World Journal of Gastroenterology

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1 ISSN (print) ISSN (online) World Journl of Gstroenterology World J Gstroenterol 17 My 7; 3(17): Published by Bishideng Publishing Group Inc

2 S Contents Weekly Volume 3 Number 17 My 7, 17 EDITORIAL 311 Esophgitis nd its cuses: Who is guilty when cid is found not guilty? Grossi L, Ciccglione AF, Mrzio L 317 Checkpoint inhibitors in gstrointestinl cncers: Expecttions nd relity Kourie HR, Tbchi S, Ghosn M FRONTIER 3 BRAF inhibitor tretment of melnom cusing colonic polyps: An lterntive hypothesis Kelleher FC, Cllghn G, Gllgher C, O Sullivn H REVIEW 33 Genes, emotions nd gut microbiot: The next frontier for the gstroenterologist Pnduro A, River-Iñiguez I, Sepulved-Villegs M, Romn S 343 Mcrophge inflmmtory protein- s meditor of inflmmtion in cute liver injury Qin CC, Liu YN, Hu Y, Yng Y, Chen Z ORIGINAL ARTICLE Bsic Study 353 CXCR7/CXCL1 xis is involved in lymph node nd liver metstsis of gstric crcinom Xin Q, Zhng N, Yu HB, Zhng Q, Cui YF, Zhng CS, M Z, Yng Y, Liu W 366 Low-grde slightly elevted nd polypoid colorectl denoms disply differentil β-ctenin-tcf/lef ctivity, c-myc, nd cyclin D1 expression Yng TW, Go YH, M SY, Wu Q, Li ZF Retrospective Cohort Study 377 Pncreticoduodenectomy in ptients 75 yers of ge: Are there ny differences with other ge rnges in oncologicl nd surgicl outcomes? Results from tertiry referrl center Piell S, De Psten M, Pollini T, Zncn G, Ciprni D, De Mrchi G, Lndoni L, Esposito A, Csetti L, Mlleo G, Mrchegini G, Tuveri M, Mrrno E, Mggino L, Secchettin E, Bonmini D, Bssi C, Slvi R Retrospective Study 384 New flexible endoscopic controlled stpler technique for the tretment of Zenker s diverticulum: A cse series Wilmsen J, Bumbch R, Stüker D, Weingrt V, Neser F, Gölder SK, Pfundstein C, Nötzel EC, Rösch T, Fiss S My 7, 17 Volume 3 Issue 17

3 Contents World Journl of Gstroenterology Volume 3 Number 17 My 7, Comprison of imging-bsed nd pthologicl dimensions in pncretic neuroendocrine tumors Piell S, Impellizzeri H, Znolin E, Mrchegini G, Miotto M, Mlpg A, De Robertis R, D'Onofrio M, Rusev B, Cpelli P, Cingrlini S, Butturini G, Dvì MV, Amodio A, Bssi C, Scrp A, Slvi R, Lndoni L 399 Octogenrin liver grfts: Is their use for trnsplnt currently justified? Jiménez-Romero C, Cmbr F, Cso O, Mnrique A, Clvo J, Mrccuzco A, Rioj P, Lor D, Justo I 3111 Rte of locl tumor progression following rdiofrequency bltion of pthologiclly erly heptocellulr crcinom Ho Y, Numt K, Ishii T, Fukud H, Med S, Nkno M, Tnk K 31 Prognostic vlue of the neutrophil-to-lymphocyte rtio for heptocellulr crcinom ptients with portl/ heptic vein tumor thrombosis Li SH, Wng QX, Yng ZY, Jing W, Li C, Sun P, Wei W, Shi M, Guo RP Clinicl Trils Study 3133 Dignostic vlue of gdobente dimeglumine-enhnced heptocyte-phse mgnetic resonnce imging in evluting heptic fibrosis nd heptitis Li XM, Chen Z, Xio EH, Shng QL, M C Observtionl Study 314 Consequences of metbolic syndrome on postopertive outcomes fter pncreticoduodenectomy Zrzvdjin Le Bin A, Fuks D, Chopinet S, Gujoux S, Cesretti M, Costi R, Belgumkr AP, Smdj C, Gyet B 315 Effect of counseling-supported tretment with the Mediterrnen diet nd physicl ctivity on the severity of the non-lcoholic ftty liver disese Gelli C, Trocchi M, Abenvoli L, Di Renzo L, Glli A, De Lorenzo A Prospective Study 3163 Cost-effectiveness of enhnced liver fibrosis test to ssess liver fibrosis in chronic heptitis C virus nd lcoholic liver disese ptients Soto M, Smpietro-Colom L, Lslvi L, Mir A, Jiménez W, Nvs M 3174 Impct of gstroesophgel reflux control through tilored proton pump inhibition therpy or fundopliction in ptients with Brrett s esophgus Bldque-Silv F, Vieth M, Debel M, Håknson B, Thorell A, Lunet N, Song H, Mscrenhs-Sriv M, Pereir G, Lundell L, Mrschll HU 3184 Comprison of endoscopic ultrsound, computed tomogrphy nd mgnetic resonnce imging in ssessment of detiled structures of pncretic cystic neoplsms Du C, Chi NL, Linghu EQ, Li HK, Sun LH, Jing L, Wng XD, Tng P, Yng J II My 7, 17 Volume 3 Issue 17

4 Contents World Journl of Gstroenterology Volume 3 Number 17 My 7, 17 LETTER TO THE EDITOR 3193 Efficcy nd sfety of stellte gnglion block in chronic ulcertive colitis Lipov E, Cndido K III My 7, 17 Volume 3 Issue 17

