Gene Summary

Gene:CXCR2; chemokine (C-X-C motif) receptor 2
Aliases: CD182, IL8R2, IL8RA, IL8RB, CMKAR2, CDw128b
Summary:The protein encoded by this gene is a member of the G-protein-coupled receptor family. This protein is a receptor for interleukin 8 (IL8). It binds to IL8 with high affinity, and transduces the signal through a G-protein activated second messenger system. This receptor also binds to chemokine (C-X-C motif) ligand 1 (CXCL1/MGSA), a protein with melanoma growth stimulating activity, and has been shown to be a major component required for serum-dependent melanoma cell growth. This receptor mediates neutrophil migration to sites of inflammation. The angiogenic effects of IL8 in intestinal microvascular endothelial cells are found to be mediated by this receptor. Knockout studies in mice suggested that this receptor controls the positioning of oligodendrocyte precursors in developing spinal cord by arresting their migration. This gene, IL8RA, a gene encoding another high affinity IL8 receptor, as well as IL8RBP, a pseudogene of IL8RB, form a gene cluster in a region mapped to chromosome 2q33-q36. Alternatively spliced variants, encoding the same protein, have been identified. [provided by RefSeq, Nov 2009]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:C-X-C chemokine receptor type 2
Source:NCBIAccessed: 25 June, 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 25 June 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 25 June, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

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: CXCR2 (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.

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.

Zhou SL, Zhou ZJ, Hu ZQ, et al.
CXCR2/CXCL5 axis contributes to epithelial-mesenchymal transition of HCC cells through activating PI3K/Akt/GSK-3β/Snail signaling.
Cancer Lett. 2015; 358(2):124-35 [PubMed] Related Publications
Upregulation of CXCR2 in tumor cells has been documented in several types of cancer. As one of its ligands, CXCL5 is associated with neutrophil infiltration and poor prognosis in hepatocellular carcinoma (HCC). However, little is known about the role of the CXCR2/CXCL5 axis in the invasion and metastasis of HCC cells. In this study, we examined CXCR2 expression in human HCC cell lines and in three independent cohorts of HCC patients. The molecular effects of high expression levels of CXCR2 and CXCL5 in HCC cells were determined using qRT-PCR, western blot analysis, immunofluorescence, matrigel invasion assay, and xenograft mouse models. We found that high levels of CXCR2 correlated with progression and poor prognosis in human HCC. CXCR2/CXCL5 together promoted cell spreading by inducing the epithelial-mesenchymal transition (EMT) through activation of the PI3K/Akt/GSK-3β/Snail signaling pathway. In clinical HCC samples, high expression of both CXCR2 and CXCL5 showed a significant correlation with the activation of PI3K/Akt/GSK-3β/Snail signaling and EMT phenotype. In conclusion, our data showed that the CXCR2/CXCL5 axis contributes to EMT of HCC cells through activating PI3K/Akt/GSK-3β/Snail signaling, and it may serve as a potential therapeutic target.

Shen Y, Tantai J, Zhao H
Ranking candidate genes of esophageal squamous cell carcinomas based on differentially expressed genes and the topological properties of the co-expression network.
Eur J Med Res. 2014; 19:52 [PubMed] Article available free on PMC after 01/10/2015 Related Publications
BACKGROUND: The aim of this study was to identify the candidate genes of esophageal squamous cell carcinoma (ESCC).
METHODS: Gene expression profiling of 17 ESCC samples and 17 adjacent normal samples, GSE20347, was downloaded from Gene Expression Omnibus database. The raw data were preprocessed, and the differentially expressed genes (DEGs) between ESCC and normal samples were identified by using SAM software (false discovery rate <0.001). Then, the co-expression network of DEGs was constructed based on Pearson's correlation test (r-value ≥0.8). Furthermore, the topological properties of the co-expression network were analyzed through NetworkAnalyzer (default settings) of Cytoscape. The expression fold changes of DEGs and topological properties were utilized to identify the candidate genes of ESCC (Crin score >4), which were further analyzed based on DAVID functional enrichment analysis (P-value <0.05).
RESULTS: A total of 1,063 DEGs were identified, including 490 up-regulated and 573 down-regulated DEGs. Then, the co-expression network of DEGs was constructed, containing 999 nodes and 46,323 edges. Based on the expression fold changes of DEGs and the topological properties of the co-expression network, DEGs were ranked, and the top 24 genes were candidate genes of ESCC, such as CRISP3, EREG, CXCR2, and CRNN. Furthermore, the 24 genes were significantly enriched in bio-functions regarding cell differentiation, glucan biosynthetic process and immune response.
CONCLUSION: The present study suggested that CRISP3, EREG, CXCR2, and CRNN might be causative genes of ESCC, and play vital roles in the development of ESCC. However, further experimental studies are needed to confirm our results.

Lohri C, Schaltegger CS, VAN DEN Broek M, et al.
Neutrophil expression of ICAM1, CXCR1, and VEGFR1 in patients with breast cancer before and after adjuvant chemotherapy.
Anticancer Res. 2014; 34(9):4693-9 [PubMed] Related Publications
BACKGROUND: Distinct populations of neutrophils have been identified based on the expression of intercellular adhesion molecule 1 (ICAM1, CD54) and chemokine receptor 1 (CXCR1, interleukin 8 receptor α).
AIM: We analyzed the expression of vascular endothelial growth factor receptor 1 (VEGFR1), a physiological negative regulator of angiogenesis, on distinct populations of neutrophils from the blood of patients before and after adjuvant chemotherapy for breast cancer.
MATERIALS AND METHODS: Neutrophil populations were distinguished as reverse transmigrated (ICAM1(high)/CXCR1(low)), naïve (ICAM1(low)/CXCR1(high)), or tissue-resident neutrophils (ICAM1(low)/CXCR1(low)), and their VEGFR1 expression quantified.
RESULTS: Reverse transmigrated ICAM1(high)/CXCR1(low) neutrophilic granulocytes decreased significantly after chemotherapy and these were also the cells with highest mean fluorescence intensity for VEGFR1.
CONCLUSION: Chemotherapy mainly reduces the number of reverse transmigrated long-lived ICAM1(high)/CXCR1(low) VEGFR1-expressing neutrophils. The decrease of antiangiogenic VEGFR1 may have a potential impact on tumour angiogenesis in patients undergoing adjuvant chemotherapy.

