Differential Expression Of CXCR4 Research Articles

Interplay between CXCR4 and CCR2 regulates bone marrow exit of dendritic cell progenitors

Conventional dendritic cells (cDCs) are found in most tissues and play a key role in initiation of immunity. cDCs require constant replenishment from progenitors called pre-cDCs that develop in the bone marrow (BM) and enter the blood circulation to seed all tissues. This process can be markedly accelerated in response to inflammation (emergency cDCpoiesis). Here, we identify two populations of BM pre-cDC marked by differential expression of CXCR4. We show that CXCR4lo cells constitute the migratory pool of BM pre-cDCs, which exits the BM and can be rapidly mobilized during challenge. We further show that exit of CXCR4lo pre-cDCs from BM at steady state is partially dependent on CCR2 and that CCR2 upregulation in response to type I IFN receptor signaling markedly increases efflux during infection with influenza A virus. Our results highlight a fine balance between retention and efflux chemokine cues that regulates steady-state and emergency cDCpoiesis.

Bone Marrow (BM) Delivery of Genetically-Modified (gm) Adult CD34+ Hematopoietic Stem and Progenitor Cells (HSPC) Improves Homing and Engraftment of Short-Term Progenitors over Long-Term Repopulating Hematopoietic Stem Cells

Gene therapy/editing of CD34+ HSPC ex vivo, followed by their transplantation, can cure a variety of hematologic diseases. However, a substantial loss of HSPC occurs from collection to transplant. Losses occur during processing for HSPC enrichment, ex vivo genetic manipulation and culture, formulation, and testing prior to transplant. Further, HSPC are lost to peripheral organs during homing when delivered intravenously (IV), reducing the effective gm HSPC dose; a loss compounded by the lack of helper cells that aid in the homing and engraftment process which are removed during enrichment. Direct BM delivery of gm HSPC can overcome some of these limitations. This has been tried previously, with non-enriched whole cord blood (CB) and non-gm HSPC, with conflicting results. We hypothesized that BM delivery of a limited dose of gm adult HSPC would improve long-term repopulation over that of IV delivery by bypassing HSPC loss during homing. Using bioluminescent imaging, we determined that CB HSPC transduced with a luciferase lentiviral vector (LV) delivered by intra-femoral (IF) injection localized to the injected femur, validating our injection method. Next, we delivered mobilized peripheral blood (MPB) HSPC transduced with a GFP LV into irradiated NOD.LtSz-scid IL2rg -/- (NSG) mice via IV or IF injection in limiting dilution. Total human engraftment (hCD45+ cells), transduced human engraftment (hCD45+GFP+ cells), and multi-lineage engraftment were measured in the BM at 3- and 6-months post-transplant. HSPC gave rise to a bi-lineage (B-myeloid) graft at 3 months, suggesting hematopoietic progenitor cell (HPC) engraftment, and a multi-lineage graft (hCD33+, hCD19+, hCD3+, and hCD34+ cells) at 6 months, suggesting engraftment from a long-term repopulating cell or hematopoietic stem cell (HSC). At 3 months, IF delivery of HSPC resulted in significantly higher total and transduced human cell engraftment, measured in the non-injected femur (Table 1). The engraftment was bi-lineage. At 6 months, IF delivery of HSPC no longer significantly increased engraftment over IV delivery (Table 1). However, a multi-lineage graft was present, indicating full hematopoietic repopulation. There was no significant difference in the lineage output between either delivery method at 3 or 6 months. These data suggest that HPC homed and engrafted more efficiently than HSC, when delivered IF. Alternatively, IF delivery altered the BM microenvironment, allowing preferential homing of HPC. However, CD34- cells injected IF, to simulate pressure and passage of cells through the BM with IF delivery, followed by IV delivery of CD34+ cells (sham IF with IV HSPC delivery) resulted in similar homing patterns to CD34+ cells delivered IV (p=0.1, Figure 1A), suggesting that differences between IV and IF delivery were likely due to cell-intrinsic rather than cell-extrinsic differences between HPC and HSC. To study the mechanism of preferential engraftment of HPC over HSC with IF delivery, we analyzed expression of the major homing receptors CXCR4 and VLA-4 on HPC and HSC. CXCR4 (Figure 1B) and VLA-4 were both expressed at significantly higher levels on HPC than on HSC (CXCR4 p<0.01; VLA-4 p<0.05) and their expression increased with increasing culture time and with HSPC cycling. However, VLA-4 expression was significantly increased in GFP+ (MFI 65313 ± 4750) compared to GFP- (MFI 48969 ± 2099; p<0.01) HSPC. CXCR4 expression was similar in both GFP+ (MFI 4261 ± 189) and GFP- (MFI 5245 ± 1186) HSPC, mimicking the in vivo engraftment pattern of GFP+ and GFP- cells, suggesting that CXCR4 may be the molecule responsible for enhancing HPC homing and engraftment with BM delivery. An initial experiment shows that when we remove the high CXCR4 expressing CD34+38+ HPC and deliver HSC-enriched CD34+38- cells IV or IF, IF delivery results in higher long-term engraftment (additional experiments ongoing, Figure 1C, D). These data support the hypothesis that cell-intrinsic differences in the homing behavior of HSC and HPC is likely due to their differential expression of CXCR4. Studies underway on blockade of CXCR4 or VLA-4 on gm HPC and/or gm HSC followed by their IF or IV delivery will be presented. Overall, we show IV delivery of gm HSPC is comparable to BM delivery. However, as HSC-enriched cells become clinically available for genetic therapies, BM delivery of enriched gm HSC may result in superior engraftment. Disclosures Malik: Aruvant Sciences, Forma Therapeutics, Inc.: Consultancy; Aruvant Sciences, CSL Behring: Patents & Royalties.