5 Contents World Journl of Gstroenterology Volume 3 Number 17 My 7, 17 ABOUT COVER Editoril bord member of World Journl of Gstroenterology, Murizio Degiuli, FRCS (Gen Surg), MD, PhD, Associte Professor, Hed, Deprtment of Oncology, University of Turin, School of Medicine, Sn Luigi University Hospitl, Orbssno- Turin 143, Itly AIMS AND SCOPE World Journl of Gstroenterology (World J Gstroenterol, WJG, print ISSN , online ISSN 19-84, DOI: ) is peer-reviewed open ccess journl. WJG ws estblished on October 1, It is published weekly on the 7 th, 14 th, 1 st, nd 8 th ech month. The WJG Editoril Bord consists of 1375 experts in gstroenterology nd heptology from 68 countries. The primry tsk of WJG is to rpidly publish high-qulity originl rticles, reviews, nd commentries in the fields of gstroenterology, heptology, gstrointestinl endoscopy, gstrointestinl surgery, heptobiliry surgery, gstrointestinl oncology, gstrointestinl rdition oncology, gstrointestinl imging, gstrointestinl interventionl therpy, gstrointestinl infectious diseses, gstrointestinl phrmcology, gstrointestinl pthophysiology, gstrointestinl pthology, evidence-bsed medicine in gstroenterology, pncretology, gstrointestinl lbortory medicine, gstrointestinl moleculr biology, gstrointestinl immunology, gstrointestinl microbiology, gstrointestinl genetics, gstrointestinl trnsltionl medicine, gstrointestinl dignostics, nd gstrointestinl therpeutics. WJG is dedicted to become n influentil nd prestigious journl in gstroenterology nd heptology, to promote the development of bove disciplines, nd to improve the dignostic nd therpeutic skill nd expertise of clinicins. INDEXING/ABSTRACTING World Journl of Gstroenterology (WJG) is now indexed in Current Contents /Clinicl Medicine, Science Cittion Index Expnded (lso known s SciSerch ), Journl Cittion Reports, Index Medicus, MEDLINE, PubMed, PubMed Centrl, Digitl Object Identifier, nd Directory of Open Access Journls. The 15 edition of Journl Cittion Reports relesed by Thomson Reuters (ISI) cites the 15 impct fctor for WJG s.787 (5-yer impct fctor:.848), rnking WJG s 38 mong 78 journls in gstroenterology nd heptology (qurtile in ctegory Q). FLYLEAF I-IX Editoril Bord EDITORS FOR THIS ISSUE Responsible Assistnt Editor: Xing Li Responsible Electronic Editor: Fen-Fen Zhng Proofing Editor-in-Chief: Lin-Sheng M Responsible Science Editor: Ze-Mo Gong Proofing Editoril Office Director: Jin-Lei Wng NAME OF JOURNAL World Journl of Gstroenterology ISSN ISSN (print) ISSN (online) LAUNCH DATE October 1, 1995 FREQUENCY Weekly EDITORS-IN-CHIEF Dmin Grci-Olmo, MD, PhD, Doctor, Professor, Surgeon, Deprtment of Surgery, Universidd Autonom de Mdrid; Deprtment of Generl Surgery, Fundcion Jimenez Diz University Hospitl, Mdrid 84, Spin Stephen C Strom, PhD, Professor, Deprtment of Lbortory Medicine, Division of Pthology, Krolinsk Institutet, Stockholm , Sweden Andrzej S Trnwski, MD, PhD, DSc (Med), Professor of Medicine, Chief Gstroenterology, VA Long Bech Helth Cre System, University of Cliforni, Irvine, CA, 591 E. Seventh Str., Long Bech, CA 98, United Sttes EDITORIAL BOARD MEMBERS All editoril bord members resources online t EDITORIAL OFFICE Jin-Lei Wng, Director Yun Qi, Vice Director Ze-Mo Gong, Vice Director World Journl of Gstroenterology Bishideng Publishing Group Inc 791 Stoneridge Drive, Suite 51, Plesnton, CA 94588, USA Telephone: Fx: E-mil: editoriloffice@wjgnet.com Help Desk: PUBLISHER Bishideng Publishing Group Inc 791 Stoneridge Drive, Suite 51, Plesnton, CA 94588, USA Telephone: Fx: E-mil: bpgoffice@wjgnet.com Help Desk: PUBLICATION DATE My 7, 17 COPYRIGHT 17 Bishideng Publishing Group Inc. Articles published by this Open-Access journl re distributed under the terms of the Cretive Commons Attribution Noncommercil License, which permits use, distribution, nd reproduction in ny medium, provided the originl work is properly cited, the use is non commercil nd is otherwise in complince with the license. SPECIAL STATEMENT All rticles published in journls owned by the Bishideng Publishing Group (BPG) represent the views nd opinions of their uthors, nd not the views, opinions or policies of the BPG, except where otherwise explicitly indicted. INSTRUCTIONS TO AUTHORS Full instructions re vilble online t wjgnet.com/bpg/gerinfo/4 ONLINE SUBMISSION IV My 7, 17 Volume 3 Issue 17

6 Submit Mnuscript: DOI: /wjg.v3.i World J Gstroenterol 17 My 7; 3(17): ISSN (print) ISSN (online) ORIGINAL ARTICLE Bsic Study CXCR7/CXCL1 xis is involved in lymph node nd liver metstsis of gstric crcinom Qi Xin, N Zhng, Hi-Bo Yu, Qin Zhng, Yn-Fen Cui, Chun-Shn Zhng, Zhe M, Yn Yng, Wei Liu Qi Xin, Qin Zhng, Chun-Shn Zhng, Zhe M, Deprtment of Pthology, Tinjin Third Centrl Hospitl, Tinjin Key Lbortory of Artificil Cells, Tinjin 317, Chin Qi Xin, Qin Zhng, Chun-Shn Zhng, Zhe M, The Third Centrl Clinicl College of Tinjin Medicl University, Tinjin 317, Chin N Zhng, Yn Yng, Wei Liu, Deprtment of Pthology, Dgng Hospitl, Tinjin 37, Chin Hi-Bo Yu, The Second Hospitl of Tinjin Medicl University, Tinjin 311, Chin Yn-Fen Cui, Tinjin Medicl University Cncer Institute nd Hospitl, Tinjin 37, Chin Author contributions: Xin Q, Zhng N nd Yu HB contributed eqully to this work; Xin Q, Zhng N nd Yu HB designed the reserch; Xin Q, Cui YF, M Z, Yng Y nd Liu W performed the reserch; Yu HB nd Zhng CS contributed new regents or nlytic tools; Xin Q, Zhng N nd Yu HB nlyzed the dt; Xin Q nd Zhng Q wrote the pper. Supported by the Tinjin Binhi New Are Helth Industry Medicl nd Helth Science Project, No. 11BHKY1; Tinjin Binhi New Are Science nd Technology Development Strtegy Reserch Project, No. 1DK15W7; nd Tinjin Binhi New Are Port Are Socil Development Science nd Technology Project, No Institutionl review bord sttement: This study ws reviewed nd pproved by the Ethics Committee of Tinjin Third Centrl Hospitl, Tinjin, Chin. Conflict-of-interest sttement: The uthors declre no competing finncil interests nd hve no conflicts of interest to disclose. Dt shring sttement: No dditionl dt re vilble. Open-Access: This rticle is n open-ccess rticle which ws selected by n in-house editor nd fully peer-reviewed by externl reviewers. It is distributed in ccordnce with the Cretive Commons Attribution Non Commercil (CC BY-NC 4.) license, which permits others to distribute, remix, dpt, build upon this work non-commercilly, nd license their derivtive works on different terms, provided the originl work is properly cited nd the use is non-commercil. See: licenses/by-nc/4./ Mnuscript source: Unsolicited mnuscript Correspondence to: Dr. N Zhng, Deprtment of Pthology, Dgng Hospitl, Tinjin Binhi New Are, Tinjin 311, Chin @163.com Telephone: Received: December 13, 16 Peer-review strted: December 16, 16 First decision: December 9, 16 Revised: Jnury 17, 17 Accepted: Mrch, 17 Article in press: Mrch, 17 Published online: My 7, 17 Abstrct AIM To investigte the role of CXC chemokine receptor (CXCR)-7 nd CXCL1 in lymph node nd liver metstsis of gstric crcinom. METHODS In 16 cses of gstric cncer, the expression of CXCR7 nd CXCL1 in tumor nd mtched tumordjcent non-cncer tissues, in the lymph nodes round the stomch nd in the liver ws detected using immunohistochemistry to nlyze the reltionship between CXCR7/CXCL1 expression nd clinicopthologicl fetures nd to determine whether CXCR7 nd CXCL1 constitute biologicl xis to 353 My 7, 17 Volume 3 Issue 17