Di Mitri D, Toso A, Chen JJ, et al.
Tumour-infiltrating Gr-1+ myeloid cells antagonize senescence in cancer.
Nature. 2014; 515(7525):134-7 [PubMed] Related Publications
Aberrant activation of oncogenes or loss of tumour suppressor genes opposes malignant transformation by triggering a stable arrest in cell growth, which is termed cellular senescence. This process is finely tuned by both cell-autonomous and non-cell-autonomous mechanisms that regulate the entry of tumour cells to senescence. Whether tumour-infiltrating immune cells can oppose senescence is unknown. Here we show that at the onset of senescence, PTEN null prostate tumours in mice are massively infiltrated by a population of CD11b(+)Gr-1(+) myeloid cells that protect a fraction of proliferating tumour cells from senescence, thus sustaining tumour growth. Mechanistically, we found that Gr-1(+) cells antagonize senescence in a paracrine manner by interfering with the senescence-associated secretory phenotype of the tumour through the secretion of interleukin-1 receptor antagonist (IL-1RA). Strikingly, Pten-loss-induced cellular senescence was enhanced in vivo when Il1ra knockout myeloid cells were adoptively transferred to PTEN null mice. Therapeutically, docetaxel-induced senescence and efficacy were higher in PTEN null tumours when the percentage of tumour-infiltrating CD11b(+)Gr-1(+) myeloid cells was reduced using an antagonist of CXC chemokine receptor 2 (CXCR2). Taken together, our findings identify a novel non-cell-autonomous network, established by innate immunity, that controls senescence evasion and chemoresistance. Targeting this network provides novel opportunities for cancer therapy.

Sun Q, Sun F, Wang B, et al.
Interleukin-8 promotes cell migration through integrin αvβ6 upregulation in colorectal cancer.
Cancer Lett. 2014; 354(2):245-53 [PubMed] Related Publications
Colorectal cancer (CRC), which is notorious for high morbidity and mortality around the world, shows a predilection for metastasis to liver. Interleukin-8 (IL-8), a chemokine with a defining CXC amino acid motif, has been reported to promote CRC cell migration and is associated with poor prognosis of CRC. However, the underlying molecular mechanism of IL-8-mediated migration remains obscure. In this study, we first demonstrated the cross talk between IL-8 and integrin αvβ6. We analyzed 139 human CRC samples, and found that the immunohistochemical expression of αvβ6 was significantly correlated with expression of IL-8. Furthermore, IL-8 increased the migration through integrin αvβ6 in human CRC cells, and both CXCR1 and CXCR2 were primarily involved during the process. IL-8 upregulated αvβ6 expression in a dose-dependent manner through activation of ERK and Ets-1 signaling pathway. Taken together, our results indicated that IL-8 enhances the migration of CRC cells by increasing αvβ6 integrin expression through the ERK/Ets-1 pathway. Targeting integrin αvβ6 in IL-8 expressing tumors might be a potential therapeutic strategy for CRC patients.

Samuel T, Fadlalla K, Gales DN, et al.
Variable NF-κB pathway responses in colon cancer cells treated with chemotherapeutic drugs.
BMC Cancer. 2014; 14:599 [PubMed] Article available free on PMC after 01/10/2015 Related Publications
BACKGROUND: The nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway is activated in cells exposed to various stimuli, including those originating on the cell surface or in the nucleus. Activated NF-κB signaling is thought to enhance cell survival in response to these stimuli, which include chemotherapy and radiation. In the present effort, we determined which anticancer drugs preferentially activate NF-κB in colon cancer cells.
METHODS: NF-κB reporter cells were established and treated with 5-fluorouracil (5-FU, DNA/RNA damaging), oxaliplatin (DNA damaging), camptothecin (CTP, topoisomerase inhibitor), phleomycin (radiomimetic), or erlotinib (EGFR inhibitor). The activation of NF-κB was assessed by immunofluorescence for p65 translocation, luciferase assays, and downstream targets of NF-κB activation (cIAP2, and Bcl-XL) were evaluated by immunoblotting, by ELISA (CXCL8 and IL-6 in culture supernatants), or by gene expression analysis.
RESULTS: Colon cancer cells responded variably to different classes of therapeutic agents, and these agents initiated variable responses among different cell types. CPT activated NF-κB in SW480 colon cancer cells in a dose-dependent manner, but not in HCT116 cells that were either wild-type or deficient for p53. In SW480 colon cancer cells, NF-κB activation by CPT was accompanied by secretion of the cytokine CXCL8, but not by up-regulation of the anti-apoptotic genes, cIAP2 or Bcl-XL. On the contrary, treatment of HCT116 cells with CPT resulted in up-regulation of CXCR2, a receptor for CXCL8, without an increase in cytokine levels. In SW480 cells, NF-κB reporter activity, but not cytokine secretion, was inhibited by SM-7368, an NF-κB inhibitor.
CONCLUSION: The results show that, in response to cancer therapeutic agents, NF-κB activation varies with the cellular make up and that drug-induced NF-κB activation may be functionally uncoupled from anti-apoptotic outcomes found for other stimuli. Some cancer cells in a heterogeneous tumor tissue may, under therapeutic pressure, release soluble factors that have paracrine activity on neighboring cells that express the cognate receptors.

