Gene Summary

Gene:CXCR4; chemokine (C-X-C motif) receptor 4
Summary:This gene encodes a CXC chemokine receptor specific for stromal cell-derived factor-1. The protein has 7 transmembrane regions and is located on the cell surface. It acts with the CD4 protein to support HIV entry into cells and is also highly expressed in breast cancer cells. Mutations in this gene have been associated with WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome. Alternate transcriptional splice variants, encoding different isoforms, have been characterized. [provided by RefSeq, Jul 2008]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:C-X-C chemokine receptor type 4
Source:NCBIAccessed: 06 August, 2015


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 06 August 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 06 August, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (6)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: CXCR4 (cancer-related)

Lourenco S, Teixeira VH, Kalber T, et al.
Macrophage migration inhibitory factor-CXCR4 is the dominant chemotactic axis in human mesenchymal stem cell recruitment to tumors.
J Immunol. 2015; 194(7):3463-74 [PubMed] Article available free on PMC after 01/10/2015 Related Publications
Mesenchymal stromal cells (MSCs) are inherently tumor homing and can be isolated, expanded, and transduced, making them viable candidates for cell therapy. This tumor tropism has been used to deliver anticancer therapies to various tumor models. In this study, we sought to discover which molecules are the key effectors of human MSC tumor homing in vitro and using an in vivo murine model. In this study, we discover a novel role for macrophage migration inhibitory factor (MIF) as the key director of MSC migration and infiltration toward tumor cells. We have shown this major role for MIF using in vitro migration and invasion assays, in presence of different receptor inhibitors and achieving a drastic decrease in both processes using MIF inhibitor. Additionally, we demonstrate physical interaction between MIF and three receptors: CXCR2, CXCR4, and CD74. CXCR4 is the dominant receptor used by MIF in the homing tumor context, although some signaling is observed through CXCR2. We demonstrate downstream activation of the MAPK pathway necessary for tumor homing. Importantly, we show that knockdown of either CXCR4 or MIF abrogates MSC homing to tumors in an in vivo pulmonary metastasis model, confirming the in vitro two-dimensional and three-dimensional assays. This improved understanding of MSC tumor tropism will further enable development of novel cellular therapies for cancers.

Chang TP, Poltoratsky V, Vancurova I
Bortezomib inhibits expression of TGF-β1, IL-10, and CXCR4, resulting in decreased survival and migration of cutaneous T cell lymphoma cells.
J Immunol. 2015; 194(6):2942-53 [PubMed] Article available free on PMC after 15/03/2016 Related Publications
Increased expression of the immunosuppressive cytokines, TGF-β1 and IL-10, is a hallmark of the advanced stages of cutaneous T cell lymphoma (CTCL), where it has been associated with suppressed immunity, increased susceptibility to infections, and diminished antitumor responses. Yet, little is known about the transcriptional regulation of TGF-β1 and IL-10 in CTCL, and about their function in regulating the CTCL cell responses. In this article, we show that TGF-β1 and IL-10 expression in CTCL cells is regulated by NF-κB and suppressed by bortezomib (BZ), which has shown promising results in the treatment of CTCL. However, although the TGF-β1 expression is IκBα dependent and is regulated by the canonical pathway, the IL-10 expression is IκBα independent, and its inhibition by BZ is associated with increased promoter recruitment of p52 that characterizes the noncanonical pathway. TGF-β1 suppression decreases CTCL cell viability and increases apoptosis, and adding exogenous TGF-β1 increases viability of BZ-treated CTCL cells, indicating TGF-β1 prosurvival function in CTCL cells. In addition, TGF-β1 suppression increases expression of the proinflammatory cytokines IL-8 and IL-17 in CTCL cells, suggesting that TGF-β1 also regulates the IL-8 and IL-17 expression. Importantly, our results demonstrate that BZ inhibits expression of the chemokine receptor CXCR4 in CTCL cells, resulting in their decreased migration, and that the CTCL cell migration is mediated by TGF-β1. These findings provide the first insights into the BZ-regulated TGF-β1 and IL-10 expression in CTCL cells, and indicate that TGF-β1 has a key role in regulating CTCL survival, inflammatory gene expression, and migration.

McDermott DH, Gao JL, Liu Q, et al.
Chromothriptic cure of WHIM syndrome.
Cell. 2015; 160(4):686-99 [PubMed] Article available free on PMC after 12/02/2016 Related Publications
Chromothripsis is a catastrophic cellular event recently described in cancer in which chromosomes undergo massive deletion and rearrangement. Here, we report a case in which chromothripsis spontaneously cured a patient with WHIM syndrome, an autosomal dominant combined immunodeficiency disease caused by gain-of-function mutation of the chemokine receptor CXCR4. In this patient, deletion of the disease allele, CXCR4(R334X), as well as 163 other genes from one copy of chromosome 2 occurred in a hematopoietic stem cell (HSC) that repopulated the myeloid but not the lymphoid lineage. In competitive mouse bone marrow (BM) transplantation experiments, Cxcr4 haploinsufficiency was sufficient to confer a strong long-term engraftment advantage of donor BM over BM from either wild-type or WHIM syndrome model mice, suggesting a potential mechanism for the patient's cure. Our findings suggest that partial inactivation of CXCR4 may have general utility as a strategy to promote HSC engraftment in transplantation.

Castillo JJ, Ghobrial IM, Treon SP
Biology, prognosis, and therapy of Waldenström Macroglobulinemia.
Cancer Treat Res. 2015; 165:177-95 [PubMed] Related Publications
Waldenström Macroglobulinemia (WM) is a rare B-cell lymphoma characterized by the uncontrolled accumulation of malignant lymphoplasmacytic cells, mainly in the bone marrow, and monoclonal IgM production. Despite its rarity, our understanding of the biology of this disease has improved significantly in recent years with the identification of recurrent mutations in the MYD88 and CXCR4 genes. Based on the diversity of clinical features observed in WM patients, therapy should be highly personalized having into account several factors such as age, co-morbidities, IgM levels, and presence of hyperviscosity, coagulopathy, cryoglobulinemia, or cold agglutinin disease. In this chapter, we review the recent advances in the biology of WM and the current therapeutic options for untreated and relapsed WM patients. Finally, we discuss the role of prognostic factors and current evidence supporting an improvement in the survival of WM patients in the last decade.

