXCR4 expression in cerebral EC and indicate an important role for CXCL12 in T cell subset recruitment across the BBB in CNS inflammation.

36: Neuropharmacology, 2009 Sep 13, 16(3)
SDF-1alpha/CXCL12 enhances GABA and glutamate synaptic activity at serotonin neurons in the rat dorsal raphe nucleus.

[Abstract]The serotonin (5-hydroxytryptamine; 5-HT) system has a well-characterized role in depression. Recent reports describe comorbidities of mood-immune disorders, suggesting an immunological component may contribute to the pathogenesis of depression as well. Chemokines, immune proteins which mediate leukocyte trafficking, and their receptors are widely distributed in the brain, mediate neuronal patterning, and modulate various neuropathologies. The purpose of this study was to investigate the neuroanatomical relationship and functional impact of the chemokine stromal cell-derived factor-1alpha/CXCL12 and its receptor, CXCR4, on the serotonin dorsal raphe nucleus (DRN) system in the rat using anatomical and electrophysiological techniques. Immunohistochemical analysis indicates that over 70% of 5-HT neurons colocalize with CXCL12 and CXCR4. At a subcellular level, CXCL12 localizes throughout the cytoplasm whereas CXCR4 concentrates to the outer membrane and processes of 5-HT neurons. CXCL12 and CXCR4 also colocalize on individual DRN cells. Furthermore, electrophysiological studies demonstrate CXCL12 depolarization of 5-HT neurons indirectly via glutamate synaptic inputs. CXCL12 also enhances the frequency of spontaneous inhibitory and excitatory postsynaptic currents (sIPSC and sEPSC). CXCL12 concentration-dependently increases evoked IPSC amplitude and decreases evoked IPSC paired-pulse ratio selectively in 5-HT neurons, effects blocked by the CXCR4 antagonist AMD3100. These data indicate presynaptic enhancement of GABA and glutamate release at 5-HT DRN neurons by CXCL12. Immunohistochemical analysis further shows CXCR4 localization to DRN GABA neurons, providing an anatomical basis for CXCL12 effects on GABA release. Thus, CXCL12 indirectly modulates 5-HT neurotransmission via GABA and glutamate synaptic afferents. Future therapies targeting CXCL12 and other chemokines may treat serotonin related mood disorders, particularly depression experienced by immune-compromised individuals.

37: Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie, 2009 Sep 2, 16(3)
Tamoxifen epigenetically modulates CXCL12 expression in MCF-7 breast cancer cells.

[Abstract]The CXCL12 chemokine binds to the CXCR4 receptor and contributes to survival, proliferation, and migration of malignant cells. Recent reports indicate that breast cancer cells lacking expression of CXCL12 but exhibiting CXCR4 can metastasize to target organs that secrete CXCL12. We observed that Tamoxifen (Tam), similarly to 5-dAzaC, results in significantly increased levels of CXCL12 transcript and protein in MCF-7 breast cancer cells. Bisulfite sequencing suggests that Tam, similarly to 5-dAzaC, may increase CXCL12 expression via reduction in methylation of cytosine in the cytosine-guanosine (CpG) dinucleotide island of the CXCL12 promoter of MCF-7 cells. Our results, together with findings of other researches, may suggest that Tam epigenetically activates CXCL12 expression in breast cancer cells and can make these cells less susceptible to attraction by exogenous CXCL12 to metastasis sites.

38: Diabetologia, 2009 Nov, 52(11)
Podocytes produce homeostatic chemokine stromal cell-derived factor-1/CXCL12, which contributes to glomerulosclerosis, podocyte loss and albuminuria in a mouse model of type 2 diabetes.

