The Experts below are selected from a list of 18624 Experts worldwide ranked by ideXlab platform
Adriano Marchese - One of the best experts on this subject based on the ideXlab platform.
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The Endosomal Sorting Complex Required for Transport Pathway Mediates Chemokine Receptor CXCR4-promoted Lysosomal Degradation of the Mammalian Target of Rapamycin Antagonist DEPTOR
The Journal of biological chemistry, 2015Co-Authors: Rita Verma, Adriano MarcheseAbstract:G protein-coupled Receptor (GPCR) signaling mediates many cellular functions, including cell survival, proliferation, and cell motility. Many of these processes are mediated by GPCR-promoted activation of Akt signaling by mammalian target of rapamycin complex 2 (mTORC2) and the phosphatidylinositol 3-kinase (PI3K)/phosphoinositide-dependent kinase 1 (PDK1) pathway. However, the molecular mechanisms by which GPCRs govern Akt activation by these kinases remain poorly understood. Here, we show that the endosomal sorting complex required for transport (ESCRT) pathway mediates Akt signaling promoted by the Chemokine Receptor CXCR4. Pharmacological inhibition of heterotrimeric G protein Gαi or PI3K signaling and siRNA targeting ESCRTs blocks CXCR4-promoted degradation of DEPTOR, an endogenous antagonist of mTORC2 activity. Depletion of ESCRTs by siRNA leads to increased levels of DEPTOR and attenuated CXCR4-promoted Akt activation and signaling, consistent with decreased mTORC2 activity. In addition, ESCRTs likely have a broad role in Akt signaling because ESCRT depletion also attenuates Receptor tyrosine kinase-promoted Akt activation and signaling. Our data reveal a novel role for the ESCRT pathway in promoting intracellular signaling, which may begin to identify the signal transduction pathways that are important in the physiological roles of ESCRTs and Akt.
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the e3 ubiquitin ligase atrophin interacting protein 4 binds directly to the Chemokine Receptor CXCR4 via a novel ww domain mediated interaction
Molecular Biology of the Cell, 2009Co-Authors: Deepali Bhandari, Seth L Robia, Adriano MarcheseAbstract:The E3 ubiquitin ligase atrophin interacting protein 4 (AIP4) mediates ubiquitination and down-regulation of the Chemokine Receptor CXCR4. AIP4 belongs to the Nedd4-like homologous to E6-AP carboxy terminus domain family of E3 ubiquitin ligases, which typically bind proline-rich motifs within target proteins via the WW domains. The intracellular domains of CXCR4 lack canonical WW domain binding motifs; thus, whether AIP4 is targeted to CXCR4 directly or indirectly via an adaptor protein remains unknown. Here, we show that AIP4 can interact directly with CXCR4 via a novel noncanonical WW domain-mediated interaction involving serine residues 324 and 325 within the carboxy-terminal tail of CXCR4. These serine residues are critical for mediating agonist-promoted binding of AIP4 and subsequent ubiquitination and degradation of CXCR4. These residues are phosphorylated upon agonist activation and phosphomimetic mutants show enhanced binding to AIP4, suggesting a mechanism whereby phosphorylation mediates the interaction between CXCR4 and AIP4. Our data reveal a novel noncanonical WW domain-mediated interaction involving phosphorylated serine residues in the absence of any proline residues and suggest a novel mechanism whereby an E3 ubiquitin ligase is targeted directly to an activated G protein-coupled Receptor.