Desurmont T, Skrypek N, Duhamel A, et al.
Overexpression of chemokine receptor CXCR2 and ligand CXCL7 in liver metastases from colon cancer is correlated to shorter disease-free and overall survival.
Cancer Sci. 2015; 106(3):262-9 [PubMed] Related Publications
Our aim was to analyze the potential role of chemokine receptors CXCR2 and CXCR4 signalling pathways in liver metastatic colorectal cancer (CRC) relapse. CXCR2, CXCR4, and their chemokine ligands were evaluated in liver metastases of colorectal cancer in order to study their correlation with overall and disease-free survival of patients having received, or not received, a neoadjuvant chemotherapy regimen. Quantitative RT-PCR and CXCR2 immunohistochemical staining were carried out using CRC liver metastasis samples. Expression levels of CXCR2, CXCR4, and their ligands were statistically analyzed according to treatment with neoadjuvant chemotherapy and patients' outcome. CXCR2 and CXCL7 overexpression are correlated to shorter overall and disease-free survival. By multivariate analysis, CXCR2 and CXCL7 expressions are independent factors of overall and disease-free survival. Neoadjuvant chemotherapy increases significantly the expression of CXCR2: treated group 1.89 (0.02-50.92) vs 0.55 (0.07-3.22), P = 0.016. CXCL7 was overexpressed close to significance, 0.40 (0.00-7.85) vs 0.15 (0.01-7.88), P = 0.12. We show the involvement of CXCL7/CXCR2 signalling pathways as a predictive factor of poor outcome in metastatic CRC. 5-Fluorouracil-based chemotherapy regimens increase the expression of these genes in liver metastasis, providing one explanation for aggressiveness of relapsed drug-resistant tumors. Selective blockage of CXCR2/CXCL7 signalling pathways could provide new potential therapeutic opportunities.

Lin SS, Fan W, Sun L, et al.
The saponin DT-13 inhibits gastric cancer cell migration through down-regulation of CCR5-CCL5 axis.
Chin J Nat Med. 2014; 12(11):833-40 [PubMed] Related Publications
AIM: To investigate the effect of DT-13 on gastric cancer cell migration, and to explore the possible mechanisms underlying the anti-metastasis activity of DT-13.
METHODS: Growth inhibition of DT-13 was analyzed by the MTT assay. Cell migration was measured by the scratch-wound assay and transwell double chamber assay. To investigate the possible mechanisms underlying the anti-metastasis activity of DT-13, chemokine receptors that are involved in cancer metastasis (CCR2, CCR5, CCR7, CXCR4, and CXCR6) were detected by conventional PCR. The effect of DT-13 on CCR5 and CXCR4 expression was further evaluated by quantitative PCR and Western blot, respectively. The secretion of CCL5 (ligand of CCR5) and SDF-1 (ligand of CXCR4) were detected by enzyme-linked immunosorbent assay (ELISA).
RESULTS: DT-13 inhibited BGC-823 and HGC-27 cell growth in a dose dependent manner, and the estimated IC50 value for 24 h treatment was 23.5 ± 5.1 μmol·L(-1) for BGC-823 cells and 35.6 ± 7.6 μmol·L(-1) for HGC-27 cells. DT-13 also significantly decreased gastric cancer cell migration. DT-13 significantly decreased the gene expression of CCR5 in both BGC-823 and HGC-27 gastric cancer cells, and moderately reduced the expression of CXCR4. Similar to the results of gene expression, significant down-regulation of CCR5 protein was observed, but CXCR4 protein levels were much less affected. CCL5 secretion, but not SDF-1 production, was inhibited by DT-13.
CONCLUSION: DT-13 inhibited gastric cancer cell migration by down-regulation of the CCR5-CCL5 axis.

Kato H, Wakabayashi H, Naito Y, et al.
Anti-tumor necrosis factor therapy inhibits lung metastasis in an osteosarcoma cell line.
Oncology. 2015; 88(3):139-46 [PubMed] Related Publications
BACKGROUND: Osteosarcoma is the most common primary malignancy of bone, and patients often develop pulmonary metastases. In a previous study, tumor necrosis factor (TNF)-α treatment of human osteosarcoma cells increases their metastatic ability in an animal model. TNF-α can act as a tumor necrosis factor and also as a tumor-promoting factor. In the present study, the effect of a TNF-α inhibitor on osteosarcoma aggressiveness and pulmonary metastases was investigated in vitro and in vivo.
METHODS: The effect of infliximab, a TNF-α inhibitor, on a metastatic osteosarcoma 143B cell growth and motility was investigated in vitro. An orthotopic xenograft model of 143B cell growth and spontaneous metastasis in SCID mice was used to assess the in vivo effect of infliximab.
RESULTS: Infliximab greatly reduced cell motility and pulmonary metastases in 143B cells. The mechanism of pulmonary metastasis inhibition involved decreased expression of CXC chemokine receptor 4 (CXCR4), Rho (small GTPase protein), and its effector.
CONCLUSIONS: These results suggest a novel role for TNF-α inhibition in the reduction or prevention of pulmonary metastases of osteosarcoma in this animal model. TNF-α inhibition may become a preventive therapeutic option for the pulmonary metastases of osteosarcoma.