[Abstract]AIMS/HYPOTHESIS: Chemokine (C-X-C motif) ligand 12 (CXCL12) (also known as stromal cell-derived factor-1 [SDF-1]-alpha) is a homeostatic chemokine with multiple roles in cell homing, tumour metastasis, angiogenesis and tissue regeneration after acute injuries. However, its role in chronic diseases remains poorly defined, e.g. in chronic glomerular diseases like diabetic glomerulosclerosis. We hypothesised that CXCL12 may have a functional role during the evolution of diabetic glomerulosclerosis, either by assisting glomerular repair or by supporting the maladaptive tissue remodelling in response to hyperglycaemia and glomerular hyperfiltration. METHODS: To define the functional role of CXCL12 in the progression of glomerular disease, we used the CXCL12-specific inhibitor NOX-A12, an L: -enantiomeric RNA oligonucleotide (Spiegelmer). A mouse model of type 2 diabetes (db/db mice) was used. Male db/db mice, uni-nephrectomised at 6 weeks of age, received subcutaneous injections with a PEGylated form of NOX-A12, non-functional control Spiegelmer or vehicle on alternate days from 4 to 6 months of age. RESULTS: Immunostaining localised renal CXCL12 production to glomerular podocytes in db/db mice with early or advanced diabetic nephropathy. CXCL12 inhibition significantly reduced the degree of glomerulosclerosis, increased the number of podocytes, prevented the onset of albuminuria and maintained the peritubular vasculature without affecting blood glucose levels, body weight or glomerular macrophage infiltration. CONCLUSIONS/INTERPRETATION: We conclude that podocytes produce CXCL12, which contributes to proteinuria and glomerulosclerosis in our mouse model of type 2 diabetes. This novel pathomechanism provides the first evidence that CXCL12 could be a therapeutic target in (diabetic) glomerulosclerosis.

39: Biochimica et biophysica acta, 2009 Dec, 1790(12)
Glycosaminoglycans and syndecan-4 are involved in SDF-1/CXCL12-mediated invasion of human epitheloid carcinoma HeLa cells.

[Abstract]BACKGROUND: In addition to their physiologic effects in inflammation and angiogenesis, chemokines are involved in cancer pathology. The CXC-chemokine stromal cell-derived factor-1 (SDF-1)/CXCL12 mediates its biological activities through activation of G protein-coupled receptor CXCR4 and binds to glycosaminoglycans (GAGs). METHODS: Using Bio-coat cell migration chambers, specific antagonists, flow cytometry and RNA interference, we evaluate the involvement of heparan sulfate proteoglycans (HSPG) in the SDF-1/CXCL12-induced invasion of human cervix epitheloid carcinoma HeLa cells. RESULTS: The SDF-1/CXCL12-induced cell invasion is dependent on CXCR4. Furthermore, Protein Kinase C delta (PKC delta) and c-jun NH2-terminal kinase/stress-activated protein kinase (JNK/SAPK) are implicated in this event, but not extracellular signal-regulated kinase (ERK) 1/2. Moreover, the invasion of HeLa cells induced by SDF-1/CXCL12 was dependent on matrix metalloproteinase-9 (MMP-9). The pre-incubation of HeLa cells with heparin or with anti-heparan sulfate antibodies or with beta-d-xyloside inhibited SDF-1/CXCL12-mediated cell invasion. Furthermore, the down-regulation of syndecan-4, a heparan sulfate proteoglycan, decreased SDF-1/CXCL12-mediated HeLa cell invasion. GAGs, probably on syndecan-4, are involved in SDF-1/CXCL12-mediated cell chemotaxis. GENERAL SIGNIFICANCE: These data suggest that targeting the glycosaminoglycan/chemokine interaction could be a new therapeutic approach for carcinomas in which SDF-1/CXCL12 is involved.

40: Journal of virology, 2009 Nov, 83(21)
Human uterine natural killer cells but not blood natural killer cells inhibit human immunodeficiency virus type 1 infection by secretion of CXCL12.

[Abstract]Natural killer (NK) cells derived from the human female reproductive tract (FRT) are phenotypically and functionally distinct from those obtained from peripheral blood. Because the FRT is a primary site of human immunodeficiency virus type 1 (HIV-1) infection in women, we determined whether soluble factors secreted by uterine-derived NK (uNK) cells inhibit HIV-1 infection. Clonal populations of uNK cells were activated with interleukin-12 (IL-12) and IL-15, and conditioned media (CM) from these cultures evaluated for their ability to inhibit infection of cells by HIV-1(IIIB), HIV-1(NL4.3), and HIV-1(HC4) (X4-tropic) or HIV-1(BaL) (R5-tropic) viruses. We found that soluble factors secreted by activated uNK cells significantly inhibited X4-tropic virus infection of TZM-bl cells, peripheral blood mononuclear cells, and primary human endometrial cells, but not infection by HIV-1(BaL). In contrast, CM from peripheral blood NK (bNK) cells did not inhibit HIV-1 infection of cells. Analysis of factors secreted from uNK clones with anti-HIV-1 activity demonstrated significantly higher levels of CXCL12 compared to uNK clones without this activity, and the HIV inhibitory activity was neutralized by antibodies to CXCL12. Collectively, these data demonstrate that human uNK cells release chemokines with anti-HIV-1 activity for X4-tropic strains and this suggest that these chemokines may contribute to the inhibition of X4-tropic strain transmission across mucosal tissues.