Inherent engraftment differences between CD45.1 and CD45.2 HSCs are caused by differential expression of Cxcr4

Inherent engraftment differences between CD45.1 and CD45.2 HSCs are caused by differential expression of Cxcr4

Differential expression of CXCR4 and CXCR7 with various stem cell markers in paired human primary and recurrent glioblastomas.

The chemokine CXCL12 (also termed SDF-1, stromal cell-derived factor-1) and its receptors CXCR4 and CXCR7 are known to play a pivotal role in tumor progression including glioblastomas (GBM). Previous investigations focused on the expression and functional roles of CXCR4 and CXCR7 in different GBM cell subpopulations, but comparative analysis in matched primary versus recurrent GBM samples are still lacking. Thus, here we investigated the expression of CXCR4 and CXCR7 on mRNA and protein level using matched primary and recurrent GBM pairs. Additionally, as GBM CXCR4-positive stem-like cells are supposed to give rise to recurrence, we compared the expression of both receptors in primary and recurrent GBM cells expressing either neural (MUSASHI-1) or embryonic stem cell markers (KLF-4, OCT-4, SOX-2, NANOG). We were able to show that both CXCR4 and CXCR7 were expressed at considerable mRNA and protein levels. CXCR7 was downregulated in relapse cases, and different groups regarding CXCR4/CXCR7 expression differences between primary and recurrent samples could be distinguished. A co-expression of both receptors was rare. In line with this, CXCR4 was co-expressed with all investigated neural and embryonic stem cell markers in both primary and recurrent tissues, whereas CXCR7 was mostly found on stem cell marker-negative cells, but was co-expressed with KLF-4 on a distinct GBM cell subpopulation. These results point to an individual role of CXCR4 and CXCR7 in stem cell marker-positive GBM cells in glioma progression and underline the opportunity to develop new therapeutic tools for GBM intervention.

Expression of chemokines and chemokine receptors in brain tumor tissue derived cells.