Alamo P, Gallardo A, Di Nicolantonio F, et al.
Higher metastatic efficiency of KRas G12V than KRas G13D in a colorectal cancer model.
FASEB J. 2015; 29(2):464-76 [PubMed] Related Publications
Although all KRas (protein that in humans is encoded by the KRas gene) point mutants are considered to have a similar prognostic capacity, their transformation and tumorigenic capacities vary widely. We compared the metastatic efficiency of KRas G12V (Kirsten rat sarcoma viral oncogene homolog with valine mutation at codon 12) and KRas G13D (Kirsten rat sarcoma viral oncogene homolog with aspartic mutation at codon 13) oncogenes in an orthotopic colorectal cancer (CRC) model. Following subcutaneous preconditioning, recombinant clones of the SW48 CRC cell line [Kras wild-type (Kras WT)] expressing the KRas G12V or KRas G13D allele were microinjected in the mouse cecum. The percentage of animals developing lymph node metastasis was higher in KRas G12V than in KRas G13D mice. Microscopic, macroscopic, and visible lymphatic foci were 1.5- to 3.0-fold larger in KRas G12V than in KRas G13D mice (P < 0.05). In the lung, only microfoci were developed in both groups. KRas G12V primary tumors had lower apoptosis (7.0 ± 1.2 vs. 7.4 ± 1.0 per field, P = 0.02), higher tumor budding at the invasion front (1.2 ± 0.2 vs. 0.6 ± 0.1, P = 0.04), and a higher percentage of C-X-C chemokine receptor type 4 (CXCR4)-overexpressing intravasated tumor emboli (49.8 ± 9.4% vs. 12.8 ± 4.4%, P < 0.001) than KRas G13D tumors. KRas G12V primary tumors showed Akt activation, and β5 integrin, vascular endothelial growth factor A (VEGFA), and Serpine-1 overexpression, whereas KRas G13D tumors showed integrin β1 and angiopoietin 2 (Angpt2) overexpression. The increased cell survival, invasion, intravasation, and specific molecular regulation observed in KRas G12V tumors is consistent with the higher aggressiveness observed in patients with CRC expressing this oncogene.

Ribas R, Ghazoui Z, Gao Q, et al.
Identification of chemokine receptors as potential modulators of endocrine resistance in oestrogen receptor-positive breast cancers.
Breast Cancer Res. 2014; 16(5):447 [PubMed] Article available free on PMC after 12/02/2016 Related Publications
INTRODUCTION: Endocrine therapies target oestrogenic stimulation of breast cancer (BC) growth, but resistance remains problematic. Our aims in this study were (1) to identify genes most strongly associated with resistance to endocrine therapy by intersecting global gene transcription data from patients treated presurgically with the aromatase inhibitor anastrazole with those from MCF7 cells adapted to long-term oestrogen deprivation (LTED) (2) to assess the clinical value of selected genes in public clinical data sets and (3) to determine the impact of targeting these genes with novel agents.
METHODS: Gene expression and Ki67 data were available from 69 postmenopausal women with oestrogen receptor-positive (ER+) early BC, at baseline and 2 weeks after anastrazole treatment, and from cell lines adapted to LTED. The functional consequences of target genes on proliferation, ER-mediated transcription and downstream cell signalling were assessed.
RESULTS: By intersecting genes predictive of a poor change in Ki67 with those upregulated in LTED cells, we identified 32 genes strongly correlated with poor antiproliferative response that were associated with inflammation and/or immunity. In a panel of LTED cell lines, C-X-C chemokine receptor type 7 (CXCR7) and CXCR4 were upregulated compared to their wild types (wt), and CXCR7, but not CXCR4, was associated with reduced relapse-free survival in patients with ER+ BC. The CXCR4 small interfering RNA variant (siCXCR4) had no specific effect on the proliferation of wt-SUM44, wt-MCF7 and their LTED derivatives. In contrast, siCXCR7, as well as CCX733, a CXCR7 antagonist, specifically suppressed the proliferation of MCF7-LTED cells. siCXCR7 suppressed proteins associated with G1/S transition and inhibited ER transactivation in MCF7-LTED, but not wt-MCF7, by impeding association between ER and proline-, glutamic acid- and leucine-rich protein 1, an ER coactivator.
CONCLUSIONS: These data highlight CXCR7 as a potential therapeutic target warranting clinical investigation in endocrine-resistant BC.

Zhu Y, Zhang L, Zhang GD, et al.
Potential mechanisms of benzyl isothiocyanate suppression of invasion and angiogenesis by the U87MG human glioma cell line.
Asian Pac J Cancer Prev. 2014; 15(19):8225-8 [PubMed] Related Publications
Glioma is one of the most common tumors in China and chemotherapy is critical for its treatment. Recent studies showed that benzyl isothiocyanate (BITC) could inhibit the growth of glioma cells, but the mechanisms are not fully understood. This study explored the inhibitory effect of BITC on invasion and angiogenesis of U87MG human glioma cells in vitro and in vivo, as well as potential mechanisms. It was found that BITC could inhibit invasion and angiogenesis of human glioma U87MG cells by inducing cell cycle arrest at phase G2/M. It also was demonstrated that BITC decreased expression of cyclin B1, p21, MMP-2/9, VE-cadherin, CD44, CXCR4 and MTH1, the activity of the telomerase and PKCζ pathway. Microarray analysis was thus useful to explore the potential target genes related to tumorigenic processes. BITC may play important roles in the inhibition of invasion and angiogenesis of human glioma cells.

Niu H, Yang X, Xu Z, et al.
Cell surface nucleolin interacts with CXCR4 receptor via the 212 c-terminal portion.
Tumour Biol. 2015; 36(2):1099-104 [PubMed] Related Publications
Previously, we reported that CXCR4 receptor interacted with cell surface nucleolin, and the synergy of CXCR4 and nucleolin plays an essential role in malignant transformation. Here, we continued to conduct a structure-function analysis of nucleolin to identify which portion can efficaciously bind to CXCR4. In the present study, the expression of CXCR4 and nucleolin in 100 cases of papillary thyroid cancer (PTC) samples was investigated through immunohistochemistry (IHC). Subsequently, using nucleolin mutants and pull-down assay, we investigated precise interactions between CXCR4 and nucleolin in HEK-293 cells. A previous study demonstrated CXCR4 and nucleolin co-expressed in cell lines, and the present study further identified that CXCR4 and nucleolin co-expressed in PTC tissues, instead of normal tissues. The nucleolin mutant analysis revealed that nucleolin can efficaciously bind CXCR4 to activate CXCR4 signaling by 212 C-terminal domain. Conversely, N-terminal, RBD and GAR mutants of nucleolin showed no sign of activation of CXCR4 signaling, and differences were statistically insignificant (p > 0.05). In conclusion, these results suggested nucleolin is essential to activate CXCR4 signaling via 212 C-terminal domain, which is required for cell growth, migration, and invasiveness. Furthermore, nucleolin may interact with more G protein-coupled receptors, at least chemokine receptor. Our study will lay a new foundation for cancer therapy by antagonizing nucleolin and CXCR4.

