Gene Summary

Gene:ACKR3; atypical chemokine receptor 3
Aliases: RDC1, CXCR7, RDC-1, CMKOR1, CXC-R7, CXCR-7, GPR159
Summary:This gene encodes a member of the G-protein coupled receptor family. Although this protein was earlier thought to be a receptor for vasoactive intestinal peptide (VIP), it is now considered to be an orphan receptor, in that its endogenous ligand has not been identified. The protein is also a coreceptor for human immunodeficiency viruses (HIV). Translocations involving this gene and HMGA2 on chromosome 12 have been observed in lipomas. [provided by RefSeq, Jul 2008]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:atypical chemokine receptor 3
Source:NCBIAccessed: 01 September, 2019

Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 01 September 2019 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.

  • Cell Proliferation
  • TNF-Related Apoptosis-Inducing Ligand
  • Neoplasm Metastasis
  • G-Protein-Coupled Receptors
  • Lymphatic Metastasis
  • Rhabdomyosarcoma
  • Squamous Cell Carcinoma
  • Transcriptome
  • Receptors, Chemokine
  • Immunohistochemistry
  • Neoplasm Invasiveness
  • Survival Rate
  • Transfection
  • Wound Healing
  • Cancer Gene Expression Regulation
  • Signal Transduction
  • CXCR4
  • Staging
  • Messenger RNA
  • Receptors, CXCR
  • Biomarkers, Tumor
  • Tissue Array Analysis
  • Bladder Cancer
  • Western Blotting
  • RT-PCR
  • Chemokine CXCL12
  • Gene Expression Profiling
  • Breast Cancer
  • Apoptosis
  • Disease Progression
  • Chromosome 2
  • Transforming Growth Factor beta
  • siRNA
  • Cell Movement
  • beta-Arrestins
  • SOXB1 Transcription Factors
  • Gene Expression
  • Tumor Microenvironment
  • Phosphorylation
  • Acute Lymphocytic Leukaemia
Tag cloud generated 01 September, 2019 using data from PubMed, MeSH and CancerIndex

Specific Cancers (4)

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: ACKR3 (cancer-related)

Li N, Xu H, Ou Y, et al.
LPS-induced CXCR7 expression promotes gastric Cancer proliferation and migration via the TLR4/MD-2 pathway.
Diagn Pathol. 2019; 14(1):3 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Lipopolysaccharide (LPS) from Helicobacter pylori (HP) plays an important role in gastric cancer occurrence and development. Toll-like receptor 4 (TLR4) and myeloid differential protein-2 (MD-2) are also reported to be involved in gastric cancer cell proliferation and invasion. CXC chemokine receptor 7 (CXCR7), a second receptor for CXCL12, has been detected in multiple types of tumor tissues. Nevertheless, the biological function and regulation of CXCR7 and its relationship with TLR4 and MD-2 in gastric cancer are not completely understood and therefore warrant further study.
METHODS: CXCR7 expression was examined in 150 gastric cancer tissues using immunohistochemistry (IHC). RT-PCR and western blotting were used to detect CXCR7 expression in several gastric cancer cell lines (SGC7901, AGS, MGC-803, MKN-45 and BGC823). shRNAs were designed using a pGPU6/GFP/Neo vector. A CCK-8 assay was used to assess cell proliferation, and transwell assays were performed to assess cell migration. In addition, a gastric cancer xenograft model was generated.
RESULTS: The LPS-TLR4-MD-2 pathway elevates CXCR7 expression in SGC7901 cells, and TLR4/MD-2-mediated increases in CXCR7 levels modulate the proliferation and migration of tumor cells. Knockdown of TLR4 and MD-2 demonstrated that both are essential for LPS-induced CXCR7 expression, which in turn is responsible for LPS-induced SGC7901 cell proliferation and migration. Moreover, higher TLR4, MD-2 and CXCR7 expression was detected in gastric cancer tissues than in paracancerous normal control tissues. The expression levels of TLR4, MD-2 and CXCR7 were closely related to gastric cancer TNM stage and lymph node metastasis. In an animal model, significant differences in CXCR7 expression in tumor masses were observed between the control group and experimental group.
CONCLUSIONS: The results of this study indicate that CXCR7 plays an important role in gastric cancer progression via inflammatory mechanisms, suggesting that CXCR7 could provide a basis for the development and clinical application of a targeted drug for gastric cancer.

Cabrero-de Las Heras S, Martínez-Balibrea E
CXC family of chemokines as prognostic or predictive biomarkers and possible drug targets in colorectal cancer.
World J Gastroenterol. 2018; 24(42):4738-4749 [PubMed] Free Access to Full Article Related Publications
Colorectal cancer (CRC) is the third most common cancer in men and the second most common cancer in women, worldwide. In the early stages of the disease, biomarkers predicting early relapse would improve survival rates. In metastatic patients, the use of predictive biomarkers could potentially result in more personalized treatments and better outcomes. The CXC family of chemokines (CXCL1 to 17) are small (8 to 10 kDa) secreted proteins that attract neutrophils and lymphocytes. These chemokines signal through chemokine receptors (CXCR) 1 to 8. Several studies have reported that these chemokines and receptors have a role in either the promotion or inhibition of cancer, depending on their capacity to suppress or stimulate the action of the immune system, respectively. In general terms, activation of the CXCR1/CXCR2 pathway or the CXCR4/CXCR7 pathway is associated with tumor aggressiveness and poor prognosis; therefore, the specific inhibition of these receptors is a possible therapeutic strategy. On the other hand, the lesser known CXCR3 and CXCR5 axes are generally considered to be tumor suppressor signaling pathways, and their stimulation has been suggested as a way to fight cancer. These pathways have been studied in tumor tissues (using immunohistochemistry or measuring mRNA levels) or serum [using enzyme-linked immuno sorbent assay (ELISA) or multiplexing techniques], among other sample types. Common variants in genes encoding for the CXC chemokines have also been investigated as possible biomarkers of the disease. This review summarizes the most recent findings on the role of CXC chemokines and their receptors in CRC and discusses their possible value as prognostic or predictive biomarkers as well as the possibility of targeting them as a therapeutic strategy.

