Improved radiolabeling of PEGylated protein: PEGylated annexin V for noninvasive imaging of tumor apoptosis.
We have developed a one-step procedure to introduce both polyethylene glycol (PEG) and the metal chelator diethylenetriaminepentaacetic acid (DTPA) to proteins through a heterofunctional PEG precursor. The PEG precursor contains DTPA at one end and an amine-reactive isothiocyanate (SCN-) functional group at the other end. It was obtained as lyophilized powder and could be stored at 4 degrees C for several months. Protein conjugation was achieved by simply mixing the proteins and the PEG precursor SCN-PEG-DTPA in an aqueous solution. As exemplified by the PEGylation and radiolabeling of annexin V, the resulting conjugate 111In-DTPA-PEG-annexin V showed selective binding to apoptotic cells in vitro and increased blood half-life in vivo. The PEGylated, radiolabeled annexin V may be useful in the noninvasive imaging of apoptosis.
Wen
Xiaoxia
X
Division of Diagnostic Imaging, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.
Wu
Qing-Ping
QP
Ke
Shi
S
Wallace
Sidney
S
Charnsangavej
Chusilp
C
Huang
Peng
P
Liang
Dong
D
Chow
Diana
D
Li
Chun
C
D000818:Animals; D017304:Annexin A5 / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D017209:Apoptosis; D045744:Cell Line, Tumor; D006801:Humans; D009369:Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D004369:Pentetic Acid / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D011868:Radioisotopes; D051381:Rats; D017207:Rats, Sprague-Dawley
D017304:Annexin A5; D011868:Radioisotopes; D011092:Polyethylene Glycols; D004369:Pentetic Acid