Gil M, Komorowski MP, Seshadri M, et al.
CXCL12/CXCR4 blockade by oncolytic virotherapy inhibits ovarian cancer growth by decreasing immunosuppression and targeting cancer-initiating cells.
J Immunol. 2014; 193(10):5327-37 [PubMed] Article available free on PMC after 15/11/2015 Related Publications
Signals mediated by the chemokine CXCL12 and its receptor CXCR4 are involved in the progression of ovarian cancer through enhancement of tumor angiogenesis and immunosuppressive networks that regulate dissemination of peritoneal metastasis and development of cancer-initiating cells (CICs). In this study, we investigated the antitumor efficacy of a CXCR4 antagonist expressed by oncolytic vaccinia virus (OVV) against an invasive variant of the murine epithelial ovarian cancer cell line ID8-T. This variant harbors a high frequency of CICs that form multilayered spheroid cells and express the hyaluronan receptor CD44, as well as stem cell factor receptor CD117 (c-kit). Using an orthotopic ID8-T tumor model, we observed that i.p. delivery of a CXCR4 antagonist-expressing OVV led to reduced metastatic spread of tumors and improved overall survival compared with oncolysis alone. Inhibition of tumor growth with the armed virus was associated with efficient killing of CICs, reduced expression of ascitic CXCL12 and vascular endothelial growth factor, and decreases in i.p. numbers of endothelial and myeloid cells, as well as plasmacytoid dendritic cells. These changes, together with reduced recruitment of T regulatory cells, were associated with higher ratios of IFN-γ(+)/IL-10(+) tumor-infiltrating T lymphocytes, as well as induction of spontaneous humoral and cellular antitumor responses. Similarly, the CXCR4 antagonist released from virally infected human CAOV2 ovarian carcinoma cells inhibited peritoneal dissemination of tumors in SCID mice, leading to improved tumor-free survival in a xenograft model. Our findings demonstrate that OVV armed with a CXCR4 antagonist represents a potent therapy for ovarian CICs with a broad antitumor repertoire.

Zaitseva L, Murray MY, Shafat MS, et al.
Ibrutinib inhibits SDF1/CXCR4 mediated migration in AML.
Oncotarget. 2014; 5(20):9930-8 [PubMed] Article available free on PMC after 15/11/2015 Related Publications
Pharmacological targeting of BTK using ibrutinib has recently shown encouraging clinical activity in a range of lymphoid malignancies. Recently we reported that ibrutinib inhibits human acute myeloid leukemia (AML) blast proliferation and leukemic cell adhesion to the surrounding bone marrow stroma cells. Here we report that in human AML ibrutinib, in addition, functions to inhibit SDF1/CXCR4-mediated AML migration at concentrations achievable in vivo. It has previously been shown that SDF1/CXCR4-induced migration is dependent on activation of downstream BTK in chronic lymphocytic leukaemia (CLL) and multiple myeloma. Here we show that SDF-1 induces BTK phosphorylation and downstream MAPK signalling in primary AML blast. Furthermore, we show that ibrutinib can inhibit SDF1-induced AKT and MAPK activation. These results reported here provide a molecular mechanistic rationale for clinically evaluating BTK inhibition in AML patients and suggests that in some AML patients the blasts count may initially rise in response to ibrutinib therapy, analgous to similar clinical observations in CLL.

Chatterjee S, Behnam Azad B, Nimmagadda S
The intricate role of CXCR4 in cancer.
Adv Cancer Res. 2014; 124:31-82 [PubMed] Article available free on PMC after 15/11/2015 Related Publications
Chemokines mediate numerous physiological and pathological processes related primarily to cell homing and migration. The chemokine CXCL12, also known as stromal cell-derived factor-1, binds the G-protein-coupled receptor CXCR4, which, through multiple divergent pathways, leads to chemotaxis, enhanced intracellular calcium, cell adhesion, survival, proliferation, and gene transcription. CXCR4, initially discovered for its involvement in HIV entry and leukocytes trafficking, is overexpressed in more than 23 human cancers. Cancer cell CXCR4 overexpression contributes to tumor growth, invasion, angiogenesis, metastasis, relapse, and therapeutic resistance. CXCR4 antagonism has been shown to disrupt tumor-stromal interactions, sensitize cancer cells to cytotoxic drugs, and reduce tumor growth and metastatic burden. As such, CXCR4 is a target not only for therapeutic intervention but also for noninvasive monitoring of disease progression and therapeutic guidance. This review provides a comprehensive overview of the biological involvement of CXCR4 in human cancers, the current status of CXCR4-based therapeutic approaches, as well as recent advances in noninvasive imaging of CXCR4 expression.

Lee HW, Cho HJ, Lee SJ, et al.
Tpl2 induces castration resistant prostate cancer progression and metastasis.
Int J Cancer. 2015; 136(9):2065-77 [PubMed] Related Publications
Progression to metastatic castration resistant prostate cancer (CRPC) is the major lethal pathway of prostate cancer (PC). Herein, we demonstrated that tumor progression locus 2 (Tpl2) kinase is the fundamental molecule provoking progression and metastasis of CRPC. Tpl2 upregulates CXCR4 and focal adhesion kinase (FAK) to activate CXCL12/CXCR4 and FAK/Akt signalling pathway. Consequently, epithelial-mesenchymal transition (EMT) and stemness of androgen depletion independent (ADI) PC cells are induced, which is dependent on the kinase activity of Tpl2. In vitro, proliferation, clonogenicity, migration, invasion and chemoresistance of ADI PC cells were enhanced by Tpl2. In vivo, Tpl2 overexpression and downregulation showed significant stimulatory and inhibitory effects on tumorigenic and metastatic potential of ADI PC cells, respectively. Moreover, the prognostic effects of Tpl2 and expressional correlation between Tpl2 and EMT-related molecules/CXCR4 were validated in clinical PC databases. Since Tpl2 exerts metastatic progression promoting activities in CRPC, Tpl2 could serve as a novel therapeutic target for metastatic CRPC.