Ando N, Furuichi Y, Kasai S, et al.
Chemosensitivity is differentially regulated by the SDF-1/CXCR4 and SDF-1/CXCR7 axes in acute lymphoblastic leukemia with MLL gene rearrangements.
Leuk Res. 2018; 75:36-44 [PubMed] Related Publications
Although recent advances in chemotherapy have markedly improved outcome of acute lymphoblastic leukemia (ALL), infantile ALL with MLL gene rearrangements (MLL+ALL) is refractory to chemotherapy. We have shown that specific cytokines FLT3 ligand and TGFβ1 both of which are produced from bone marrow stromal cells synergistically induced MLL+ALL cells into chemo-resistant quiescence, and that treatment of MLL+ALL cells with inhibitors against FLT3 and/or TGFβ1 receptor partially but significantly converts them toward chemo-sensitive. In the present study, we showed that MLL+ALL cells expressed CXCR4 and CXCR7, both receptors for the same chemokine stromal cell derived factor-1 (SDF-1), but their biological events were differentially regulated by the SDF-1/CXCR4 and SDF-1/CXCR7 axes and particularly exerted an opposite effect for determining chemo-sensitivity of MLL+ALL cells; enhancement via the SDF-1/CXCR4 axis vs. suppression via the SDF-1/CXCR7 axis. Because cytosine-arabinoside-induced apoptosis of MLL+ALL cells was inhibited by pretreatment with the CXCR4 inhibitor but rather accelerated by pretreatment with the CXCR7 inhibitor, an application of the CXCR7 inhibitor may become a good treatment option in future for MLL+ALL patients. MLL+ALL has a unique gene profile distinguishable from other types of ALL and AML, and should be investigated separately in responses to biological active agents including chemokine inhibitors.

Song ZY, Wang F, Cui SX, et al.
CXCR7/CXCR4 heterodimer-induced histone demethylation: a new mechanism of colorectal tumorigenesis.
Oncogene. 2019; 38(9):1560-1575 [PubMed] Related Publications
Both chemokine receptors (CXCRs) 7 and 4 can facilitate immune cell migration and mediate a vast array of physiological and pathological events. Herein we report, in both human and animal studies, that these two CXCRs can form heterodimers in vivo and promote colorectal tumorigenesis through histone demethylation. Compared with adjacent non-neoplastic tissue, human colorectal cancer (CRC) tissue showed a significant higher expression of CXCR4 and CXCR7, which was colocalized in the cancer cell epithelium. The CXCR/CXCR4 heterodimerization was associated with increased histone demethylase JMJD2A. Villin-CXCR7-CXCR4 transgenic mice demonstrated a greater degree of exacerbated colitis and tumorigenesis than villin-CXCR7 and villin-CXCR4 mice. The CXCR7/CXCR4 heterodimerization also promoted APC mutation-driven colorectal tumorigenesis in APC

Benhadjeba S, Edjekouane L, Sauvé K, et al.
Feedback control of the CXCR7/CXCL11 chemokine axis by estrogen receptor α in ovarian cancer.
Mol Oncol. 2018; 12(10):1689-1705 [PubMed] Free Access to Full Article Related Publications
Ovarian cancer (OC) is one of the most intractable diseases, exhibiting tremendous molecular heterogeneity and lacking reliable methods for screening, resulting in late diagnosis and widespread peritoneal dissemination. Menopausal estrogen replacement therapy is a well-recognized risk factor for OC, but little is known about how estrogen might contribute to this disease at the cellular level. This study identifies chemokine receptor CXCR7/ACKR3 as an estrogen-responsive gene, whose expression is markedly enhanced by estrogen through direct recruitment of ERα and transcriptional active histone modifications in OC cells. The gene encoding CXCR7 chemokine ligand I-TAC/CXCL11 was also upregulated by estrogen, resulting in Ser-118 phosphorylation, activation, and recruitment of estrogen receptor ERα at the CXCR7 promoter locus for positive feedback regulation. Both CXCR7 and CXCL11, but not CXCR3 (also recognized to interact with CXCL11), were found to be significantly increased in stromal sections of microdissected tumors and positively correlated in mesenchymal subtype of OC. Estrogenic induction of mesenchymal markers SNAI1, SNAI2, and CDH2 expression, with a consequent increase in cancer cell migration, was shown to depend on CXCR7, indicating a key role for CXCR7 in mediating estrogen upregulation of mesenchymal markers to induce invasion of OC cells. These findings identify a feed-forward mechanism that sustains activation of the CXCR7/CXCL11 axis under ERα control to induce the epithelial-mesenchymal transition pathway and metastatic behavior of OC cells. Such interplay underlies the complex gene profile heterogeneity of OC that promotes changes in tumor microenvironment and metastatic acquisition.

Moreno MJ, Gallardo A, Novelli S, et al.
CXCR7 expression in diffuse large B-cell lymphoma identifies a subgroup of CXCR4+ patients with good prognosis.
PLoS One. 2018; 13(6):e0198789 [PubMed] Free Access to Full Article Related Publications
The CXCR4/CXCL12 axis has been extensively associated with different types of cancer correlating with higher aggressiveness and metastasis. In diffuse large B-cell lymphoma (DLBCL), the expression of the chemokine receptor CXCR4 is involved in the dissemination of malignant B cells and is a marker of poor prognosis. CXCR7 is a chemokine receptor that binds to the same ligand as CXCR4 and regulates de CXCR4-CXCL12 axis. These findings together with the report of CXCR7 prognostic value in several tumor types, led us to evaluate the expression of CXCR7 in diffuse large B-cell lymphoma biopsies. Here, we describe that CXCR7 receptor is an independent prognostic factor that associates with good clinical outcome. Moreover, the expression of CXCR7 associates with increased survival in CXCR4+ but not in CXCR4- DLBCL patients. Thus, the combined immunohistochemical evaluation of both CXCR7 and CXCR4 expression in DLBCL biopsies may improve their prognostic value as single markers. Finally, we show that CXCR7 overexpression in vitro is able to diminish DLBCL cell survival and increase their sensitivity to antitumor drugs. Hence, further studies on the CXCR7 receptor may establish its role in DLBCL and the molecular mechanisms that modulate CXCR4 activity.