Chemokine and chemokine receptor expression by tumor cells contributes to tumor growth and angiogenesis and thus these factors may be considered as tumor markers. Here we aimed to characterize cells directly extracted from glioma, meningioma, and secondary brain tumors as well as non-tumoral cells in vitro. Cells were isolated from brain tissues using 0.2% collagenase and characterized by flow cytometry. Expression of SDF-1, CXCR4, CXCR7, RANTES, CCR5, MCP-1 and IP-10 was defined using flow cytometry and qRT-PCR methods. Brain tissue isolated cells were observed as spindle-shaped cell populations. No significant differences were observed for expression of SDF-1, CXCR4, CXCR7, RANTES, CCR5, and IP-10 transcripts. However, the expression of CXCR4 was approximately 13-fold and 110-fold higher than its counterpart, CXCR7, in meningioma and glioma cells, respectively. CXCR7 was not detectable in secondary tumors but CXCR4 was expressed. In non tumoral cells, CXCR7 had 1.3-fold higher mRNA expression than CXCR4. Flow cytometry analyses of RANTES, MCP- 1, IP-10, CCR5 and CXCR4 expression showed no significant difference between low and high grade gliomas. Differential expression of CXCR4 and CXCR7 in brain tumors derived cells compared to non-tumoral samples may have crucial impacts on therapeutic interventions targeting the SDF-1/CXCR4/CXCR7 axis.

Expression patterns of SDF1/CXCR4 in human invasive breast carcinoma and adjacent normal stroma: Correlation with tumor clinicopathological parameters and patient survival

SDF-1/CXCR4 axis is involved in various steps of breast tumorigenesis such as tumor growth, angiogenesis and metastasis. The goal of the present study is to demonstrate in detail the immunohistochemical distribution of SDF-1 and CXCR4 in invasive breast carcinomas and identify possible correlation of their expression patterns with clinicopathological parameters and patients survival. We investigated the immunoexpression of CXCR4 and SDF1 in 76 invasive breast carcinomas. Both SDF-1 and CXCR4 had statistically significant higher expression in carcinomas compared with adjacent normal breast tissue. Furthermore the expression of CXCR4 in intratumoral fibroblasts had a positive correlation with overall and disease-free survival, while SDF1 membranous immunopositivity in normal breast epithelial cells was a risk factor for relapse. In addition, expression of SDF1 in fibroblasts of normal breast tissue was positively associated with tumor grade. Overall, our results suggest that the differential expression of CXCR4 in intratumoral stroma and SDF1 in adjacent normal mammary cells may predict clinical outcome in breast cancer patients.

Differential Expression of CXCL12 and CXCR4 During Human Fetal Neural Progenitor Cell Differentiation

Stromal cell-derived factor 1 alpha (SDF-1alpha, CXCL12) and its receptor CXCR4 play an important role in the central nervous system (CNS) development and adulthood by mediating cell migration, enhancing precursor cell proliferation, assisting in neuronal circuit formation, and possibly regulating migration during repair. The expression pattern of CXCR4 and CXCL12 during neurogenesis has not been thoroughly elucidated. In this study, we investigated the expression of CXCL12 and CXCR4 during neural progenitor cells (NPC) differentiation by microarray analysis and reverse transcriptase-polymerase chain reaction (RT-PCR) using human fetal NPC as a model system. The production of CXCL12 was measured by enzyme-linked immunosorbent assay (ELISA). CXCR4 expression was determined by florescence-activated cell sorting (FACS) analysis, immunocytochemical staining, and CXCR4-mediated inhibition of cyclic AMP (cAMP) accumulation. Our data demonstrated that CXCR4 expression is significantly upregulated when NPC are differentiated into neuronal precursors, whereas CXCL12 is upregulated when differentiated into astrocytes. We also provide evidence that CXCR4 localization changes as neurons mature. In neuronal precursors, CXCR4 is localized in both neuronal processes and the cell body, whereas in mature neurons, it is primarily expressed on axons and dendrites. This differential expression of CXCR4 and CXCL12 may be important for the temporal regulation of neuronal migration and circuit formation during development and possibly in adult neurogenesis and repair.