7 Xin Q et l. CXCR7/CXCL1 xis nd gstric crcinom promote lymph node nd liver metstsis of gstric cncer. Furthermore, the CXCR7 gene ws silenced nd overexpressed in humn gstric cncer SGC-791 cells, nd cell prolifertion, migrtion nd invsiveness were mesured by the MTT, wound heling nd Trnswell ssys, respectively. RESULTS CXCR7 expression ws up-regulted in gstric cncer tissues (P =.11). CXCR7/CXCL1 expression ws significntly relted to high tumor stge nd lymph node (r =.338, P =.) nd liver metstsis (r =.69, P =.). The expression of CXCL1 in lymph node nd liver metstsis ws higher thn tht in primry gstric cncer tissues (χ = 6.669, P =.1; χ = 5379, P =.), nd the expression of CXCL1 in lymph node nd liver metstsis of gstric cncer ws consistent with the positive expression of CXCR7 in primry gstric cncer (r =.338, P =.; r =.69, P =.). Overexpression of the CXCR7 gene promoted cell prolifertion, migrtion nd invsion. Silencing of the CXCR7 gene suppressed SGC-791 cell prolifertion, migrtion nd invsion. Humn gstric cncer cell lines expressed CXCR7 nd showed vigorous prolifertion nd migrtory responses to CXCL1. CONCLUSION The CXCR7/CXCL1 xis is involved in lymph node nd liver metstsis of gstric cncer. CXCR7 is considered potentil therpeutic trget for the tretment of gstric cncer. Key words: Gstric cncer; Lymph node metstsis; Stroml cell derived fctor-1; Liver metstsis; CXC chemokine receptor-7 The Author(s) 17. Published by Bishideng Publishing Group Inc. All rights reserved. Core tip: The CXC chemokine receptor (CXCR)-7/ CXCL1 xis could ply n importnt role in metstsis of certin cncers. However, little is known bout the effect of CXCR7/CXCL1 on the process of gstric cncer. This study investigted the role of CXCL1 nd CXCR7 in lymph node nd liver metstsis of gstric crcinom. We found tht the CXCR7/CXCL1 xis ws involved in the lymph node nd liver metstsis of gstric cncer. Overexpression of the CXCR7 gene promoted cell prolifertion, migrtion nd invsion. Silencing of the CXCR7 gene suppressed these processes. CXCR7 ws considered potentil therpeutic trget for the tretment of gstric cncer. Xin Q, Zhng N, Yu HB, Zhng Q, Cui YF, Zhng CS, M Z, Yng Y, Liu W. CXCR7/CXCL1 xis is involved in lymph node nd liver metstsis of gstric crcinom. World J Gstroenterol 17; 3(17): Avilble from: URL: wjgnet.com/17-937/full/v3/i17/353.htm DOI: org/1.3748/wjg.v3.i INTRODUCTION Gstric crcinom is disese with high deth rte, mking it the second most common cuse of cncer deth worldwide, following lung cncer. The high mortlity of gstric cncer is due to metstsis, nd the most common metsttic site is the lymph nodes, followed by the liver, indicting n urgent need for new dignostic mrkers nd tretment pproches [1,]. In recent yers, chemokines nd their receptors hve been found to be expressed on cncer cells nd my medite cncer progression nd metstsis. Mlignnt cells cn express chemokine receptors nd respond to chemokine grdients, which my be relted to the growth nd spred of cncer. Stroml cell-derived fctor 1 (SDF-1) is very importnt chemotctic fctor tht stimultes prolifertion, dissocition, migrtion, nd invsion in wide vriety of tumor cells, including gstric cncer [3-5]. For mny yers, CXCR4 ws believed to be the only receptor for CXCL1. However, severl recent reports hve provided evidence tht CXCR7 (RDC-1) is n identified chemokine receptor tht shres the sme lignd (CXCL1) s CXCR4. CXCL1 binds to CXCR7 with greter ffinity thn CXCR4 (Kd =.4 nmol/l vs 3.6 nmol/l) []. In humns, CXCR7 is expressed in embryonic neuronl nd hert tissue, some hemtopoietic cells, nd ctivted endothelium [6,7], but on few other norml cell types. Moreover, CXCR7 is expressed in vrious cncers, including brest cncer [8], lung cncer [9], nd gliom [1], nd ws shown to promote the growth nd metstsis of vrious tumor models [9,1]. The min lignd for CXCR7 is CXCL1, which binds to CXCR7 with high ffinity, but CXCR7 my lso bind the lterntive lignd CXCL11 with low ffinity. Although CXCR7 is expressed by mny different tumors, studies of CXCR7 expression in gstric cncer re few in number. Zhi et l [11] nd M et l [1] hve reported tht CXCR7 trnscripts hve been detected in gstric cncer cells, including MGC 83, SGC 791 nd BGC 83 cells, nd Lee et l [5] reported tht CXCR7 ws differentilly expressed in gstric denocrcinom tissues. However, most of the studies concerning CXCL1 nd CXCR7 hve been conducted in vitro, nd the definitive pthophysiologicl functions of the CXCR7/CXCL1 xis in humn gstric cncer require further reserch. In this study, we investigted the expression of CXCR7 nd CXCL1 in gstric tissues, norml gstric mucos, lymph nodes nd liver tissues. Using combintion of overexpression nd RNA interference pproches, we precisely interrogted the role of CXCR7 in gstric cncer cell growth, migrtion nd invsion in vitro. MATERIALS AND METHODS Mterils The study included surgiclly resected specimens 354 My 7, 17 Volume 3 Issue 17

