CXC Chemokine Receptor 4 Overexpression Research Articles

Stromal cell-derived factor-1 downregulation contributes to neuroprotection mediated by CXC chemokine receptor 4 interactions after intracerebral hemorrhage in rats.

Stromal cell-derived factor-1 (SDF-1) and CXC chemokine receptor 4 (CXCR4) have a substantial role in neuronal formation, differentiation, remodeling, and maturation and participate in multiple physiological and pathological events. In this study, we investigated the role of SDF-1/CXCR4 in neural functional injury and neuroprotection after intracerebral hemorrhage (ICH). Western blot, immunofluorescence and immunoprecipitation were used to detect SDF-1/CXCR4 expression and combination respectively after ICH. TUNEL staining, Lactate dehydrogenase assay, Reactive oxygen species assay, and Enzyme-linked immunosorbent assay to study neuronal damage; Brain water content to assay brain edema, Neurological scores to assess short-term neurological deficits. Pharmacological inhibition and genetic intervention of SDF-1/CXCR4 signaling were also used in this study. ICH induced upregulation of SDF-1/CXCR4 and increased their complex formation, whereas AMD3100 significantly reduced it. The levels of TNF-α and IL-1β were significantly reduced after AMD3100 treatment. Additionally, AMD3100 treatment can alleviate neurobehavioral dysfunction of ICH rats. Conversely, simultaneous SDF-1/CXCR4 overexpression induced the opposite effect. Moreover, immunoprecipitation confirmed that SDF-1/CXCR4 combined to initiate neurodamage effects. This study indicated that inhibition of SDF-1/CXCR4 complex formation can rescue the inflammatory response and alleviate neurobehavioral dysfunction after ICH. SDF-1/CXCR4 may have applications as a therapeutic target after ICH.

Natural polysaccharide-based smart CXCR4-targeted nano-system for magnified liver fibrosis therapy

Activated hepatic stellate cells (aHSCs), the main source of extracellular matrix deposition, are key targets in liver fibrosis. However, no effective drug specific to aHSCs has been clinically applied due to poor drug delivery efficiency. Herein, we designed a CXC chemokine receptor 4 (CXCR4)-targeted reactive oxygen species (ROS)-responsive platform AMD-Dex-ROS-responsive-sorafenib (ARS) based on natural polysaccharide and thioctic acid frame, which can deliver anti-fibrosis drug represented by sorafenib specifically to aHSCs on account of CXCR4 over-expression on aHSCs, and smartly disassemble via ROS-responsive thioketal rupture relying on high intracellular ROS in HSCs, realized on-demand drug release and effective liver fibrosis reversion. Notably, in this platform, the CXCR4 antagonist AMD3100 not only enhanced aHSCs targeting efficiency of sorafenib but also effectively magnified the aHSCs elimination of sorafenib by blocking stroma cell derived factor-1 (SDF-1)/CXCR4-induced aHSCs protection, resulting in synergistic anti-fibrosis effect. The platform provided a new approach for drug delivery system design and liver fibrosis treatment.

CXCR4 overexpression: An indicator of poor survival and predictor of response to immunotherapy in patients with metastatic colorectal cancer.

3546 Background: CXC-chemokine receptor 4 (CXCR4) is a ubiquitous chemokine receptor activated by the CXCL12 ligand and is implicated in tumor invasion, metastasis, and immune cell (IC) trafficking. High CXCR4 expression is associated with poor prognosis in colorectal cancer (CRC). < 10% of metastatic CRC cases harbor microsatellite instability (MSI-H) and demonstrate lower tumor mutation burden (TMB), decreased IC infiltration, and lack of response to current immunotherapy regimens. This study aims to interrogate the role of CXCR4 mRNA expression on the the tumor microenvironment (TME) and its prognostic and predictive value to tailor immunotherapeutic treatment strategies in CRC. Methods: A total of 15,026 CRC samples were analyzed using whole-exome sequencing, whole-transcriptome sequencing, and immunohistochemistry (Caris Life Sciences, Phoenix, AZ). Study cohort was stratified by CXCR4 mRNA expression levels in quartiles (Q1 (low) vs Q4 (high)). IC fraction was calculated by QuantiSeq, and real-world overall survival information was obtained from insurance claims data and calculated from tissue collection time to last day of contact. Statistical significance was determined using chi-square/Fisher-Exact and adjusted for multiple comparisons (q < 0.05). Results: Samples obtained from metastatic sites showed higher CXCR4 mRNA expression than those from primary tumors (22.7 vs 18.6 median transcripts per million (TPM), p < 0.001). CXCR4 mRNA expression was significantly lower in liver metastases than in non-liver metastases (21.2 vs 24.8 TPM, p < 0.001). Median CXCR4 mRNA expression was highest in the consensus molecular subtypes 4 (33.3 TPM) and lowest in 3 (13.0 TPM, p < 0.05). CXCR4 mRNA expression was positively associated with TMB-H, MSI-H/dMMR, and positive PD-L1 IHC status. In the TME, high CXCR4 mRNA expression was observed in tumors with a higher IC infiltration including B cells, M1/M2 macrophages, NK cells, CD8+ T cells and T-regs, regardless of MSI status. High CXCR4 mRNA expression in the primary tumor was associated with poor prognosis (HR 0.77, 95% CI 0.70-0.85; p < 0.001), regardless of MSI-status. In metastatic tumors, low mRNA expression was correlated with improved survival (HR 0.89, 95% CI 0.80-0.99; p = 0.34); however, this did not reach statistical significance in the MSS cohort (HR 0.90, 95% CI 0.80-1.0; p = 0.06). Of note, high CXCR4 mRNA expression was associated with improved survival in all patients with CRC who received pembrolizumab (HR 2.12, 95% CI 1.16-3.91; p = 0.013). Conclusions: This is the largest clinical dataset to date demonstrating high CXCR4 expression as a predictor for poor survival in CRC. Furthermore, high CXCR4 expression was associated with improved outcome after checkpoint inhibition immunotherapy, indicating its strong potential as a predictive biomarker that could inform immunotherapeutic strategies in CRC.