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arrestin 2 interacts with the ubiquitin protein isopeptide ligase atrophin interacting protein 4 and mediates endosomal sorting of the Chemokine Receptor CXCR4
Journal of Biological Chemistry, 2007Co-Authors: Deepali Bhandari, Jeffrey L. Benovic, Joann Trejo, Adriano MarcheseAbstract:The Chemokine Receptor CXCR4 is rapidly targeted for lysosomal degradation by the E3 ubiquitin ligase atrophin-interacting protein 4 (AIP4). Although it is known that AIP4 mediates ubiquitination and degradation of CXCR4 and that perturbations in these events contribute to disease, the mechanisms mediating AIP4-dependent regulation of CXCR4 degradation remain poorly understood. Here we show that AIP4 directly interacts with the amino-terminal half of nonvisual arrestin-2 via its WW domains. We show that depletion of arrestin-2 by small interfering RNA blocks agonist-promoted degradation of CXCR4 by preventing CXCR4 trafficking from early endosomes to lysosomes. Surprisingly, CXCR4 internalization and ubiquitination remain intact, suggesting that the interaction between arrestin-2 and AIP4 is not required for ubiquitination of the Receptor at the plasma membrane but perhaps for a later post-internalization event. Accordingly, we show that activation of CXCR4 promotes the interaction between AIP4 and arrestin-2 that is consistent with a time when AIP4 co-localizes with arrestin-2 on endocytic vesicles. Taken together, our data suggest that the AIP4.arrestin-2 complex functions on endosomes to regulate sorting of CXCR4 into the degradative pathway.
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the e3 ubiquitin ligase aip4 mediates ubiquitination and sorting of the g protein coupled Receptor CXCR4
Developmental Cell, 2003Co-Authors: Adriano Marchese, Camilla Raiborg, Francesca Santini, James H Keen, Harald Alfred Stenmark, Jeffrey L. BenovicAbstract:Ubiquitination of the Chemokine Receptor CXCR4 serves as a targeting signal for lysosomal degradation, but the mechanisms mediating ubiquitination and lysosomal sorting remain poorly understood. Here we report that the Nedd4-like E3 ubiquitin ligase AIP4 mediates ubiquitination of CXCR4 at the plasma membrane, and of the ubiquitin binding protein Hrs on endosomes. CXCR4 activation promotes CXCR4 colocalization with AIP4 and Hrs within the same region of endosomes. Endosomal sorting of CXCR4 is dependent on Hrs as well as the AAA ATPase Vps4, the latter involved in regulating the ubiquitination status of both CXCR4 and Hrs. We propose a model whereby AIP4, Hrs, and Vps4 coordinate a cascade of ubiquitination and deubiquitination events that sort CXCR4 to the degradative pathway.
Jeffrey L. Benovic - One of the best experts on this subject based on the ideXlab platform.
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G Protein-Coupled Receptor Kinase 3 and Protein Kinase C Phosphorylate the Distal C-Terminal Tail of the Chemokine Receptor CXCR4 and Mediate Recruitment of b-Arrestin
2020Co-Authors: Jiansong Luo, John M. Busillo, Jeffrey L. Benovic, Ralf Stumm, J L, J M BAbstract:ABSTRACT Phosphorylation of G protein-coupled Receptors (GPCRs) is a key event for cell signaling and regulation of Receptor function. Previously, using tandem mass spectrometry, we identified two phosphorylation sites at the distal C-terminal tail of the Chemokine Receptor CXCR4, but were unable to determine which specific residues were phosphorylated. Here, we demonstrate that serines (Ser) 346 and/or 347 (Ser-346/7) of CXCR4 are phosphorylated upon stimulation with the agonist CXCL12 as well as a CXCR4 pepducin, ATI-2341. ATI-2341, a Ga i bg heterotrimer-biased CXCR4 agonist, induced more robust phosphorylation of Ser-346/7 compared with CXCL12. Knockdown of G protein-coupled Receptor kinase (GRK) 2, GRK3, or GRK6 reduced CXCL12-induced phosphorylation of Ser-346/7 with GRK3 knockdown having the strongest effect, while inhibition of the conventional protein kinase C (PKC) isoforms, particularly PKCa, reduced phosphorylation of Ser-346/7 induced by either CXCL12 or ATI-2341. The loss of GRK3-or PKC-mediated phosphorylation of Ser-346/7 impaired the recruitment of b-arrestin to CXCR4. We also found that a pseudo-substrate peptide inhibitor for PKCz effectively inhibited CXCR4 phosphorylation and signaling, most likely by functioning as a nonspecific CXCR4 antagonist. Together, these studies demonstrate the role Ser-346/7 plays in arrestin recruitment and initiation of Receptor desensitization and provide insight into the dysregulation of CXCR4 observed in patients with various forms of WHIM syndrome