41: Expert opinion on therapeutic targets, 2009 Oct, 13(10)
Targeting the CXCR4/CXCL12 axis in systemic lupus erythematosus.

[Abstract]BACKGROUND: CXCR4 antagonists have garnered much interest as promising treatments for cancer metastases and HIV. Given its ability to attract multiple leukocyte subsets and stimulate B cell production and myelopoeisis, recent attention has been directed to these inhibitors in the treatment of autoimmune diseases, such as systemic lupus erythematosus (SLE). OBJECTIVE: To assess the potential of CXCR4 antagonists in SLE. METHODS: We reviewed literature on the expression of CXCR4 and its ligand CXCL12, and the effects of CXCR4 antagonists in murine and human SLE. RESULTS/CONCLUSIONS: CXCR4 and CXCL12 have been found at abundant levels in peripheral blood leukocyte subsets as well as immune and non-immune organs in lupus-prone murine models. While SLE patients have displayed upregulated, downregulated, or unchanged levels of CXCR4 in circulating blood lymphocytes, CXCR4 and CXCL12 were found prominently in the skin and kidney, suggesting that the ultimate destinations of CXCR4(+) cells include these areas. CXCR4 antagonists have been explored in murine lupus models, in which disease severity and nephritis significantly improved. While clinical trials of CXCR4 antagonists in SLE have yet to be initiated, these inhibitors appear to have the potential to improve disease prognosis in severe lupus patients, particularly those with lupus nephritis.

42: Oral oncology, 2009 Nov, 45(11)
Lipopolysaccharides increase the amount of CXCR4, and modulate the morphology and invasive activity of oral cancer cells in a CXCL12-dependent manner.

[Abstract]Recently, it has been reported that bacterial infections play an important role in the development of cancers of the upper aero digestive tract. To examine the influence of bacterial infections on oral cancer, human oral carcinoma T3M-1 cells were treated with lipopolysaccharide (LPS) for 24 h as a model of infection. The LPS treatment increased the mRNA expression of CXCR4 and invasiveness in T3M-1 cells stimulated with CXCL12. The Rho family of small guanosine triphosphatases regulates the dynamics of the actin cytoskeleton that underlie cellular functions such as cell shape changes, migration and polarity. In T3M-1 cells treated with LPS and stimulated with CXCL12, Rac and Cdc42 were activated and caused an increase in the development of filopodia. The present findings suggest that bacterial infections enhance the invasiveness of T3M-1 cells via CXCL12/CXCR4 interaction and Cdc42-activation. Furthermore, filopodia are critical to this process.

43: Steroids, 2009 Nov-Dec, 74(13-14)
Estrogen-induced stromal cell-derived factor-1 (SDF-1/Cxcl12) expression is repressed by progesterone and by Selective Estrogen Receptor Modulators via estrogen receptor alpha in rat uterine cells and tissues.

[Abstract]Endometriosis, defined as the presence of endometrial glands and stroma at extra-uterine sites, is a gynecological condition that affects women of reproductive age. Consistent with its uterine origins, endometriotic lesions and resulting symptoms are hormonally responsive. To investigate Progesterone Receptor (PR)-based therapies, we measured physiological endpoints and gene expression in rat models of uterine cell estrogenic activity. Estrogen-induced ELT-3 rat leiomyoma cell proliferation was significantly inhibited by progesterone (P4), while the antiprogestin RU486 or the Selective PR Modulator (SPRM) asoprisnil, did not block proliferation. Stromal cell-derived factor-1 (SDF-1/Cxcl12) gene expression was induced by estrogen, and was repressed by the Selective Estrogen Receptor Modulators (SERMs), the antiestrogen ICI 182,780, and P4, but not by RU486 or the ERbeta-selective ligand ERB-041. In ELT-3 cells, asoprisnil demonstrated partial PR agonism on SDF-1 gene repression. Magnetic Resonance Imaging was used to monitor development of ectopic cysts in a rat surgical model of endometriosis. SERMs and P4 significantly decreased cyst volumes comparably by approximately 60%. However, ERB-041 and asoprisnil had no effect on cyst volume, and RU486 increased cyst volume by 20%. SDF-1 expression was modestly, but significantly, increased in the cyst compared to eutopic uterus, and P4 and raloxifene could repress the expression. We showed that SDF-1 was similarly regulated in human cells. These data suggest that transcriptional regulation of SDF-1 is a surrogate marker of estrogenic activities via ERalpha in rat uterine cells, and that SDF-1 repression by PR agonists can predict the ability to oppose the actions of estrogen in vivo.

