title: Leucine-rich repeat-containing G-protein-coupled receptor 5 is associated with invasion, metastasis, and could be a potential therapeutic target in human gastric cancer.
abstract: BACKGROUND
  Leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5), which is identified as a novel intestinal stem cell marker, is overexpressed in various tumours. In this study, we explore Lgr5 expression in gastric carcinoma and analyse its role in invasion, metastasis, and prognosis in carcinoma.
  
  
  METHODS
  A combination of immunohistochemistry, western blotting, and quantitative reverse transcription-polymerase chain reaction were used to detect mRNA and protein expression levels of Lgr5 and matrix metalloproteinase 2 (MMP2). Small interfering RNA against Lgr5 was designed, synthesised, and transfected into AGS cells. The effects of Lgr5 siRNA on cell invasion were detected by transwell invasion chamber assay and wound healing assay.
  
  
  RESULTS
  Leucine-rich repeat-containing G-protein-coupled receptor 5 expression was significantly higher in gastric carcinomas than in normal mucosa. Leucine-rich repeat-containing G-protein-coupled receptor 5 expression positively correlated with the depth of invasion, lymph node metastasis, distance of metastasis, and MMP2 expression levels. Multivariate analysis showed that Lgr5 had an independent effect on survival, and that it positively correlated with MMP2. Leucine-rich repeat-containing G-protein-coupled receptor 5 siRNAs inhibited Lgr5 mRNA and protein expression. Transwell assays indicated that these siRNAs resulted in significantly fewer cells migrating through the polycarbonate membrane, and wound healing assay also indicated that siRNAs decreased the migration of cells. Inhibition of Lgr5 resulted in a significant decrease in MMP2 and β-catenin levels compared with those in controls.
  
  
  CONCLUSIONS
  Leucine-rich repeat-containing G-protein-coupled receptor 5 was correlated with invasion and metastasis. Leucine-rich repeat-containing G-protein-coupled receptor 5 inhibition could serve as a novel therapeutic approach.
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, 28 Fuxing Road, Beijing 100853, China.
authors.forename: H Q
authors.initials: HQ
authors.lastname: Xi
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, 28 Fuxing Road, Beijing 100853, China.
authors.forename: A Z
authors.initials: AZ
authors.lastname: Cai
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, 28 Fuxing Road, Beijing 100853, China.
authors.forename: X S
authors.initials: XS
authors.lastname: Wu
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, 28 Fuxing Road, Beijing 100853, China.
authors.forename: J X
authors.initials: JX
authors.lastname: Cui
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, 28 Fuxing Road, Beijing 100853, China.
authors.forename: W S
authors.initials: WS
authors.lastname: Shen
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, 28 Fuxing Road, Beijing 100853, China.
authors.forename: S B
authors.initials: SB
authors.lastname: Bian
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, 28 Fuxing Road, Beijing 100853, China.
authors.forename: N
authors.initials: N
authors.lastname: Wang
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, 28 Fuxing Road, Beijing 100853, China.
authors.forename: J Y
authors.initials: JY
authors.lastname: Li
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, 28 Fuxing Road, Beijing 100853, China.
authors.forename: C R
authors.initials: CR
authors.lastname: Lu
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, 28 Fuxing Road, Beijing 100853, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Song
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, 28 Fuxing Road, Beijing 100853, China.
authors.forename: B
authors.initials: B
authors.lastname: Wei
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, 28 Fuxing Road, Beijing 100853, China.
authors.forename: L
authors.initials: L
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor; D045744:Cell Line, Tumor; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008207:Lymphatic Metastasis / Q000235:genetics; D008297:Male; D008875:Middle Aged; D058990:Molecular Targeted Therapy; D009361:Neoplasm Invasiveness / Q000235:genetics; D011379:Prognosis; D043562:Receptors, G-Protein-Coupled / Q000096:biosynthesis / Q000235:genetics*; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000235:genetics* / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; C116884:LGR5 protein, human; D043562:Receptors, G-Protein-Coupled