title: Knockdown of neuropilin-1 suppresses invasion, angiogenesis, and increases the chemosensitivity to doxorubicin in osteosarcoma cells - an in vitro study.
abstract: OBJECTIVE
  Neuropilin-1 (NRP-1) is a novel co-receptor for vascular endothelial growth factor (VEGF). NRP-1 expression in osteosarcoma tissues was significantly higher, and high NRP-1 expression was more frequently occurred in osteosarcoma tissues with advanced clinical stage, positive distant metastasis and poor response to chemotherapy. We tested a hypothesis that the NRP-1 gene plays a role in the invasiveness, angiogenesis and chemoresistance of human OS.
  
  
  METHODS
  To determine the role of NRP-1 in OS, NRP-1 was stably transfected into the human OS cell line MG-63 to increase the NPR-1 level, and NRP-1 siRNA was stably transfected into the human OS cell line SaOS-2 to knockdown of NRP-1. The effect of NRP-1 on invasion and angiogenesis was assessed by Matrigel invasion assay and in vitro angiogenesis assay. Chemosensitivity to doxorubicin was assessed by MTT assay in the MG-63 and SaOS-2 cells following NRP-1 overexpression or siRNA-induced downregulation of NRP-1.
  
  
  RESULTS
  The NRP-1 transfected MG-63 cells showed a markedly higher level of invasion in Matrigel invasion assay. The capillary-like structure formation of endothelial cells was also increased by coculture with the NRP-1 transfected MG-63 cells. On the contrary, the NRP-1 siRNA transfected SaOS-2 cells showed a markedly lower level of invasion in Matrigel invasion assay. The capillary-like structure formation of endothelial cells was also repressed by coculture with the NRP-1 siRNA transfected SaOS-2 cells. NRP-1 overexpression in MG-63 cells increased survival of cells after exposure to doxorubicin. In contrast, downregulation of NRP-1 expression in SaOS-2 cells markedly increased chemosensitivity after exposure to doxorubicin.
  
  
  CONCLUSIONS
  We suggest that NRP-1 could be used as a biomarker for OS progression and a novel therapeutic or chemopreventive target for human OS treatment.
authors.affiliation: Department of Spine, the Affiliated Hospital of Qingdao University, Qingdao. China. Revisedyb@126.com.
authors.forename: B
authors.initials: B
authors.lastname: Yue
authors.forename: J-F
authors.initials: JF
authors.lastname: Ma
authors.forename: G
authors.initials: G
authors.lastname: Yao
authors.forename: M-D
authors.initials: MD
authors.lastname: Yang
authors.forename: H
authors.initials: H
authors.lastname: Cheng
authors.forename: G-Y
authors.initials: GY
authors.lastname: Liu
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D001859:Bone Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement; D004317:Doxorubicin / Q000494:pharmacology*; D055785:Gene Knockdown Techniques; D006801:Humans; D009361:Neoplasm Invasiveness; D009389:Neovascularization, Pathologic; D039942:Neuropilin-1 / Q000235:genetics* / Q000378:metabolism; D012516:Osteosarcoma / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D034741:RNA, Small Interfering / Q000235:genetics
chemical_list: D000903:Antibiotics, Antineoplastic; D014408:Biomarkers, Tumor; D034741:RNA, Small Interfering; D039942:Neuropilin-1; D004317:Doxorubicin