Differential Expression of CXCR4 Is Associated with the Metastatic Potential of Human Non–Small Cell Lung Cancer Cells

To evaluate the relation between CXCR4 expression and the presence of metastatic disease in human non-small cell lung cancer (NSCLC) patients and investigate whether modulation of CXCR4 expression could serve as a potential pathway in preventing metastasis of NSCLC. CXCR4 expression in 36 patients with NSCLC and 10 normal lung tissues was detected by real-time PCR and immunohistochemistry. CXCR4 expression in two human NSCLC clones (95C and 95D) with different metastatic potential was determined by real-time PCR and flow cytometry. 95C and 95D cells were transfected with the plasmid DNA containing CXCR4 coding gene or CXCR4 antisense nucleotide fragment, respectively, and the effects on in vitro cell migration, invasion, and adhesion and in vivo metastasis were measured. Up-regulated expression of CXCR4 was detected in 34 tumors, which were further divided into 17 high expression cancers and 17 low expression cancers by their staining intensities. High CXCR4 tumors (13 of 17) were more prone to clinical metastasis in comparison with low expression tumors. CXCR4 was differentially expressed in 95C and 95D cells with low or high metastatic potential, and the surface expression of CXCR4 were 50% up-regulated or down-regulated following the stable transfection. The metastatic potential of NSCLC in vitro, such as migration, invasion, and adhesion, were significantly enhanced or impaired. In addition, neutralizing the interactions of stromal cell-derived factor-1/CXCR4 in vitro with CXCR4-specific antibodies inhibited the CXCR4-dependent migration, invasion, and adhesion. Furthermore, s.c. inoculation of lung cancer cells with low expression of CXCR4 in nude mice showed 0- to 2-fold decrease in lung metastatic foci than that with high expression of CXCR4. Differential expression of CXCR4 is associated with the metastatic potential of human NSCLC, raising the possibility that blockade of CXCR4/stromal cell-derived factor-1 interaction may lead the way to design novel therapeutic tools for the treatment of metastatic NSCLC patients.

Cytokine Induced Changes in the Hematopoietic Stem Cell Trafficking Regulatory Peptidase CD26.

Hematopoietic stem cell transplantation (HSCT) serves as a successful treatment option for patients with malignant or non-malignant severe hematologic diseases. However, large numbers of transplantable donor cells are needed and patient survival is compromised when donor cell numbers are limited, as is the case when umbilical cord blood (CB) donor cells are utilized as a donor source for transplantation into adult patients. Given that CB is readily available, has a lower histocompatibility requirement, and has a reduced risk of graft vs. host disease (GVHD) there are advantages to utilizing CB for HSCT, in particular when an appropriate matched donor is not available. However, in the majority of cases potential recipients have been confined to children because in adults, the amount of CB collected appears to be a limiting factor. Given the promise of CB for HSCT there is significant potential and application for improvements in the efficiency of Hematopoietic Stem Cell (HSC) trafficking to the bone marrow (BM) in both scenarios. To facilitate our long term goal of improving HSCT efficiency, we have recently delineated a novel method by where the inhibition of peptidase CD26 on donor HSC and Progenitor Cells (HPC) increases the number of donor HSC/HPC trafficking to recipient's BM, resulting in a significant increase in HSC transplant efficiency.CD26 (DPPIV/dipeptidylpeptidase IV) is a membrane bound extracellular peptidase that cleaves dipeptides from the N-terminus of polypeptide chains. Natural substrates of CD26 protease activity include the pancreatic polypeptide family, the glucagon family, and the chemokine family. Since the removal of N-terminal amino acids from chemokines frequently result in significant changes in functional activity, proteolytic cleavage of chemokines has significant implications with respect to their ability to act on cells. We have previously shown that that suppression of CD26 activity, by the use of CD26 inhibitors or the use of CD26−/− donor cells, increases the efficiency of HSC/HPC settlement and growth in the transplanted recipient. This translates into an increase in overall recipient survival in mice.We report here the results of experiments that examine the ability of several cytokines to alter CD26 on the surface of CD34+CD38− phenotypically defined HSC/HPC from CB. HSC isolated from CB were treated with varying dilutions of either Stem Cell Factor (SCF/steel factor/kit ligand), Granulocyte-Colony Stimulating Factor (G-CSF), Granulocyte Macrophage-Colony Stimulating Factor (GM-CSF), Erythropoietin (EPO), or Trombopoietin (TPO) during culture in IMDM, 20% FBS, 37°C, 5%CO2 for 18 hours and then analyzed for changes in CD26. We observed significant dose dependent increases in the percentage of cells expressing CD26 and the amount of CD26 being expressed on each cell in samples treated with G-CSF, GM-CSF, and SCF as measured by multi-varient flow cytometric analysis. More modest changes in CD26 expression were observed during EPO and TPO treatment. Differential expression of CXCR4 was also noted. We feel these observations have important clinical implications with respect treatment of donor cells prior to transplantation and treatment of patients post HSCT.

