Met receptor tyrosine kinase signaling induces secretion of the angiogenic chemokine interleukin-8/CXCL8 in pancreatic cancer

At diagnosis, the majority of pancreatic cancer patients present with advanced disease when curative resection is no longer feasible and current therapeutic treatments are largely ineffective. An improved understanding of molecular targets for effective intervention of pancreatic cancer is thus urgent. The Met receptor tyrosine kinase is one candidate implicated in pancreatic cancer. Notably, Met is over expressed in up to 80% of invasive pancreatic cancers but not in normal ductal cells correlating with poor overall patient survival and increased recurrence rates following surgical resection. However the functional role of Met signaling in pancreatic cancer remains poorly understood. Here we used RNA interference to directly examine the pathobiological importance of increased Met signaling for pancreatic cancer. We show that Met knockdown in pancreatic tumor cells results in decreased cell survival, cell invasion, and migration on collagen I in vitro. Using an orthotopic model for pancreatic cancer, we provide in vivo evidence that Met knockdown reduced tumor burden correlating with decreased cell survival and tumor angiogenesis, with minimal effect on cell growth. Notably, we report that Met signaling regulates the secretion of the pro-angiogenic chemokine interleukin-8/CXCL8. Our data showing that the interleukin-8 receptors CXCR1 and CXCR2 are not expressed on pancreatic tumor cells, suggests a paracrine mechanism by which Met signaling regulates interleukin-8 secretion to remodel the tumor microenvironment, a novel finding that could have important clinical implications for improving the effectiveness of treatments for pancreatic cancer.     

Presenilin-2 polymorphisms and risk of sporadic AD: evidence from a meta-analysis

Pancreatic cancer is a malignant neoplasm of the pancreas that usually has a poor prognosis. The investigation of targets that effectively inhibit pancreatic cancer cell proliferation should provide a fundamental basis for the clinical application of gene therapy. Here, high expression levels of ABCC4 protein in thirty-six pancreatic cancer specimens were quantified using an immunohistochemical assay, and the potential of ABCC4 as a therapeutic target for pancreatic cancer was investigated. Inhibition of ABCC4 expression at the mRNA and protein levels was achieved in Panc-1 and BxPC-3 pancreatic cancer cells infected with a lentivirus expressing an ABCC4 short hairpin RNA (shRNA). The downregulation of ABCC4 expression in Panc-1 and BxPC-3 cells significantly inhibited their proliferation and colony formation in vitro, compared to cells infected with mock control (p < 0.05). Moreover, the specific downregulation of ABCC4 led to the accumulation of cells at the G1 phase of the cell cycle. Our findings reveal that the ABCC4 gene promotes pancreatic cancer cell growth and represents a promising target for gene therapy in pancreatic cancer.     

miR-30d suppresses proliferation and invasiveness of pancreatic cancer by targeting the SOX4/PI3K-AKT axis and predicts poor outcome

Aberrant expression of miR-30d is associated with the development and progression of several human cancers. However, its biological roles and underlying mechanisms in pancreatic cancer are largely unknown. The expression of miR-30d in pancreatic cancer was evaluated in public databases and further valuated by real-time quantitative PCR, western blot, and immunohistochemistry in a cohort of pancreatic cancer patients. The role of miR-30d in the proliferation and metastasis of pancreatic cancer cells was determined using in vitro and in vivo assays. Bioinformatics analyses were performed to examine potential target genes of miR-30d. Luciferase reporter assay and functional rescue experiments were used to elucidate the mechanisms of miR-30d. miR-30d was found frequently decreased in pancreatic cancer compared with nontumor tissues, and downregulation of miR-30d predicted poor prognosis and early relapse of pancreatic cancer patients. Overexpression of miR-30d significantly repressed the growth and metastasis of pancreatic cancer cells both in vitro and in vivo. Bioinformatics analyses identified sex-determining region Y-box 4 (SOX4) as a target gene of miR-30d. Mechanically, miR-30d exerted its tumor suppressive effect by directly targeting SOX4, which caused inhibition of the PI3K-AKT signaling pathway. Overexpression of SOX4 partially antagonized the inhibitory effects of miR-30d. Our study demonstrated that dysregulation of the miR-30d/SOX4/PI3K-AKT axis promotes the development and progression of pancreatic cancer. These findings suggest miR-30d as a promising and reliable therapeutic target for pancreatic cancer.Subject terms: Oncogenes, Oncogenesis     