Salazar N, Carlson JC, Huang K, et al.
A Chimeric Antibody against ACKR3/CXCR7 in Combination with TMZ Activates Immune Responses and Extends Survival in Mouse GBM Models.
Mol Ther. 2018; 26(5):1354-1365 [PubMed] Free Access to Full Article Related Publications
Glioblastoma (GBM) is the least treatable type of brain tumor, afflicting over 15,000 people per year in the United States. Patients have a median survival of 16 months, and over 95% die within 5 years. The chemokine receptor ACKR3 is selectively expressed on both GBM cells and tumor-associated blood vessels. High tumor expression of ACKR3 correlates with poor prognosis and potential treatment resistance, making it an attractive therapeutic target. We engineered a single chain FV-human FC-immunoglobulin G1 (IgG

Werner TA, Forster CM, Dizdar L, et al.
CXCR4/CXCR7/CXCL12 axis promotes an invasive phenotype in medullary thyroid carcinoma.
Br J Cancer. 2017; 117(12):1837-1845 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Medullary thyroid carcinoma (MTC) is a rare and challenging endocrine malignancy. Once spread, the therapeutic options are limited and the outcome poor. For these patients, the identification of new druggable biological markers is of great importance. Here, we investigated the prognostic and biological role of the C-X-C chemokine receptors type 4 and 7 (CXCR4/7) in MTC.
METHODS: Eighty-six MTC and corresponding non-neoplastic thyroid specimens were immunohistochemically stained for CXCR4/7 using tissue microarray technology and expression levels correlated with clinicopathological variables. Medullary thyroid carcinoma cell line TT was treated with recombinant human SDF1α/CXCL12 (rh-SDF1α) and CXCR4 antagonists AMD3100 and WZ811. Changes in cell cycle activation, tumour cell invasiveness as well as changes in mRNA expression levels of genes associated with epithelial-mesenchymal transition (EMT) were investigated.
RESULTS: High CXCR4 expression was associated with large tumour size and metastatic disease. CXCR4 antagonists significantly reduced tumour cell invasiveness, while the treatment with rh-SDF1α stimulated invasive growth, caused cell cycle activation and induced EMT.
CONCLUSIONS: The CXCR4/CXCR7/CXCL12 axis plays an important role in MTC. We provide first evidence that the chemokine receptors might serve as potential therapeutic targets in patients with advanced MTC and offer new valuable insight into the underlying molecular machinery of metastatic MTC.

Qiao Y, Zhang C, Li A, et al.
IL6 derived from cancer-associated fibroblasts promotes chemoresistance via CXCR7 in esophageal squamous cell carcinoma.
Oncogene. 2018; 37(7):873-883 [PubMed] Related Publications
Various factors and cellular components in the tumor microenvironment are key drivers associated with drug resistance in many cancers. Here, we analyzed the factors and molecular mechanisms involved in chemoresistance in patients with esophageal squamous cell carcinoma (ESCC). We found that interleukin 6 (IL6) derived mainly from cancer-associated fibroblasts played the most important role in chemoresistance by upregulating C-X-C motif chemokine receptor 7 (CXCR7) expression through signal transducer and activator of transcription 3/nuclear factor-κB pathway. CXCR7 knockdown resulted in the inhibition of IL6-induced proliferation and chemoresistance. In addition, CXCR7 silencing significantly decreased gene expression associated with stemness, chemoresistance and epithelial-mesenchymal transition and suppressed the proliferation ability of ESCC cells in three-dimensional culture systems and angiogenesis assay. In clinical samples, ESCC patients with high expression of CXCR7 and IL6 presented a significantly worse overall survival and progression-free survival upon receiving cisplatin after operation. These results suggest that the IL6-CXCR7 axis may provide a promising target for the treatment of ESCC.

Espinoza-Sánchez NA, Vadillo E, Balandrán JC, et al.
Evidence of lateral transmission of aggressive features between different types of breast cancer cells.
Int J Oncol. 2017; 51(5):1482-1496 [PubMed] Free Access to Full Article Related Publications
Breast cancer (BrC) is a major public health problem worldwide. The intra-tumoral heterogeneity and tumor cell plasticity importantly contribute to disease progression and treatment failure. However, the dynamic interactions between different tumor clones, as well as their contribution to tumor aggressiveness are still poorly understood. In this study, we provide evidence of a lateral transmission of aggressive features between aggressive and non-aggressive tumor cells, consisting of gain of expression of cancer stem cell markers, increased expression of CXCL12 receptors CXCR4 and CXCR7 and increased invasiveness in response to CXCL12, which correlated with high levels of secretion of pro-inflammatory mediators G-CSF, GM-CSF, MCP-1, IL-8 and metalloproteinases 1 and 2 by the aggressive cells. Noteworthy, we found no evidence of a TGF-β participation in the inducible-invasive phenotype. Altogether, our results provide evidence of communication between tumor cells with different potentials for aggressiveness, which could influence intra-tumoral population dynamics promoting the emergence of clones with novel functions. Understanding these interactions will provide better targets for diagnosis, prognosis and therapeutic strategies.