The post-transcriptional inhibition of CXCR4 expression by miR-139 regulates the proliferation of human kidney cancer cells.

The C-X-C chemokine receptor 4 (CXCR4) has been reported to be involved in several cancer related processes. The current study was designed to investigate the role of CXCR4 in human kidney cancer and to unveil the underlying molecular mechanisms. The results showed the expression of CXCR4 to be significantly (P<0.05) upregulated in human renal cancer tissues and cell lines. Silencing of CXCR4 lead to a significant (P<0.05) decline of cell proliferation and colony formation of the Caki-1 and A498 kidney cancer cells. Moreover, the migration and invasion of the Caki-1 and A498 cells was also significantly (P<0.05) inhibited upon CXCR4 silencing. TargetScan analysis and dual luciferase assay revealed that CXCR4 interacts with microRNA-139 (miR-139). The expression of miR-139 was found to be significantly (P<0.05) downregulated in human kidney cancer cells lines. Overexpression of miR-139 caused post-transcriptional suppression of CXCR4 expression and significant (P<0.05) inhibition of the Caki-1 and A498 cell proliferation. Nonetheless, CXCR4 overexpression could nullify the inhibitory effects of miR-139 on the proliferation of Caki-1 and A498 cells. Taken together, the results revealed that CXCR/miR-139 axis regulates the proliferation, migration, and invasion of human kidney cancer cells and may act as a therapeutic target.

Silencing of specificity protein 1 protects H9c2 cells against lipopolysaccharide-induced injury via binding to the promoter of chemokine CXC receptor 4 and suppressing NF-κB signaling

ABSTRACT G protein-coupled protein receptor CXC chemokine receptor 4 (CXCR4) has been shown to be involved in the development of sepsis; however, it remains unclear whether CXCR4 participates in the septic myocardial injury. In our study, treatment with lipopolysaccharide (LPS) increased the expression of specificity protein 1 (SP1) and CXCR4 in H9c2 cells. Notably, a positive association between SP1 and CXCR4 expression was observed in LPS-treated H9c2 cells, and SP1 positively regulated CXCR4 expression in H9c2 cells. Moreover, silencing of SP1 or CXCR4 suppressed LPS-induced inflammation and cell apoptosis in H9c2 cells, as evidenced by the increase in cell viability and decrease in lactate dehydrogenase release, interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α levels, and caspase-3 activity. Additionally, overexpression of CXCR4 abolished the protective effects of SP1 silencing on LPS-induced injury in H9c2 cells. SP1 was also shown to enhance the promoter activity of CXCR4 by directly binding with the binding motif site – 109/–100 in CXCR4 promoter. Besides, downregulation of SP1 or CXCR4 blocked LPS-induced activation of the NF-кB signaling in H9c2 cells. Furthermore, inhibition of NF-кB signaling by DHMEQ abolished LPS-induced myocardial inflammation and apoptosis. In conclusion, silencing of SP1 protected H9c2 cells against LPS-induced injury by binding to the promoter of CXCR4 and suppressing the NF-κB signaling pathway. Hence, our findings provide evidence that manipulation of SP1 or CXCR4 may be an effective approach to promote prevention or recovery of septic myocardial injury, and thereby, may serve as a potential therapeutic strategy for sepsis.