de Haas S, Delmar P, Bansal AT, et al.
Genetic variability of VEGF pathway genes in six randomized phase III trials assessing the addition of bevacizumab to standard therapy.
Angiogenesis. 2014; 17(4):909-20 [PubMed] Related Publications
BACKGROUND: Despite extensive translational research, no validated biomarkers predictive of bevacizumab treatment outcome have been identified.
METHODS: We performed a meta-analysis of individual patient data from six randomized phase III trials in colorectal, pancreatic, lung, renal, breast, and gastric cancer to explore the potential relationships between 195 common genetic variants in the vascular endothelial growth factor (VEGF) pathway and bevacizumab treatment outcome.
RESULTS: The analysis included 1,402 patients (716 bevacizumab-treated and 686 placebo-treated). Twenty variants were associated (P < 0.05) with progression-free survival (PFS) in bevacizumab-treated patients. Of these, 4 variants in EPAS1 survived correction for multiple testing (q < 0.05). Genotype-by-treatment interaction tests revealed that, across these 20 variants, 3 variants in VEGF-C (rs12510099), EPAS1 (rs4953344), and IL8RA (rs2234671) were potentially predictive (P < 0.05), but not resistant to multiple testing (q > 0.05). A weak genotype-by-treatment interaction effect was also observed for rs699946 in VEGF-A, whereas Bayesian genewise analysis revealed that genetic variability in VHL was associated with PFS in the bevacizumab arm (q < 0.05). Variants in VEGF-A, EPAS1, and VHL were located in expression quantitative loci derived from lymphoblastoid cell lines, indicating that they affect the expression levels of their respective gene.
CONCLUSIONS: This large genetic analysis suggests that variants in VEGF-A, EPAS1, IL8RA, VHL, and VEGF-C have potential value in predicting bevacizumab treatment outcome across tumor types. Although these associations did not survive correction for multiple testing in a genotype-by-interaction analysis, they are among the strongest predictive effects reported to date for genetic variants and bevacizumab efficacy.

Maxwell PJ, Neisen J, Messenger J, Waugh DJ
Tumor-derived CXCL8 signaling augments stroma-derived CCL2-promoted proliferation and CXCL12-mediated invasion of PTEN-deficient prostate cancer cells.
Oncotarget. 2014; 5(13):4895-908 [PubMed] Article available free on PMC after 01/10/2015 Related Publications
Impaired PTEN function is a genetic hallmark of aggressive prostate cancers (CaP) and is associated with increased CXCL8 expression and signaling. The current aim was to further characterize biological responses and mechanisms underpinning CXCL8-promoted progression of PTEN-depleted prostate cancer, focusing on characterizing the potential interplay between CXCL8 and other disease-promoting chemokines resident within the prostate tumor microenvironment. Autocrine CXCL8-stimulation (i) increased expression of CXCR1 and CXCR2 in PTEN-deficient CaP cells suggesting a self-potentiating signaling axis and (ii) induced expression of CXCR4 and CCR2 in PTEN-wild-type and PTEN-depleted CaP cells. In contrast, paracrine CXCL8 signaling induced expression and secretion of the chemokines CCL2 and CXCL12 from prostate stromal WPMY-1 fibroblasts and monocytic macrophage-like THP-1 cells. In vitro studies demonstrated functional co-operation of tumor-derived CXCL8 with stromal-derived chemokines. CXCL12-induced migration of PC3 cells and CCL2-induced proliferation of prostate cancer cells were dependent upon intrinsic CXCL8 signaling within the prostate cancer cells. For example, in co-culture experiments, CXCL12/CXCR4 signaling but not CCL2/CCR2 signaling supported fibroblast-mediated migration of PC3 cells while CXCL12/CXCR4 and CCL2/CCR2 signaling underpinned monocyte-enhanced migration of PC3 cells. Combined inhibition of both CXCL8 and CXCL12 signaling was more effective in inhibiting fibroblast-promoted cell motility while repression of CXCL8 attenuated CCL2-promoted proliferation of prostate cancer cells. We conclude that tumor-derived CXCL8 signaling from PTEN-deficient tumor cells increases the sensitivity and responsiveness of CaP cells to stromal chemokines by concurrently upregulating receptor expression in cancer cells and inducing stromal chemokine synthesis. Combined chemokine targeting may be required to inhibit their multi-faceted actions in promoting the invasion and proliferation of aggressive CaP.

Wilson BJ, Saab KR, Ma J, et al.
ABCB5 maintains melanoma-initiating cells through a proinflammatory cytokine signaling circuit.
Cancer Res. 2014; 74(15):4196-207 [PubMed] Article available free on PMC after 01/08/2015 Related Publications
The drug efflux transporter ABCB5 identifies cancer stem-like cells (CSC) in diverse human malignancies, where its expression is associated with clinical disease progression and tumor recurrence. ABCB5 confers therapeutic resistance, but other functions in tumorigenesis independent of drug efflux have not been described that might help explain why it is so broadly overexpressed in human cancer. Here we show that in melanoma-initiating cells, ABCB5 controls IL1β secretion, which serves to maintain slow cycling, chemoresistant cells through an IL1β/IL8/CXCR1 cytokine signaling circuit. This CSC maintenance circuit involved reciprocal paracrine interactions with ABCB5-negative cancer cell populations. ABCB5 blockade induced cellular differentiation, reversed resistance to multiple chemotherapeutic agents, and impaired tumor growth in vivo. Together, our results defined a novel function for ABCB5 in CSC maintenance and tumor growth.

Zhang G, Miyake M, Lawton A, et al.
Matrix metalloproteinase-10 promotes tumor progression through regulation of angiogenic and apoptotic pathways in cervical tumors.
BMC Cancer. 2014; 14:310 [PubMed] Article available free on PMC after 01/08/2015 Related Publications
BACKGROUND: Cancer invasion and metastasis develops through a series of steps that involve the loss of cell to cell and cell to matrix adhesion, degradation of extracellular matrix and induction of angiogenesis. Different protease systems (e.g., matrix metalloproteinases, MMPs) are involved in these steps. MMP-10, one of the lesser studied MMPs, is limited to epithelial cells and can facilitate tumor cell invasion by targeting collagen, elastin and laminin. Enhanced MMP-10 expression has been linked to poor clinical prognosis in some cancers, however, mechanisms underlying a role for MMP-10 in tumorigenesis and progression remain largely unknown. Here, we report that MMP-10 expression is positively correlated with the invasiveness of human cervical and bladder cancers.
METHODS: Using commercial tissue microarray (TMA) of cervical and bladder tissues, MMP-10 immunohistochemical staining was performed. Furthermore using a panel of human cells (HeLa and UROtsa), in vitro and in vivo experiments were performed in which MMP-10 was overexpressed or silenced and we noted phenotypic and genotypic changes.
RESULTS: Experimentally, we showed that MMP-10 can regulate tumor cell migration and invasion, and endothelial cell tube formation, and that MMP-10 effects are associated with a resistance to apoptosis. Further investigation revealed that increasing MMP-10 expression stimulates the expression of HIF-1α and MMP-2 (pro-angiogenic factors) and PAI-1 and CXCR2 (pro-metastatic factors), and accordingly, targeting MMP-10 with siRNA in vivo resulted in diminution of xenograft tumor growth with a concomitant reduction of angiogenesis and a stimulation of apoptosis.
CONCLUSION: Taken together, our findings show that MMP-10 can play a significant role in tumor growth and progression, and that MMP-10 perturbation may represent a rational strategy for cancer treatment.

