title: Design, synthesis and validation of integrin α2β1-targeted probe for microPET imaging of prostate cancer.
abstract: OBJECTIVE
  The ability of PET to aid in the diagnosis and management of recurrent and/or disseminated metastatic prostate cancer may be enhanced by the development of novel prognostic imaging probes. Accumulating experimental evidence indicates that overexpression of integrin α(2)β(1) may correlate with progression in human prostate cancer. In this study, (64)Cu-labeled integrin α(2)β(1)-targeted PET probes were designed and evaluated for the imaging of prostate cancer.
  
  
  METHODS
  DGEA peptides conjugated with a bifunctional chelator (BFC) were developed to image integrin α(2)β(1) expression with PET in a subcutaneous PC-3 xenograft model. The microPET images were reconstructed by a two-dimensional ordered subsets expectation maximum algorithm. The average radioactivity accumulation within a tumor or an organ was quantified from the multiple region of interest volumes.
  
  
  RESULTS
  The PET tracer demonstrated prominent tumor uptake in the PC-3 xenograft (integrin α(2)β(1)-positive). The receptor specificity was confirmed in a blocking experiment. Moreover, the low tracer uptake in a CWR-22 tumor model (negative control) further confirmed the receptor specificity.
  
  
  CONCLUSIONS
  The sarcophagine-conjugated DGEA peptide allows noninvasive imaging of tumor-associated α(2)β(1) expression, which may be a useful PET probe for evaluating the metastatic potential of prostate cancer.
authors.affiliation: Department of Radiology, University of Southern California, 1510 San Pablo Street, Los Angeles, CA 90033, USA.
authors.forename: Chiun-Wei
authors.initials: CW
authors.lastname: Huang
authors.forename: Zibo
authors.initials: Z
authors.lastname: Li
authors.forename: Hancheng
authors.initials: H
authors.lastname: Cai
authors.forename: Kai
authors.initials: K
authors.lastname: Chen
authors.forename: Tony
authors.initials: T
authors.lastname: Shahinian
authors.forename: Peter S
authors.initials: PS
authors.lastname: Conti
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic; D003301:Copper Radioisotopes; D015195:Drug Design; D004355:Drug Stability; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D038982:Integrin alpha2beta1 / Q000378:metabolism*; D008297:Male; D051379:Mice; D015335:Molecular Probes / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D049268:Positron-Emission Tomography / Q000379:methods*; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D021381:Protein Transport; D011854:Radiochemistry; D015203:Reproducibility of Results
chemical_list: D003301:Copper Radioisotopes; D038982:Integrin alpha2beta1; D015335:Molecular Probes; D009842:Oligopeptides; C113781:aspartyl-glycyl-glutamyl-alanine