Prec-O1-04 - CXCR4/CXCL12 axis as a potential therapeutic target in mycosis fungoides: an in-vitro study

The C-X-C chemokine receptor 4 (CXCR4) is overexpressed in the tumor cells of many solid and hematologic neoplasms. Its ligand, C-X-C chemokine ligand 12 (CXCL12), is secreted by cells in the tumor microenvironment, mostly by stromal fibroblasts. The engagement of CXCL12 to CXCR4 results in activation of several intracellular signal transduction pathways, including, the proapoptotic p38, the prosurvival AKT, and the chemotaxis mediator ERK. The balance between activation of AKT and activation of p38 will determine the fate of cell viability. Plerixafor, AMD3100 (AMD), is a CXCR4 antagonist that reversibly blocks the binding of CXCR4 to CXCL12. AMD is already in clinical use as bone marrow stem cell or progenitor cell mobilizers. AMD and other CXCR4 inhibitors are investigated either alone or in combination with other systemic treatments in numerous clinical trials in cancer. CXCR4 and CXCL12 are known to be overexpressed in MF skin biopsies, but the exact differential contribution of the lymphoma vs the reactive T-cells is not clear. We previously have shown that primary MF-fibroblast culture (MF-Fs) established from MF biopsies, secrete high CXCL12 which promotes the migration of MyLa (MF cell line), protect them from chemotherapy and both effects were suppressed by AMD. We studied the role of CXCR4 as essential key protein in the survival of MF, and the effect and mechanism of CXCR4 antagonist on MyLa cell viability. We found that MyLa cells express higher CXCR4 vs CD3+CD4+ PBMCs from healthy donor (FACS). Single cell analysis of skin MF biopsy by flow mass cytometry (CyTOF) revealed sub-population of T- cells expressing the highest intensity of CXCR4, CD30, PD-1, and PDL-1 compared to all other immune cells, and therefore are suspected as the lymphoma cells overexpressing CXCR4. AMD was toxic to MyLa cells with higher toxicity to MyLa co-cultured with MF-Fs than MyLa alone (MTT viability assay, trypan blue staining), and promotes their death through apoptosis (FACS). AMD-induced death was selective to MyLa cells compared to healthy PBMCs, when both were co-cultured with MF-Fs. The phosphorylation of p38 and AKT in MyLa co-cultured with MF-Fs were reduced upon AMD treatment (Western blot). Spheroids of MyLa cells with MF-Fs were established to show the toxic effect of AMD in 3D co-culture model. The intracellular signaling pathways mediated by AMD was studied by phospho-proteomic analysis of MyLa cells co-cultured with MF-Fs. In sum, we showed the overexpression of CXCR4 in subpopulation of T cells suspected as the lymphoma cells in skin biopsy, and the pivotal role of overexpressed CXCR4 in the survival of MF cell line. The apoptotic effect mediated by AMD indicates that disrupting the interaction between stroma derived CXCL12 and MF derived CXCR4 might be a new therapeutic option in MF.

Pleiotropic Roles of CXCR4 in Wound Repair and Regeneration.

Wound healing is a multi-step process that includes multiple cellular events such as cell proliferation, cell adhesion, and chemotactic response as well as cell apoptosis. Accumulating studies have documented the significance of stromal cell-derived factor-1 (SDF-1)/C-X-C chemokine receptor 4 (CXCR4) signaling in wound repair and regeneration. However, the molecular mechanism of regeneration is not clear. This review describes various types of tissue regeneration that CXCR4 participates in and how the efficiency of regeneration is increased by CXCR4 overexpression. It emphasizes the pleiotropic effects of CXCR4 in regeneration. By delving into the specific molecular mechanisms of CXCR4, we hope to provide a theoretical basis for tissue engineering and future regenerative medicine.

CXCR4 Promotes Growth and Metastasis of Esophageal Squamous Cell Carcinoma as a Critical Downstream Mediator of HIF-1α

Background: Recent studies have shown that C-X-C chemokine receptor 4(CXCR4) plays an important role in a variety of tumours. However, its role and regulated mechanism in esophageal squamous cell carcinoma (ESCC) remain unclear. Methods: Immunohistochemistry, Western blot and qPCR were used to detect the expression of CXCR4 and HIF-1α. HIF-1α downstream target gene was detected by RNA-seq. The invasion and metastasis ability of HIF-1α/CXCR4 axis to ESCC cells were detected by transwell and animal experiments. Dual-luciferase analysis and chromatin immunoprecipitation assay showed that HIF-1α directly binds to the HRE site in the CXCR4 promoter. Findings: We showed that CXCR4 was enriched in ESCC tissues compared with corresponding normal tissues and predicted lymph node metastasis and poor prognosis. CXCR4 overexpression promotes the proliferation, migration and invasion of ESCC. In addition, we revealed that hypoxia-inducible factor-1α (HIF-1α) regulated CXCR4 expression via binding to a hypoxia response element in its promoter, and the HIF-1α-enhanced metastasis ability of ESCC cells was reversed by CXCR4 knockdown or treatment with MSX-122, a CXCR4 antagonist. Interpretation: In showing that the dysregulated HIF-1α/CXCR4 axis promotes ESCC malignancy, the results suggested that CXCR4 is a potential therapeutic target for ESCC. Funding: This research was supported by the National Natural Science Foundation of China (81772619, 82002551), the Science and Technology Project of Tianjin Municipal Health Commission (RC20119), the Bethune Charitable Foundation-Excelsior Surgical Fund (HZB-20190528-18), and the Clinical Trial Project of Tianjin Medical University (2017kylc006). Declaration of Interest: The authors declare no conflict of interest. Ethical Approval: All operations for human subjects were approved by the ethics committee of our hospital, and all patients provided informed consent. Gene Expression Omnibus (GEO) data were downloaded from the website (https://www.ncbi.nlm.nih.gov/geo/).