Katsura M, Shoji F, Okamoto T, et al.
Correlation between CXCR4/CXCR7/CXCL12 chemokine axis expression and prognosis in lymph-node-positive lung cancer patients.
Cancer Sci. 2018; 109(1):154-165 [PubMed] Free Access to Full Article Related Publications
The CXCR4/CXCR7/CXCL12 chemokine axis plays important roles in the migration of tumor cells during cancer development by modulating site-specific distant metastasis including to regional lymph nodes. We investigated the correlation of these chemokine expressions to prognosis in lymph-node-positive non-small-cell lung cancer (NSCLC) patients. A total of 140 surgically resected specimens of primary site (PS) and metastatic lymph nodes (MLN) of NSCLC involving hilar and/or mediastinal lymph nodes (N1-2) were collected. CXCR4, CXCR7 and CXCL12 expressions were evaluated. Cox regression analysis was performed to determine whether these chemokines were independent prognostic factors in N1-2 NSCLC. High expression of CXCR4 in PS and CXCL12 in MLN was associated with poor overall survival (OS) (P = .025 and .033, respectively). Significant correlations between CXCR4 expression in PS and CXCL12 expression in MLN were observed (P = .040). There was significant difference in OS between 2 groups according to expressions of CXCR4 in PS and CXCL12 in MLN (P = .0033). Expression of CXCL12 in MLN was identified as an independent prognostic factor (HR 1.79, 95% CI 1.08-3.04, P = .023). CXCL12 in MLN was mainly expressed by tumor cells compared with stromal cells (56% vs 25%, respectively, P < .0001). CXCR4/CXCL12 may play roles in tumor progression in MLN and is associated with poor prognosis of lymph-node-positive NSCLC patients.

Haghshenas MR, Ashraf MJ, Khademi B, et al.
Chemokine and chemokine receptor patterns in patients with benign and malignant salivary gland tumors: a distinct role for CCR7.
Eur Cytokine Netw. 2017; 28(1):27-35 [PubMed] Related Publications
To explore the molecular mechanisms involved in pathophysiology of malignant and benign salivary gland tumors (SGTs), we investigated main tumor-inducing chemokines and chemokine receptors, CXCL12/CXCR4/ACKR3 (CXCR7), CXCR3/CXCL10, CCR5/CCL5, CCL21/CCR7, CCL2, CCR4, CXCR5, CCR6, and CXCL8 in tumor tissues. Parotid tissues were obtained from 30 patients with malignant and benign SGTs. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to determine the mRNA expression pattern of the mentioned chemokines/chemokine receptors and immunohistochemistry (IHC) was performed to verify the expression of CCR7. Expression levels of CCR7 and CCR4 transcripts were higher in the tumor tissues of malignant cases in comparison to benign ones (p = 0.03 and 0.02). Immunohistochemistry analysis confirmed that the protein level of CCR7 concurred with the mRNA expression. CCL2 gene transcripts were observed with a higher expression in patients with tumor-free lymph nodes (LN

Waldschmidt JM, Simon A, Wider D, et al.
CXCL12 and CXCR7 are relevant targets to reverse cell adhesion-mediated drug resistance in multiple myeloma.
Br J Haematol. 2017; 179(1):36-49 [PubMed] Related Publications
Cell adhesion-mediated drug resistance (CAM-DR) by the bone marrow (BM) is fundamental to multiple myeloma (MM) propagation and survival. Targeting BM protection to increase the efficacy of current anti-myeloma treatment has not been extensively pursued. To extend the understanding of CAM-DR, we hypothesized that the cytotoxic effects of novel anti-myeloma agents may be abrogated by the presence of BM stroma cells (BMSCs) and restored by addition of the CXCL12 antagonist NOX-A12 or the CXCR4 inhibitor plerixafor. Following this hypothesis, we evaluated different anti-myeloma agents alone, with BMSCs and when combined with plerixafor or NOX-A12. We verified CXCR4, CD49d (also termed ITGA4) and CD44 as essential mediators of BM adhesion on MM cells. Additionally, we show that CXCR7, the second receptor of stromal-derived-factor-1 (CXCL12), is highly expressed in active MM. Co-culture proved that co-treatment with plerixafor or NOX-A12, the latter inhibiting CXCR4 and CXCR7, functionally interfered with MM chemotaxis to the BM. This led to the resensitization of MM cells to the anti-myeloma agents vorinostat and pomalidomide and both proteasome inhibitors bortezomib and carfilzomib. Within a multicentre phase I/II study, NOX-A12 was tested in combination with bortezomib-dexamethasone, underlining the feasibility of NOX-A12 as an active add-on agent to antagonize myeloma CAM-DR.

Hoy JJ, Kallifatidis G, Smith DK, Lokeshwar BL
Inhibition of androgen receptor promotes CXC-chemokine receptor 7-mediated prostate cancer cell survival.
Sci Rep. 2017; 7(1):3058 [PubMed] Free Access to Full Article Related Publications
The atypical C-X-C chemokine receptor 7 (CXCR7) has been implicated in supporting aggressive cancer phenotypes in several cancers including prostate cancer. However, the mechanisms driving overexpression of this receptor in cancer are poorly understood. This study investigates the role of androgen receptor (AR) in regulating CXCR7. Androgen deprivation or AR inhibition significantly increased CXCR7 expression in androgen-responsive prostate cancer cell lines, which was accompanied by enhanced epidermal growth factor receptor (EGFR)-mediated mitogenic signaling, promoting tumor cell survival through an androgen-independent signaling program. Using multiple approaches we demonstrate that AR directly binds to the CXCR7 promoter, suppressing transcription. Clustered regularly interspaced short palindromic repeats (CRISPR) directed Cas9 nuclease-mediated gene editing of CXCR7 revealed that prostate cancer cells depend on CXCR7 for proliferation, survival and clonogenic potential. Loss of CXCR7 expression by CRISPR-Cas9 gene editing resulted in a halt of cell proliferation, severely impaired EGFR signaling and the onset of cellular senescence. Characterization of a mutated CXCR7-expressing LNCaP cell clone showed altered intracellular signaling and reduced spheroid formation potential. Our results demonstrate that CXCR7 is a potential target for adjuvant therapy in combination with androgen deprivation therapy (ADT) to prevent androgen-independent tumor cell survival.