Polishchuk LA, Telegeev GD
Role of the hybrid Bcr/Abl kinase in the pathogenesis of chronic myeloid leukemia lacking C-Abl and CXCR4 proteins.
Exp Oncol. 2014; 36(3):138-43 [PubMed] Related Publications
Philadelphia chromosome is a result of chromosomal rearrangement that leads to the appearing of the hybrid gene bcr/abl. A hybrid mRNA transcribes from bcr-promoter and many copies of hybrid molecules of Bcr/Abl protein are formed as a result of bcr/abl gene expression. It is supposed that a hybrid Abl molecule, replacing the normal one, in majority of cases functions abnormally or does not function at all. Also it is possible that Abl moiety of Bcr/Abl protein which is possibly recognized by some hypothetical cell control system interpreted by cell as an overproduction of c-abl. This, probably, leads to blocking the normal C-Abl molecules production from the normal c-abl gene transcribed from the second non-aberrant chromosome 9. Based on C-Abl physiological functions in conjunction with the most important proteins of which functions directly depend on its activity we tried to outline the research directions that might explain disruptions of the processes at chronic myeloleukosis such as cell migration due to CXCL12/CXCR4 axis activation, reparation, apoptosis, control for mitochondria state, and to propose new perspective therapeutic approaches based on all this knowledge.

Hu SC, Yu HS, Yen FL, et al.
CXCR7 expression correlates with tumor depth in cutaneous squamous cell carcinoma skin lesions and promotes tumor cell survival through ERK activation.
Exp Dermatol. 2014; 23(12):902-8 [PubMed] Related Publications
The chemokine receptor CXCR7 has been demonstrated to be involved in the development of certain cancers, but its role in cutaneous squamous cell carcinoma (SCC) has not been previously investigated. We seek to determine whether CXCR7 is expressed in human cutaneous SCC skin lesions and SCC cell lines. In addition, we evaluate whether CXCR7 plays a role in SCC cell proliferation, survival and migration and which signalling pathways are involved. Using quantitative RT-PCR to analyse the mRNA expression of 19 different chemokine receptors, we found that CXCR7 was much more highly expressed compared to other chemokine receptors in cutaneous SCC cell lines (HSC-1 and HSC-5). On immunohistochemical staining, CXCR7 was found to be expressed in 70% (28 of 40) of human cutaneous SCC tissue specimens, and its expression correlated with tumor depth >4 mm and cancer stage ≥II. CXCR7 but not CXCR4 protein was expressed on the surface of HSC-1 and HSC-5 cells by flow cytometry. Activation of the CXCR7 receptor by CXCL12 promoted survival of HSC-1 and HSC-5 cells through the ERK pathway, but had no significant effect on cell proliferation or migration. In summary, our findings indicate that CXCR7 is frequently expressed in cutaneous SCC skin lesions and its expression correlates with tumor depth and cancer stage. CXCR7 is the predominant chemokine receptor expressed in SCC cell lines, and activation of CXCR7 by CXCL12 promotes survival of SCC cells through the ERK pathway. These findings provide new insights into the significance of CXCR7 in the pathophysiology of SCC.

Onish C, Mori-Kimachi S, Hirade T, et al.
Internal tandem duplication mutations in FLT3 gene augment chemotaxis to Cxcl12 protein by blocking the down-regulation of the Rho-associated kinase via the Cxcl12/Cxcr4 signaling axis.
J Biol Chem. 2014; 289(45):31053-65 [PubMed] Article available free on PMC after 07/11/2015 Related Publications
Internal tandem duplication mutations in the Flt3 gene (ITD-FLT3) enhance cell migration toward the chemokine Cxcl12, which is highly expressed in the therapy-protective bone marrow niche, providing a potential mechanism underlying the poor prognosis of ITD-FLT3(+) acute myeloid leukemia. We aimed to investigate the mechanisms linking ITD-FLT3 to increased cell migration toward Cxcl12. Classification of the expression of Cxcl12-regulated genes in ITD-FLT3(+) cells demonstrated that the enhanced migration of ITD-FLT3(+) cells toward Cxcl12 was associated with the differential expression of genes downstream of Cxcl12/Cxcr4, which are functionally distinct from those expressed in ITD-FLT3(-) cells but are independent of the Cxcr4 expression levels. Among these differentially regulated genes, the expression of Rock1 in the ITD-FLT3(+) cells that migrated toward Cxcl12 was significantly higher than in ITD-FLT3(-) cells that migrated toward Cxcl12. In ITD-FLT3(-) cells, Rock1 expression and Mypt1 phosphorylation were transiently up-regulated but were subsequently down-regulated by Cxcl12. In contrast, the presence of ITD-FLT3 blocked the Cxcl12-induced down-regulation of Rock1 and early Mypt1 dephosphorylation. Likewise, the FLT3 ligand counteracted the Cxcl12-induced down-regulation of Rock1 in ITD-FLT3(-) cells, which coincided with enhanced cell migration toward Cxcl12. Rock1 antagonists or Rock1 shRNA abolished the enhanced migration of ITD-FLT3(+) cells toward Cxcl12. Our findings demonstrate that ITD-FLT3 increases cell migration toward Cxcl12 by antagonizing the down-regulation of Rock1 expression. These findings suggest that the aberrant modulation of Rock1 expression and activity induced by ITD-FLT3 may enhance acute myeloid leukemia cell chemotaxis to the therapy-protective bone marrow niche, where Cxcl12 is abundantly expressed.