\u03b2-arrestin mediates communication between plasma membrane and intracellular GPCRs to regulate signaling

It has become increasingly apparent that G protein-coupled receptor (GPCR) localization is a master regulator of cell signaling. However, the molecular mechanisms involved in this process are not well understood. To date, observations of intracellular GPCR activation can be organized into two categories: a dependence on OCT3 cationic channel-permeable ligands or the necessity of endocytic trafficking. Using CXC chemokine receptor 4 (CXCR4) as a model, we identified a third mechanism of intracellular GPCR signaling. We show that independent of membrane permeable ligands and endocytosis, upon stimulation, plasma membrane and internal pools of CXCR4 are post-translationally modified and collectively regulate EGR1 transcription. We found that β-arrestin-1 (arrestin 2) is necessary to mediate communication between plasma membrane and internal pools of CXCR4. Notably, these observations may explain that while CXCR4 overexpression is highly correlated with cancer metastasis and mortality, plasma membrane localization is not. Together these data support a model where a small initial pool of plasma membrane-localized GPCRs are capable of activating internal receptor-dependent signaling events.

CXCR4 and RIF1 overexpression induces resistance of epithelial ovarian cancer to cisplatin-based chemotherapy.

The chemoresistance of epithelial ovarian cancer (EOC) is a major problem. Thus, the search for novel biomarkers associated with cisplatin sensitivity is overwhelming. Previous studies have shown that CXC chemokine receptor 4 (CXCR4) is associated with tumor growth, angiogenesis, and distant metastases, and replication timing regulatory factor 1 (RIF1) is responsible for the repair of double-strand DNA breaks. This study, thus, aimed to identify the correlation between CXCR4 and RIF1 overexpression and cisplatin sensitivity in EOC. Fifty-five EOC patients were recruited to assess the chemosensitivity of EOC to cisplatin-based chemotherapy at the Oncology Department in Tanta University Hospitals, Egypt. The results showed that patients with a higher CXCR4 and RIF1 expression exhibited a significantly lower chemosensitivity, worse overall survival, and poorer progression-free survival. The only prognostic associated with overall survival was CXCR4. Our study showed that CXCR4 and RIF1expression levels are not associated only with poor prognostic features of epithelial ovarian cancer but also with its chemoresistance to cisplatin, and consequently, with worse overall survival and progression free survival.

Enhanced recruitment and hematopoietic reconstitution of bone marrow-derived mesenchymal stem cells in bone marrow failure by the SDF-1/CXCR4.

Aplastic anemia (AA) is a bone marrow failure disease. It is difficult to treat AA, and in addition, relapses are common because of its complex disease pathogenesis. Allogeneic bone marrow-derived mesenchymal stem cells (BMSCs) infusion is an effective and safe treatment option for the AA patients. However, it found that BMSCs infusion in AA patients is less than 30% effective. Therefore, the key to improve the efficacy of BMSCs treatment in these patients is to enhance their homing efficiency to the target sites. Studies have shown that stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor 4 (CXCR4) axis plays an important role in promoting BMSCs homing. In this study, human BMSCs were transduced with lentivirus stably expressing CXCR4-BMSCs. Transduced BMSCs resemble normal BMSCs in many ways. Migration ability of CXCR4-BMSCs toward SDF-1 was increased because of the overexpression of CXCR4. In the mice with bone marrow failure, the migration and colonization ability of CXCR4-BMSCs to the bone marrow was significantly improved as seen by IVIS imaging and FACS. The SDF-1 level in the bone marrow failure mice was significantly higher than in the normal mice. Thus, from our study, it is clear that after CXCR4-BMSCs were infused into mice with bone marrow failure, SDF-1 interacted with CXCR4 receptor, leading cells to migrate and colonize to bone marrow. Because of the high SDF-1 expression in mouse bone marrow and CXCR4 receptor expression in cells, BMSCs homing was increased.