Cui YX, Bradbury R, Flamini V, et al.
MicroRNA-7 suppresses the homing and migration potential of human endothelial cells to highly metastatic human breast cancer cells.
Br J Cancer. 2017; 117(1):89-101 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: MicroRNA-7 (miR-7) has been observed as a potent tumour suppressor in multiple cancer types including breast cancer. The aim of this study was to investigate the response sensitivities of metastatic breast cancer cells to miR-7 and the roles of miR-7 in the interaction of endothelial cells and metastatic cancer cells.
METHODS: Expression profile of miRNAs in a breast cancer specimen cohort and breast cancer cells were determined using real-time quantitative miRNA assays. Effect of the altering expression of miR-7 on migration, invasion, proliferation, interaction and underlying molecular mechanism of breast cancer cells and endothelial cells was investigated after treatment with the synthesised mimic of miR-7. Luciferase activity analysis was performed to validate Wave-3 as a novel target of miR-7.
RESULTS: miR-7 expression was negatively correlated with the stage, grade and survival of the breast cancer patients. There was also differential expression of miRNAs including miR-7 in the breast cancer cells. The synthesised mimic of miR-7 inhibits the motility and wound healing potential of breast cancer cells. The highly metastatic MDA-MB-231 cells are more sensitive to the miR-7 treatment than the poorly invasive MCF-7 cells. Treatment with miR-7 downregulated the expression of EGFR, IGF1R and Wave3 in MDA-MB-231 cells but not in MCF-7 cells. In addition, we further demonstrated that miR-7 inhibited the proliferation, migration and invasion of endothelial cells. And more importantly, miR-7 suppressed the homing and migration of endothelial cells to more aggressive tumour cell conditions.
CONCLUSIONS: Given the dual inhibitory effect of miR-7 on metastatic breast cancer cells alone and the interaction of endothelial cells with the tumour-conditioned microenvironment, we suggest miR-7 may be a new therapeutic candidate for its capacity not only to prevent breast cancer cell spreading but also to inhibit tumour-associated angiogenesis in the metastatic breast cancer.

Xin Q, Zhang N, Yu HB, et al.
CXCR7/CXCL12 axis is involved in lymph node and liver metastasis of gastric carcinoma.
World J Gastroenterol. 2017; 23(17):3053-3065 [PubMed] Free Access to Full Article Related Publications
AIM: To investigate the role of CXC chemokine receptor (CXCR)-7 and CXCL12 in lymph node and liver metastasis of gastric carcinoma.
METHODS: In 160 cases of gastric cancer, the expression of CXCR7 and CXCL12 in tumor and matched tumor-adjacent non-cancer tissues, in the lymph nodes around the stomach and in the liver was detected using immunohistochemistry to analyze the relationship between CXCR7/CXCL12 expression and clinicopathological features and to determine whether CXCR7 and CXCL12 constitute a biological axis to promote lymph node and liver metastasis of gastric cancer. Furthermore, the CXCR7 gene was silenced and overexpressed in human gastric cancer SGC-7901 cells, and cell proliferation, migration and invasiveness were measured by the MTT, wound healing and Transwell assays, respectively.
RESULTS: CXCR7 expression was up-regulated in gastric cancer tissues (
CONCLUSION: The CXCR7/CXCL12 axis is involved in lymph node and liver metastasis of gastric cancer. CXCR7 is considered a potential therapeutic target for the treatment of gastric cancer.

Zhou H, Chen Q, Tan W, et al.
Integrated clinicopathological features and gene microarray analysis of pancreatic neuroendocrine tumors.
Gene. 2017; 625:72-77 [PubMed] Related Publications
Pancreatic neuroendocrine tumors are relatively rare pancreatic neoplasms over the world. Investigations about molecular biology of PNETs are insufficient for nowadays. We aimed to explore the expression of messenger RNA and regulatory processes underlying pancreatic neuroendocrine tumors from different views. The expression profile of GSE73338 were downloaded, including samples with pancreatic neuroendocrine tumors. First, the Limma package was utilized to distinguish the differentially expressed messenger RNA. Gene Ontology classification and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis were performed to explore the functions and pathways of target genes. In addition, we constructed a protein-protein interaction network. NEK2, UBE2C, TOP2A and PPP1R1A were revealed with continuous genomic alterations in higher tumor stage. 91 up-regulated and 36 down-regulated genes were identified to be differentially expressed in malignant PNETs. Locomotory behavior was significantly enriched for biological processes of metastasis PNETs. GCGR and GNAS were identified as the hub of proteins in the protein-protein interaction sub-network of malignant PNETs. We showed the gene expression differences in PNETs according to different clinicopathological aspects. NEK2, UBE2C, TOP2A are positively associated with high tumor grade, and PPP1R1A negatively. GCGR and GNAS are regarded as the hub of the PPI sub-network. CXCR4 may affect the progression of PNETs via the CXCR4-CXCL12-CXCR7 chemokine receptor axis. However, more studies are required.

Han Y, Wu C, Wang J, Liu N
CXCR7 maintains osteosarcoma invasion after CXCR4 suppression in bone marrow microenvironment.
Tumour Biol. 2017; 39(5):1010428317701631 [PubMed] Related Publications
The major cause of death in osteosarcoma is the invasion and metastasis. Better understanding of the molecular mechanism of osteosarcoma invasion is essential in developing effective tumor-suppressive therapies. Interaction between chemokine receptors plays a crucial role in regulating osteosarcoma invasion. Here, we investigated the relationship between CXCR7 and CXCR4 in osteosarcoma invasion induced by bone marrow microenvironment. Human bone marrow mesenchymal stem cells were co-cultured with osteosarcoma cells to mimic actual bone marrow microenvironment. Osteosarcoma cell invasion and CXCL12/CXCR4 activation were observed within this co-culture model. Interestingly, in this co-culture model, osteosarcoma cell invasion was not inhibited by suppressing CXCR4 expression with neutralizing antibody or specific inhibitor AMD3100. Downstream signaling extracellular signal-regulated kinase and signal transducer and activator of transcription 3 were not significantly affected by CXCR4 inhibition. However, suppressing CXCR4 led to CXCR7 upregulation. Constitutive expression of CXCR7 could maintain osteosarcoma cell invasion when CXCR4 was suppressed. Simultaneously, inhibiting CXCR4 and CXCR7 compromised osteosarcoma invasion in co-culture system and suppressed extracellular signal-regulated kinase and signal transducer and activator of transcription 3 signals. Moreover, bone marrow microenvironment, not CXCL12 alone, is required for CXCR7 activation after CXCR4 suppression. Taken together, suppressing CXCR4 is not enough to impede osteosarcoma invasion in bone marrow microenvironment since CXCR7 is activated to sustain invasion. Therefore, inhibiting both CXCR4 and CXCR7 could be a promising strategy in controlling osteosarcoma invasion.