44: Biochemical and biophysical research communications, 2009 Oct 16, 388(2)
PI3Kgamma activation by CXCL12 regulates tumor cell adhesion and invasion.

[Abstract]Tumor dissemination is a complex process, in which certain steps resemble those in leukocyte homing. Specific chemokine/chemokine receptor pairs have important roles in both processes. CXCL12/CXCR4 is the most commonly expressed chemokine/chemokine receptor pair in human cancers, in which it regulates cell adhesion, extravasation, metastatic colonization, angiogenesis, and proliferation. All of these processes require activation of signaling pathways that include G proteins, phosphatidylinositol-3 kinase (PI3K), JAK kinases, Rho GTPases, and focal adhesion-associated proteins. We analyzed these pathways in a human melanoma cell line in response to CXCL12 stimulation, and found that PI3Kgamma regulates tumor cell adhesion through mechanisms different from those involved in cell invasion. Our data indicate that, following CXCR4 activation after CXCL12 binding, the invasion and adhesion processes are regulated differently by distinct downstream events in these signaling cascades.

45: Neuropharmacology, 2010 Jan, 58(1)
Differential regulation of CXCL12 and PACAP mRNA expression after focal and global ischemia.

[Abstract]Pituitary adenylate cyclase activating peptide (PACAP) and the chemokine stromal cell-derived factor (SDF-1) have been implicated in neuroprotection, neurogenesis, and regeneration. Focal ischemia is associated with rapid upregulation of PACAP in perifocal neurons and delayed induction of SDF-1 in hypoxic/ischemic tissues, the latter process being involved in the recruitment of stem cells and inflammatory cells. Here, we studied mRNA patterns of PACAP, SDF-1 and the cognate receptors PAC1 and CXCR4 by in situ hybridization in the rat hippocampus after transient global ischemia, a rat model for programmed death of CA1 pyramidal neurons. Cell death in CA1 was not associated with local induction of PACAP and SDF-1 expression or recruitment of CXCR4-expressing infiltrates. However, there was a transient, almost complete loss of SDF-1 expression in microvessels in all hippocampal regions. Granule cells transiently showed a decrease of SDF-1 and an increase of PACAP expression. While PAC1 mRNA was moderately decreased throughout the hippocampus, CXCR4 expression was selectively increased in the subgranular layer. We propose that altered PACAP and SDF-1 gene expression in granule cells plays a role in regulated neurogenesis after global ischemia. The finding that programmed neuronal death after global ischemia was not associated with SDF-1 upregulation or recruitment of CXCR4-expressing cells is in sharp contrast to SDF-1/CXCR4-mediated infiltration of infarct tissue after focal ischemia. Hence, the different modes of neuronal death after focal and global ischemia are associated with distinct SDF-1 and PACAP gene regulation patterns and distinct reorganization mechanisms.

46: European journal of cancer (Oxford, England : 1990), 2009 Sep, 45(14)
CXCL12/SDF1 expression by breast cancers is an independent prognostic marker of disease-free and overall survival.

