title: Osteotropic cancer diagnosis by an osteocalcin inspired molecular imaging mimetic.
abstract: BACKGROUND
  Although microcalcifications of hydroxyapatite can be found in both benign and malignant osteotropic tumors, they are mostly seen in proliferative lesions, including carcinoma. The aim of this present study is to develop a molecular imaging contrast agent for selective identification of hydroxyapatite calcification in human osteotropic tumor tissues ex vivo and in human osteosarcoma cells in vitro.
  
  
  METHODS
  A bioinspired biomarker, hydroxyapatite binding peptide (HABP), was designed to mimic natural protein osteocalcin property in vivo. A fluorescein isothiocyanate dye conjugated HABP (HABP-19) was utilized to characterize hydroxyapatite on human osteotropic tumor tissue sections ex vivo and to selectively image hydroxyapatite calcifications in human osteosarcoma cells in vitro.
  
  
  RESULTS
  Using a HABP-19 molecular imaging probe, we have shown that it is possible to selectively image hydroxyapatite calcifications in osteotropic cancers ex vivo and in human SaOS-2 osteosarcoma cells in vitro.
  
  
  CONCLUSIONS
  Hydroxyapatite calcifications were selectively detected in osteotropic tissues ex vivo and in the early stage of the calcification process of SaOS-2 human osteosarcoma in vitro using our HABP-19 molecular imaging probe. This new target-selective molecular imaging probe makes it possible to study the earliest events associated with hydroxyapatite deposition in various osteotropic cancers at the cellular and molecular levels.
  
  
  CONCLUSIONS
  It potentially could be used to diagnose and treat osteotropic cancer or to anchor therapeutic agents directing the local distribution of desired therapy at calcified sites.
authors.affiliation: Department of Translational Imaging, Weill Medical College of Cornell University, Houston, TX 77030, USA. jl2zt@virginia.edu
authors.forename: Jae Sam
authors.initials: JS
authors.lastname: Lee
authors.forename: Ching-Hsuan
authors.initials: CH
authors.lastname: Tung
mesh_terms: D001859:Bone Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D045744:Cell Line, Tumor; D017886:Durapatite / Q000378:metabolism; D016650:Fluorescein-5-isothiocyanate; D006801:Humans; D018716:Molecular Mimicry; D015675:Osteocalcin / Q000378:metabolism*; D012516:Osteosarcoma / Q000175:diagnosis* / Q000378:metabolism; D046888:Tissue Array Analysis
chemical_list: D015675:Osteocalcin; D017886:Durapatite; D016650:Fluorescein-5-isothiocyanate
keywords: ARS; Alizarin Red S; CM; CO; CS; Calcification; FB; Gla; HA; HABP; Hydroxyapatite; MX; Max; Molecular imaging; OCN; OS; Osteocalcin; Osteotropic; SM; TG; TMA; calcium oxalate; chondrosarcoma; control media; fibroblastic; hydroxyapatite; hydroxyapatite binding peptide; maxilla; myxoid; osteocalcin; osteosarcoma; stimulating media; telangiectatic; tissue microarray; β-GP; β-Glycerophosphate; γ-carboxyglutamic acid