Levidou G, Sachanas S, Pangalis GA, et al.
Immunohistochemical analysis of IL-6, IL-8/CXCR2 axis,  Tyr p-STAT-3, and SOCS-3 in lymph nodes from patients with chronic lymphocytic leukemia: correlation between microvascular characteristics and prognostic significance.
Biomed Res Int. 2014; 2014:251479 [PubMed] Article available free on PMC after 01/08/2015 Related Publications
A number of studies have looked into the pathophysiological role of angiogenesis in CLL, but the results have often been inconsistent. We aimed to gain direct insight into the angiogenic process in lymph nodes involved by CLL, focusing on proangiogenic cytokines and microvessel morphometry. The tissue levels of VEGF, Th-2 cytokines IL-6 and IL-8, IL-8 receptor CXCR2, and tyrosine p-STAT-3/SOCS-3 axis modulating cytokine expression were evaluated immunohistochemically in 62 CLL/SLL cases. Microvascular characteristics were evaluated by image analysis. Results were analyzed with regard to clinicopathological characteristics. Proliferation centers (PCs) were less well vascularised compared to non-PC areas. IL-8 and CXCR2 expression was distinctly uncommon as opposed to IL-6, VEGF and SOCS-3, which were detected in the vast majority of cases. The latter two molecule expressions were more pronounced in the PCs in ∼ 40% of the cases. p-STAT-3 immunoreactivity was recorded in 66.67% of the cases with a predilection for PCs. Microvessel morphometry was unrelated to proangiogenic cytokines, p-STAT-3, SOCS-3, or survival. Microvascular caliber and VEGF expression were higher in Binet stage A, whereas IL-6 expression was higher in stage C. VEGF and p-STAT-3 exerted a favorable effect on progression, which remained significant in multivariate analysis, thereby constituting potential outcome predictors in CLL patients.

Wang J, Taylor A, Showeil R, et al.
Expression profiling and significance of VEGF-A, VEGFR2, VEGFR3 and related proteins in endometrial carcinoma.
Cytokine. 2014; 68(2):94-100 [PubMed] Related Publications
BACKGROUND: Angiogenesis plays a key role in the progression of various tumors, including endometrial carcinomas. Several cytokines and their associated receptors are shown to be involved, particularly VEGF-A with VEGFR1, -2 and -3.
METHODS: The expressions of VEGF-A, VEGFR2 and VEGFR3 were studied in by immunohistochemistry in 76 endometrial carcinoma specimens. VEGFR2 and VEGFR3 receptor expression were also studied by qRT-PCR in 17 tumors in comparison to normal endometrium. The expression profiles were correlated with tumor type, grade, stage, lymphovascular invasion, disease free survival, and the expressions of other cytokine receptors (EGFR, CXCR1 and CXCR2).
RESULTS: Immunohistochemically, 63% of endometrial cancers expressed VEGF-A, 55% VEGFR2 and 26% VEGFR3. VEGFR3 was significantly correlated with tumor stage (p=0.02), with a trend towards poorer disease free survival (p=0.09). VEGF-A was significantly correlated with microvessel density (p<0.01). Using qRT-PCR, increased expression of VEGFR2 (17.2-fold) and VEGFR3 (21.9-fold) was seen in endometrial carcinomas compared with normal endometrium, with significant correlations among the expression levels of VEGFR2, VEGFR3, EGFR, CXCR1 and CXCR2.
CONCLUSION: Our study suggests that evaluation of VEGFR3 expression in tumors may provide prognostic data, and help identify patients who would best benefit from anti-angiogenic therapeutic agents. This is the first report showing correlations between the expressions levels of the different receptors.

Caccuri F, Rueckert C, Giagulli C, et al.
HIV-1 matrix protein p17 promotes lymphangiogenesis and activates the endothelin-1/endothelin B receptor axis.
Arterioscler Thromb Vasc Biol. 2014; 34(4):846-56 [PubMed] Related Publications
OBJECTIVE: AIDS-related lymphomas are high grade and aggressively metastatic with poor prognosis. Lymphangiogenesis is essential in supporting proliferation and survival of lymphoma, as well as tumor dissemination. Data suggest that aberrant lymphangiogenesis relies on action of HIV-1 proteins rather than on a direct effect of the virus itself. HIV-1 matrix protein p17 was found to accumulate and persist in lymph nodes of patients even under highly active antiretroviral therapy. Because p17 was recently found to exert a potent proangiogenic activity by interacting with chemokine (C-X-C motif) receptors 1 and 2, we tested the prolymphangiogenic activity of the viral protein.
APPROACH AND RESULTS: Human primary lymph node-derived lymphatic endothelial cells were used to perform capillary-like structure formation, wound healing, spheroids, and Western blot assays after stimulation with or without p17. Here, we show that p17 promotes lymphangiogenesis by binding to chemokine (C-X-C motif) receptor-1 and chemokine (C-X-C motif) receptor-2 expressed on lymph node-derived lymphatic endothelial cells and activating the Akt/extracellular signal-regulated kinase signaling pathway. In particular, it was found to induce capillary-like structure formation, sprout formation from spheroids, and increase lymph node-derived lymphatic endothelial cells motility. The p17 lymphangiogenic activity was, in part, sustained by activation of the endothelin-1/endothelin receptor B axis. A Matrigel plug assay showed that p17 was able to promote the outgrowth of lymphatic vessels in vivo, demonstrating that p17 directly regulates lymphatic vessel formation.
CONCLUSIONS: Our results suggest that p17 may generate a prolymphangiogenic microenvironment and plays a role in predisposing the lymph node to lymphoma growth and metastasis. This finding offers new opportunities to identify treatment strategies in combating AIDS-related lymphomas.