Imaging CXCL12-CXCR4 Signaling in Ovarian Cancer Therapy

Chemokine CXCL12 and receptor CXCR4 have emerged as promising therapeutic targets for ovarian cancer, a disease that continues to have a dismal prognosis. CXCL12-CXCR4 signaling drives proliferation, survival, and invasion of ovarian cancer cells, leading to tumor growth and metastasis. Pleiotropic effects of CXCR4 in multiple key steps in ovarian cancer suggest that blocking this pathway will improve outcomes for patients with this disease. To quantify CXCL12-CXCR4 signaling in cell-based assays and living mouse models of ovarian cancer, we developed a click beetle red luciferase complementation reporter that detects activation of CXCR4 based on recruitment of the cytosolic adapter protein β-arrestin 2. Both in two-dimensional and three-dimensional cell cultures, we established that bioluminescence from this reporter measures CXCL12-dependent activation of CXCR4 and inhibition of this pathway with AMD3100, a clinically-approved small molecule that blocks CXCL12-CXCR4 binding. We used this imaging system to quantify CXCL12-CXCR4 signaling in a mouse model of metastatic ovarian cancer and showed that treatment with AMD3100 interrupted this pathway in vivo. Combination therapy with AMD3100 and cisplatin significantly decreased tumor burden in mice, although differences in overall survival were not significantly greater than treatment with either agent as monotherapy. These studies establish a molecular imaging reporter system for analyzing CXCL12-CXCR4 signaling in ovarian cancer, which can be used to investigate biology and therapeutic targeting of this pathway in cell-based assays and living mice.     

MicroRNA 483-3p suppresses the expression of DPC4/Smad4 in pancreatic cancer

Both deregulation of tumor-suppressor genes and misexpression of microRNAs (miRNAs) have been implicated in the development of pancreatic cancer, but their relationship during this process remains less clear. Here, we report that the expression of miR-483-3p is strongly enhanced in pancreatic cancer tissues compared to side normal tissues using a miRNA-array differential analysis. Furthermore, DPC4/Smad4 is identified as a target of miR-483-3p and their expression levels are inversely correlated in human clinical specimens. Ectopic expression of miR-483-3p significantly represses DPC4/Smad4 protein levels in pancreatic cancer cell lines, and simultaneously promotes cell proliferation and colony formation in vitro. Our findings identify miR-483-3p as a potent regulator of DPC4/Smad4, which may provide a novel therapeutic strategy for the treatment of DPC4/Smad4-driven pancreatic cancer.     

Distinct populations of cancer stem cells determine tumor growth and metastatic activity in human pancreatic cancer

Pancreatic adenocarcinoma is currently the fourth leading cause for cancer-related mortality. Stem cells have been implicated in pancreatic tumor growth, but the specific role of these cancer stem cells in tumor biology, including metastasis, is still uncertain. We found that human pancreatic cancer tissue contains cancer stem cells defined by CD133 expression that are exclusively tumorigenic and highly resistant to standard chemotherapy. In the invasive front of pancreatic tumors, a distinct subpopulation of CD133(+) CXCR4(+) cancer stem cells was identified that determines the metastatic phenotype of the individual tumor. Depletion of the cancer stem cell pool for these migrating cancer stem cells virtually abrogated the metastatic phenotype of pancreatic tumors without affecting their tumorigenic potential. In conclusion, we demonstrate that a subpopulation of migrating CD133(+) CXCR4(+) cancer stem cells is essential for tumor metastasis. Strategies aimed at modulating the SDF-1/CXCR4 axis may have important clinical applications to inhibit metastasis of cancer stem cells.     

Epigenetic changes of CXCR4 and its ligand CXCL12 as prognostic factors for sporadic breast cancer