8 Xin Q et l. CXCR7/CXCL1 xis nd gstric crcinom from 16 ptients (7 men nd 88 women, ged 65.7 ± 11.4 yers) with gstric cncer. All of the ptients underwent gstrectomy t the Tinjin Medicl University Cncer Institute nd Hospitl. Non-tumorl gstric tissues were obtined t lest 5 cm from the tumor t the sme time. The cses were lmost evenly divided between the two mjor types of gstric cncer: intestinl (1 ptients) nd diffuse (4 ptients). These two types re defined by the Luren s histologicl clssifiction [13]. According to the Union for Interntionl Cncer Control tumor node metstsis (TNM) clssifiction [14], cncers were clssified s pt1 + T (n = 66) nd pt3 + pt4 (n = 94), with positive nodl involvement in 96 cses (ll confirmed by histopthologicl exmintion) nd 3 cses hving liver metstsis t the time of gstrectomy (confirmed by either histopthologicl exmintion or computed tomogrphy). The lymph nodes round the stomch did not hve metstsis in 64 cses. Twenty-nine liver tissues with no metstsis cme from resected specimens of non-neoplstic diseses, nd 9 liver metstsis tissues were from ptients with intestinltype gstric cncer (fter the imging dignosis of liver metstsis of gstric cncer, one of the 3 ptients refused to undergo fine-needle spirtion). Ptients enrolled in the study hd not received ny chemo- or rdiotherpy before dignosis. Routine chemotherpy hd been given to the ptients with n dvnced-stge disese fter opertion, but no rdition tretment ws performed in ny of ptients included in our study. Ptients were excluded if they hd previously been exposed to ny trgeted therpy, chemotherpy, rdiotherpy, or intervention therpy for gstric cncer. Regents The humn recombinnt CXCL1 nd the mouse ntihumn CXCR7 monoclonl ntibody were obtined from Dko Compny. CXCR7-specific sirna nd CXCR7 overexpressing vector were purchsed from Snt Cruz Biotechnology (Snt Cruz, CA, United Sttes). The CCK-8 regent kit ws purchsed from Sigm (United Sttes). Totl RNA extrction kits (RNAfst) were purchsed from Fstgen Biotechnology (Shnghi); reverse trnscription kits were purchsed from TKR (Jpn). PCR primers were synthesized by Shnghi Bioengineering & Technology Services. Millicell smll chmbers were purchsed from Millipore (United Sttes); Mtrigel nd MTS kits were purchsed from BD Biosciences (United Sttes). The PCR mplifiction pprtus ws produced by Gene Compny; ll of the primers used in RT-PCR were designed nd synthesized by Beijing Aoke. Cell lines nd cell culture Humn gstric cncer SGC-791 cells were mintined under stndrd conditions (37 nd 5% CO) in tissue culture flsks nd were grown in minimum essentil medium supplemented with 1% fetl bovine serum (FBS). Cells in the logrithmic growth phse were used in ll experiments. Immunohistochemistry Immunohistochemicl stining ws performed using the Ultr Tek HRP nd nti-cxcr7 ntibody ccording to the mnufcturer s instructions. In brief, sections were prepred from gstric cncer tissue blocks, mounted on chrged slides with APES (Sigm), nd fixed for 1- h t 6 before stining. Next, the sections were deprffinized in xylene nd rehydrted in grded lcohol solutions. After ntigen retrievl by heting (95 ) in citrte buffer (ph 6) for 15 min, endogenous peroxidse ws blocked by the tretment of sections with 3% hydrogen peroxidse for 1 min. After blocking with % bovine serum lbumin (BSA) for 1 min, the slides were incubted with nti-cxcr7 ntibody (1:) diluted in ntibody diluents (S3; Dko) overnight in humid chmber t 4. The slides were wshed nd then incubted with the nti-mouse biotinylted secondry ntibody for min, followed by incubtion with HRP-conjugted streptvidin for min. The slides were wshed nd treted with 3,3 -diminobenzidine (DAB) chromogen for 5 min nd counterstined with Myer s hemtoxylin, followed by mounting. The cell membrne or cytoplsm showed light yellow or brown yellow stining, nd five rndomly selected high-mgnifiction ( 4) fields were ssessed using the following scoring scles. The rnge of positive cells ws scored s follows:, no positive cells; 1, 1%-9%;, 3%-59%; 3, 6% stining. The stining intensity ws scored s:, negtive; 1, mild yellow stining;, moderte brown stining; or 3, drk brown stining. According to the product of the rnge of positive cells nd stining intensity score, (-) negtive expression referred to score < nd (+) positive expression referred to score. Estblishment of stble overexpression nd knockdown cell lines Humn gstric cncer SGC-791 cells were cultured in RPMI supplemented with 1% FBS, under the conditions of 37, 5% CO, nd sturted humidity. The humn CXCR7 sequence ws digested out from the pcdna plsmid (kindly provided by ChemoCentryx, Mountin View, CA, United Sttes). CXCR7 sirna (sc-3541) ws purchsed from Snt Cruz Biotechnology. Trnsfections were performed using Lipofectmine ccording to the mnufcturer s instructions. The smples were treted with EndoFectin TM, nd the CXCR7 overexpression cell line nd CXCR7 knockdown cell line were estblished. The following groups were included: group A: blnk control group (Control), blnk vector group (Vector), nd CXCR7 overexpression group; group B: blnk control group (Control), blnk vector group (Vector), nd CXCR7 knockdown group. 355 My 7, 17 Volume 3 Issue 17

9 Xin Q et l. CXCR7/CXCL1 xis nd gstric crcinom Rel-time PCR ssy Cells were cultured to rech 7%-8% confluence in six-well pltes. Totl RNA ws extrcted from the cells using the Ultrpure RNA Kit (CWbio Co., Ltd, Ct. #CW581) ccording to the mnufcturer s instructions, nd the gene expression ws mesured. The rection temperture ws 94. After 5 min of denturtion, 4 cycles of mplifiction were performed using the ABI 75 rel time PCR system; ech cycle consisted of predenturtion t 95 for 1 min, denturtion t 95 for 15 s nd extension t 6 for 6 s. The rection ws ctivted t 7 for 1 min, nd then terminted t 4. GAPDH ws used s n internl control. Chemi Imge 55 utomted electrophoresis gel imge nlyzer ws used to determine the reltive men gry vlues (A) of the trget product nd β-ctin internl control; the expression index (I) of the trget product mrna ws clculted using the formul: I = Aproduct/A β-ctin. Western blot ssy Cells were cultured to rech 7%-8% confluence in six-well pltes, nd then the cells were digested nd collected. Whole protein ws obtined using RIPA lysis buffer nd centrifuged t 1 g for 1 min. The totl protein concentrtion ws mesured by the bicinchoninic cid method. Next, 1 mg of protein lystes were seprted by 1% SDS-PAGE. The proteins were trnsferred to PVDF membrnes nd the membrnes were blocked with 5% skimmed milk with PBST contining.5% Tween t room temperture for h. The primry ntibody (CXCR7, 1:) ws dded nd incubted t room temperture for h. The membrne ws wshed with PBST three times nd then incubted with the secondry ntibody for 1 h. The immunorective bnds were wshed nd observed. α-actin ws used s n internl control. Cell prolifertion ssy Following intervention, the cells were digested with trypsin, prepred into cells/well suspensions with serum-free medium, nd then inoculted into 96-well culture plte t μl per well, followed by the ddition of μl of CCK-8 solution nd 1 ng/ml CXCL1. The plte ws returned to 5% CO incubtor t 37 with sturtion humidity for h, 48 h, or 96 h. Finlly, the plte ws plced in n enzymelinked immunossy nlyzer, nd the bsorbnce vlue (OD) of ech well ws mesured t 45 nm. Ech group hd six wells; the cell prolifertion vlues of ech group were clculted. Cell migrtion ssy The cell migrtion ssy ws conducted s previously described. After incubtion for 6 h, the growth medium ws chnged to bsl medium with CXCL1 (1 ng/ml). Twenty-four hours lter, the wounds were observed using bright-field microscopy, nd multiple imges were tken t res flnking the intersections of the wound nd mrker lines t the strt nd end of the experiment. The gp distnce of the wound ws mesured t three different sites using Photoshop softwre, nd the dt were normlized to the verge of the control. Grphs were plotted ginst the percentge of the migrtion distnce the cells moved before nd fter tretment. Cell invsion ssy Cell invsion in response to CXCL1 ws ssyed in the Biocot Mtrigel invsion chmber (Becton Dickinson, United Sttes) using n 8-μm porosity polycrbonte filter membrne tht ws coted with Mtrigel. The Trnswell chmber ws pre-cooled t 4. Next, the upper chmber ws evenly lid with ml of Mtrigel nd ws incubted t 37 for 3 h. Approximtely cells were dded into the upper chmber, nd 6 ml of medium with.1% BSA ws dded into the lower chmber with fibronectin (5 mg/ml). Next, the cells were cultured t 37 for 4 h. The cells were fixed on the upper lyer of the membrne by formlin. The number of invsive cells ws determined by counting the hemtoxylin-stined cells. For quntifiction, the cells were counted under microscope in five fields (up, down, medin, left, nd right. ). Sttisticl nlysis SPSS17. softwre ws used for dt processing. Mesurement dt re expressed s the men ± SD nd were compred using nlysis of vrince. Pirwise comprisons between groups were performed using the Student-Newmn-Keuls method. The bove hypothesis test ws two-sided; ssocitions between expression levels in gstric cncer nd clinicopthologicl fetures were determined using χ -test. The vribles considered for the univrite nlysis consisted of ptient-relted nd tumor-relted vribles. Person correltion nlysis ws used for correltion nlysis. P <.5 ws considered to be sttisticlly significnt. RESULTS Expression levels of CXCL1 nd CXCR7 proteins in gstric crcinom nd djcent norml gstric tissues To scertin whether the expression of CXCL1 nd CXCR7 proteins is elevted in gstric cncer tissues, we first evluted CXCL1 nd CXCR7 expression by immunohistochemicl nlyses in tumor tissues nd norml gstric tissues. In cncer tissues, CXCR7 ws highly expressed (Figure 1A), with positive expression rte of 78.75% (16/16). CXCL1 ws lso highly expressed in gstric cncer (Figure 1C), with n expression rte of 68.13% (19/16). But 356 My 7, 17 Volume 3 Issue 17

