Schottelius, M.* ; Wurzer, A.* ; Wissmiller, K.* ; Beck, R.* ; Koch, M. ; Gorpas, D. ; Notni, J.* ; Buckle, T.* ; van Oosterom, M.N.* ; Steiger, K.* ; Ntziachristos, V. ; Schwaiger, M.* ; van Leeuwen, F.W.B.* ; Wester, H.J.*
     
 
    
        
Synthesis and preclinical characterization of the PSMA-targeted hybrid tracer PSMA-I&F for nuclear and fluorescence imaging of prostate cancer.
    
    
        
    
    
        
        J. Nucl. Med. 60, 71-78 (2018)
    
    
    
		
		
			
				The prostate-specific membrane antigen (PSMA)-targeted radiotracers Ga-68/Lu-177-PSMA-I&T and Tc-99m-PSMA-I&S (for imaging and surgery) are currently successfully used for clinical PET imaging, radionuclide therapy, and radioguided surgery of metastatic prostate cancer. To additionally exploit the high sensitivity and spatial resolution of fluorescence imaging for improved surgical guidance, a PSMA-I&T-based hybrid tracer, PSMA-I&F (DOTAGA-k(Sulfo-Cy5)-y-nal-k-Sub-KuE), has been developed and evaluated. Methods: The in vitro PSMA-targeting efficiency of PSMA-I&F, the reference PSMA-I&T, and their corresponding Ga-nat-/Ga-68- and Lu-nat/Lu-177 counterparts was determined in LNCaP cells via competitive binding assays (IC50) and dual-tracer radioligand and fluorescence internalization studies. Biodistribution and small-animal PET imaging studies were performed in CB17 SCID and LNCaP xenograft-bearing SHO mice, respectively, and complemented by intraoperative far-red fluorescence imaging using a clinical laparoscope. Additionally, fully automated serial cryosectioning and fluorescence imaging of 1 tumor-bearing animal as well as PSMA immunohistochemistry and fluorescence microscopy of organ cryosections (tumor, kidney, spleen) were also performed. Results: Compared with the parent PSMA-I&T analogs, the PSMA affinities of PSMA-I&F and its Ga-nat-/Lu-nat-complexes remained high and unaffected by dye conjugation (7.9 < IC50 < 10.5 nM for all ligands). The same was observed for the internalization of Ga-68- and Lu-177-PSMA-I&F. In vivo, blood clearance of Ga-68- and Lu-177-PSMA-I&F was only slightly delayed by high plasma protein binding (94%-95%), and very low accumulation in nontarget organs was observed already at 1 h after injection. Dynamic PET imaging confirmed PSMA-specific (as demonstrated by coinjection of 2-PMPA) uptake into the LNCaP xenograft (4.5% +/- 1.8 percentage injected dose per gram) and the kidneys (106% +/- 23 percentage injected dose per gram). Tumor-to-background ratios of 2.1, 5.2, 9.6, and 9.6 for blood, liver, intestines, and muscle, respectively, at 1 h after injection led to excellent imaging contrast in Ga-68-PSMA-I&F PET and in intraoperative fluorescence imaging. Furthermore, fluorescence imaging of tissue cryosections allowed high-resolution visualization of intraorgan PSMA-I&F distribution in vivo and its correlation with PSMA expression as determined by immunohistochemistry. Conclusion: Thus, with its high PSMA-targeting efficiency and favorable pharmacokinetic profile, Ga-68/Lu-177-PSMA-I&F serves as an excellent proof-of-concept compound for the general feasibility of PSMA-I&T-based hybrid imaging. The PSMA-I&T scaffold represents a versatile PSMA-targeted lead structure, allowing relatively straightforward adaptation to the different structural requirements of dedicated nuclear or hybrid imaging agents.
			
			
				
			
		 
		
			
				
					
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        Publikationstyp
        Artikel: Journalartikel
    
 
    
        Dokumenttyp
        Wissenschaftlicher Artikel
    
 
    
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        Schlagwörter
        Psma ; Prostate Cancer ; Fluorescence ; Hybrid Tracer ; Intraoperative Guidance; Dual-modality; Guided Surgery; Radioguided Surgery; Surgical Guidance; Ligands; Agents; Therapy; Optimization; Radionuclide; Inhibitor
    
 
    
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        Sprache
        englisch
    
 
    
        Veröffentlichungsjahr
        2018
    
 
    
        Prepublished im Jahr 
        
    
 
    
        HGF-Berichtsjahr
        2018
    
 
    
    
        ISSN (print) / ISBN
        0161-5505
    
 
    
        e-ISSN
        1535-5667
    
 
    
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	    Band: 60,  
	    Heft: 1,  
	    Seiten: 71-78 
	    Artikelnummer: ,  
	    Supplement: ,  
	
    
 
  
        
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            Verlag
            Society of Nuclear Medicine and Molecular Imaging
        
 
        
            Verlagsort
            1850 Samuel Morse Dr, Reston, Va 20190-5316 Usa
        
 
	
        
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        Begutachtungsstatus
        Peer reviewed
    
 
     
    
        POF Topic(s)
        30205 - Bioengineering and Digital Health
    
 
    
        Forschungsfeld(er)
        Enabling and Novel Technologies
    
 
    
        PSP-Element(e)
        G-505500-001
    
 
    
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        Erfassungsdatum
        2018-10-29