SDF-1/CXCR4 Augments the Therapeutic Effect of Bone Marrow Mesenchymal Stem Cells in the Treatment of Lipopolysaccharide-Induced Liver Injury by Promoting Their Migration Through PI3K/Akt Signaling Pathway

Mesenchymal stem cells (MSCs) are thought to have great potential in the therapy of acute liver injury. It is possible that these cells may be regulated by the stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor-4 (CXCR4) signaling axis, which has been shown to promote stem cells migration in the inflammation-associated diseases. However, the effects of SDF-1/CXCR4 axis on the MSCs-transplantation-based treatment for acute liver injury and the underlying mechanisms are largely unknown. In this study, we sought to determine whether SDF-1/CXCR4 would augment the therapeutic effect of bone marrow mesenchymal stem cells (BMSCs) by promoting their migration, which may result from activating the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway, in a rat acute liver injury model induced by lipopolysaccharide (LPS). We found that BMSCs transplantation markedly attenuated liver injury and improved the survival of LPS-treated rats. Of interest, overexpression of CXCR4 in BMSCs could substantially promote their migration both in vitro and in vivo, and result in even better therapeutic effects. This might be attributed to the activation of PI3K/Akt signaling pathway in BMSCs that is downstream of CXCR4, as demonstrated by the use of the CXCR4 antagonist AMD3100 and PI3K pathway inhibitor LY294002 assays in vitro and in vivo. Together, our results unraveled a novel molecular mechanism for the therapeutic effect of BMSCs for the treatment of acute liver injury, which may shed a new light on the clinical application of BMSCs for acute liver failure.

ClC-3 Deficiency Impairs the Neovascularization Capacity of Early Endothelial Progenitor Cells by Decreasing CXCR4/JAK-2 Signalling

BackgroundEndothelial progenitor cell (EPC) therapy has been suggested as a major breakthrough in the treatment of ischemic diseases. However, the molecular mechanism that underlies EPC functional regulation is still unclear. MethodsWe examined the angiogenic capacity of EPCs in a hindlimb ischemia model of wild-type and ClC-3 knockout mice. ResultsMice lacking of ClC-3 exhibited reduced blood flow recovery and neovascularization in ischemic muscles 7 and 14 days after hind limb ischemia. Moreover, compared with wild-type EPCs, the hindlimb blood reperfusion in mice receiving ClC-3 knockout EPCs was significantly impaired, accompanied by reduced EPC homing and retention. In vitro, EPCs derived from ClC-3 knockout mice displayed impaired migratory, adhesive, and angiogenic activity. CXC chemokine receptor 4 (CXCR4) expression was significantly reduced in EPC from ClC-3 knockout mice compared with wild-type. Moreover, the expression and phosphorylation of Janus kinase 2 (JAK-2), a downstream signalling of CXCR4, was also reduced in ClC-3 knockout EPC, indicating that CXCR4/JAK-2 signalling is dysregulated by ClC-3 deficiency. Consistent with this assumption, the migratory capacity of wild-type EPCs was attenuated by either CXCR4 antagonist AMD3100 or JAK-2 inhibitor AG490. More importantly, the impaired migratory capacity of ClC-3 knockout EPCs was rescued by overexpression of CXCR4. ConclusionsClC-3 plays a critical role in the angiogenic capacity of EPCs and EPC-mediated neovascularization of ischemic tissues. Disturbance of CXCR4/JAK-2 signalling may contribute to the functional impairment of ClC-3 deficient EPCs. Thus, ClC-3 may be a potential therapeutic target for modulating neovascularization in ischemic diseases.

Relationship between CXC chemokine receptor 4 expression and prognostic significance in acute myeloid leukemia.

CXC chemokine receptor 4 (CXCR4) expression on acute myeloid leukemia (AML) cells correlated with stromal cell derived factor-1α (SDF-1α) and retained hematopoietic progenitors and leukemia cells within the bone marrow microenvironment. Here, we examined CXCR4 expression in 134 de novo AML and 21 controls by flow cytometry, evaluated the relationship between CXCR4 expression and clinical characteristics, and elucidated the prognostic significance of CXCR4 expression in AML prospectively. We found that the CXCR4 expression was significantly higher in AML patients than controls (P = .000). One hundred thirty four cases of de novo AML patients were divided into 2 groups according to the median of CXCR4 relative fluorescence intensity (RFI). CXCR4 high group (RFI >4.23) had markedly shorter overall survival (OS) and disease-free survival (DFS) than CXCR4 low group (RFI ≤4.23) in 106 AML patients who received chemotherapy (P = .002; .026, respectively). Furthermore, in the 87 non-M3 patients who received induction therapy, there was a significant decrease for OS but not for DFS in the CXCR4 high group (P = .047 and .178, respectively). Moreover, high levels of CXCR4 expression independently increased the risk of relapse in both all AML and non-M3 patients who achieved complete remission (CR) after chemotherapy (odds ratio = 1.090, P = .010; odds ratio = 1.068, P = .048, respectively). Collectively, our data suggest that CXCR4 overexpression was an independent prognostic factor for disease relapse and poorer OS in both all AML and non-M3 patients. CXCR4 expression levels can be determined at disease presentation by the flow rapidly and easily. As such, CXCR4 could be used as a potential therapeutic target in AML patients with poor prognosis.