Moreno MJ, Bosch R, Dieguez-Gonzalez R, et al.
CXCR4 expression enhances diffuse large B cell lymphoma dissemination and decreases patient survival.
J Pathol. 2015; 235(3):445-55 [PubMed] Related Publications
The chemokine receptor CXCR4 has been implicated in the migration and trafficking of malignant B cells in several haematological malignancies. Over-expression of CXCR4 has been identified in haematological tumours, but data concerning the role of this receptor in diffuse large B cell lymphoma (DLBCL) are lacking. CXCR4 is a marker of poor prognosis in various neoplasms, correlating with metastatic disease and decreased survival of patients. We studied CXCR4 involvement in cell migration in vitro and dissemination in vivo. We also evaluated the prognostic significance of CXCR4 in 94 biopsies of DLBCL patients. We observed that the level of expression of CXCR4 in DLBCL cell lines correlated positively with in vitro migration. Expression of the receptor was also associated with increased engraftment and dissemination, and decreased survival time in NOD/SCID mice. Furthermore, administration of a specific CXCR4 antagonist, AMD3100, decreased dissemination of DLBCL cells in a xenograft mouse model. In addition, we found that CXCR4 expression is an independent prognostic factor for shorter overall survival and progression-free survival in DLBCL patients. These results show that CXCR4 mediates dissemination of DLBCL cells and define for the first time its value as an independent prognostic marker in DLBCL patients.

Razmkhah M, Arabpour F, Taghipour M, et al.
Expression of chemokines and chemokine receptors in brain tumor tissue derived cells.
Asian Pac J Cancer Prev. 2014; 15(17):7201-5 [PubMed] Related Publications
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.

Hu TH, Yao Y, Yu S, et al.
SDF-1/CXCR4 promotes epithelial-mesenchymal transition and progression of colorectal cancer by activation of the Wnt/β-catenin signaling pathway.
Cancer Lett. 2014; 354(2):417-26 [PubMed] Related Publications
Stromal cell-derived factor 1 (SDF-1) and its receptor, CXCR4, play an important role in angiogenesis and are associated with tumor progression. This study aimed to investigate the role of SDF-1/CXCR4-mediated epithelial-mesenchymal transition (EMT) and the progression of colorectal cancer (CRC) as well as the underlying mechanisms. The data showed that expression of CXCR4 and β-catenin mRNA and protein was significantly higher in CRC tissues than in distant normal tissues. CXCR4 expression was associated with β-catenin expression in CRC tissues, whereas high CXCR4 expression was strongly associated with low E-cadherin, high N-cadherin, and high vimentin expression, suggesting a cross talk between the SDF-1/CXCR4 axis and Wnt/β-catenin signaling pathway in CRC. In vitro, SDF-1 induced CXCR4-positive colorectal cancer cell invasion and EMT by activation of the Wnt/β-catenin signaling pathway. In contrast, SDF-1/CXCR4 axis activation-induced colorectal cancer invasion and EMT was effectively inhibited by the Wnt signaling pathway inhibitor Dickkopf-1. In conclusion, CXCR4-promoted CRC progression and EMT were regulated by the Wnt/β-catenin signaling pathway. Thus, targeting of the SDF-1/CXCR4 axis could have clinical applications in suppressing CRC progression.

Liu W, Wang Y, Wang H, Wang A
Anticancer effects of chemokine receptor 4(CXCR4) gene silenced by CXCR4-siRNA in nude mice model of ovarian cancer.
Cell Biochem Biophys. 2014; 70(3):1893-900 [PubMed] Related Publications
The aim is to study the anticancer effect of CXCR4 gene knockdown by CXCR4-siRNA in nude mice model of ovarian cancer. Injecti the SW626 tumor cells which had been transfected by vectors to make nude mouse model of ovarian cancer. The model mice were divided into interference group, negative control group, and blank control group. When the level of target genes were knocked down, the tumor volume was monitored and the tumor quality was measured; the expression of CXCR4 gene in the xenograft tumor was detected by RT-PCR, Western blot, and immunohistochemical staining. Nude mice model with implanted tumor were built successfully, after observing for 20 days. While the CXCR4 was knocked down, the abilities of invasion were weakened; the tumor volume and the tumor quality were also decreased. The CXCR4 mRNA and protein of the interference group decreased significantly (P < 0.05). The animal experiment was confirmed that silencing of CXCR4 gene by siRNA can obviously inhibit the tumorigenesis of ovarian cancer. Our work will provide the theoretical basis for genes interference therapy of ovarian cancer in future.

Borge M, Remes Lenicov F, Nannini PR, et al.
The expression of sphingosine-1 phosphate receptor-1 in chronic lymphocytic leukemia cells is impaired by tumor microenvironmental signals and enhanced by piceatannol and R406.
J Immunol. 2014; 193(6):3165-74 [PubMed] Related Publications
Chronic lymphocytic leukemia (CLL) is characterized by the progressive accumulation of clonal B lymphocytes. Proliferation occurs in lymphoid tissues upon interaction of leukemic cells with a supportive microenvironment. Therefore, the mobilization of tissue-resident CLL cells into the circulation is a useful therapeutic strategy to minimize the reservoir of tumor cells within survival niches. Because the exit of normal lymphocytes from lymphoid tissues depends on the presence of sphingosine-1 phosphate (S1P) and the regulated expression of S1P receptor-1 (S1PR1), we investigated whether the expression and function of S1PR1 can be modulated by key microenvironment signals. We found that activation of CLL cells with CXCL12, fibroblast CD40L(+), BCR cross-linking, or autologous nurse-like cells reduces their S1PR1 expression and the migratory response toward S1P. Moreover, we found that S1PR1 expression was reduced in the proliferative/activated subset of leukemic cells compared with the quiescent subset from the same patient. Similarly, bone marrow-resident CLL cells expressing high levels of the activation marker CD38 showed a lower expression of S1PR1 compared with CD38(low) counterparts. Finally, given that treatment with BCR-associated kinase inhibitors induces a transient redistribution of leukemic cells from lymphoid tissues to circulation, we studied the effect of the Syk inhibitors piceatannol and R406 on S1PR1 expression and function. We found that they enhance S1PR1 expression in CLL cells and their migratory response toward S1P. Based on our results, we suggest that the regulated expression of S1PR1 might modulate the egress of the leukemic clone from lymphoid tissues.