Chemokines and their receptors are involved in the development and cancer progression. The chemokine CXCL12 interacts with its receptor, CXCR4, to promote cellular adhesion, survival, proliferation and migration. The CXCR4 gene is upregulated in several types of cancers, including skin, lung, pancreas, brain and breast tumors. In pancreatic cancer and melanoma, CXCR4 expression is regulated by DNA methylation within its promoter region. In this study we examined the role of cytosine methylation in the regulation of CXCR4 expression in breast cancer cell lines and also correlated the methylation pattern with the clinicopathological aspects of sixty-nine primary breast tumors from a cohort of Brazilian women. RT-PCR showed that the PMC-42, MCF7 and MDA-MB-436 breast tumor cell lines expressed high levels of CXCR4. Conversely, the MDA-MB-435 cell line only expressed CXCR4 after treatment with 5-Aza-CdR, which suggests that CXCR4 expression is regulated by DNA methylation. To confirm this hypothesis, a 184 bp fragment of the CXCR4 gene promoter region was cloned after sodium bisulfite DNA treatment. Sequencing data showed that cell lines that expressed CXCR4 had only 15% of methylated CpG dinucleotides, while the cell line that not have CXCR4 expression, had a high density of methylation (91%). Loss of DNA methylation in the CXCR4 promoter was detected in 67% of the breast cancer analyzed. The absence of CXCR4 methylation was associated with the tumor stage, size, histological grade, lymph node status, ESR1 methylation and CXCL12 methylation, metastasis and patient death. Kaplan-Meier curves demonstrated that patients with an unmethylated CXCR4 promoter had a poorer overall survival and disease-free survival. Furthermore, patients with both CXCL12 methylation and unmethylated CXCR4 had a shorter overall survival and disease-free survival. These findings suggest that the DNA methylation status of both CXCR4 and CXCL12 genes could be used as a biomarker for prognosis in breast cancer.     

Selection of peptide inhibitor to matrix metalloproteinase-2 using phage display and its effects on pancreatic cancer cell lines PANC-1 and CFPAC-1

Despite tremendous advances in cancer treatment and survival rates, pancreatic cancer remains one of the most deadly afflictions and the fourth leading cause of cancer deaths in the world. Matrix Metalloproteinases (MMPs) are thought to be involved in cancer progression. Matrix metalloproteinase (MMP)-2 is known to play a pivotal role in tumor invasion, metastasis and angiogenesis, and validated to be the anticancer target. Inhibition of MMP-2 activity is able to reduce the cancer cell invasion and suppress tumor growth in vivo. Two novel peptides, M204C4 and M205C4, which could specially inhibit MMP-2 activity, were identified by a phage display library screening. We showed that M204C4 and M205C4 inhibited the activity of MMP-2 in a dose dependent manner in vitro. Two peptides reduced MMP-2 mediated invasion of the pancreatic cancer cell lines PANC-1 and CFPAC-1, but not affected the expression and release of MMP-2. Furthermore, these two peptides could suppress tumor growth in vivo. Our results indicated that two peptides selected by phase display technology may be used as anticancer drugs in the future.     

Purification of immature neuronal cells from neural stem cell progeny

Large-scale proliferation and multi-lineage differentiation capabilities make neural stem cells (NSCs) a promising renewable source of cells for therapeutic applications. However, the practical application for neuronal cell replacement is limited by heterogeneity of NSC progeny, relatively low yield of neurons, predominance of astrocytes, poor survival of donor cells following transplantation and the potential for uncontrolled proliferation of precursor cells. To address these impediments, we have developed a method for the generation of highly enriched immature neurons from murine NSC progeny. Adaptation of the standard differentiation procedure in concert with flow cytometry selection, using scattered light and positive fluorescent light selection based on cell surface antibody binding, provided a near pure (97%) immature neuron population. Using the purified neurons, we screened a panel of growth factors and found that bone morphogenetic protein-4 (BMP-4) demonstrated a strong survival effect on the cells in vitro, and enhanced their functional maturity. This effect was maintained following transplantation into the adult mouse striatum where we observed a 2-fold increase in the survival of the implanted cells and a 3-fold increase in NeuN expression. Additionally, based on the neural-colony forming cell assay (N-CFCA), we noted a 64 fold reduction of the bona fide NSC frequency in neuronal cell population and that implanted donor cells showed no signs of excessive or uncontrolled proliferation. The ability to provide defined neural cell populations from renewable sources such as NSC may find application for cell replacement therapies in the central nervous system.     