Zhao ZW, Fan XX, Song JJ, et al.
ShRNA knock-down of CXCR7 inhibits tumour invasion and metastasis in hepatocellular carcinoma after transcatheter arterial chemoembolization.
J Cell Mol Med. 2017; 21(9):1989-1999 [PubMed] Free Access to Full Article Related Publications
To investigate the effects of lentiviral vector-mediated shRNA suppressing CXCR7 on tumour invasion and metastasis in hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE). HCCLM3 cell lines were cultured and assigned into the CXCR7-shRNA, negative control (NC) and blank groups. The qRT-PCR and Western blotting were applied to detect the mRNA and protein expressions of CXCR7, CXCR4 and MMP-2 in HCCLM3 cells. Cell proliferation and invasion were evaluated by MTT and Transwell assays. A Buffalo rat model of HCC was established. Fifty model rats were divided into the CXCR7-shRNA + TACE, CXCR7-shRNA, TACE, NC and control groups. Immunohistochemistry was performed to detect the expressions of CXCR7, MMP-2, vascular endothelial growth factor (VEGF) and intratumoral CD31-positive vessel count in tumour tissues of mice. Compared with the blank and NC groups, the mRNA and protein expressions of CXCR7 and MMP-2 were decreased in the CXCR7-shRNA group. The cell proliferation and invasion rates of the CXCR7-shRNA group were lower than the blank and NC groups. At the 4th week after TACE, tumour weight of the CXCR7-shRNA + TACE group increased continuously. The CXCR7-shRNA + TACE group showed longer survival time and smaller tumour sizes than other groups. Compared with other groups, the CXCR7-shRNA + TACE and CXCR7-shRNA groups had less number of lung metastatic nodules and lower expressions of CXCR7, MMP-2, VEGF and CD31-positive vessel count. CXCR7-shRNA inhibits tumour invasion and metastasis to improve the efficacy of TACE in HCC by reducing the expressions of CXCR7, MMP-2 and VEGF.

Knebel FH, Uno M, Galatro TF, et al.
Serum amyloid A1 is upregulated in human glioblastoma.
J Neurooncol. 2017; 132(3):383-391 [PubMed] Related Publications
Serum amyloid A1 (SAA1) is a sensitive acute phase reactant primarily produced by the liver in response to acute inflammation. We have recently shown that SAA affects proliferation, migration, and invasion of glioblastoma cell lines, which suggest its participation in the malignant process. Consistently, levels of SAA have been used as a non-invasive biomarker for the prognosis of many cancers. In this study, we aimed to investigate SAA serum levels and expression of SAA genes in human astrocytomas tissues. Serum and tissue samples were obtained from patients with astrocytoma grades I to III and glioblastoma (GBM or grade IV). Levels of circulating SAA were significantly higher in the serum of patients with AGII-IV when compared to non-neoplastic samples derived from non-neoplastic patients (NN) (p > 0.0001). Quantitative real time PCR (qRT-PCR) of 148 astrocytomas samples (grades I-IV) showed that SAA1 mRNA was significantly higher in GBM when compared to AGI-III and NN samples (p < 0.0001). Immunohistochemistry analysis revealed cytoplasmic positivity for SAA in GBM. There was no correlation of SAA1 with clinical end-point of overall survival among GBM patients. However, it was found a positive correlation between SAA1 and genes involved in tumor progression, such as: HIF1A (r = 0.50; p < 0.00001), CD163 (r = 0.52; p < 0.00001), CXCR4 (r = 0.42; p < 0.00001) and CXCR7 (r = 0.33; p = 0.002). In conclusions, we show that astrocytoma patients have increased levels of serum SAA and SAA1 is expressed and secreted in GBM, and its co-expression with tumor-related genes supports its involvement in GBM angiogenesis and progression.

Gu HQ, Zhang ZB, Zhang JW, et al.
The role of the SDF-1/ CXCR7 axis on the growth and invasion ability of endometrial cancer cells.
Arch Gynecol Obstet. 2017; 295(4):987-995 [PubMed] Related Publications
PURPOSE: Stroma-derived factor-1 (SDF-1) and its receptor C-X-C chemokine receptor-4 (CXCR4) are involved in human endometrial carcinoma (EC) progression. CXCR7 is another important receptor of SDF-1 and has a higher affinity with SDF-1 compared with that of CXCR4. This paper aims to study the effects of the SDF-1/CXCR7 axis on the growth and invasion ability of EC cells.
METHODS: CXCR7 expression was evaluated by quantitative RT-PCR, immunohistochemistry, immunocytochemistry and Western blotting in EC cell lines and 30 cases of primary EC tissue from patients. EC cell line proliferation and migration were assessed following knockdown of CXCR7 by MTT and transwell assays.
RESULTS: The results showed that CXCR7 was highly expressed at both mRNA and protein levels in the EC cells and tissue. siCXCR7 effectively silenced CXCR7 in Ishikawa and AN3CA cells. Treatment with 17β-oestradiol (17β-E2) significantly increased the levels of CXCR7 and SDF-1 in Con, siCon and siCXCR7 treated Ishikawa. siCXCR7 persistently inhibited CXCR7 expression, even in cells treated with 17β-E2. Moreover, in vitro functional analyses, silencing CXCR7 resulted in decreased proliferation in Ishikawa and AN3CA cells. Treatment with 17β-E2 and SDF-1 significantly promoted the growth and migration in siCon treated Ishikawa and AN3CA. Interestingly, in response to 17β-E2 and SDF-1 stimulation, siCXCR7 continuously inhibited the growth and invasion of Ishikawa and AN3CA cells.
CONCLUSION: Our results indicate that SDF-1/CXCR7 plays a positive role in the proliferation and invasion of EC cells. CXCR7 inhibition treatment may provide a promising strategy for anti-tumour therapy for EC.