Singh V, Jaiswal PK, Kapoor R, et al.
Impact of chemokines CCR5∆32, CXCL12G801A, and CXCR2C1208T on bladder cancer susceptibility in north Indian population.
Tumour Biol. 2014; 35(5):4765-72 [PubMed] Related Publications
Chemokines are small inducible pro-inflammatory cytokines. In the present study, we tested association of chemokine single nucleotide polymorphisms (SNPs) viz., CCR5∆32, CXCL12G801A and CXCR2C1208T genes in bladder cancer (BC) patients and normal healthy controls of north Indians. Genotyping of the above SNPs were done in 200 BC cases and 200 healthy controls, using RFLP and amplification refractory mutation system-polymerase chain reaction methodology. A significant association was found in CXCL12G801A with BC risk. In case of CXCL12G801A polymorphism, the heterozygous (GA) genotype showed significantly high risk (p < 0.001, odds ratio (OR) = 2.72), whereas A allele carrier (GA + AA) also showed risk with BC (p < 0.001, OR = 2.44). In CXCR2C1208T polymorphism, the variant genotype (TT) showed significant risk for BC (p = 0.028, OR = 1.58). The variant allele (T) of CXCR2C1208T polymorphism was found to be associated with BC risk (p = 0.003, OR = 1.29). Interestingly, smoking was also found to modulate 1.16-fold risks for BC in case of CXCR2C1208T, variant genotype (TT). Upon analyzing the gene-gene interaction between CXCR2C1208T and CXCL12G801A, the combination CT-GA showed 4-fold risk for BC (p = 0.009). Our results indicated that polymorphism in CXCR2C1208T and CXCL12G801A showed high risk for BC in north Indian population. However, CCR5∆32 exhibited no association. Study with large sample size and diverse ethnicity are required to validate these observations.

Bi LK, Zhou N, Liu C, et al.
Kidney cancer cells secrete IL-8 to activate Akt and promote migration of mesenchymal stem cells.
Urol Oncol. 2014; 32(5):607-12 [PubMed] Related Publications
BACKGROUND: Mesenchymal stem cells (MSCs) are multipotent adult stem cells that have the capability of homing to cancer cells. Thus, MSCs play an important role in the development, metastasis, and drug resistance of cancers. The mechanisms underlying the homing of MSCs in kidney cancer are still poorly understood.
METHODS: In the present study, enzyme-linked immunosorbent assay was used to measure the level of IL-8 in patients with kidney cancer and in the culture medium of kidney cancer cells. Immunofluorescence staining and reverse transcription polymerase chain reaction were utilized to explore the main receptor for IL-8 in MSCs. Transwell migration assay was performed to measure the migration ability of MSCs and Western blot test was performed to test the activation of signaling pathways.
RESULTS: The serum level of IL-8 was markedly increased in patients with kidney cancer, and 2 kidney cancer cell lines were found to secrete IL-8. MSCs had high expression of the IL-8 receptor (CXCR2). Blocking IL-8 or CXCR2 could decrease the migration ability of MSCs. IL-8 could significantly increase Akt phosphorylation in MSCs.
CONCLUSIONS: Kidney cancer cells secrete IL-8 to activate the Akt signaling pathway via CXCR2 on MSCs, inducing the migration of MSCs, which may be one of the important mechanisms underlying the homing of MSCs in kidney cancer.

Sobolik T, Su YJ, Wells S, et al.
CXCR4 drives the metastatic phenotype in breast cancer through induction of CXCR2 and activation of MEK and PI3K pathways.
Mol Biol Cell. 2014; 25(5):566-82 [PubMed] Article available free on PMC after 01/08/2015 Related Publications
Aberrant expression of CXCR4 in human breast cancer correlates with metastasis to tissues secreting CXCL12. To understand the mechanism by which CXCR4 mediates breast cancer metastasis, MCF-7 breast carcinoma cells were transduced to express wild-type CXCR4 (CXCR4WT) or constitutively active CXCR4 (CXCR4ΔCTD) and analyzed in two-dimensional (2D) cultures, three-dimensional reconstituted basement membrane (3D rBM) cultures, and mice using intravital imaging. Two-dimensional cultures of MCF-7 CXCR4ΔCTD cells, but not CXCR4WT, exhibited an epithelial-to-mesenchymal transition (EMT) characterized by up-regulation of zinc finger E box-binding homeobox 1, loss of E-cadherin, up-regulation of cadherin 11, p120 isoform switching, activation of extracellular signal-regulated kinase 1/2, and matrix metalloproteinase-2. In contrast to the 2D environment, MCF-7 CXCR4WT cells cultured in 3D rBM exhibited an EMT phenotype, accompanied by expression of CXCR2, CXCR7, CXCL1, CXCL8, CCL2, interleukin-6, and granulocyte-macrophage colony stimulating factor. Dual inhibition of CXCR2 with CXCR4, or inhibition of either receptor with inhibitors of mitogen-activated protein kinase 1 or phosphatidylinositol 3-kinase, reversed the aggressive phenotype of MCF-7 CXCR4-expressing or MDA-MB-231 cells in 3D rBM. Intravital imaging of CXCR4-expressing MCF-7 cells revealed that tumor cells migrate toward blood vessels and metastasize to lymph nodes. Thus CXCR4 can drive EMT along with an up-regulation of chemokine receptors and cytokines important in cell migration, lymphatic invasion, and tumor metastasis.