Targeting the CXCR4-CXCL12 axis mobilizes autologous hematopoietic stem cells and prolongs islet allograft survival via programmed death ligand 1

Antagonism of CXCR4 disrupts the interaction between the CXCR4 receptor on hematopoietic stem cells (HSCs) and the CXCL12 expressed by stromal cells in the bone marrow, which subsequently results in the shedding of HSCs to the periphery. Because of their profound immunomodulatory effects, HSCs have emerged as a promising therapeutic strategy for autoimmune disorders. We sought to investigate the immunomodulatory role of mobilized autologous HSCs, via target of the CXCR4-CXL12 axis, to promote engraftment of islet cell transplantation. Islets from BALB/c mice were transplanted beneath the kidney capsule of hyperglycemic C57BL/6 mice, and treatment of recipients with CXCR4 antagonist resulted in mobilization of HSCs and in prolongation of islet graft survival. Addition of rapamycin to anti-CXCR4 therapy further promoted HSC mobilization and islet allograft survival, inducing a robust and transferable host hyporesponsiveness, while administration of an ACK2 (anti-CD117) mAb halted CXCR4 antagonist-mediated HSC release and restored allograft rejection. Mobilized HSCs were shown to express high levels of the negative costimulatory molecule programmed death ligand 1 (PD-L1), and HSCs extracted from wild-type mice, but not from PD-L1 knockout mice, suppressed the in vitro alloimmune response. Moreover, HSC mobilization in PD-L1 knockout mice failed to prolong islet allograft survival. Targeting the CXCR4-CXCL12 axis thus mobilizes autologous HSCs and promotes long-term survival of islet allografts via a PD-L1-mediated mechanism.     

Upregulated Expression of C-X-C Chemokine Receptor 4 Is an Independent Prognostic Predictor for Patients with Gastric Cancer

Aberrant chemokine (C-X-C motif) receptor CXCR4 expressions in malignant tissues have been reported, but its role in gastric cancer prognosis remains unknown. Our studies were designed to investigate the expression and prognostic significance of CXCR4 in patients with gastric cancer. CXCR4 expression was retrospectively analyzed by immunohistochemistry in 97 patients with gastric adenocarcinoma from China. Results were assessed for association with clinical features and overall survival by using Kaplan-Meier analysis. Prognostic values of CXCR4 expression and clinical outcomes were evaluated by Cox regression analysis. A molecular prognostic stratification scheme incorporating CXCR4 expression was determined by using receiver operating characteristic (ROC) analysis. The results show that CXCR4 predominantly localized in the cell membranes and cytoplasm. The protein level of CXCR4 was upregulation in gastric cancer tissues and upregulated expression of CXCR4 was only significantly associated with Lauren classification (P<0.001). Increased CXCR4 expression in gastric cancer tissues was positively correlated with poor overall survival of gastric cancer patients (P<0.001). Further multivariate Cox regression analysis suggested that intratumoral CXCR4 expression was an independent prognostic indicator for the disease. Applying the prognostic value of intratumoral CXCR4 density to TNM stage system showed a better prognostic value in patients with gastric cancer. In conclusion, intratumoral CXCR4 expression was recognized as an independent prognostic marker for the overall survival of patients with gastric cancer. On the basis of TNM stage, detection of CXCR4 expression will be helpful for predicting prognosis for patients with gastric cancer.     

Overexpression of CXCR4 is significantly associated with cisplatin-based chemotherapy resistance and can be a prognostic factor in epithelial ovarian cancer

The chemokine receptor 4 (CXCR4) plays an important role in the growth, angiogenesis and metastasis of various cancers, including epithelial ovarian cancer (EOC). However, the correlation between CXCR4 and the clinical response of EOC patients to chemotherapy remains unknown. 124 EOC patients were recruited to assess the relationship between CXCR4 and the response to cisplatin-based chemotherapy. The results showed that patients with a higher CXCR4 expression had a significantly lower chemosensitivity, a poorer progression-free survival and a lower overall survival than those with lower CXCR4 expression. In addition, knockdown of CXCR4 by small interfering RNA suppressed cell proliferation and resulted in G1/S arrest, increased apoptosis and chemosensitivity in both cisplatin-sensitive A2780 cells and cisplatin-resistant cell A2780/cis in vitro. Our data suggest that CXCR4 is one of the key molecules in cisplatin-based chemotherapy for EOC patients and that CXCR4 inhibition is a potential strategy to address the chemoresistance of EOC. [BMB Reports 2014; 47(1): 33-38]     