Mahmoodi M, Nguyen-Dumont T, Hammet F, et al.
Mutation screening of ACKR3 and COPS8 in kidney cancer cases from the CONFIRM study.
Fam Cancer. 2017; 16(3):411-416 [PubMed] Related Publications
An apparently balanced t(2;3)(q37.3;q13.2) translocation that appears to segregate with renal cell carcinoma (RCC) has indicated potential areas to search for the elusive genetic basis of clear cell RCC. We applied Hi-Plex targeted sequencing to analyse germline DNA from 479 individuals affected with clear cell RCC for this breakpoint translocation and genetic variants in neighbouring genes on chromosome 2, ACKR3 and COPS8. While only synonymous variants were found in COPS8, one of the missense variants in ACKR3:c.892C>T, observed in 4/479 individuals screened (0.8%), was predicted likely to damage ACKR3 function. Identification of causal genes for RCC has potential clinical utility, where risk assessment and risk management can offer better outcomes, with surveillance for at-risk relatives and nephron sparing surgery through earlier intervention.

Nambara S, Iguchi T, Oki E, et al.
Overexpression of CXCR7 Is a Novel Prognostic Indicator in Gastric Cancer.
Dig Surg. 2017; 34(4):312-318 [PubMed] Related Publications
BACKGROUND: Among several candidate genes that promote peritoneal dissemination extracted by comprehensive expression analysis of both in vivo selected metastatic cell lines and patients with gastric cancer, we focused on the chemokine (C-X-C motif) receptor (CXCR7) and explored its clinicopathological significance in gastric cancer.
METHODS: CXCR7 expression was evaluated by microarray data in the Singapore cohort (n = 196) and by immunohistochemistry and reverse transcription quantitative real-time polymerase chain reaction in the Japanese cohort (n = 195). The biological function of CXCR7 in gastric cancer was explored using gene set enrichment analysis (GSEA).
RESULTS: CXCR7 expression was upregulated in tumor tissues compared to normal tissues. High CXCR7 mRNA expression was associated with peritoneal dissemination and poor prognosis in the Singapore cohort. Consistent with this, the high CXCR7 mRNA expression group showed significantly poorer prognosis and a more aggressive disease course than the low expression group in the Japanese cohort. High CXCR7 mRNA expression and peritoneal dissemination were clinically relevant. GSEA revealed that CXCR7 was significantly enriched in gene expression signatures associated with tumor progression.
CONCLUSIONS: CXCR7 may be a prognostic indicator and therapeutic target for gastric cancer with peritoneal dissemination.

Chen Y, Teng F, Wang G, Nie Z
Overexpression of CXCR7 induces angiogenic capacity of human hepatocellular carcinoma cells via the AKT signaling pathway.
Oncol Rep. 2016; 36(4):2275-81 [PubMed] Related Publications
Angiogenesis is essential for tumor growth, especially in hepatocellular carcinoma (HCC). The hypervascularity is associated with poor prognosis and highly invasive HCC. The C‑X‑C chemokine receptor type 7 (CXCR7) has been implied overexpressed in many tumor types. Our study aimed to investigate the CXCR7 function in HCC. The tube formation, Transwell migration assay of human umbilical vein endothelial cells (HUVECs) and chicken chorioallantoic membrane (CAM) assay were used. We confirmed that CXCR7 induces angiogenic capacity. Moreover, overexpressing CXCR7 increased the phosphorylated (but not total) AKT expression in HCC cells. Furthermore, overexpressing CXCR7 increased the expression of tumor necrosis factor (TNF)‑α, interleukin (IL)‑6 and IL‑8 in HCC cells. Additionally, inhibition of AKT by LY294002 abrogated CXCR7‑induced angiogenic capacity in HCC cells. Our study suggested that CXCR7 plays an important pro‑angiogenic role in HCC via activation of the AKT pathway. So CXCR7 may be a potential target for anti‑angiogenic therapy in HCC.

Guo JC, Li J, Zhou L, et al.
CXCL12-CXCR7 axis contributes to the invasive phenotype of pancreatic cancer.
Oncotarget. 2016; 7(38):62006-62018 [PubMed] Free Access to Full Article Related Publications
Chemokine (C-X-C motif) receptor 7 (CXCR7) and its ligand, chemokine (C-X-C motif) ligand 12 (CXCL12), were established to be involved in biological behaviors and associated with prognosis in many cancers. However, effects, underlying mechanisms of CXCL12-CXCR7 axis in invasive phenotype of pancreatic cancer (PC) and its clinicopathologic significances have not been comprehensively explored. In the present study, it was first found by tissue microarray-based immunohistochemistry that CXCL12 and CXCR7 staining scores were significantly associated with vessel invasion and overall survival in two independent cohorts of PC. Besides, co-expression of these proteins was an independent prognosticator in multivariate analysis in both cohorts. Then, migration and invasion, but not proliferation, were decreased in CXCR7-stably silenced PC cells, whereas opposite changes were observed in CXCR7-stably overexpressed cells, accompanied by alterations of mTOR and Rho/ROCK pathways. CXCL12 stimulated migration, invasion, CXCR7 expression and phosphorylation of key mTOR proteins. AMD3100 did not influence effects of CXCL12. Two mTOR inhibitors, rapamycin and Torin1, reversed enhanced invasive phenotypes and mTOR phosphorylation in CXCR7-overexpressed cells. Moreover, CXCR7 directly interacts with mTOR. Finally, liver metastasis, but not growth, was affected by CXCR7 status in orthotopically-implanted PC models in nude mice. Collectively, CXCL12-CXCR7 axis accelerates migration and invasion of PC cells through mTOR and Rho/ROCK pathways, and predicts poor prognosis of PC.