[Abstract]The cytokine C-X-C motif chemokine 12 (CXCL12) is synthesised by metastasis target tissues and has been shown to attract tumour cells that express the receptor, C-X-C chemokine receptor type 4 (CXCR4). However, epigenetic silencing of CXCL12 has recently been reported to increase the metastatic potential of breast cancer cells and the reintroduction of the cytokine gene into MDA-MB-231 breast carcinoma cells decreases the number of metastases formed in vivo. We therefore wished to know whether CXCL12 expression correlates with relapse-free and overall survival in human breast cancer patients. The expression of C-X-C motif chemokine 12 (CXCL12) and C-X-C chemokine receptor type 4 (CXCR4) was analysed in 100 archival breast cancer samples by immunohistochemistry and in two breast cancer microarray datasets of 408 cases. Data were analysed by univariate and multivariate COX regression analyses. CXCL12 and CXCR4 are expressed by epithelial tumour cells and by stromal and endothelial cells. Microarray gene expression analysis and immunohistochemistry revealed that expression of CXCL12 but not of CXCR4 significantly correlates with disease-free and overall survival in oestrogen receptor-positive and -negative cancers. The expression of the oestrogen receptor alpha and that of CXCL12 do not correlate. CXCL12 is a strong, independent prognostic marker. We propose that saturation of the receptor through autocrine CXCL12 production reduces chemotaxis towards CXCL12-releasing metastasis target tissues.

47: Cancer biology & therapy, 2009 Sep, 8(17)
CXCL12, CXCR4 and CXCR7 expression in brain metastases.

[Abstract]Brain metastases occur in about 25% of patients who die of cancer. The most common sources of brain metastases in adults are lung, breast, kidney, colorectal cancer and melanoma. The chemokine/receptor system CXCL12/CXCR4 plays a key role in multiple biological functions; among these, homing of neoplastic cells from the primary site to the target and metastasis progression. Recently, an alternative CXCL12 receptor CXCR7 has been discovered. The aim of our study was to investigate the expression of CXCL12 and its receptors CXCR4 and CXCR7 by immunohistochemistry in 56 patients with metastatic brain disease from different non-CNS primary tumors and evaluate their prognostic relevance as well as that of other patient/treatment-related features on patient survival. CXCL12 showed an expression in tumor cells and in tumor vessels; CXCR7 was expressed by tumor and endothelial cells (both within the tumor and in the adjacent brain tissue), while CXCR4 showed a positivity in all samples with a nuclear pattern. Among the investigated immunohistochemical parameters, only CXCL12 expression in tumor endothelial cells showed a statistically significant correlation with shorter survival (p = 0.04 log-rank), perhaps identifying more aggressive tumors. Thus, this is the first study evaluating at the same time the expression of CXCL12 and its two receptors in a cohort of brain metastases.

48: Journal of leukocyte biology, 2009 Sep, 86(3)
Requirement of HMGB1 for stromal cell-derived factor-1/CXCL12-dependent migration of macrophages and dendritic cells.

[Abstract]HMGB1 finely tunes the function of DCs, thus influencing their maturation program and eventually the establishment of adaptive, T cell-dependent immune responses. Moreover, it promotes the up-regulation of receptors for lymph node chemokines, regulates the remodeling of the cytoskeleton of migrating cells, and sustains their journey to secondary lymphoid organs via a RAGE-dependent pathway. The inflammatory properties of HMGB1 depend at least partially on the ability to complex with soluble moieties, including nucleic acids, microbial products, and cytokines. Here, we show that bone marrow-derived mouse DCs release HMGB1 during CXCL12-dependent migration in vitro. Macrophages share this property, suggesting that it may be a general feature of CXCL12-responsive leukocytes. The chemotactic response to rCXCL12 of DCs and macrophages abates in the presence of the HMGB1 antagonist BoxA. HMGB1 secreted from DCs and macrophages binds to CXCL12 in the fluid phase and protects the chemokine conformation and function in a reducing environment. Altogether, our data indicate that HMGB1 release is required for CXCL12 ability to attract myeloid-derived cells and reveal a functional interaction between the two molecules that possibly contributes to the regulation of leukocyte recruitment and motility.

49: Leukemia research, 2009 Sep, 33(9)
SDF1/CXCL12 (-801GA) polymorphism is a prognostic factor after treatment initiation in Waldenstrom macroglobulinemia.

[Abstract]The interaction of the chemokine CXCL12 with CXCR4 regulates homing of tumoral cells in bone marrow in Waldenstrom macroglobulinemia (WM). We assessed the distribution and the clinical influence of the CXCL12 (-801GA) polymorphism using PCR RFLP in a series of 114 WM patients. CXCL12 (-801AA) genotype was more frequent in WM patients compared with control subjects (p = 0.01). On the other hand, CXCL12 (-801GG) patients had a shorter median survival after initiation of first line therapy than remaining patients (p = 0.01). In conclusion, the CXCL12 (-801GA) polymorphism may either be associated with a high incidence of WM or influence clinical outcome.