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SITE-SPECIFIC PHOSPHORYLATION OF CXCR4 IS DYNAMICALLY REGULATED BY MULTIPLE KINASES AND RESULTS IN DIFFERENTIAL MODULATION OF CXCR4 SIGNALING
2014Co-Authors: John M. Busillo, Sylvain Arm, Rajarshi Sengupta, Olimpia Meucci, Michel Bouvier, Jeffrey L. BenovicAbstract:The Chemokine Receptor CXCR4 is a widely expressed G protein-coupled Receptor that has been implicated in a number of diseases including HIV, cancer, and WHIM syndrome, with the latter two involving dysregulation of CXCR4 signaling. To better understand the role of phosphorylation in regulating CXCR4 signaling, tandem mass spectrometry and phospho-specific antibodies were used to identify sites of agonist-promoted phosphorylation. These studies demonstrate
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arrestin 2 interacts with the ubiquitin protein isopeptide ligase atrophin interacting protein 4 and mediates endosomal sorting of the Chemokine Receptor CXCR4
Journal of Biological Chemistry, 2007Co-Authors: Deepali Bhandari, Jeffrey L. Benovic, Joann Trejo, Adriano MarcheseAbstract:The Chemokine Receptor CXCR4 is rapidly targeted for lysosomal degradation by the E3 ubiquitin ligase atrophin-interacting protein 4 (AIP4). Although it is known that AIP4 mediates ubiquitination and degradation of CXCR4 and that perturbations in these events contribute to disease, the mechanisms mediating AIP4-dependent regulation of CXCR4 degradation remain poorly understood. Here we show that AIP4 directly interacts with the amino-terminal half of nonvisual arrestin-2 via its WW domains. We show that depletion of arrestin-2 by small interfering RNA blocks agonist-promoted degradation of CXCR4 by preventing CXCR4 trafficking from early endosomes to lysosomes. Surprisingly, CXCR4 internalization and ubiquitination remain intact, suggesting that the interaction between arrestin-2 and AIP4 is not required for ubiquitination of the Receptor at the plasma membrane but perhaps for a later post-internalization event. Accordingly, we show that activation of CXCR4 promotes the interaction between AIP4 and arrestin-2 that is consistent with a time when AIP4 co-localizes with arrestin-2 on endocytic vesicles. Taken together, our data suggest that the AIP4.arrestin-2 complex functions on endosomes to regulate sorting of CXCR4 into the degradative pathway.
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the e3 ubiquitin ligase aip4 mediates ubiquitination and sorting of the g protein coupled Receptor CXCR4
Developmental Cell, 2003Co-Authors: Adriano Marchese, Camilla Raiborg, Francesca Santini, James H Keen, Harald Alfred Stenmark, Jeffrey L. BenovicAbstract:Ubiquitination of the Chemokine Receptor CXCR4 serves as a targeting signal for lysosomal degradation, but the mechanisms mediating ubiquitination and lysosomal sorting remain poorly understood. Here we report that the Nedd4-like E3 ubiquitin ligase AIP4 mediates ubiquitination of CXCR4 at the plasma membrane, and of the ubiquitin binding protein Hrs on endosomes. CXCR4 activation promotes CXCR4 colocalization with AIP4 and Hrs within the same region of endosomes. Endosomal sorting of CXCR4 is dependent on Hrs as well as the AAA ATPase Vps4, the latter involved in regulating the ubiquitination status of both CXCR4 and Hrs. We propose a model whereby AIP4, Hrs, and Vps4 coordinate a cascade of ubiquitination and deubiquitination events that sort CXCR4 to the degradative pathway.
Hirokazu Tamamura - One of the best experts on this subject based on the ideXlab platform.