10 D ) ) es su G CL er tis ric c CX nc l rm no nt j ce Ad (C es (N (C (N tis er ric su es su tis c nc l rm no ) ) es 1 F su 15 G st nt Ad j ce tis The expression of CXCL1(N) G st The expression of CXCR7(N) E 7 C CR B CX A The expression of gstric cncer(n) Xin Q et l. CXCR7/CXCL1 xis nd gstric crcinom Figure 1 CXCR7 nd CXCL1 expression in non-tumorl tissues nd gstric cncer. A: Gstric cncer tissue shows strong expression of CXCR7; B: Nontumorl gstric tissue shows negtive expression of CXCR7; C: Gstric cncer tissue shows strong expression of CXCL1; D: Non-tumorl gstric tissue shows wek expression of CXCL1; E: CXCR7 expression in cncer tissues ws significntly higher thn tht in norml tissues; F: CXCL1 expression in cncer tissues ws significntly higher thn tht in norml tissues; G: The expression of CXCR7 nd CXCL1 ws correltive in gstric cncer tissues. P <.5, between the two groups. in norml gstric tissue, CXCL1 nd CXCR7 were expressed t very low level (Figure 1B nd D). CXCL1 nd CXCR7 expression ws significntly higher in cncer tissues thn in norml tissues (P =.11, P =.11) (Figure 1E nd F). The expression of CXCL1 nd CXCR7 ws correltive in gstric cncer tissue (P =., Figure 1G). We lso observed CXCR7 stining in inflmmtory cells nd some prts of mesenchyml tissue. CXCR7 ws detected in tumor-ssocited blood vessels in nerly ll specimens of gstric cncer, but not in blood vessels from nonmlignnt tissues. In gstric crcinom, CXCR7 expression in the gstric cncer cells within the lumen of lymph nd blood vessels ws strongly positive, nd stronger thn the expression intensity in gstric cncer tissue itself. Assocition between CXCL1 nd CXCR7 expression nd clinicl chrcteristics in ptients with gstric cncer In gstric crcinom, the expression of CXCL1 nd CXCR7 ws relted to tumor size, depth of invsion, Luren s clssifiction of the tumor, lymph node metstsis, nd clinicl stge. We did not observe ny other ssocition between CXCR7 expression nd other clinicl findings such s ge, gender, differentition (Tble ). Anlysis of CXCL1 CXCR7, CXCL1 CXCR7 / + CXCL1 CXCR7, nd CXCL1 CXCR7 gstric crcinom + + tissues showed tht CXCRL1 CXCR7 gstric 357 My 7, 17 Volume 3 Issue 17

11 Xin Q et l. CXCR7/CXCL1 xis nd gstric crcinom Tble 1 Assocition between CXCL1 nd CXCR7 expression nd clinicl chrcteristics in ptients with gstric cncer Fctor n CXCR1 expression CXCR7 expression - + χ P vlue - + χ P vlue Gender Mle Femle Age (yr) < Tumor dimeter (cm) < Luren s clssifiction Diffuse type Intestinl type Differentition Well-modertely Poorly Depth of invsion T1 + T T3 + T Clinicl stges Ⅰ + Ⅱ Ⅲ + Ⅳ Lymph node metstsis Liver metstsis P <.5 ws considered s sttisticlly significnt. Tble The reltionship between the clinicl pthologicl chrcteristics nd CXCL1/CXCR7 expression in gstric crcinom Fctor n CXCR1 + CXCR7 + CXCL1 + CXCR7 - /CXCL1 - CXCR7 + CXCR1 - CXCR7 - r P vlue Dimeter (cm).5.9 < Depth of invsion.4. T1 + T T3 + T Clinicl stges..1 Ⅰ + Ⅱ Ⅲ + Ⅳ Lymph node metstsis Liver metstsis P <.5 ws considered s sttisticlly significnt. cncer cells were more prone to lymph node nd liver metstsis, nd they were positively correlted with tumor size, depth of invsion nd clinicl stge, suggesting tht CXCL1 + CXCR7 + cells re more likely to grow nd metstsize in gstric cncer (Tble ). Expression levels of CXCL1 in lymph nodes with or without cncer cell metstsis Among the 16 lymph nodes tht we collected, 96 hd cncer metstsis nd the remining nodes were norml. The expression of CXCL1 ws lso significntly higher in the lymph nodes with metstsis thn in the lymph nodes without (χ = , P =.). And the expression of CXCL1 in lymph node metstsis ws higher thn in primry gstric cncer tissues (χ = 6.669, P =.1 )(Figure A-C). In metsttic lymph nodes, the expression of CXCL1 ws lso expressed in the peripherl inflmmtory cells. 358 My 7, 17 Volume 3 Issue 17

