Targeting phosphatidylserine for radionuclide-based molecular imaging of apoptosis.

One major characteristic of programmed cell death (apoptosis) results in the increased expression of phosphatidylserine (PS) on the outer membrane of dying cells. Consequently, PS represents an excellent target for non-invasive imaging of apoptosis by single-photon emission computed tomography (SPECT) and positron emission tomography (PET). Annexin V is a 36 kDa protein which binds with high affinity to PS in the presence of Ca ions.

Targeting Phosphatidylserine with a Cu-Labeled Peptide for Molecular Imaging of Apoptosis.

Molecular imaging of programmed cell death (apoptosis) in vivo is an innovative strategy for early assessment of treatment response and treatment efficacy in cancer patients. Externalization of phosphatidylserine (PS) to the cell membrane surface of dying cells makes this phospholipid an attractive molecular target for the development of apoptosis imaging probes. In this study, we have radiolabeled PS-binding 14-mer peptide FNFRLKAGAKIRFG (PSBP-6) with positron-emitter copper-64 (Cu) for PET imaging of apoptosis.

18F-Labeled wild-type annexin V: comparison of random and site-selective radiolabeling methods.

Early stage apoptosis is characterized by the externalization of phosphatidylserine (PS) from the inner leaflet of the plasma membrane to the outer periphery. Consequently, PS represents an excellent target for non-invasive imaging of apoptosis by positron emission tomography. Annexin V is a 36 kDa protein which binds with high affinity to PS.

Radiopharmacological evaluation of (18)F-labeled phosphatidylserine-binding peptides for molecular imaging of apoptosis.

Introduction: Radiolabeled phosphatidylserine (PS)-binding peptides represent an innovative strategy for molecular imaging of apoptosis with positron emission tomography (PET). The goal of this study was the radiopharmacological evaluation of radiolabeled peptides for their binding to PS on apoptotic cancer cells, involving metabolic stability, cellular uptake, biodistribution, and dynamic PET imaging experiments.

Methods: Binding of peptides LIKKPF, PGDLSR, FBz-LIKKPF, FBz-PGDLSR, FBAM-CLIKKPF and FBAM-CPGDLSR to PS was analyzed in a newly developed radiometric binding assay using (64)Cu-labeled wild-type annexin-V as radiotracer.