50: Anatomical science international / Japanese Association of Anatomists, 2009 Sep, 84(3)
Role of the CXCL12/CXCR4 axis in milky spots of rats bearing ascitic-type hepatoma.

[Abstract]Rat ascitic-type hepatoma AH7974 cells express CXCR4 mRNA and protein at high levels and also show vigorous migratory responses to its ligand CXCL12. We have shown that AMD3100 (a specific CXCR4 antagonist) effectively reduced tumor invasion into the milky spot in Sprague-Dawley rats inoculated with AH7974 cells. A histological analysis revealed that the milky spots from AMD3100-treated rats were both smaller and consisted of fewer constituent cells and blood vessels than those from the AH7974 inoculated rats. Alkaline phosphatase staining also showed a statistically significant reduction in the area of the milky spots in the AMD3100-treated rats in comparison to the AH7974 inoculated rats (P < 0.0001). Green fluorescence protein (GFP)-tagged AH7974 cells were constructed to detect the localization of the tumor cells in the milky spots. There were fewer GFP-tagged AH7974 cells in the AMD3100-treated rats than in the AH7974 inoculated rats. The number of eosinophils and mast cells increased in the milky spots of AH7974-inoculated rats, and angiogenesis was also seen. In comparison, both cell proliferation and angiogenesis were inhibited in the milky spots of the AMD3100-treated rats. Collectively, our results strongly suggest that the CXCR4/CXCL12 axis plays an important role in the development of peritoneal carcinomatosis. As such, CXCR4 may be a potential therapeutic target for peritoneal carcinomatosis.

51: Zhong xi yi jie he xue bao = Journal of Chinese integrative medicine, 2009 Feb, 7(2)
[Effects of Feiyanning formula on expressions of mRNAs and proteins of CXCL12 and CXCR4 in mice with Lewis tumors.]

[Abstract]Objective: To observe the effects of Feiyanning (FYN) formula, a compound traditional Chinese herbal medicine, on the expressions of CXCL12 and CXC chemokine receptor 4 (CXCR4) mRNAs and proteins in Lewis tumors in C57 mice. Methods: A total of 24 C57BL-6 mice were used in this study. Lewis cells were subcutaneously injected to the right armpit to establish the tumor-bearing model. The C57 mice bearing Lewis tumor were randomly divided into untreated group, chemotherapy group, FYN group and chemotherapy plus FYN group. Reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry were employed to measure the expressions of CXCL12 and CXCR4 mRNAs and proteins in Lewis tumors in C57 mice respectively. Results: The rates of lung cancer metastasis in the FYN group and the chemotherapy plus FYN group were markedly lower than that in the untreated group or the chemotherapy group. The expressions of CXCL12 and CXCR4 mRNAs and proteins appeared in tumor tissue in the untreated group. Although there was no significant difference in the expressions of mRNA and protein of CXCL12 among all groups (P>0.05), the expressions of mRNA and protein of CXCR4 in the untreated group and the chemotherapy group were markedly lower than those in the FYN group and the chemotherapy plus FYN group (P<0.05). Conclusion: FYN can inhibit the metastasis of Lewis tumor loaded in C57 mice. Its mechanisms may be related to its down-regulation of the expression of chemokine receptor CXCR4, and affecting the role of CXCL12-CXCR4 biological axis.

52: International journal of oncology, 2009 Mar, 34(3)
Expression of CXCL12 on pseudopalisading cells and proliferating microvessels in glioblastomas: An accelerated growth factor in glioblastomas.

[Abstract]CXCL12, an alpha-chemokine that binds to G-protein-coupled CXCR4, plays an important and unique role in the regulation of stem/progenitor cell trafficking. To elucidate the correlation between the CXCR4/CXCL12 axis and glioblastomas (GBs), the present study assessed CXCR4/CXCL12 expression in 44 astrocytic tumor tissues using immunohistochemical analyses. Several cell lines of brain tumors were also analyzed by RT-PCR analyses. Although low-grade, astrocytic tumors were rarely positive for CXCL12 immunohistochemically, all GBs showed moderate to intense immunostaining with CXCL12, with particularly intense immunostaining being observed in the pseudopalisading cells and the proliferating microvessels. Regarding CXCR4, widespread positive immunoreactivity was noted in the tumor cells in almost all cases of GBs. In contrast, RT-PCR analysis showed low expression of CXCR4/CXCL12 in the aerophilic condition of GB cells and high expression of CXCR4/CXCL12 in the hypoxic condition of GB cells. Taken together, these results suggest that secretion of CXCR4/CXCL12 by hypoxic pseudopalisading and proliferating microvascular cells contributes to an outward migration of tumor cells away from hypoxia, creating a peripherally moving wave and subsequent microvascular proliferation. Pseudopalisades and proliferating microvessels are also considered to be associated with accelerated growth in GBs. These results indicate that expression of CXCL12 is an accelerated growth factor in GBs.