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development of a 111in labeled peptide derivative targeting a Chemokine Receptor CXCR4 for imaging tumors
Nuclear Medicine and Biology, 2006Co-Authors: Seigo Ishino, Tomohiko Mori, Kazuma Ogawa, Hirofumi Hanaoka, Hirokazu Tamamura, Takahiro Mukai, Yasuhiko IidaAbstract:Abstract The Chemokine Receptor CXCR4 is highly expressed in tumor cells and plays an important role in tumor metastasis. The aim of this study was to develop a radiopharmaceutical for the imaging of CXCR4-expressing tumors in vivo. Based on structure–activity relationships, we designed a 14-residue peptidic CXCR4 inhibitor, Ac-TZ14011, as a precursor for radiolabeled peptides. For 111 In-labeling, diethylenetriaminepentaacetic acid (DTPA) was attached to the side chain of d -Lys 8 which is distant from the residues indispensable for the antagonistic activity. In-DTPA-Ac-TZ14011 inhibited the binding of a natural ligand, stromal cell-derived factor-1α, to CXCR4 in a concentration-dependent manner with an IC 50 of 7.9 nM (Ac-TZ14011: 1.2 nM). In biodistribution experiments, more 111 In-DTPA-Ac-TZ14011 accumulated in the CXCR4-expressing tumor than in blood or muscle. Furthermore, the tumor-to-blood and tumor-to-muscle ratios were significantly reduced by coinjection of Ac-TZ14011, indicating a CXCR4-mediated accumulation in tumor. These findings suggested that 111 In-DTPA-Ac-TZ14011 would be a potential agent for the imaging of CXCR4 expression in metastatic tumors in vivo.
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germinal center dark and light zone organization is mediated by CXCR4 and cxcr5
Nature Immunology, 2004Co-Authors: Christopher D C Allen, Robin Lesley, Mark K Ansel, Hirokazu Tamamura, Nobutaka Fujii, Jason G CysterAbstract:Germinal center (GC) dark and light zones segregate cells undergoing somatic hypermutation and antigen-driven selection, respectively, yet the factors guiding this organization are unknown. We report here that GC organization was absent from mice deficient in the Chemokine Receptor CXCR4. Centroblasts had high expression of CXCR4 and GC B cells migrated toward the CXCR4 ligand SDF-1 (CXCL12), which was more abundant in the dark zone than in the light zone. CXCR4-deficient cells were excluded from the dark zone in the context of a wild-type GC. These findings establish that GC organization depends on sorting of centroblasts by CXCR4 into the dark zone. In contrast, CXCR5 helped direct cells to the light zone and deficiency in CXCL13 was associated with aberrant light zone localization.
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synthesis and evaluation of pseudopeptide analogues of a specific CXCR4 inhibitor t140 the insertion of an e alkene dipeptide isostere into the βii turn moiety
Bioorganic & Medicinal Chemistry Letters, 2002Co-Authors: Hirokazu Tamamura, Akane Omagari, Naoki Yamamoto, Hideki Nakashima, Kenichi Hiramatsu, Kazuhide Miyamoto, Shinya Oishi, Yoshihiro Kuroda, Terumichi Nakagawa, Akira OtakaAbstract:Abstract A 14-residue peptide, T140, strongly inhibits the T-cell line-tropic HIV-1 (X4-HIV-1) infection, since this peptide functions as a specific antagonist against a Chemokine Receptor, CXCR4. T140 takes an antiparallel β-sheet structure with a type II′ β-turn. In the present paper, we have designed and synthesized several T140 analogues, in which an (E)-alkene dipeptide isostere was inserted into the type II′ β-turn moiety, as a bridging study to develop nonpeptidic CXCR4 inhibitors. It has been proven that the turn region of T140 can be replaced by the above surrogate with the maintenance of strong anti-HIV activity.