Li W, Ding Q, Ding Y, et al.
Oroxylin A reverses the drug resistance of chronic myelogenous leukemia cells to imatinib through CXCL12/CXCR7 axis in bone marrow microenvironment.
Mol Carcinog. 2017; 56(3):863-876 [PubMed] Related Publications
Imatinib (IM), a tyrosine-kinase inhibitor, is used in treatment of multiple cancers, most notably Philadelphia chromosome-positive (Ph

Mays AC, Feng X, Browne JD, Sullivan CA
Chemokine and Chemokine Receptor Profiles in Metastatic Salivary Adenoid Cystic Carcinoma.
Anticancer Res. 2016; 36(8):4013-8 [PubMed] Related Publications
AIM: To characterize the chemokine pattern in metastatic salivary adenoid cystic carcinoma (SACC).
MATERIALS AND METHODS: Real-time polymerase chain reaction (RT-PCR) was used to compare chemokine and chemokine receptor gene expression in two SACC cell lines: SACC-83 and SACC-LM (lung metastasis). Chemokines and receptor genes were then screened and their expression pattern characterized in human tissue samples of non-recurrent SACC and recurrent SACC with perineural invasion.
RESULTS: Expression of chemokine receptors C5AR1, CCR1, CCR3, CCR6, CCR7, CCR9, CCR10, CXCR4, CXCR6, CXCR7, CCRL1 and CCRL2 were higher in SACC-83 compared to SACC-LM. CCRL1, CCBP2, CMKLR1, XCR1 and CXCR2 and 6 chemokine genes (CCL13, CCL27, CXCL14, CMTM1, CMTM2, CKLF) were more highly expressed in tissues of patients without tumor recurrence/perineural invasion compared to those with tumor recurrence. CCRL1 (receptor), CCL27, CMTM1, CMTM2, and CKLF (chemokine) genes were more highly expressed in SACC-83 and human tissues of patients without tumor recurrence/perineural invasion.
CONCLUSION: CCRL1, CCL27, CMTM1, CMTM2 and CKLF may play important roles in the development of tumor metastases in SACC.

Tang X, Li X, Li Z, et al.
Downregulation of CXCR7 inhibits proliferative capacity and stem cell-like properties in breast cancer stem cells.
Tumour Biol. 2016; 37(10):13425-13433 [PubMed] Related Publications
Breast cancer stem cells (bCSCs) are considered an obstacle in breast cancer therapy because they exhibit long-term proliferative potential, phenotypic plasticity and high resistance to the current therapeutics. CXC chemokine receptor type 7 (CXCR7), which provides a growth advantage to breast cancer cells, has recently been demonstrated to play an important role in the maintenance of stem cell-like properties in the CSCs of glioblastoma and lung cancer, yet its role in bCSCs remains elusive. In this study, CD44

Yu PF, Huang Y, Han YY, et al.
TNFα-activated mesenchymal stromal cells promote breast cancer metastasis by recruiting CXCR2
Oncogene. 2017; 36(4):482-490 [PubMed] Free Access to Full Article Related Publications
Mesenchymal stromal cells (MSCs) tend to infiltrate into tumors and form a major component of the tumor microenvironment. Our previous work demonstrated that tumor necrosis factor α (TNFα)-activated MSCs significantly promoted tumor growth. However, the role of TNFα-treated MSCs in tumor metastasis remains elusive. Employing a lung metastasis model of murine breast cancer, we found that TNFα-activated MSCs strikingly enhanced tumor metastasis compared with normal MSCs. We analyzed the chemokine profiles and found that the expression of CCL5, CCR2 and CXCR2 ligands were enhanced in TNFα-activated MSCs. Using genetic or pharmacological strategies to inhibit CCL5 or CCR2, we demonstrated that CCL5 and CCR2 ligands were indispensable in supporting TNFα-activated MSCs to promote tumor metastasis. Analysis of immune cells revealed that CXCR2 ligands (CXCL1, CXCL 2 and CXCL5) expressed by TNFα-activated MSCs efficiently recruited CXCR2

Zhang S, Hong Z, Li Q, et al.
Effect of MicroRNA-218 on the viability, apoptosis and invasion of renal cell carcinoma cells under hypoxia by targeted downregulation of CXCR7 expression.
Biomed Pharmacother. 2016; 80:213-219 [PubMed] Related Publications
OBJECTIVE: To investigate the effect of microRNA-218 on the viability, apoptosis and invasion of renal cell carcinoma cells under hypoxia by targeted regulation of expression of chemokine receptor 7 (CXCR7).
METHODS: The expression of miR-218 in renal cell carcinoma cell lines under normal and hypoxia conditions, as well in normal renal tubular epithelial cells (HK2) was measured using RT-PCR. MiR-218 mimic and NC were transfected into renal cell carcinoma cell line ACHN using Lipofectamine™ 2000. The expression of miR-218 was analyzed using RT-PCR. The viability, apoptosis, migration and invasion of the transfected cells were assayed using the MTT assay, flow cytometry and transwell assays. The expression of CXCR7 was assayed using RT-PCR and Western blot. Luciferase reporter was used to verify the downstream target of miR-218.
RESULTS: The expression of miR-218 was lower than in renal cell carcinoma cell lines ACHN, 769-p and Caki-1 that in HK-2. The expression of miR-218 in the renal carcinoma cell lines was lower under hypoxia than under normal oxygen conditions. The expression of miR-218 in ACHN cells under normal and hypoxic conditions was significantly increased after transfection with miR-218 mimic. Compared with NC transfected cells under normal oxygen condition, the mimic-transfected cells had reduced viability, migration ability and invasion ability, and increased apoptosis, and mimic transfected-cells under hypoxia had significantly reduced viability, migration ability and invasion ability, and increased apoptosis. Overexpression of miR-218 mimic resulted in significant reduction in the expression of CXCR7 at protein and mRNA levels under normal and hypoxic conditions. Luciferase reporter assay confirmed that CXCR7 is the target protein of miR-218.
CONCLUSION: Up-regulation of miR-218 expression in renal cell carcinoma under hypoxia can result in significant and targeted down-regulation of CXCR7 expression, which could reduce cell viability, migration and invasion ability and induce apoptosis in the cancer cells.

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