Combined Evaluation of Expression of CXCR4 and Nrf2 as Prognostic Factor for Patients with Gastric Carcinoma.

CXC Chemokine Receptor 4 (CXCR4) and NFE-related factor 2 (Nrf2) have been observed implicated with cell malignant behavior of human cancers. In this study, we detected their expression in gastric carcinoma (GC) tissue specimens and related the result with clinicopathological data and patient survival. 120 GC and compared normal tissue specimens were processed to analyse the expression of CXCR4 and Nrf2. We found that the expression of CXCR4 and Nrf2 was dramatically increased in GC tissues when compared to the distant non-cancer tissues (P<0.05). CXCR4 overexpression was associated with the depth of invasion (P= 0.006), Histological grade (P=0.018), TNMstage (P= 0.021), lymph node metastasis (P < 0.001) and distant metastasis (P=0.026), whereas overexpression of Nrf2 protein was significantly associated with tumor size (P=0.045), Histological grade (P=0.026), TNMstage (P= 0.020), lymph node metastases (P < 0.001) and distant metastasis (P=0.008). Furthermore, we observed a significant co-expression of CXCR4 and Nrf2 expression in GC specimens. In the survival part, we found that GC patients with CXCR4+ and Nrf2+ had worse outcomes. The significant prognostic indicators are age, tumor size, histological grade, TNMstage, CXCR4, Nrf2, and coexpression of CXCR4 and Nrf2 in GC patients. Multivariate analysis showed that TNMstage and CXCR4+/Nrf2+ expression were risk factors. Above all we come to the conclusion that the expression of CXCR4 might partly be regulated by the level of Nrf2 and both positive expressions suggest poor prognosis of GC patients.

Role of the stromal cell derived factor-1/CXC chemokine receptor 4 axis in the invasion and metastasis of lung cancer and mechanism.

Lung cancer is the most common tumor, and has the highest incidence and mortality rates among all malignant tumors. Since stromal cell derived factor-1 (SDF-1) and CXC chemokine receptor 4 (CXCR4) are specific to binding sites, they are more important than other members of the families for tumor invasion and metastasis. We herein aimed to investigate the role of the axis of chemokine SDF-1 and its receptor CXCR4 in the invasion and metastasis of lung cancer. Sixty clinical non-small cell lung cancer (NSCLC) tissue samples were collected. The CXCR4 expressions in cancer, paracancerous and normal lung tissues were detected by immunocytochemical assay and PCR. Cells with CXCR4 overexpression (CXCR4-A549) were constructed. After induction with SDF-1, CXCR4-A549 and A549 cells were subjected to in vitro chemotaxis and invasion assays. Their proliferation and apoptosis were detected by flow cytometry. The activities of phosphoinositide 3-kinase/protein kinase B (AKT) and mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK)-related signaling pathways were detected by Western blot. The downstream signaling molecules that may be activated by SDF-1/CXCR4 were analyzed. The expressions of vascular endothelial growth factor-C and matrix metalloproteinase-2 were detected by Western blot and PCR. A mouse model was established by subcutaneous inoculation of lung cancer cells. The effects of up-regulated CXCR4 expression on the migration of lung cancer cells in vitro and their tumorigenesis and metastasis in vivo were assessed. There was no expression in normal or paracancerous tissues. The expression of CXCR4 mRNA in lung cancer tissues was 83.3% (50/60). The expressions of CXCR4 in lung squamous cell carcinoma and adenocarcinoma were similar (P>0.05). The expression of CXCR4 was 76.9% (10/13) in highly differentiated carcinoma, 82.1% (23/28) in moderately differentiated carcinoma and 84.2% (16/19) in lowly differentiated carcinoma (P>0.05). The expression of CXCR4 was 72.7% (8/11) in TNM stage I patients, 83.9% (26/31) in stage II patients, and 88.9% (16/18) in stage III patients, with significant correlations. After up-regulation of CXCR4, the invasion ability of CXCR4-A549 cells was increased 1.62-fold (P<0.05). ERK and AKT were significantly phosphorylated 30 min after SDF-1 treatment. The tumorigenic rates of six mice inoculated with CXCR4-A549 and A549 cells were both 100%, with the average tumor weights of (4.37±0.96 g) and (3.24±1.16 g) respectively (P<0.05). In the CXCR4-A549 group, metastatic tumors clearly formed in the lungs of 6 mice, but only 2 mice in the A549 group had tumor cell invasion. SDF-1/CXCR4 played a key role in the invasion and metastasis of lung cancer. The interaction between SDF-1α and CXCR4 activated a series of downstream molecules by activating ERK and AKT.