Jeong WJ, Choi IJ, Park MW, et al.
CXCR4 antagonist inhibits perineural invasion of adenoid cystic carcinoma.
J Clin Pathol. 2014; 67(11):992-8 [PubMed] Related Publications
AIM: Perineural invasion and expression of CXCR4 is characteristic of adenoid cystic carcinoma (ACC). Herein, we aimed to demonstrate CXCR4 expression in ACC, identify its association with perineural invasion and investigate the impact of CXCR4 inhibitor in vitro and in a murine perineural invasion model.
METHODS: Expression of CXCR4 was assessed in ACC cell lines and in human tissue. The effects of gene knockdown using siRNA and specific blocker of CXCR4 (AMD3100) were evaluated in vitro. A preclinical perineural invasion model was developed using BALB/c nude mouse. The effect of AMD3100 was evaluated in vivo.
RESULTS: CXCR4 was highly expressed in aggressive strains of ACC in vitro, in the tumour in the animal model and in the tumour of human tissue. SDF-1 expression was also demonstrated in the nerve of murine and human tissue. Gene knockdown by siRNA and inhibition by a CXCR4-specific inhibitor AMD3100 effectively abrogated invasion but not proliferation of ACC in vitro. The rate of perineural invasion was significantly decreased with AMD3100 treatment in the animal model.
CONCLUSIONS: CXCR4 is associated with perineural invasion in ACC. AMD3100, which can effectively diminish perineural invasion of ACC, may have an adjuvant role in the management of ACC.

Yadav SS, Prasad SB, Das M, et al.
Epigenetic silencing of CXCR4 promotes loss of cell adhesion in cervical cancer.
Biomed Res Int. 2014; 2014:581403 [PubMed] Article available free on PMC after 07/11/2015 Related Publications
In the network of chemokine signaling pathways, recent reports have described the SDF-1α/CXCR4 axis and its role in cancer progression and metastasis. Interestingly, we found downregulation of CXCR4 at both transcript and protein level in cervical cancer cell lines and primary tumors. We also found CXCR4 promoter hypermethylation in cervical cancer cell lines and primary biopsy samples. DNA hypomethylating drug 5-AZA-2'-deoxycytidine and histone deacetylase inhibitor Trichostatin A treatments in cell lines reactivate both CXCR4 transcription and protein expression. Cell adhesion assay demonstrated that autocrine SDF-1α promotes the loss of cell adhesion while paracrine SDF-1α predominantly protects the normal cervical cells from loss of cell adhesion. Cervical cancer cell line C-33A having increased expression of CXCR4 after TSA treatment showed increased cell adhesion by paracrine source of SDF-1α in comparison to untreated C-33A. These findings demonstrate the first evidence that epigenetic silencing of CXCR4 makes the cells inefficient to respond to the paracrine source of SDF-1α leading to loss of cell adhesion, one of the key events in metastases and progression of the disease. Our results provide novel insight of SDF-1α/CXCR4 signaling in tumor microenvironment which may be promising to further delineate molecular mechanism of cervical carcinogenesis.

Sakashita K, Kato I, Daifu T, et al.
In vitro expansion of CD34(+)CD38(-) cells under stimulation with hematopoietic growth factors on AGM-S3 cells in juvenile myelomonocytic leukemia.
Leukemia. 2015; 29(3):606-14 [PubMed] Related Publications
Using serum-containing culture, we examined whether AGM-S3 stromal cells, alone or in combination with hematopoietic growth factor(s), stimulated the proliferation of CD34(+) cells from patients with juvenile myelomonocytic leukemia (JMML). AGM-S3 cells in concert with stem cell factor plus thrombopoietin increased the numbers of peripheral blood CD34(+) cells to approximately 20-fold of the input value after 2 weeks in nine JMML patients with either PTPN11 mutations or RAS mutations, who received allogeneic hematopoietic transplantation. Granulocyte-macrophage colony-stimulating factor (GM-CSF) also augmented the proliferation of JMML CD34(+) cells on AGM-S3 cells. The expansion potential of CD34(+) cells was markedly low in four patients who achieved spontaneous hematological improvement. A large proportion of day-14-cultured CD34(+) cells were negative for CD38 and cryopreservable. Cultured JMML CD34(+)CD38(-) cells expressed CD117, CD116, c-mpl, CD123, CD90, but not CXCR4, and formed GM and erythroid colonies. Day-7-cultured CD34(+) cells from two of three JMML patients injected intrafemorally into immunodeficient mice stimulated with human GM-CSF after transplantation displayed significant hematopoietic reconstitution. The abilities of OP9 cells and MS-5 cells were one-third and one-tenth, respectively, of the value obtained with AGM-S3 cells. Our culture system may provide a useful tool for elucidating leukemogenesis and for therapeutic approaches in JMML.