53: Clinical & experimental metastasis, 2009, 26(3)
The CXCR4/CXCL12 axis in endometrial cancer.

[Abstract]Chemokines and their receptors seem to act as important regulators of the metastatic cascade. CXCL12 and its receptor CXCR4 were shown to be involved in human cancer progression. There is increasing evidences suggesting that the expression of CXCR4 in human cancers is correlated with poor patient prognosis and that CXCR4 neutralization can prevent metastases in vivo. Here we tested the role of the CXCR4/CXCL12 axis in a neoplasia with a reduced risk of metastatic progression, such as human endometrial cancer. CXCR4 and CXCL12 mRNA expression was measured in 41 endometrial cancers and in corresponding not affected tissues. The expression of CXCR4 was predominant in endometrial cancer (P = 0.035) whereas CXCL12 was overexpressed in normal mucosae (P = 0.002). CXCR4 expression (P = 0.035), but not CXCL12, was significantly related to cancer differentiation. Endometrial cancer cells (HEC1A) were able to generate diffuse metastases in peritoneum, lung and liver of CD-1 nude mice, but the simultaneous treatment with a neutralizing anti-CXCR4 monoclonal antibody dramatically reduced the number and the size of metastases in the animals. In conclusion, our data seem to indicate that the CXCR4-CXCL12 axis can play a role in the progression of endometrial carcinoma and that specific therapies with antagonists of chemokines receptors could be of help in the treatment of metastatic patients.

54: Omics : a journal of integrative biology, 2009 Jan 23, 37 Suppl 2(3)
Combinational Polymorphisms of Seven CXCL12-Related Genes Are Protective against Breast Cancer in Taiwan.

[Abstract]Abstract Many single nucleotide polymorphisms (SNPs) have been found to be associated with breast cancer, but their SNP interactions are seldom addressed. In this study, we focused on the joint effect for SNP combinations of seven CXCL12-related genes involved in major cancer-related pathways. SNP genotyping was determined by PCR-restriction fragment length polymorphism (RFLP) in this study (case = 220, control = 334). Different numbers of combinational SNPs with genotypes called the SNP barcodes from different chromosomes were used to evaluate their joint effect on breast cancer risk. Except for vascular endothelial growth factor (VEGF) rs3025039-CT, none of these SNPs were found to individually contribute to breast cancer risk. However, for two combined SNPs, the proportion of subjects with breast cancer was significantly low in the SNP barcode with CC-GG genotypes in rs2228014-1801157 (CXCR4-CXCL12) compared to those with non-CC-GG genotypes. Similarly, the SNP barcode of rs12812942-rs2228014-rs3025039 (CD4-CXCR4-VEGF) and rs12812942-rs3136685-rs2228014-rs1801157 (CD4- CCR7-CXCR4-CXCL12) with specific genotype patterns (AT-CC-CC and AT-AG-CC-GG) among three and four combinational SNPs were significantly low in breast cancer occurrence. More SNP combinations larger than five SNPs were also addressed, and these showed similar effects. After controlling for age, and comparing their corresponding non-SNP barcodes, the estimated odds ratios for breast cancer ranged between 0.20 and 0.71 for specific SNP barcodes with two to seven SNPs. In conclusion, we have associated the potential combined CXCL12-related SNPs with genotypes that were protective against breast cancer, and that may contribute to identification of a low-risk population for the development of breast cancer.

55: Chinese medical journal, 2009 Jan 20, 122(2)
Chemokine stromal cell-derived factor 1/CXCL12 increases homing of mesenchymal stem cells to injured myocardium and neovascularization following myocardial infarction.