12 B D C E F The expression of CXCL1 (%) A 1 The expression of CXCL1 (%) Xin Q et l. CXCR7/CXCL1 xis nd gstric crcinom 1 Primry gstric cncer tissues Lymph node with metstsis Lymph node without metstsis b c Primry gstric cncer tissues Liver with metstsis Liver without metstsis d Figure CXCL1 expression in lymph node, liver nd primry gstric cncer tissues. A: Metsttic lymph node shows strong expression of CXCL1; B: Primry gstric tissue shows strong expression of CXCL1; C: CXCL1 expression in lymph nodes with metstsis ws significntly higher thn tht in primry gstric tissue nd lymph node with no metstsis; D: Liver metstsis shows strong expression of CXCL1; E: Primry gstric tissue shows strong expression of CXCL1; F: CXCL1 expression in liver metstsis ws significntly higher thn tht in primry gstric tissue nd liver tissue with no metstsis. -dp <.5, between the two groups. 1 B The expression of number (N) The expression of number (N) A Figure 3 The reltion of CXCL1 nd CXCR7 expression. A: Correltion nlysis of CXCL1 expression in lymph nodes nd CXCR7 expression in gstric cncer; B: Correltion nlysis of CXCL1 expression in liver tissue nd CXCR7 expression in gstric cncer. P <.5, between the two groups. 1: The express of CXCL1 in lymph nodes with metstsis; : The express of CXCR7 in primry gstric cncer tissues Expression levels of CXCL1 in livers with or without cncer cell metstsis expression of CXCR7 in gstric cncer (r =.338, P =.; r =.69, P =.) (Figure 3A nd B). Among the 58 livers tht we collected, 9 livers hd cncer metstsis nd the remining livers were norml. The expression of CXCL1 ws lso significntly higher in the livers with metstsis thn in their norml counterprts (χ = 5.317, P =.1). And the expression of CXCL1 in liver metstsis of gstric cncer cells ws higher thn tht in primry type of gstric cncer (χ = 5.379, P =.) (Figure D-F). The expression of CXCL1 ws lso found in the norml liver tissues round the liver metstsis. Expression levels of CXCL1/CXCR7 in lymph node metstsis with intestinl type gstric cncer nd tht with diffuse type gstric cncer Bsed on the bove experimentl results, it is shown tht CXCL1/CXCR7 cn promote lymph node nd liver metstsis of gstric cncer. Our previous work found tht CXCL1/CXCR7 biologicl xis cn promote lymph node nd liver metstsis of intestinl type gstric cncer by immunohistochemistry, so we studied the difference in CXCL1/CXCR7 expression between lymph node metstsis with intestinl type gstric cncer nd tht with diffuse type gstric cncer. Sttisticl nlysis showed tht there ws no sttisticl difference in the expression of CXCL1/CXCR7 in these two groups (χ =.4, P =.837; χ =.65, P =.66) (Figure 4A Correltion nlysis of CXCL1 expression in lymph nodes/livers nd CXCR7 expression in gstric cncer Person correltion nlysis showed tht the positive expression of CXCL1 in lymph node nd liver met stsis of gstric cncer ws correlted with the positive 359 My 7, 17 Volume 3 Issue 17

13 A B E F The expression of CXCR7 (%) D C The expression of CXCL1 (%) Xin Q et l. CXCR7/CXCL1 xis nd gstric crcinom 1 Intestinl gstric metstsis Diffuse gstric metstsis Intestinl gstric metstsis Diffuse gstric metstsis Figure 4 CXCL1/CXCR7 expression in intestinl-type gstric cncer nd diffuse-type gstric cncer. A: CXCL1 expression in lymph node metstsis of intestinl-type gstric cncer; B: CXCL1 expression in lymph node metstsis of diffuse-type gstric cncer; C: CXCL1 expression showed no significnt difference between lymph node metstsis of intestinl-type nd diffuse-type gstric cncer; D: CXCR7 expression in lymph node metstsis of intestinl-type gstric cncer; E: CXCR7 expression in lymph node metstsis of diffuse-type gstric cncer; F: CXCR7 expression showed no significnt difference between lymph node metstsis of intestinl-type nd diffuse-type gstric cncer. P >.5. nd B). wheres cells with depleted CXCR7 grew more slowly thn control cells (Figure 6). Moreover, the CXCR7trnsfected SGC-791 cells showed substntil increse in cell number in the presence of CXCL1 (1 ng/ml), compred with non-treted ones; but prolifertion ws not incresed following CXCL1 stimultion in the cells trnsfected with the blnk vector. These results indicted tht CXCL1 enggement to CXCR7 cn induce prolifertion. CXCR7 overexpressing vector nd CXCR7 sirna vector cuse effective nd specific up/down-regultion of CXCR7 expression In order to study the potentil role of CXCR7 in SGC-791 cells, we estblished the CXCR7 over expressing vector nd CXCR7 sirna vector nd then scrmbled the overexpression nd sirna vector used to trnsfect SGC-791 cells. Two groups were built: group A: control group (Control), blnk vector group (Vector), nd CXCR7 overexpression group; group B: control group (Control), blnk vector group (Vector), nd CXCR7 knockdown group. The result ws tested using RT-PCR nd Western blot. As shown in Figure 5A, CXCR7 mrna level ws incresed in CXCR7 overexpressing cells, compred with the control group (P =.) nd the blnk vector group (P =.). In contrst, CXCR7 mrna level ws reduced in CXCR7 sirna trnsfected cells (P =., P =.) (Figure 5C). Like RT-PCR results, in CXCR7 overexpressing cells the expression level of CXCR7 protein ws incresed, but the expression level of CXCR7 protein were reduced in CXCR7 sirna trnsfected cells (Figure 5B nd D). These results demonstrted tht the expression of CXCR7 ws specificlly up-regulted/ silenced in SGC-791 cells. Effect of CXCR7 overexpression nd silencing on the migrtion bility of SGC-791 cells in vitro Besides enhnced growth dvntge of tumor cells, incresed cell invsion is determinnt hllmrk of metsttic tumor cells. Thus, we sought to explore the influence of CXCR7 on cell migrtion. Wound heling ssy showed tht ectopic overexpression of CXCR7 in SGC791 cells significntly enhnced cell migrtion induced by CXCL1 compred with the Control cells nd Vector cells (Figure 7A, P =.11); in contrst, the reverse effects were observed when CXCR7 ws silenced in SGC791 cells (Figure 7B, P =.4). Effect of CXCR7 overexpression nd silencing on the invsion bility of SGC-791 cells in vitro Invsion is lso one of the importnt steps in tumor metstsis. The CXCR7/CXCL1 interction ws reported to regulte invsive nd metsttic behvior of severl tumors. We mesured the effect of CXCR7 overexpression nd silencing on the invsion bility of SGC-791 cells in vitro by Trnswell ssy. As shown in Figure 8A nd B, SGC-791 cells spontneously invded through rtificil bsement membrne in Effect of CXCR7 overexpression nd silencing on the prolifertion bility of humn gstric cncer SGC-791 cells in vitro CCK-8 experiments showed tht cells overexpressing CXCR7 proliferted more rpidly thn control cells, 36 My 7, 17 Volume 3 Issue 17

14 Xin Q et l. CXCR7/CXCL1 xis nd gstric crcinom A Control Vector Overexpression B 1.5 CXCR7 GAPDH CXCR7 expression Control Vector Overexpression C Control Vector CXCR7 sirna D 1.5 CXCR7 GAPDH CXCR7 expression Control Vector CXCR7 sirna Figure 5 Stble expression of CXCR7 in humn SGC791 cells. A: Western blot ssy showed incresed CXCR7 expression in stble CXCR7-overexpressing humn SGC791 cells compred with the untreted control group nd blnk vector trnsfection control group; B: PCR ssy showed the sme results s the Western blot ssy; C: Western blot ssy showed decresed endogenous CXCR7 expression in stble CXCR7-silenced humn SGC 791 cells compred with the untreted control group nd blnk vector trnsfection control group; β-ctin ws used s n internl control; D: PCR ssy showed the sme results s the Western blot ssy. P <.5, vs the control nd vector groups. The dt re presented s the men ± SD; n = 4; brs indicte SD, P <.5. A Control Control + CXCL1 Vector Vector + CXCL1 CXCR7 overexpression B Control Control + CXCL1 Vector Vector + CXCL1 CXCR7 sirna 4 CXCR7 overexpression + CXCL1 c 3 CXCR7 sirna + CXCL1 OD45 NM 3 1 OD45 NM 1 c h 48 h 96 h h 48 h 96 h Figure 6 Effect of CXCR7 on prolifertion of humn gstric SGC791 cells. A: Overexpression of CXCR7 promoted cell prolifertion; B: Silencing of CXCR7 inhibited cell prolifertion. Cell prolifertion ws mesured by CCK-8 ssy t, 48 nd 96 h. P <.5, vs the control group; nd c P <.5, vs blnk vector group. Dt re presented s the men ± SD; n = 5; brs indicte SD, P <.5. the bsence of CXCL1. In ddition, we found tht CXCL1 induced significnt increse of cncer cell invsion through Mtrigel, nd CXCR7 overexpressing cells displyed incresed invsive bility compred with the Control cells nd Vector cells. Cells with CXCR7 knockdown displyed decresed invsive bility compred with the control cells nd Vector cells (Figure 8). Tken together, these findings indicte tht CXCR7 overexpression could potently enhnce the invsive bility of SGC-791 cells induced by CXCL1 nd tht silencing of CXCR7 inhibits the invsive behvior of the cells. DISCUSSION Chemokine nd chemokine receptor pirs hve been identified to ply pivotl roles in cncer initition nd progression. CXCL1 nd its receptors (CXCR4 nd CXCR7) re importnt members. They re implicted in severl spects, including the migrtion, dhesion, prolifertion nd survivl of tumor cells, nd the formtion of tumor-ssocited vessels nd invsion [15]. 361 My 7, 17 Volume 3 Issue 17