Dong YL, Kabir SM, Lee ES, Son DS
CXCR2-driven ovarian cancer progression involves upregulation of proinflammatory chemokines by potentiating NF-κB activation via EGFR-transactivated Akt signaling.
PLoS One. 2013; 8(12):e83789 [PubMed] Article available free on PMC after 01/08/2015 Related Publications
Ovarian cancer is an inflammation-associated malignancy with a high mortality rate. CXCR2 expressing ovarian cancers are aggressive with poorer outcomes. We therefore investigated molecular mechanisms involved in CXCR2-driven cancer progression by comparing CXCR2 positive and negative ovarian cancer cell lines. Stably CXCR2 transfected SKOV-3 cells had a faster growth rate as compared to control cells transfected with empty vector. Particularly, tumor necrosis factor (TNF), abundantly expressed in ovarian cancer, enhanced cell proliferation by decreasing the G0-G1 phase in CXCR2 transfected cells. TNF increased nuclear factor-κB (NF-κB) activity to a greater degree in CXCR2 transfected cells than control cells as well as provided a greater activation of IκB. CXCR2 transfected cells expressed higher levels of its proinflammatory ligands, CXCL1/2 and enhanced more proliferation, migration, invasion and colony formation. CXCR2 positive cells also activated more EGFR, which led to higher Akt activation. Enhanced NF-κB activity in CXCR2 positive cells was reduced by a PI3K/Akt inhibitor rather than an Erk inhibitor. CXCL1 added to CXCR2 positive cells led to an increased activation of IκB. CXCL1 also led to a significantly greater number of invasive cells in CXCR2 transfected cells, which was blocked by the NF-κB inhibitor, Bay 11-7082. In addition, enhanced cell proliferation in CXCR2 positive cells was more sensitive to CXCL1 antibody or an NF-κB inhibitor. Finally, CXCR2 transfection of parental cells increased CXCL1 promoter activity via an NF-κB site. Thus augmentation of proinflammatory chemokines CXCL1/2, by potentiating NF-κB activation through EGFR-transactivated Akt, contributes to CXCR2-driven ovarian cancer progression.

Gold KA, Kim ES, Liu DD, et al.
Prediction of survival in resected non-small cell lung cancer using a protein expression-based risk model: implications for personalized chemoprevention and therapy.
Clin Cancer Res. 2014; 20(7):1946-54 [PubMed] Article available free on PMC after 01/08/2015 Related Publications
PURPOSE: Patients with resected non-small cell lung cancer (NSCLC) are at risk for recurrence of disease, but we do not have tools to predict which patients are at highest risk. We set out to create a risk model incorporating both clinical data and biomarkers.
EXPERIMENTAL DESIGN: We assembled a comprehensive database with archival tissues and clinical follow-up from patients with NSCLC resected between 2002 and 2005. Twenty-one proteins identified from our preclinical studies as related to lung carcinogenesis were investigated, including pathways related to metabolism, DNA repair, inflammation, and growth factors. Expression of proteins was quantified using immunohistochemistry. Immunohistochemistry was chosen because it is widely available and can be performed on formalin-fixed paraffin-embedded specimens. Cox models were fitted to estimate effects of clinical factors and biomarkers on recurrence-free survival (RFS) and overall survival (OS).
RESULTS: A total of 370 patients are included in our analysis. With median follow-up of 5.3 years, median OS is 6.4 years. A total of 209 cases with recurrence or death were observed. Multicovariate risk models for RFS and OS were developed including relevant biomarkers, age, and stage. Increased expression of phospho-adenosine monophosphate-activated protein kinase (pAMPK), phospho-mTOR (pmTOR), epithelial cell adhesion molecule (EpCAM), and calcium/calmodulin-dependent serine protein kinase were significant (P < 0.05) predictors for favorable RFS; insulin receptor, chemokine (C-X-C motif) receptor 2 (CXCR2), and insulin-like growth factor-1 receptor predicted for unfavorable RFS. Significant (P < 0.05) predictors for favorable OS include pAMPK, pmTOR, and EpCAM; CXCR2 and flap structure-specific endonuclease-1 predicted unfavorable OS.
CONCLUSION: We have developed a comprehensive risk model predictive for recurrence in our large retrospective database, which is one of the largest reported series of resected NSCLC.

Lee YS, Choi D, Kim NY, et al.
CXCR2 inhibition enhances sulindac-mediated suppression of colon cancer development.
Int J Cancer. 2014; 135(1):232-7 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
Small chemical compound sulindac has been approved as a preventive approach against colon cancer for its effectiveness in treatment of precancerous adenoma. Due to its severe toxicities in the cardiovascular, gastrointestinal and renal systems, however, a combination of low-dose sulindac with other chemopreventive agents has been sought after as an alternative therapeutic strategy that could increase its effectiveness, while minimizing its adverse effects. To identify the promising alternative approach, we investigated the therapeutic potential of targeting the interleukin (IL)-8/CXCR2 pathway in colon cancer treatment using both loss-of-function (CXCR2 knockout) and gain-of-function (IL-8 overexpression) mouse models, as the IL-8/CXCR2 pathway has been shown to be activated in intestinal tumors of both human and experimental animals. We found that deletion of CXCR2 gene and ectopic expression of IL-8 suppresses and enhances, respectively, intestinal tumor development caused by a mutation in the APC gene. Moreover, a single copy deletion of CXCR2 gene resulted in abrogation of COX-2 and Gro-α upregulation in intestinal tumors caused by the APC mutation. Moreover, a single copy (heterozygote) deletion of CXCR2 gene was sufficient to synergize with a low-dose sulindac treatment in suppressing APCmin-induced intestinal polyposis. Together, our study provides a therapeutic justification of combined inhibition of CXCR2 and sulindac treatment in colon cancer prevention.

Grépin R, Guyot M, Giuliano S, et al.
The CXCL7/CXCR1/2 axis is a key driver in the growth of clear cell renal cell carcinoma.
Cancer Res. 2014; 74(3):873-83 [PubMed] Related Publications
Mutations in the von Hippel-Lindau gene upregulate expression of the central angiogenic factor VEGF, which drives abnormal angiogenesis in clear cell renal cell carcinomas (ccRCC). However, the overexpression of VEGF in these tumors was not found to correlate with overall survival. Here, we show that the proangiogenic, proinflammatory cytokine CXCL7 is an independent prognostic factor for overall survival in this setting. CXCL7 antibodies strongly reduced the growth of ccRCC tumors in nude mice. Conversely, conditional overexpression of CXCL7 accelerated ccRCC development. CXCL7 promoted cell proliferation in vivo and in vitro, in which expression of CXCL7 was induced by the central proinflammatory cytokine interleukin (IL)-1β. ccRCC cells normally secrete low amounts of CXCL7; it was more highly expressed in tumors due to high levels of IL-1β there. We found that a pharmacological inhibitor of the CXCL7 receptors CXCR1 and CXCR2 (SB225002) was sufficient to inhibit endothelial cell proliferation and ccRCC growth. Because CXCR1 and CXCR2 are present on both endothelial and ccRCC cells, their inhibition affected both the tumor vasculature and the proliferation of tumor cells. Our results highlight the CXCL7/CXCR1/CXCR2 axis as a pertinent target for the treatment of ccRCC.