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a low molecular weight inhibitor against the Chemokine Receptor CXCR4 a strong anti hiv peptide t140
Biochemical and Biophysical Research Communications, 1998Co-Authors: Hirokazu Tamamura, Toshio Hattori, Xiaoyan Zhang, Rieko Arakaki, Kenji Kanbara, Akane Omagari, Akira Otaka, Toshiro Ibuka, Naoki Yamamoto, Hideki NakashimaAbstract:T22 ([Tyr5,12, Lys7]-polyphemusin II) is an 18-residue peptide amide, which has strong anti-HIV activity. T22 inhibits the T cell line-tropic (T-tropic) HIV-1 infection through its specific binding to a Chemokine Receptor CXCR4, which serves as a coReceptor for the entry of T-tropic HIV-1 strains. Herein, we report our finding of novel 14-residue CXCR4 inhibitors, T134 and T140, on the basis of the T22 structure. In the assays we examined, T140 showed the highest inhibitory activity against HIV-1 entry and the strongest inhibitory effect on the binding of an anti-CXCR4 monoclonal antibody (12G5) to CXCR4 among all the CXCR4 inhibitors that have been reported up to now.
Deepali Bhandari - One of the best experts on this subject based on the ideXlab platform.
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the e3 ubiquitin ligase atrophin interacting protein 4 binds directly to the Chemokine Receptor CXCR4 via a novel ww domain mediated interaction
Molecular Biology of the Cell, 2009Co-Authors: Deepali Bhandari, Seth L Robia, Adriano MarcheseAbstract:The E3 ubiquitin ligase atrophin interacting protein 4 (AIP4) mediates ubiquitination and down-regulation of the Chemokine Receptor CXCR4. AIP4 belongs to the Nedd4-like homologous to E6-AP carboxy terminus domain family of E3 ubiquitin ligases, which typically bind proline-rich motifs within target proteins via the WW domains. The intracellular domains of CXCR4 lack canonical WW domain binding motifs; thus, whether AIP4 is targeted to CXCR4 directly or indirectly via an adaptor protein remains unknown. Here, we show that AIP4 can interact directly with CXCR4 via a novel noncanonical WW domain-mediated interaction involving serine residues 324 and 325 within the carboxy-terminal tail of CXCR4. These serine residues are critical for mediating agonist-promoted binding of AIP4 and subsequent ubiquitination and degradation of CXCR4. These residues are phosphorylated upon agonist activation and phosphomimetic mutants show enhanced binding to AIP4, suggesting a mechanism whereby phosphorylation mediates the interaction between CXCR4 and AIP4. Our data reveal a novel noncanonical WW domain-mediated interaction involving phosphorylated serine residues in the absence of any proline residues and suggest a novel mechanism whereby an E3 ubiquitin ligase is targeted directly to an activated G protein-coupled Receptor.
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arrestin 2 interacts with the ubiquitin protein isopeptide ligase atrophin interacting protein 4 and mediates endosomal sorting of the Chemokine Receptor CXCR4
Journal of Biological Chemistry, 2007Co-Authors: Deepali Bhandari, Jeffrey L. Benovic, Joann Trejo, Adriano MarcheseAbstract:The Chemokine Receptor CXCR4 is rapidly targeted for lysosomal degradation by the E3 ubiquitin ligase atrophin-interacting protein 4 (AIP4). Although it is known that AIP4 mediates ubiquitination and degradation of CXCR4 and that perturbations in these events contribute to disease, the mechanisms mediating AIP4-dependent regulation of CXCR4 degradation remain poorly understood. Here we show that AIP4 directly interacts with the amino-terminal half of nonvisual arrestin-2 via its WW domains. We show that depletion of arrestin-2 by small interfering RNA blocks agonist-promoted degradation of CXCR4 by preventing CXCR4 trafficking from early endosomes to lysosomes. Surprisingly, CXCR4 internalization and ubiquitination remain intact, suggesting that the interaction between arrestin-2 and AIP4 is not required for ubiquitination of the Receptor at the plasma membrane but perhaps for a later post-internalization event. Accordingly, we show that activation of CXCR4 promotes the interaction between AIP4 and arrestin-2 that is consistent with a time when AIP4 co-localizes with arrestin-2 on endocytic vesicles. Taken together, our data suggest that the AIP4.arrestin-2 complex functions on endosomes to regulate sorting of CXCR4 into the degradative pathway.
Lang Yang - One of the best experts on this subject based on the ideXlab platform.