Differential role of CD133 and CXCR4 in renal cell carcinoma

The chemokine receptor CXCR4 and CD133, putative stem cell markers, were previously described in renal cancer (RCC). To evaluate the biological and prognostic role of CD133 and CXCR4 in RCC the expression was evaluated through qPCR and immunoblotting in human renal cancer cell lines (786-O, A498, ACHN, CAKI-1, SN12C, TK10, UO31) and patients biopsies. Renal cancer cells and surgical biopsies expressed functional CXCR4 while CD133 was not detectable. CXCR4 and CD133 expression was then evaluated in 240 renal cancer patients through immunohistochemistry. CXCR4 and CD133 were low in 19.1% and 59.6%; intermediate in 20% and 17.9%; high in 60.8% and 22.5% of the cases, respectively. CXCR4 was overexpressed in tumours (p= 0.02), while CD133 was over expressed in healthy tissues (p= 0.04). Disease free survival Kaplan Meier plots suggest that prognosis is unfavourable for patients whose primary tumours express CXCR4 (p= 0.0199) but nor CD133 (p= 0.151) neither the concomitant CXCR4-CD133 (p=0.848) high expression affected prognosis. Analysis of prognostic factors suggests that age, clinical presentation, AJCC stage and CXCR4 had a significant prognostic value at the univariate analysis. The CXCR4 predictive ability was confirmed at the multivariate analysis while no prognostic role was identified for CD133. Thus concomitant CD133 and CXCR4 evaluation is not worth in RCC patient while the CXCR4 prognostic role encourage CXCR4 antagonists as promising therapeutic option.     

Angiopoietin-2, an angiogenic regulator, promotes initial growth and survival of breast cancer metastases to the lung through the integrin-linked kinase (ILK)-AKT-B cell lymphoma 2 (Bcl-2) pathway

The early onsets of breast cancer metastasis involve cell retention, survival, and resistant to apoptosis and subsequent growth at target vascular beds and tissues in distant organs. We previously reported that angiopoietin-2 (Ang2), an angiogenic regulator stimulates MCF-7 breast tumor metastasis from their orthotopic sites to distant organs through the α(5)β(1) integrin/integrin-linked kinase (ILK)/Akt pathway. Here, by using an experimental tumor metastasis model and in vitro studies, we further dissect the underlying mechanism by which Ang2 promotes the initial growth and survival of MCF-7 breast cancer metastasis in the lung of animals. We show that Ang2 increases cell survival and suppresses cell apoptosis through ILK-induced phosphorylation of Akt1, Akt2, and up-regulation of Bcl-2 in breast cancer cells. Inhibition of ILK, Akt1, and Akt2, and their effector Bcl-2 diminishes Ang2-stimulated breast cancer cell survival and Ang2-attenuated apoptosis in vitro, and initial survival and growth of breast cancer metastasis in the lung of animals. Additionally, siRNA knockdown of endogenous Ang2 in three human metastatic breast cancer cell lines also inhibits phosphorylation of Akt, expression of Bcl-2, and tumor cell survival, migration, and increases cell apoptosis. Since increased expression of Ang2 correlates with elevated potential of human breast cancer metastasis in clinic, our data underscore the importance that up-regulated Ang2 not only stimulates breast cancer growth and metastasis at late stages of the process, but is also critical at the initiating stages of metastases onset, thereby suggesting Ang2 as a promising therapeutic target for treating patients with metastatic breast cancer.     

Co-targeting BET bromodomain BRD4 and RAC1 suppresses growth,stemness and tumorigenesis by disrupting the c-MYC-G9a-FTH1axis and downregulating HDAC1 in molecular subtypes of breast cancer

BET bromodomain BRD4 and RAC1 oncogenes are considered important therapeutic targets for cancer and play key roles in tumorigenesis, survival and metastasis. However, combined inhibition of BRD4-RAC1 signaling pathways in different molecular subtypes of breast cancer including luminal-A, HER-2 positive and triple-negative breast (TNBC) largely remains unknown. Here, we demonstrated a new co-targeting strategy by combined inhibition of BRD4-RAC1 oncogenic signaling in different molecular subtypes of breast cancer in a context-dependent manner. We show that combined treatment of JQ1 (inhibitor of BRD4) and NSC23766 (inhibitor of RAC1) suppresses cell growth, clonogenic potential, cell migration and mammary stem cells expansion and induces autophagy and cellular senescence in molecular subtypes of breast cancer cells. Mechanistically, JQ1/NSC23766 combined treatment disrupts MYC/G9a axis and subsequently enhances FTH1 to exert antitumor effects. Furthermore, combined treatment targets HDAC1/Ac-H3K9 axis, thus suggesting a role of this combination in histone modification and chromatin modeling. C-MYC depletion and co-treatment with vitamin-C sensitizes different molecular subtypes of breast cancer cells to JQ1/NSC23766 combination and further reduces cell growth, cell migration and mammosphere formation. Importantly, co-targeting RAC1-BRD4 suppresses breast tumor growth in vivo using xenograft mouse model. Clinically, RAC1 and BRD4 expression positively correlates in breast cancer patient''s samples and show high expression patterns across different molecular subtypes of breast cancer. Both RAC1 and BRD4 proteins predict poor survival in breast cancer patients. Taken together, our results suggest that combined inhibition of BRD4-RAC1 pathways represents a novel and potential therapeutic approach in different molecular subtypes of breast cancer and highlights the importance of co-targeting RAC1-BRD4 signaling in breast tumorigenesis via disruption of C-MYC/G9a/FTH1 axis and down regulation of HDAC1.     

