Author:
Kratz Harald,Haeckel Akvile,Michel Roger,Schönzart Lena,Hanisch Uli,Hamm Bernd,Schellenberger Eyk
Abstract
Abstract
Background
Annexin A5 (anxA5) has been found useful for molecular imaging of apoptosis and other biological processes.
Methods
Here, we report an optimised two-step synthesis of annexin A5-diethylene triamine pentaacetic acid (DTPA) (anxA5-DTPA) for positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging with a single purification step. The use of a recombinant annexin A5 (cys-anxA5) with a single thiol group allowed regionally specific coupling, without affecting the binding domain of cys-anxA5.
Results
The metal complexing capacity of anxA5-DTPA was investigated by labelling with 111In3+ and Eu3+. Binding of modified anxA5-DTPA to apoptotic cells was tested in competition experiments with a fluorescent anxA5 derivative (anxA5-FITC) using flow cytometry and compared with that of wildtype anxA5 or non-binding anxA5-DTPA (M1234-anxA5-DTPA). The binding affinity to apoptotic cells of the anxA5-DTPA conjugate does not differ from that of wildtype anxA5.
Conclusions
This two-step synthesis of annexin A5-DTPA resulted in biologically active anxA5-DTPA, which can be labelled with radionuclides for use in SPECT and PET imaging.
Publisher
Springer Science and Business Media LLC
Subject
Radiology, Nuclear Medicine and imaging
Reference21 articles.
1. Sosnovik DE, Schellenberger EA, Nahrendorf M, Novikov MS, et al.: Magnetic resonance imaging of cardiomyocyte apoptosis with a novel magneto-optical nanoparticle. Magn Reson Med 2005, 54: 718–724. 10.1002/mrm.20617
2. Schutters K, Reutelingsperger C: Phosphatidylserine targeting for diagnosis and treatment of human diseases. Apoptosis 2010, 15: 1072–1082. 10.1007/s10495-010-0503-y
3. Haas RLM, de Jong D, Valdés Olmos RA, Hoefnagel CA, et al.: In vivo imaging of radiation-induced apoptosis in follicular lymphoma patients. Int J Radiat Oncol Biol Phys 2004, 59: 782–787. 10.1016/j.ijrobp.2003.11.017
4. Kartachova M, Haas RLM, Olmos RAV, Hoebers FJP, van Zandwijk N, Verheij M: In vivo imaging of apoptosis by 99mTc-Annexin V scintigraphy: visual analysis in relation to treatment response. Radiother Oncol 2004, 72: 333–339. 10.1016/j.radonc.2004.07.008
5. Belhocine T, Steinmetz N, Hustinx R, Bartsch P, et al.: Increased uptake of the apoptosis-imaging agent 99Tc recombinant human Annexin V in human tumors after one course of chemotherapy as a predictor of tumor response and patient prognosis. Clin Cancer Res 2002, 8: 2766–2774.