title: Neuropilin-1 is associated with clinicopathology of gastric cancer and contributes to cell proliferation and migration as multifunctional co-receptors.
abstract: BACKGROUND
  Neuropilin-1 (NRP-1) is a transmembrane glycoprotein participating in the growth and metastasis of cancer cells as multifunctional co-receptors by interacting with the signaling pathways. However, its role in gastric cancer has not yet been clarified. This study aims to investigate whether NRP-1 expression is associated with the clinicopathology of gastric cancer, and involved in the growth and metastasis of gastric cancer cells.
  
  
  METHODS
  NRP-1 expression in clinical gastric cancer specimens was examined by immunohistochemistry and its association with clinicopathology analyzed. The expression of NRP-1 in a panel of human gastric cancer cells was examined by real-time RT-PCR and immunoblotting. Stable transfectants depleted of NRP-1, termed MGC-803-NRP(low), were generated from MGC-803 cells. Cell proliferation was analyzed by the Cell Counting Kit-8 and Bromodeoxyuridine incorporation assays, and migrating ability analyzed by migration assays. The xenograft model was used to assess the effects of NRP-1 depletion on tumorigenesis, growth, metastasis and therapeutic potentials. The role of NRP-1 as co-receptors in the signaling pathways stimulated by ligands was examined. The key molecules involved in cell proliferation, migration and related signaling pathways were detected by immunoblotting.
  
  
  RESULTS
  Gastric cancer tissues expressed higher levels of NRP-1 compared to normal gastric mucosa. Its expression correlated with clinical staging, tumor differentiation and pathological types. NRP-1 depletion inhibited cell proliferation by inducing cell cycle arrest in the G1/S phase by upregulating p27, and downregulating cyclin E and cyclin-dependent kinase 2. NRP-1 depletion reduced the ability of cells to migrate by inhibiting the phosphorylation of focal adhesion kinase. NRP-1 depletion suppressed tumorigenesis, tumor growth and lung metastasis by inhibiting cell proliferation and tumor angiogenesis in situ. Therapeutic NRP-1 shRNA inhibited the growth of established BGC823 tumors. Depletion of NRP-1 inhibited the activation of VEGF/VEGFR2, EGF/EGFR and HGF/c-Met pathways stimulated by respective recombinant human VEGF-165, EGF and HGF proteins.
  
  
  CONCLUSIONS
  The present results indicate that NRP-1 may be a potentially valuable biomarker and therapeutic target for gastric cancer.
authors.affiliation: Department of General Surgery, Qingdao Municipal Hospital, Qingdao, 266011, China. linhao6368@sina.com.
authors.forename: Linhao
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of General Surgery, the First Affiliated Hospital of Harbin Medical University, No. 23 Youzheng Street, Harbin, 150001, China. jiangxian1209@163.com.
authors.forename: Xian
authors.initials: X
authors.lastname: Jiang
authors.affiliation: Department of Obstetrics and Gynecology, Qingdao Municipal Hospital, Qingdao, 266011, China. zhangqian6368@sina.com.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of General Surgery, the First Affiliated Hospital of Harbin Medical University, No. 23 Youzheng Street, Harbin, 150001, China. xuesongdong@hotmail.com.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Dong
authors.affiliation: Department of Gastroenterology, Qingdao Municipal Hospital, No. 1 Jiaozhou Road, Qingdao, 266011, China. drgyq@163.com.
authors.forename: Yuqiang
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Gastroenterology, Qingdao Municipal Hospital, No. 1 Jiaozhou Road, Qingdao, 266011, China. qdxhhyl@sina.com.
authors.forename: Yuanlong
authors.initials: Y
authors.lastname: He
authors.affiliation: Department of General Surgery, the First Affiliated Hospital of Harbin Medical University, No. 23 Youzheng Street, Harbin, 150001, China. qiaohaiquan@hotmail.com.
authors.forename: Haiquan
authors.initials: H
authors.lastname: Qiao
authors.affiliation: Department of Gastroenterology, Qingdao Municipal Hospital, No. 1 Jiaozhou Road, Qingdao, 266011, China. 18661678225@163.com.
authors.forename: Fangyu
authors.initials: F
authors.lastname: Xie
authors.affiliation: Department of Gastroenterology, Qingdao Municipal Hospital, No. 1 Jiaozhou Road, Qingdao, 266011, China. xiangjunxie2005@126.com.
authors.forename: Xiangjun
authors.initials: X
authors.lastname: Xie
authors.affiliation: Department of General Surgery, the First Affiliated Hospital of Harbin Medical University, No. 23 Youzheng Street, Harbin, 150001, China. kevsun88@hotmail.com.
authors.forename: Xueying
authors.initials: X
authors.lastname: Sun
mesh_terms: D000818:Animals; D002097:C-Reactive Protein / Q000235:genetics* / Q000378:metabolism*; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D051379:Mice; D009368:Neoplasm Transplantation; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism*; D011379:Prognosis; D015398:Signal Transduction; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D016019:Survival Analysis; D000099153:Pentraxins
chemical_list: D002097:C-Reactive Protein; D009419:Nerve Tissue Proteins; D000099153:Pentraxins