EGFR、HER2、CXCR4在tied,细胞肺癌中的表达及临床意义

目的：研究EGFR（epidermal growth factor receptor）、HER2（ human epidermalgrowth factor receptor-2）及CXCR4（chemokine（C-X-C motif） receptor 4）在NSCLC 中的表达,分析它们与NSCLC 临床病理特征的的关系。方法：选择我科2009 年7 月-2012年12 月收治的75 例非小细胞肺癌（NSCLC）患者为研究对象,支气管镜活检得到NSCLC肿瘤组织标本,免疫组织化学技术分别检测EGFR、HER2、CXCR4在NSCLC 组织中的表达,并分析EGFR、HER2、CXCR4 的表达与NSCLC 患者临床病理指标和生存期的相关性。结果：EGFR、HER2 及CXCR4在NSCLC中的表达与患者淋巴转移及远处转移有关（P〈0.05）。EGFR、HER2 及CXCR4在NSCLC 中的表达均呈正相关,EGFR 与HER2,EGFR 与CXCR4,HER2 与CXCR4 的相关系数分别为r=0.296（P〈0.01）,r=0.578（P〈0.01）,r=0.426（P〈0.01）。3 种基因表达越多,患者中位生存时间越短（P〈0.05）。结论：EGFR、HER2 及CXCR4 与NSCLC的发生发展关系密切,针对性的多个靶向抑制,可更好发挥抑癌作用。根据三者不同的表达情况初步筛选出针对靶向治疗的单一或联合靶点,有助于为NSCLC 患者提供个体化的治疗方案。为进一步治疗提供依据。     

ROS-mediated regulation of CXCR4 in cancer

Oxidative stress and the accumulation of reactive oxygen specie (ROS) play a role in cancer cells developing an advanced, phenotypic signature that associates with metastasis and progression. Increased ROS concentrations are involved in promoting cancer development and metastasis by inducing expression of oncogenes, suppressing activity of anti-survival molecules and by activating various cell survival and proliferation signaling pathways. Oxidative stress is higher in the epithelium of cancer patients than patients without the disease, and antioxidant trials are currently being explored as a therapeutic option. However, studies have shown that ROS increases expression of CXCR4 in cancer and immune cells. CXCR4 expression in tumors strongly correlates to metastasis and poor prognosis. Herein, we discuss an emerging relationship between ROS and CXCR4 in cancer cells.     

CXCR1+CD4+ T cells in human allergic disease

Chemokine receptors play an important role in the migration of leukocytes to sites of allergic inflammation in humans. In this study, we have identified increased expression of the chemokine receptor CXCR1 on CD4+ T lymphocytes derived from patients with atopic disease compared with normal donors. Enhanced expression of CXCR1 by atopic donors was identified on freshly isolated peripheral blood cells and on expanded cell populations derived from nasal mucosal biopsies and from the periphery. Identification of CXCR1 expression on CD4 cells in the nasal mucosa was confirmed by double immunofluorescence. In addition, expression of CXCR1 was dramatically decreased in patients undergoing successful treatment of allergic rhinitis by specific immunotherapy. CXCR1 provided a functional receptor capable of regulating T cells in the context of allergic disease, since expression of CXC chemokine ligand 8 was up-regulated at the site of allergic inflammation and freshly isolated CXCR1+CD4+ cells from atopic donors showed an enhanced functional response to this ligand. CXCR1 expression on CD4+ T cells was increased in vitro in response to the pro-Th2 cytokine IL-4. Phenotypic analysis reveals that IFN-gamma expression was lower in the CXCR1+CD4+ cells. The identification of CXCR1 as a marker of allergic rhinitis reveals a possible target for therapeutic intervention in atopic disease.