The N-terminal polypeptide derived from viral macrophage inflammatory protein II reverses breast cancer epithelial-to-mesenchymal transition via a PDGFRα-dependent mechanism.

NT21MP, a 21-residue peptide derived from the viral macrophage inflammatory protein II, competed effectively with the natural ligand of CXC chemokine receptor 4 (CXCR4), stromal cell-derived factor 1-alpha, to induce apoptosis and inhibit growth in breast cancer. Its role in tumor epithelial-to-mesenchymal transition (EMT) regulation remains unknown. In this study, we evaluated the reversal of EMT upon NT21MP treatment and examined its role in the inhibition of EMT in breast cancer. The parental cells of breast cancer (SKBR-3 and MCF-7) and paclitaxel-resistant (SKBR-3 PR and MCF-7 PR) cells were studied in vitro and in combined immunodeficient mice. The mice injected with SKBR-3 PR cells were treated with NT21MP through the tail vein or intraperitoneally with paclitaxel or saline. Sections from tumors were evaluated for tumor weight and EMT markers based on Western blot. In vitro, the effects of NT21MP, CXCR4 and PDGFRα on tumor EMT were assessed by relative quantitative real-time reverse transcription–polymerase chain reaction, western blot and biological activity in breast cancer cell lines expressing high or low levels of CXCR4. Our results illustrated that NT21MP could reverse the phenotype of EMT in paclitaxel-resistant cells. Furthermore, we found that NT21MP governed PR-mediated EMT partly due to controlling platelet-derived growth factors A and B (PDGFA and PDGFB) and their receptor (PDGFRα). More importantly, NT21MP down-regulated AKT and ERK1/2 activity, which were activated by PDGFRα, and eventually reversed the EMT. Together, these results indicated that CXCR4 overexpression drives acquired paclitaxel resistance, partly by activating the PDGFA and PDGFB/PDGFRα autocrine signaling loops that activate AKT and ERK1/2. Inhibition of the oncogenic EMT process by targeting CXCR4/PDGFRα-mediated pathways using NT21MP may provide a novel therapeutic approach towards breast cancer.

A fully human CXCR4 antibody demonstrates diagnostic utility and therapeutic efficacy in solid tumor xenografts.

For physiologically important cancer therapeutic targets, use of non-invasive imaging for therapeutic guidance and monitoring may improve outcomes for treated patients. The CXC chemokine receptor 4 (CXCR4) is overexpressed in many cancers including non-small cell lung cancer (NSCLC) and triple negative breast cancer (TNBC). CXCR4 overexpression contributes to tumor growth, progression and metastasis. There are several CXCR4-targeted therapeutic agents currently in clinical trials. Since CXCR4 is also crucial for normal biological functions, its prolonged inhibition could lead to unwanted toxicities. While CXCR4-targeted imaging agents and inhibitors have been reported and evaluated independently, there are currently no studies demonstrating CXCR4-targeted imaging for therapeutic guidance.Monoclonal antibodies (mAbs) are commonly used for cancer therapy and imaging. Here, an 89Zr-labeled human CXCR4-mAb (89Zr-CXCR4-mAb) was evaluated for detection of CXCR4 expression with positron emission tomography (PET) while its native unmodified analogue was evaluated for therapy in relevant models of NSCLC and TNBC. In vitro and in vivo evaluation of 89Zr-CXCR4-mAb showed enhanced uptake in NSCLC xenografts with a high expression of CXCR4. It also had the ability to detect lymph node metastases in an experimental model of metastatic TNBC. Treatment of high and low CXCR4 expressing NSCLC and TNBC xenografts with CXCR4-mAb demonstrated a therapeutic response correlating with the expression of CXCR4. Considering the key role of CXCR4 in normal biological functions, our results suggest that combination of 89Zr-CXCR4-mAb-PET with non-radiolabeled mAb therapy may provide a precision medicine approach for selecting patients with tumors that are likely to be responsive to this treatment.

Prognostic Significance of CXCR4 Overexpression in Pediatric Acute Myeloid Leukemia with Low-Risk: A Report from the Japanese Pediatric Leukemia/Lymphoma Study Group