15 Xin Q et l. CXCR7/CXCL1 xis nd gstric crcinom B Control Control + CXCL1 Vector Vector + CXCL1 + O ve O ve r CX exp CL re 1 ssi o io n ss re re or ct Ve or ct Ve xp + l+ Co nt ro l Co nt ro CX CL 1 CX CL 1 n A CXCR7 overexpression Migrtion distnce (μm) h 4 h CXCR7 overexpression + CXCL1 1 D CX CR CL 7 s 1 irn A Control Control + CXCL1 Vector Vector + CXCL1 CX NA sir CR 7 CX ct o Ve Ve ct o r r+ l+ Co nt ro l ro nt Co CX CL 1 CX CL 1 + C 3 CXCR7 sirna Migrtion distnce (μm) CXCR7 sirna + CXCL Figure 7 Effect of CXCR7 on migrtion of humn gstric SGC791 cells. A: Overexpression of CXCR7 promoted CXCL1 induced enhncement of SGC-791 cell migrtion in vitro; B: Men wound width from three independent fields/wells is indicted; C: Silencing of CXCR7 inhibits CXCL1 induced enhncement of SGC-791 cell migrtion in vitro; D: Men wound width from three independent fields/wells is indicted. P <.5, vs the control group nd blnk vector group. The dt re presented s the men ± SD; n = 3; brs indicte SD. CXCR7, initilly nmed receptor Dog cdna1/rdc1, is second receptor for CXCL1, nd it cn bind chemokines CXCL11/ITAC nd mcrophge migrtory [16,17] inhibitory fctor (MIF). Due to the muttion t the [18] DRAILIV motif, CXCR7 cnnot ctivte G proteins tht re ssocited with typicl chemokine receptors. CXCR7 hs been proposed s decoy receptor, minly functioning to shpe the CXCL1 grdient for [19,] the guidnce of cell migrtion in different models. By contrst, other studies provided evidence tht CXCR7 cn ctivte downstrem signl trnsduction molecules nd cytokine production, promote the survivl of tumor cells by preventing poptosis, nd impct cell dhesion nd invsion through complex [9,1,1] signling processes. To the best of our knowledge, this study is the first demonstrting tht CXCR7 ws widely expressed in humn gstric cncer tissue by immunohistochemistry nd tht the expression of CXCR7 ws incresed compred with tht in norml gstric tissues. CXCR7 ws present on tumor-ssocited blood vessels but not on the norml vsculture. Immunohistochemicl stining of humn brest nd lung cncer tissue lso reveled extensive CXCR7 expression on tumor[9] ssocited blood vessels nd cncer cells. Additionlly, in heptocellulr crcinom, the suppression of CXCR7 expression by RNA interference impirs in vitro cellulr [] VEGF secretion nd ngiogenesis. Thus, CXCR7 my contribute to gstric cncer development by regulting ngiogenesis; in humn heptocellulr crcinom cells, the overexpression of CXCR7 induces the [3] ngiogenic cpcity vi the AKT signling pthwy. In gstric cncer cells, CXCR7 is highly expressed, but CXCR7 is poorly expressed in norml gstric cells. This result suggests tht CXCR7 might ply role in gstric tumorigenesis. In our in vitro studies, we found tht the prolifertion of gstric cncer cells ws significntly incresed in the presence of CXCR7 overexpression nd showed significnt profile responses to CXCL1. Importntly, silencing CXCR7 cn effectively suppress this prolifertive cpcity of gstric cncer cells. This suggested tht CXCR7/ 36 My 7, 17 Volume 3 Issue 17

16 Xin Q et l. CXCR7/CXCL1 xis nd gstric crcinom A Control Vector CXCR7 overexpression CXCL1 ng/ml CXCL1 1 ng/ml Cell invsion count Control Control + CXCL1 Vector Vector + CXCL1 CXCR7 overexpression CXCR7 overexpression + CXCL1 B Control Vector CXCR7 sirna CXCL1 ng/ml CXCL1 1 ng/ml Cell invsion count c Control Control + CXCL1 Vector Vector + CXCL1 CXCR7 sirna CXCR7 sirna + CXCL1 Figure 8 Effect of CXCR7 on invsion of humn gstric SGC791 cells. A: Overexpression of CXCR7 promoted CXCL1 induced enhncement of SGC-791 cell invsion in vitro; B: Silencing of CXCR7 decresed CXCL1 induced enhncement of SGC-791 cell invsion in vitro. P <.5, vs the control group; nd c P <.5, vs blnk vector group. The dt re presented s the men ± SD; n = 3; brs indicte SD, P <.5. CXCL1 cn promote the prolifertion of gstric cncer cells, nd the nti-prolifertive effect of the downregultion of CXCR7 my be n importnt fctor in the growth mechnism. Bsed on our experimentl results, we believe tht CXCR7/CXCL1 cn promote the growth of gstric cncer cells. These findings re similr to observtions in heptocellulr nd brest crcinom models [8,4]. However, in thyroid cncer K1 cells nd TFF3-dependent ctivtion of cells, the overexpression of CXCR7 hd no effect on cell prolifertion [5,6]. Different studies hve described tht in different tumor cell types, depending on the differentition sttus nd environment, CXCR7 my ply different role. In prostte cncer, IL-8-regulted CXCR7 stimultes EGFR signling to promote prostte cncer growth, nd the growth-promoting ctivity does not require its lignds [7]. However, in heptocellulr crcinom, CXCR7 ctivtes the ERK pthwy to medite cell prolifertion. The mechnisms by which CXCR7 prticiptes in the growth of gstric cncer cells wrrnt further investigtion, nd the specific mechnism will be further studied in our future work. Additionlly, we found tht the expression of CXCR7 in the cncer cells in metsttic vsculr lumen ws higher thn tht in gstric crcinom tissues, suggesting tht CXCR7 my hve role in the metstsis of gstric cncer. Our clinicopthologicl study reveled tht CXCR7 expression ws significntly positive in gstric cncer with high tumor stge nd lymph node nd liver metstses. The lrger the tumor dimeter nd infiltrtion depth, the stronger the expression of CXCR7. Regrding the different clinicl stges, the expression level of CXCR7 in stge Ⅲ + Ⅳ ws significntly higher thn tht in stge Ⅰ + Ⅱ gstric cncer. These results suggested tht the expression of CXCR7 might be involved in the invsion nd metstsis of gstric cncer cells, nd CXCR7-positive gstric cncer my hve strong migrtory potentil. CXCL1 + CXCR7 + gstric cncer tissues re more prone to lymph node nd liver metstses compred to CXCL1 + CXCR7 - /CXCL1 - CXCR7 + nd CXCL1 - CXCR7 - gstric cncer tissues. A tumor dimeter greter thn 3.5 cm, depth T3 + T4, nd stge Ⅲ + Ⅳ showed stronger CXCL1 + CXCR7 + expression in gstric cncer. Our results from the in vitro experiments ppered to support this hypothesis. In this study, we lso found tht CXCR7, by binding to CXCL1, cn promote invsion in SGC791 cells, nd CXCR7/CXCL1 cn promote gstric cncer cell invsion, confirming the results of previous study in other prts of tissues nd cells. Additionlly, in prostte cncer, CXCR7 potentilly promoted invsion through its downstrem trgets CD44 nd cdherin-11 [8]. It hs been shown tht higher levels of CXCL1 in trget orgns such s the liver or lymph nodes ttrct nd recruit cncer cells, which subsequently form liver or lymph node metstses [9]. In gstric cncer, the CXCR4/CXCL1 signling xis plyed n importnt role in the process of lymph node metstsis nd liver metstsis [15,3]. Additionlly, CXCR4-expressing gstric crcinom cells re preferentilly ttrcted 363 My 7, 17 Volume 3 Issue 17