Expression of CXCR4 predicts lymph node metastasis in early breast cancer

9525 Background: Recent experimental studies have suggested that interactions between the chemokine receptor CXCR4 and its ligand CXCL12 in host organs may play a role in breast cancer progression. There is currently no data if CXCR4 expression is associated with metastatic potential in early breast cancer. Therefore, we studied the differential expression of CXCR4 in small size lymph node positive and lymph node negative breast cancers to evaluate whether CXCR4 predicts metastasis to axillary lymph nodes. Methods: CXCR4 expression was evaluated on paraffin-embedded tissue sections obtained from patients with T1N0 (n=98) and T1N1 (n=99) breast cancer, using immunohistochemical staining. The intensity, staining percentage, and localization pattern (nuclear, cytoplasmic) were assessed, and positivity was categorized as follows: high cytoplasmic only versus others, and predominantly nuclear versus others. The expression patterns were correlated with lymph node status, and with other prognostic markers includ...

TCR-mediated activation of allergen-specific CD45RO(+) memory T lymphocytes results in down-regulation of cell-surface CXCR4 expression and a strongly reduced capacity to migrate in response to stromal cell-derived factor-1.

The selective migration of functional T(h) lymphocyte subsets with different cytokine production profiles into inflamed tissue is likely to depend on the state of activation of the cells, as well as on the differential expression of various adhesion molecules and chemokine receptors. In this study, we have analyzed the effect of allergen-specific activation on the expression of the chemokine receptor CXCR4 on T lymphocytes. We show that stimulation of peripheral blood mononuclear cells from atopic patients with the allergen Der p results in down-regulation of CXCR4 surface expression on Der p-activated CD25(+)CD45RO(+) antigen-specific memory cells which was caused by a decrease in CXCR4 gene transcription and did not seem to be mediated by endogenous cytokines, such as IFN-gamma. In contrast, however, CXCR4 surface expression was enhanced on naive CD25(-)CD45RO(-) and resting CD25(-)CD45RO(+) memory T cells, as a result of the presence of endogenous IL-4, most likely produced by Der p-activated memory T cells. Antigen-specific CD25(+)CD45RO(+) T lymphocytes, purified 7 days after stimulation with Der p, had a strongly reduced capacity to migrate in response to stimulation with stromal cell-derived factor (SDF)-1, the ligand for CXCR4. Together, these results suggest that differential expression of CXCR4 on activated and resting T cells is due to the counteracting effects of TCR-mediated down-regulation and IL-4-mediated up-regulation of this chemokine receptor respectively, and furthermore indicate that antigen-activated memory T cells are unlikely to migrate into inflamed tissue in response to SDF-1.