Hartimath SV, van Waarde A, Dierckx RA, de Vries EF
Evaluation of N-[(11)C]methyl-AMD3465 as a PET tracer for imaging of CXCR4 receptor expression in a C6 glioma tumor model.
Mol Pharm. 2014; 11(11):3810-7 [PubMed] Related Publications
The chemokine receptor CXCR4 and its ligand CXCL12 play an important role in tumor progression and metastasis. CXCR4 receptors are expressed by many cancer types and provide a potential target for treatment. Noninvasive detection of CXCR4 may aid diagnosis and improve therapy selection. It has been demonstrated in preclinical studies that positron emission tomography (PET) with a radiolabeled small molecule could enable noninvasive monitoring of CXCR4 expression. Here, we prepared N-[(11)C]methyl-AMD3465 as a new PET tracer for CXCR4. N-[(11)C]Methyl-AMD3465 was readily prepared by N-methylation with [(11)C]CH3OTf. The tracer was obtained in a 60 ± 2% yield (decay corrected), the purity of the tracer was >99%, and specific activity was 47 ± 14 GBq/μmol. Tracer stability was tested in vitro using liver microsomes and rat plasma; excellent stability was observed. The tracer was evaluated in rat C6 glioma and human PC-3 cell lines. In vitro cellular uptake of N-[(11)C]methyl-AMD3465 was receptor mediated. The effect of transition metal ions (Cu(2+), Ni(2+), and Zn(2+)) on cellular binding was examined in C6 cells, and the presence of these ions increased the cellular binding of the tracer 9-, 7-, and 3-fold, respectively. Ex vivo biodistribution and PET imaging of N-[(11)C]methyl-AMD3465 were performed in rats with C6 tumor xenografts. Both PET and biodistribution studies demonstrated specific accumulation of the tracer in the tumor (SUV 0.6 ± 0.2) and other CXCR4 expressing organs, such as lymph node (1.5 ± 0.2), liver (8.9 ± 1.0), bone marrow (1.0 ± 0.3), and spleen (1.0 ± 0.1). Tumor uptake was significantly reduced (66%, p < 0.01) after pretreatment with Plerixafor (AMD3100). Biodistribution data indicates a tumor-to-muscle ratio of 7.85 and tumor-to-plasma ratio of 1.14, at 60 min after tracer injection. Our data demonstrated that N-[(11)C]methyl-AMD3465 is capable of detecting physiologic CXCR4 expression in tumors and other CXCR4 expressing tissues. These results warrant further evaluation of N-[(11)C]methyl-AMD3465 as a potential PET tracer for CXCR4 receptor imaging.

Miyoshi K, Kohashi K, Fushimi F, et al.
Close correlation between CXCR4 and VEGF expression and frequent CXCR7 expression in rhabdomyosarcoma.
Hum Pathol. 2014; 45(9):1900-9 [PubMed] Related Publications
CXC chemokine receptor 4 (CXCR4) expression is reportedly correlated with both vascular endothelial growth factor (VEGF) expression and poor prognosis in a variety of cancers. Its relation to CXC chemokine receptor 7 (CXCR7) is also noted in several malignancies, including rhabdomyosarcoma (RMS) cell lines. However, the correlations between these chemokine receptors and angiogenic factors have not yet been adequately investigated in RMS clinical specimens. By immunohistochemistry, we assessed CXCR4, CXCR7, CC chemokine receptor 6, CC chemokine receptor 7, VEGF expression, microvessel density, and MIB-1 labeling index in 82 formalin-fixed RMS specimens, including 34 primary alveolar RMS and 44 primary embryonal RMS (ERMS). Twenty-six frozen samples were available for investigation by quantitative reverse transcription polymerase chain reaction to detect the messenger RNA expression levels of these molecules. We also evaluated their significance with respect to clinicopathological factors and patient survival rates. Primary RMS showed high expression of CXCR7 (83.1%) regardless of the histologic subtype. High cytoplasmic CXCR4 and high VEGF expression revealed significant correlations in both ERMS and alveolar RMS (P = .0051 and P = .0003, respectively). By univariate analysis of ERMS cases, the tumors with high VEGF expression showed significantly poor prognoses (P = .0017). High VEGF expression also was the independent adverse prognostic factor for ERMS. Because CXCR4, CXCR7, and VEGF are widely expressed in RMS, the combination of these antagonists may provide a potential target for molecular therapy.

Ge J, Hu Y, Gui Y, et al.
Chemotherapy-induced alteration of SDF-1/CXCR4 expression in bone marrow-derived mesenchymal stem cells from adolescents and young adults with acute lymphoblastic leukemia.
J Pediatr Hematol Oncol. 2014; 36(8):617-23 [PubMed] Related Publications
Bone marrow-derived mesenchymal stem cells (BM-MSCs) in the marrow stroma provide a scaffold for hematopoiesis. Chemokine stromal cell-derived factor-1 (SDF-1) and its receptor CXCR4 have been shown to affect the engraftment of hematopoietic stem cells. However, little is known about SDF-1/CXCR4's functions in regulating BM-MSCs in humans. As an initial step toward this issue, we have evaluated expression of SDF-1/CXCR4 in the BM-MSCs from a cohort of adolescents and young adults with acute lymphoblastic leukemia (ALL). We found a decrease of the CXCR4 level and an increase of the SDF-1 level in these MSCs of ALL. Moreover, cell migration appeared to be impaired in the MSCs of ALL. These changes were reversed by chemotherapy. Taken together, alteration of SDF-1/CXCR4 expression could be potentially developed as biomarkers for monitoring the effectiveness of chemotherapy.

Lucansky V, Krmencikova-Fliegl M, Stanek L, Vonka V
Administration of a plasmid that expresses SDF-1α affects the oncogenic potential of mouse bcr-abl-transformed cells.
Mol Med Rep. 2014; 10(4):2116-22 [PubMed] Related Publications
Stromal-derived factor 1α (SDF‑1α, also known as CXCL12) is a chemokine that exerts its effects through the G-protein coupled receptors, C-X-C chemokine receptor type 4 (CXCR4) and 7 (CXCR7). There is marked evidence that the SDF-1/CXCR4 axis is involved in the pathogenesis of leukemia and therapies that target this axis are under development. The present study aimed to increase the efficacy of a DNA-based bcr-abl vaccine by simultaneously immunizing mice with a plasmid carrying the whole SDF-1α gene. Bcr-abl‑transformed 12B1 cells were used to challenge the mice. These cells have the oncogenic potential to induce both leukemia following intravenous inoculation and lymphoma-type solid tumors after subcutaneous inoculation. Administering an SDF‑1 carrying plasmid together with the bcr-abl vaccine resulted in increased survival following a challenge with subcutaneously administered 12B1 cells, although the difference was not statistically significant. However, there was a difference when the animals that developed subcutaneous tumors were only taken into consideration. In doubly-treated mice, significantly more mice failed to develop solid tumors than mice that had only received the bcr-abl vaccine. By contrast, the occurrence of fatal leukemia was significantly higher in the mice that were treated with the SDF-1 plasmid, regardless of whether they were immunized with the bcr-abl-vaccine. No humoral or cellular immune responses against SDF‑1 were detected in the treated mice, which suggested that the changes in oncogenic potential of 12B1 cells were due to the activity of SDF-1 itself.

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