17 Xin Q et l. CXCR7/CXCL1 xis nd gstric crcinom to the peritonel cvity, where its lignd, SDF-1, is produced bundntly by peritonel mesothelil cells [31]. Unlike CXCR4, however, CXCR7 fils to signl through Gαi proteins nd does not fcilitte cell migrtion in response to CXCL1; it ppers to ct s CXCL1 scvenger controlling the chemokine levels in fvor of CXCR4-medited chemotxis [3]. Additionlly, some reports hve found tht CXCR7 could not medite cncer cell migrtion [33,34]. However, significnt increse in CXCL1 ws found in lymph nodes nd livers with cncer cell metstsis compred with tht in norml lymph nodes nd livers, nd the positive expression of CXCL1 in lymph node nd liver metstsis of gstric cncer ws consistent with the positive expression of CXCR7 in gstric cncer. This confirmed tht cncer cells with highly expressed CXCR7 cn migrte towrds CXCL1 grdient estblished in specific trget orgns. Additionlly, the overexpression of CXCR7 in SGC791 cells significntly enhnced cell migrtion by binding to CXCL1 in vitro. By contrst, the reverse effects were observed when CXCR7 ws silenced in SGC791 cells. Our studies strongly supported tht the CXCR7/CXCL1 signling xis could promote migrtion in gstric cncer. CXCR7, which cnnot signl directly through G protein-linked pthwys, cn nevertheless ffect cellulr signling networks by forming heteromeric complex with CXCR4. The CXCR4-CXCR7 heterodimer complex recruits â-rrestin, resulting in the preferentil ctivtion of â-rrestin-linked signling pthwys [35]. In lte neurl progenitor cells (NPCs), CXCR7 medites migrtion to CXCL1 in the bsence of CXCR4 through extrcellulr signl-regulted kinses (ERK) 1/ [36] but TFF3 induced cell migrtion independently from the ERK1/ signling pthwy [6]. In conclusion, the results in this study indicte tht CXCR7 ws highly expressed in gstric cncer tissue nd ws incresed with tumor clinicl stge. The CXCR7/CXCL1 signling xis ppers to be involved in the lymph node nd liver metstsis of gstric cncer. Bsed on these results, specific therpies with chemokine receptor ntgonists could be helpful in the tretment of ptients with gstric cncer metstsis. COMMENTS Bckground Gstric cncer is one of the most common mlignnt tumors. Most deths from gstric cncer re cused by tretment filure due to metstsis, of which lymph node nd liver metstses re the most common cuse. Therefore, inhibition of gstric cncer metstsis is thought to be n importnt therpeutic strtegy. However, the moleculr mechnisms involved in this process hve not been fully elucidted. Reserch frontiers Mny studies hve shown tht CXC chemokine receptor-7 (CXCR7) ws expressed in mny types of cncer cells. The CXCR7/nd stroml cell-derived fctor-1 (CXCL1) xis plys mjor role in survivl, prolifertion, migrtion nd dhesion of mny kinds of tumor cells. However, little is known bout the effect of CXCL1/CXCR7 on the process of gstric cncer. Thus, the definitive pthophysiologicl function of the CXCR7/CXCL1 xis in lymph node nd liver metstsis of gstric cncer needs further reserch. Innovtions nd brekthroughs Little is known bout the effect of CXCL1/CXCR7 on the process of gstric cncer. This study found tht CXCR7 is expressed in gstric cncer nd CXCR7/CXCL1 xis is involved in lymph node nd liver metstsis of gstric cncer. Furthermore, this in vitro study suggested tht silencing of the CXCR7 gene suppressed prolifertion, migrtion nd invsion of gstric cncer cells. Applictions By understnding how the CXCR7/CXCL1 xis is involved in lymph node nd liver metstsis of gstric cncer, this study could represent future strtegy for therpeutic intervention in ptients with lymph node nd liver metstsis of gstric cncer. Terminology Chemokines re fmily of smll heprin-binding nd secretory proteins, nd through interctions with their corresponding receptors, they cn control nd ctivte mny types of cells. According to the position of the four conserved cysteine residues in the mino cid sequence, they re clssified into four groups: CXC, CX3C, CC nd C. CXCL1 is member of the CXC subfmily. For long time, CXCR4 ws thought to be the only receptor for CXCL1. However, severl recent reports hve provided evidence tht CXCR7 is nother receptor of CXCL1. CXCL1 binds to CXCR7 with greter ffinity thn CXCR4. Peer-review The uthors reported tht the CXCR7/CXCL1 xis could ply n importnt role in metstsis of gstric crcinom. They concluded tht the CXCR7/CXCL1 xis ws involved in the lymph node nd liver metstsis of gstric cncer. This study ws interesting nd excellent, nd this rticle ws well written. REFERENCES 1 Abe P, Mueller W, Schütz D, McKy F, Thelen M, Zhng P, Stumm R. CXCR7 prevents excessive CXCL1-medited downregultion of CXCR4 in migrting corticl interneurons. 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J Biol Chem 11; 86: [PMID: DOI: 1.174/jbc.M ] 36 Chen Q, Zhng M, Li Y, Xu D, Wng Y, Song A, Zhu B, Hung Y, Zheng JC. CXCR7 Medites Neurl Progenitor Cells Migrtion to CXCL1 Independent of CXCR4. Stem Cells 15; 33: [PMID: DOI: 1.1/stem.] P- Reviewer: Aoygi K, Kourklis G S- Editor: Yu J L- Editor: Wng TQ E- Editor: Zhng FF 365 My 7, 17 Volume 3 Issue 17

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