Shi M, Chen MS, Sekar K, et al.
A blood-based three-gene signature for the non-invasive detection of early human hepatocellular carcinoma.
Eur J Cancer. 2014; 50(5):928-36 [PubMed] Related Publications
BACKGROUND: Identifying early stages of disease in high-risk individuals for the development of hepatocellular carcinoma (HCC) would greatly improve the clinical outcomes of these individuals. The aim of this study was to develop a blood-based gene set that could identify early-stage HCC.
METHODS: Comprehensive gene expression profiling of purified RNA of peripheral blood mononuclear cells (PBMC) was performed using microarrays. Gene signatures were developed through bioinformatics-driven approaches and their diagnostic value was evaluated by custom-designed, quantitative, multiplex polymerase chain reaction (PCR) assays.
RESULTS: Bioinformatics-driven analysis of microarray data derived from PBMC RNA samples of patients with HCC (N=10), pancreatic cancer (N=3), gastric cancer (N=3) and 10 normal individuals identified six genes that were differentially expressed in HCC. Subsequent multiplex-PCR validation and univariate analyses performed with an independent cohort of 114 HCC patients, 48 normal individuals and 14 patients with chronic hepatitis B (CHB) validated that three genes, namely Chemokine (C-X-C motif) receptor 2 (CXCR2), C-C chemokine receptor type 2 (CCR2) and E1A-Binding Protein P400 (EP400), were able to identify HCC individually with accuracies of 82.4%, 78.4% and 65%, respectively. In combination, these three genes gave an area under the curve (AUC) of 0.96 (95% confidence interval (CI), 0.93-0.99) using multivariate logistic regression and yielded a sensitivity of 93% and a specificity of 89%. When these three genes were used in combination with alpha-fetoprotein (AFP) to predict HCC, the accuracy of predicting HCC improved slightly with an AUC of 0.99 (95% CI, 0.98-1.0), sensitivity of 93% and specificity of 95%.
CONCLUSIONS: CXCR2, CCR2 and EP400 can provide a promising non-invasive multiplex PCR diagnostic assay to monitor high-risk individuals for the development of HCC.

Huang P, Xu X, Wang L, et al.
The role of EGF-EGFR signalling pathway in hepatocellular carcinoma inflammatory microenvironment.
J Cell Mol Med. 2014; 18(2):218-30 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
Epidermal growth factor (EGF) and their receptor (EGFR) play an important role in the development of cancer proliferation, and metastasis, although the mechanism remains unclear. The present study aimed at investigating the role of EGF-EGFR signalling pathway in the development of human hepatocellular carcinoma (HCC) inflammatory environment. Gene profiles of inflammatory cytokines from HCC were measured. Cell bio-behaviours of HCC with low or high metastasis were detected by the live cell monitoring system. Cell proliferation was measured by CCK8. The protein level of CXCL5 and CXCL8 was measured by ELISA. The phosphorylation of PI3K, ERK, MAPK was measured by western blot. EGF significantly induced cell proliferation in HepG2 cells, but not in HCCLM3 cells. EGF prompted the cell movement in both HepG2 and HCCLM3 and regulated the production of CXCL5 and CXCL8 from HCC, which were inhibited by EGFR inhibitor, Erk inhibitor (U0126), or PI3K inhibitors (BEZ-235 and SHBM1009). HCC proliferation, metastasis and production of inflammatory cytokines were regulated via EGF-EGFR signal pathways. CXCL5 could interact with CXCL8, possibly by CXCR2 or the cross-talk between CXCR2 and EGFR. EGF-EGFR signaling pathway can be the potential target of therapies for HCC.

Gacche RN, Meshram RJ
Targeting tumor micro-environment for design and development of novel anti-angiogenic agents arresting tumor growth.
Prog Biophys Mol Biol. 2013; 113(2):333-54 [PubMed] Related Publications
Angiogenesis: a process of generation of new blood vessels has been proved to be necessary for sustained tumor growth and cancer progression. Inhibiting angiogenesis pathway has long been remained a significant hope for the development of novel, effective and target orientated antitumor agents arresting the tumor proliferation and metastasis. The process of neoangiogenesis as a biological process is regulated by several pro- and anti-angiogenic factors, especially vascular endothelial growth factor, fibroblast growth factor, epidermal growth factor, hypoxia inducible factor 1 and transforming growth factor. Every endothelial cell destined for vessel formation is equipped with receptors for these angiogenic peptides. Moreover, numerous other angiogenic cytokines such as platelet derived growth factor (PGDF), placenta growth factor (PGF), nerve growth factor (NGF), stem-cell factor (SCF), and interleukins-2, 4, 6 etc. These molecular players performs critical role in regulating the angiogenic switch. Couple of decade's research in molecular aspects of tumor biology has unraveled numerous structural and functional mysteries of these angiogenic peptides. In present article, a detailed update on the functional and structural peculiarities of the various angiogenic peptides is described focusing on structural opportunities made available that has potential to be used to modulate function of these angiogenic peptides in developing therapeutic agents targeting neoplastic angiogenesis. The data may be useful in the mainstream of developing novel anticancer agents targeting tumor angiogenesis. We also discuss major therapeutic agents that are currently used in angiogenesis associated therapies as well as those are subject of active research or are in clinical trials.

Adalsteinsson VA, Tahirova N, Tallapragada N, et al.
Single cells from human primary colorectal tumors exhibit polyfunctional heterogeneity in secretions of ELR+ CXC chemokines.
Integr Biol (Camb). 2013; 5(10):1272-81 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
Cancer is an inflammatory disease of tissue that is largely influenced by the interactions between multiple cell types, secreted factors, and signal transduction pathways. While single-cell sequencing continues to refine our understanding of the clonotypic heterogeneity within tumors, the complex interplay between genetic variations and non-genetic factors ultimately affects therapeutic outcome. Much has been learned through bulk studies of secreted factors in the tumor microenvironment, but the secretory behavior of single cells has been largely uncharacterized. Here we directly profiled the secretions of ELR+ CXC chemokines from thousands of single colorectal tumor and stromal cells, using an array of subnanoliter wells and a technique called microengraving to characterize both the rates of secretion of several factors at once and the numbers of cells secreting each chemokine. The ELR+ CXC chemokines are highly redundant, pro-angiogenic cytokines that signal via the CXCR1 and CXCR2 receptors, influencing tumor growth and progression. We find that human primary colorectal tumor and stromal cells exhibit polyfunctional heterogeneity in the combinations and magnitudes of secretions for these chemokines. In cell lines, we observe similar variance: phenotypes observed in bulk can be largely absent among the majority of single cells, and discordances exist between secretory states measured and gene expression for these chemokines among single cells. Together, these measures suggest secretory states among tumor cells are complex and can evolve dynamically. Most importantly, this study reveals new insight into the intratumoral phenotypic heterogeneity of human primary tumors.

