title: Dual integrin and gastrin-releasing peptide receptor targeted tumor imaging using 18F-labeled PEGylated RGD-bombesin heterodimer 18F-FB-PEG3-Glu-RGD-BBN.
abstract: Radiolabeled RGD and bombesin peptides have been extensively investigated for tumor integrin alpha(v)beta(3) and GRPR imaging, respectively. Due to the fact that many tumors are both integrin and GRPR positive, we designed and synthesized a heterodimeric peptide Glu-RGD-BBN, which is expected to be advantageous over the monomeric peptides for dual-receptor targeting. A PEG(3) spacer was attached to the glutamate alpha-amino group of Glu-RGD-BBN to enhance the (18)F labeling yield and to improve the in vivo kinetics. PEG(3)-Glu-RGD-BBN possesses the comparable GRPR and integrin alpha(v)beta(3) receptor-binding affinities as the corresponding monomers, respectively. The dual-receptor targeting properties of (18)F-FB-PEG(3)-Glu-RGD-BBN were observed in PC-3 tumor model. (18)F-FB-PEG(3)-Glu-RGD-BBN with high tumor contrast and favorable pharmacokinetics is a promising PET tracer for dual integrin and GRPR positive tumor imaging. This heterodimer strategy may also be an applicable method to develop other molecules with improved in vitro and in vivo characterizations for tumor diagnosis and therapy.
authors.affiliation: The Molecular Imaging Program at Stanford, Department of Radiology, Biophysics, Stanford University School of Medicine, Stanford, California 94305, USA.
authors.forename: Zhaofei
authors.initials: Z
authors.lastname: Liu
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Yan
authors.forename: Frederic T
authors.initials: FT
authors.lastname: Chin
authors.forename: Fan
authors.initials: F
authors.lastname: Wang
authors.forename: Xiaoyuan
authors.initials: X
authors.lastname: Chen
mesh_terms: D000818:Animals; D001839:Bombesin / Q000737:chemistry / Q000493:pharmacokinetics*; D019281:Dimerization; D005462:Fluorine Radioisotopes; D039302:Integrin alphaVbeta3 / Q000378:metabolism*; D009374:Neoplasms, Experimental / Q000000981:diagnostic imaging* / Q000378:metabolism; D009842:Oligopeptides / Q000737:chemistry / Q000493:pharmacokinetics*; D011877:Radionuclide Imaging; D018004:Receptors, Bombesin / Q000378:metabolism*
chemical_list: D005462:Fluorine Radioisotopes; D039302:Integrin alphaVbeta3; D009842:Oligopeptides; D018004:Receptors, Bombesin; C047981:arginyl-glycyl-aspartic acid; D001839:Bombesin