[Abstract]BACKGROUND: Heart failure due to ischemic heart disease is still a major health problem. Myocardium regeneration emerges as a novel therapeutic method for treating myocardial infarction (MI). However, it is affected by many factors. The present study was aimed to investigate the effect of chemokine stromal cell-derived factor 1 (SDF-1)/CXCL12 on mesenchymal stem cells (MSCs) homing to injured myocardium in a rat myocardial infarction model. METHODS: A rat myocardial infarction model was established by permanent left anterior descending branch ligation. Mesenchymal stem cells from donor rats were cultured in IMDM and labeled with bromodeoxyuridine. The rats were divided into two groups. SDF-1 expression was measured by in situ hybridization and immunohistochemistry in the sham operated or infarcted hearts at 1, 2, 4, 7, 14 and 28 days post operation in the SDF-1 detection group. The rats in the intervention groups were injected with SDF-1, anti-SDF-1 antibody or saline 4 days after myocardial infarction. Then, a total of 5 x 10(6) cells in 2.5 ml of phosphate-buffered saline were injected through the tail vein. The number of the labeled MSCs in the infarcted hearts was counted on the 3rd day post injection. Cardiac function and blood vessel density were assessed on the 28th day post injection. RESULTS: Self-generating SDF-1 expression was increased at the first day post MI, peaked at the 7th day and decreased thereafter while it remained unchanged in sham operated hearts. The MSCs enrichment in the host hearts were more abundant in the MI groups than in the non-MI group (P = 0.000); the MSCs enrichment in the host hearts were more abundant in the SDF-1 injected group than in the anti-SDF-1 antibody and saline injected groups (P = 0.000). Cardiac function was improved more in the SDF-1 injected group than in the anti-SDF-1 antibody and saline injected groups (P = 0.000). Neovascularization in the SDF-1 injected group increased significantly compared to the other groups (P = 0.000). CONCLUSION: Myocardial SDF-1 expression was increased only in the early phase post MI. SDF-1 may enhance MSCs homing to the injured heart and improve cardiac function by promoting neovascularization.

56: Journal of medical primatology, 2008 Dec, 37 Suppl 2(3)
Association between decreased CXCL12 and CCL25 expression and increased apoptosis in lymphoid tissues of cynomolgus macaques during SIV infection.

[Abstract]BACKGROUND: Chemokines likely play multiple roles in HIV-1 and SIV pathogenesis. To examine potential associations between chemokine expression levels and apoptosis of cells in lymphoid tissues during SIV infection, we measured chemokine and cytokine mRNA levels in multiple lymphoid tissues compartments from uninfected and SIV-infected cynomolgus macaques (Macaca fascicularis). METHODS: Real-time RT-PCR was used to measure host mRNA levels in macaque lymphoid tissues. Proliferating or apoptotic cells were identified in lymphoid tissues by immunohistochemistry. RESULTS: We found that CXCL12 and CCL25 mRNAs in SIV-infected lymphoid tissues were decreased and their levels were negatively correlated with the numbers of proliferating and apoptotic cells. In vitro analyses revealed that CXCL12 and CCL25 were capable of reducing apoptosis induced by SIV infection. CONCLUSIONS: These findings suggest that increased apoptosis in lymphoid tissues due to reduced levels of anti-apoptotic chemokines might be a mechanism that contributes to loss of immune function following pathogenic SIV infection.

57: Clinical & experimental metastasis, 2010 Feb, 27(2)
Role of the CXCR4/CXCL12 signaling axis in breast cancer metastasis to the brain.

[Abstract]Breast cancer is the most common malignancy and second leading cause of cancer death in women. Ninety percent of mortality in breast cancer is often associated with metastatic progression or relapse in patients. Critical stages in the development of aggressive breast cancer include the growth of primary tumors and their ability to spread to foreign organs and form metastases, as well as the establishment of an independent blood supply within the new tumors. Hence, it is imperative to characterize the key molecules that regulate the metastasis of human breast cancer cells. The expression of CXCR4/CXCL12 in breast tumors has been correlated with a poor prognosis, increased metastasis, resistance to conventional therapeutic agents and a poor outcome in the pathogenesis of breast cancer. However, effective anti-CXCR4 therapy remains a challenge. Here, we will review the putative involvement of the CXCR4/CXCL12 signaling axis in breast cancer metastasis to the brain. Characterization of signaling events important for breast cancer cell growth and their metastasis to the brain should provide insights into breast cancer therapies and improved, successful treatments for breast cancer.


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