Background:The outcome of acute myeloid leukemia (AML) has been improved by advanced risk-stratified chemotherapy based on prognostic factors. However, the long-term survival rate remains 60-70% and further investigation is needed. Core binding factor (CBF)-AML, characterized by t(8;21) or inv(16)/t(16;16), is the most frequent subtype in pediatric AML. Although CBF-AML is generally classified as a low-risk (LR) group, approximately 30% of the patients relapsed within 3 years in the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG) AML-05 trial. This finding suggests that the LR patients had other risk factors that could account for their adverse outcome. CXC chemokine receptor 4 (CXCR4) is a G protein-coupled receptor that helps leukemia cells adhere to bone marrow stromal cells that affect the cell survival and proliferation. There are several reports that CXCR4 overexpression is an adverse prognostic factor in adult AML; however, few studies have examined their significance in pediatric AML. Here, we retrospectively examined whether CXCR4 overexpression can be an adverse prognostic factor in pediatric AML with LR.Patients and Methods:From 2006 to 2010, 485 de novo pediatric AML patients aged <18 years were registered in the AML-05 trial. Overall, 42 patients were excluded, mainly because of misdiagnosis. The risk groups were defined as follows: all of the CBF-AML patients with complete remission (CR) after the initial induction course without FLT3 -ITD were included in the LR group, while patients with -7, 5q-, t(16;21)(p11;q22), Ph1, or non-CR after the initial induction course or with FLT3-ITD were included in the high-risk (HR) group. Patients with no LR or HR features were in the intermediate-risk. CXCR4 mRNA expression was analyzed by quantitative RT-PCR using diagnostic bone marrow samples. CXCR4 expression levels were dichotomized based on the average expression level.Results and Discussion:A total of 248 samples were available for this study. No significant differences in the clinical outcomes were observed between these 248 patients and the 195 patients who did not have CXCR4 data (EFS, P =0.55; OS, P =0.87). CXCR4 overexpression (CXCR4 +) was present in 81 patients (32.7%). CXCR4 + was not correlated with age, sex, and WBC count. CBF-AML was similarly distributed between CXCR4 + and CXCR4 - patients. The frequency of FLT3 -ITD in CXCR4 + patients was significantly higher in CXCR4 - patients (P =0.049), while there were no significant differences in that of KIT and CEBPA mutation (P =0.08 and 0.71, respectively). In total (n=248), no significant differences were observed between CXCR4 + and CXCR4 - patients in 3-year OS (68.6% vs. 75.1%, P =0.42) and 3-year EFS (65.6% vs. 58.9%, P =0.27). However, in the LR group (n=93), a significant difference was observed between CXCR4 + and CXCR4 - patients in 3-year OS (79.2% vs. 98.3%, P =0.008), whereas no significant difference was observed in 3-year EFS (83.3% vs. 69.6%, P =0.33). We have revealed that KIT mutations are adverse prognostic factors in t(8;21) pediatric AML in our recent study (Leukemia, 2015). In t(8;21) AML without KIT mutations (n=44), a significant difference was observed between CXCR4 + and CXCR4 - patients in 3-year OS (76.1% vs. 100.0%, P =0.01), whereas no significant difference was observed in 3-year EFS (77.8% vs. 74.2%, P =0.85). Multivariate Cox regression analysis, including CXCR4 +, KIT mutation, and age identified CXCR4 + as the only prognostic factor predicting poor OS in the cohort of AML with LR (hazard ratio, 11.01; P =0.01), but not EFS (hazard ratio, 0.54; P =0.21). The results suggest that CXCR4 + is associated with an adverse prognosis in pediatric AML with LR. The adverse outcome was restricted in OS, not in EFS, suggesting that CXCR4 + may be associated with the poor prognosis after recurrence, although the underlying mechanism remains unknown. Furthermore, it is noteworthy that the OS of LR patients with CXCR4 - was quite high, which should be confirmed in larger studies.Conclusions:We identified the adverse prognostic significance of CXCR4 overexpression in pediatric AML with LR. The adverse prognosis may be restricted after recurrence. Further studies of the underlying biology are required. There are several promising CXCR4 antagonists including AMD3100, therefore, our findings will help to develop better therapeutic approaches in pediatric AML with LR. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

EZH2-mediated loss of miR-622 determines CXCR4 activation in hepatocellular carcinoma.

The CXC chemokine receptor 4 (CXCR4) exerts a variety of functions at different steps of hepatocellular carcinoma (HCC) progression. The molecular mechanisms and therapeutic value of CXCR4 in the development of HCC remain undefined. Here we show that aberrant CXCR4 overexpression is associated with poor prognosis and aggressive characteristics of HCC. Suppression of CXCR4 activity via CXCR4 knockdown, AMD3100 or neutralizing antibody administration inhibits hepatoma cell tumorigenesis in vitro and in vivo. CXCR4 overexpression displays the opposite effects. Using Mir library screening we identify miR-622 as a regulator of CXCR4. Further studies show that miR-622 directly target the 3′ untranslated region of CXCR4 and is transcriptionally repressed by EZH2-induced H3K27 trimethylation and promoter methylation. EZH2/miR-622 promotes tumorigenesis through CXCR4. EZH2-mediated loss of miR-622 is found to correlate with CXCR4 overexpression and unfavourable prognosis in HCC patients. This study establishes EZH2/miR-622/CXCR4 as a potential adverse prognostic factor and therapeutic target for HCC patients.