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transcription factor runx2 up regulates Chemokine Receptor CXCR4 to promote invasive and metastatic potentials of human gastric cancer
Oncotarget, 2016Co-Authors: Lang Yang, Chengdong Ji, Dongfang Xiang, Yanxia Wang, Ji Ming Wang, Xia Zhang, Xi Yu, Feng Qian, Peng Zhang, Xiuwu BianAbstract:// Zheng-Jun Guo 1 , Lang Yang 1 , Feng Qian 2 , Yan-Xia Wang 1 , Xi Yu 1 , Cheng-Dong Ji 1 , Wei Cui 1 , Dong-Fang Xiang 1 , Xia Zhang 1 , Peng Zhang 1 , Ji Ming Wang 3 , You-Hong Cui 1 , Xiu-Wu Bian 1, 4 1 Institute of Pathology and Southwest Cancer Center, and Key Laboratory of Tumor Immunopathology, Ministry of Education of China, Third Military Medical University, Chongqing, China 2 Department of General Surgery, Southwest Hospital, Third Military Medical University, Chongqing, China 3 Laboratory of Molecular Immunoregulation, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA 4 Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University, Guangzhou, China Correspondence to: Xiu-Wu Bian, e-mail: bianxiuwu@263.net You-Hong Cui, e-mail: cuiyouhongx@yahoo.com Keywords: RUNX2, gastric cancer, invasion, metastasis, CXCR4 Received: August 12, 2015 Accepted: February 06, 2016 Published: March 21, 2016 ABSTRACT Runt-related transcription factor 2 (RUNX2) is a regulator of embryogenesis and development, but has also been implicated in the progression of certain human cancer. This study aimed to elucidate the role of RUNX2 in the invasive and metastatic potentials of human gastric cancer (GC) and the underlying mechanisms. We found that the levels of RUNX2 expression in gastric cancer tissues were correlated with the differentiation degrees, invasion depth and lymph node metastasis. COX regression analysis indicated that RUNX2 was an independent prognostic indicator for GC patients. RUNX2 significantly increased the migration and invasion ability of GC cells in vitro and enhanced the invasion and metastatic potential of GC cells in an orthotopic GC model of nude mice. Mechanistically, RUNX2 directly bound to the promoter region of the gene coding for the Chemokine Receptor CXCR4 to enhance its transcription. CXCR4 knockdown or treatment with AMD3100, a CXCR4 inhibitor, attenuated RUNX2-promoted invasion and metastasis. These results demonstrate that RUNX2 promotes the invasion and metastasis of human GC by transcriptionally up-regulating the Chemokine Receptor CXCR4. Therefore, the RUNX2-CXCR4 axis is a potential therapeutic target for GC.
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transcription factor runx2 up regulates Chemokine Receptor CXCR4 to promote invasive and metastatic potentials of human gastric cancer
Oncotarget, 2016Co-Authors: Zhengjun Guo, Dongfang Xiang, Yanxia Wang, Ji Ming Wang, Xia Zhang, Feng Qian, Lang Yang, Peng Zhang, Wei Cui, Youhong CuiAbstract:Runt-related transcription factor 2 (RUNX2) is a regulator of embryogenesis and development, but has also been implicated in the progression of certain human cancer. This study aimed to elucidate the role of RUNX2 in the invasive and metastatic potentials of human gastric cancer (GC) and the underlying mechanisms. We found that the levels of RUNX2 expression in gastric cancer tissues were correlated with the differentiation degrees, invasion depth and lymph node metastasis. COX regression analysis indicated that RUNX2 was an independent prognostic indicator for GC patients. RUNX2 significantly increased the migration and invasion ability of GC cells in vitro and enhanced the invasion and metastatic potential of GC cells in an orthotopic GC model of nude mice. Mechanistically, RUNX2 directly bound to the promoter region of the gene coding for the Chemokine Receptor CXCR4 to enhance its transcription. CXCR4 knockdown or treatment with AMD3100, a CXCR4 inhibitor, attenuated RUNX2-promoted invasion and metastasis. These results demonstrate that RUNX2 promotes the invasion and metastasis of human GC by transcriptionally up-regulating the Chemokine Receptor CXCR4. Therefore, the RUNX2-CXCR4 axis is a potential therapeutic target for GC.