title: Dual-color imaging of angiogenesis and its inhibition in bone and soft tissue sarcoma.
abstract: BACKGROUND
  Angiogenesis is a critical step in tumor growth, progression, and metastasis. Soft tissue and bone sarcoma are resistant to most therapeutic approaches. Angiogenesis of these tumors may be an effective target. We hypothesized that we could inhibit tumor growth by targeting angiogenesis in a mouse model of sarcoma. We demonstrate in this report, using powerful color-coded fluorescent imageable tumor-host models, the onset of angiogenesis of these sarcomas and its inhibition.
  
  
  METHODS
  Transgenic mice were used as the host in which green fluorescent protein (GFP) is driven by a regulatory element of the stem cell marker nestin (ND-GFP). Nascent blood vessels express ND-GFP in this model. We visualized, by dual-color fluorescence imaging, angiogenesis of sarcoma formed by the HT-1080 human fibrosarcoma cell line expressing red fluorescent protein (RFP) in the ND-GFP mice. Tumor cells were injected into either the muscle or the bone.
  
  
  RESULTS
  Nestin was highly expressed in proliferating endothelial cells and nascent blood vessels in the growing tumors, including the surrounding tissues. Immunohistochemical staining showed that CD31 colocalized in ND-GFP-expressing nascent blood vessels. The density of nascent blood vessels in the tumor was readily quantitated. The mice were given daily i.p. injections of 5 mg/kg of doxorubicin after implantation of tumor cells. Doxorubicin significantly decreased the mean nascent blood vessel density in the tumors as well as decreased tumor volume.
  
  
  CONCLUSIONS
  The dual-color model of the ND-GFP nude mouse and RFP sarcoma cells is useful for the visualization and quantitation of bone and soft tissue tumor angiogenesis and evaluation of angiogenic inhibitors for such tumors. These data suggest targeting angiogenesis of sarcomas as a promising clinical approach.
authors.affiliation: Department of Surgery, University of California San Diego, San Diego, California, USA.
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Hayashi
authors.forename: Kensuke
authors.initials: K
authors.lastname: Yamauchi
authors.forename: Norio
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsuchiya
authors.forename: Katsuro
authors.initials: K
authors.lastname: Tomita
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Amoh
authors.forename: Robert M
authors.initials: RM
authors.lastname: Hoffman
authors.forename: Michael
authors.initials: M
authors.lastname: Bouvet
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000627:therapeutic use; D001859:Bone Neoplasms / Q000098:blood supply* / Q000188:drug therapy / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004317:Doxorubicin / Q000627:therapeutic use; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology; D005354:Fibrosarcoma / Q000098:blood supply* / Q000188:drug therapy / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D007381:Intermediate Filament Proteins / Q000235:genetics / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence / Q000379:methods*; D009389:Neovascularization, Pathologic / Q000378:metabolism / Q000473:pathology* / Q000517:prevention & control*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D064231:Nestin; D012039:Regional Blood Flow; D012509:Sarcoma / Q000098:blood supply* / Q000188:drug therapy / Q000378:metabolism; D000097573:Red Fluorescent Protein
chemical_list: D000903:Antibiotics, Antineoplastic; D004317:Doxorubicin; D049452:Green Fluorescent Proteins; D007381:Intermediate Filament Proteins; D008164:Luminescent Proteins; D009419:Nerve Tissue Proteins; D064231:Nestin; D000097573:Red Fluorescent Protein; C577484:NES protein, human; C577485:Nes protein, mouse