Hu W, Wang J, Luo G, et al.
Proteomics-based analysis of differentially expressed proteins in the CXCR1-knockdown gastric carcinoma MKN45 cell line and its parental cell.
Acta Biochim Biophys Sin (Shanghai). 2013; 45(10):857-66 [PubMed] Related Publications
C-X-C chemokine receptor types 1 (CXCR1), a cell-surface G-protein-coupled receptor has been found to be associated with tumorigenesis, development, and progression of some tumors. Previously, we have found that CXCR1 overexpression is associated with late-stage gastric adenocarcinoma. We also have demonstrated that knockdown of CXCR1 could inhibit cell proliferation in vitro and in vivo. In this study, we compared the changes of protein expression profile between gastric carcinoma MKN45 cell line and CXCR1-knockdown MKN45 cell line by 2D electrophoresis. Among the 101 quantified proteins, 29 spots were significantly different, among which 13 were down-regulated and 16 were up-regulated after CXCR1 knockdown. These proteins were further identified by mass spectrometry analysis. Among them, several up-regulated proteins such as hCG2020155, Keratin8, heterogeneous nuclear ribonucleoprotein C (C1/C2), and several down-regulated proteins such as Sorcin, heat shock protein 27, serpin B6 isoform b, and heterogeneous nuclear ribonucleoprotein K were confirmed. These proteins are related to cell cycle, the transcription regulation, cell adherence, cellular metabolism, drug resistance, and so on. These results provide an additional support to the hypothesis that CXCR1 might play an important role in proliferation, invasion, metastasis, and prognosis, and drug resistance of gastric carcinoma.

Raccosta L, Fontana R, Maggioni D, et al.
The oxysterol-CXCR2 axis plays a key role in the recruitment of tumor-promoting neutrophils.
J Exp Med. 2013; 210(9):1711-28 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
Tumor-infiltrating immune cells can be conditioned by molecules released within the microenvironment to thwart antitumor immune responses, thereby facilitating tumor growth. Among immune cells, neutrophils play an important protumorigenic role by favoring neoangiogenesis and/or by suppressing antitumor immune responses. Tumor-derived oxysterols have recently been shown to favor tumor growth by inhibiting dendritic cell migration toward lymphoid organs. We report that tumor-derived oxysterols recruit protumor neutrophils in a liver X receptor (LXR)-independent, CXCR2-dependent manner, thus favoring tumor growth by promoting neoangiogenesis and immunosuppression. We demonstrate that interfering with the oxysterol-CXCR2 axis delays tumor growth and prolongs the overall survival of tumor-bearing mice. These results identify an unanticipated protumor function of the oxysterol-CXCR2 axis and a possible target for cancer therapy.

Hao J, Zhang Y, Ye R, et al.
Mechanotransduction in cancer stem cells.
Cell Biol Int. 2013; 37(9):888-91 [PubMed] Related Publications
The cancer stem cell (CSC) concept, which arose about a decade ago, proposes that tumor growth is sustained by a subpopulation of highly malignant cells. These cells, termed CSCs, are capable of extensive self-renewal that contributes to metastasis and treatment resistance. Therefore, therapeutic strategies that target CSCs should be developed for improving outcomes of cancer patients. Recent progress has highlighted the importance of physical properties of the extracellular matrix and mechanotransduction pathway in cancer cells during cancer development. On the other hand, the significance of CXCR1, an upstream signal of FAK/PI3K/Akt has been revealed in CSCs. FAK/PI3K/Akt is a key signal mediator in mechanotransduction pathway. Therefore, mechanotransduction could be a new target for CSCs, and would be an innovative way to treat cancer by inhibiting FAK/PI3K/Akt.

Lo MC, Yip TC, Ngan KC, et al.
Role of MIF/CXCL8/CXCR2 signaling in the growth of nasopharyngeal carcinoma tumor spheres.
Cancer Lett. 2013; 335(1):81-92 [PubMed] Related Publications
Macrophage migration inhibitory factor (MIF) and CXCL8 (also named IL-8) are strongly expressed in the tissues of nasopharyngeal carcinoma (NPC). However, their role in the growth of NPC has not been fully examined. This study aims to evaluate the functions of MIF and CXCL8 on the growth of NPC tumor spheres. The elevated expression of CXCL8 in tumor over normal tissues was confirmed in 37 pairs of biopsies from NPC patients. In the in vitro study, all the poorly differentiated NPC cell lines, including the EBV-positive C666-1, and the EBV-negative CNE-1, CNE-2, SUNE-1, HNE-1 and HONE-1 cells, were found to express CXCL8 and MIF. Therefore, the EBV-positive C666-1 cell was selected to examine for the role of MIF and CXCL8 in the growth of the NPC tumor spheres. Functional study showed that the growth of C666-1 tumor spheres, under the nutrient poor or growth factor supplemented culture conditions, could be inhibited by the CXCL8 specific peptide inhibitor. The growth of the tumor spheres could also be reduced by the CXCR2 specific inhibitor SB225002 or the PI3K/AKT inhibitor LY294002, indicating that the endogenously produced CXCL8 plays an autocrine role in the growth of the tumor spheres. Further mechanistic studies revealed that the gene expression of CXCL8 could be reduced by the MIF specific small interfering RNA (siRNA) or NF-κB inhibitor parthenolide, and the growth of tumor spheres was also reduced after MIF siRNA transfection. Taken together, the present study highlights the role of MIF/CXCL8/CXCR2 axis in the growth of NPC tumor spheres. Chemotherapeutic interference of this signaling pathway may help to control the growth of the NPC tumor.

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