Journal Article DKFZ-2026-02128

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Sarcosine-Based Pharmacokinetic Optimization and Fluorescent Dye Library Evaluation of Dual-Labeled PSMA Inhibitors for Fluorescence-Guided Surgery.

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2026
MDPI Basel

Pharmaceuticals 19(8), 1187 () [10.3390/ph19081187]
 GO

Abstract: Objectives: Fluorescence-guided surgery (FGS) targeting prostate-specific membrane antigen (PSMA) holds promise for improving surgical precision in prostate cancer. Since conjugation of fluorescent dyes to targeting vectors can substantially alter pharmacokinetic properties, we systematically evaluated a library of fluorescent dyes conjugated to a PSMA-617-derived scaffold incorporating sarcosine-based spacers to identify candidates with favorable biodistribution and optical profiles for clinical translation. Methods: Nineteen fluorescent dyes spanning NIR, large Stokes shift, and STED-compatible categories were conjugated to a dual-labeled PSMA-617-derived precursor (Glu-urea-Lys-2Nal-TXA-Sar10-Lys(DOTA)-Sar5-βAla; hereafter DP). Compounds were radiolabeled with 68Ga or 177Lu and characterized for serum stability, lipophilicity, binding affinity, and internalization in LNCaPPSMA+ cells. In vivo pharmacokinetics were assessed in LNCaP xenograft-bearing BALB/c nu/nu mice by µPET/MRI (1 and 2 h p.i., 500 pmol 68Ga), organ distribution (0.5, 1, and 2 h p.i., 60 pmol 177Lu), and clinical-grade endoscopic fluorescence imaging. Results: All conjugates retained hydrophilic character (logD: -3.72 to -1.79), low nanomolar binding affinity (Ki: 18-87 nM), and high serum stability (94-100% intact at 24 h). Despite comparable in vitro properties, dye conjugation markedly influenced in vivo pharmacokinetics: tumor uptake at 2 h p.i. ranged from 1 to 23%ID/g and kidney accumulation from 3 to 82%ID/g. Visible-range dyes exhibited faster renal washout within the imaging window and higher tumor-to-background contrast than NIR fluorophores. Fluorescence signal intensity did not correlate with radiotracer-derived uptake, underscoring the importance of dye-specific photophysical properties. Conclusions: DP-12 (SulfoCy5), DP-15 (Alexa Fluor 647), and DP-18 (Tide Fluor 5WS) were identified as lead candidates combining favorable pharmacokinetics with strong fluorescence contrast, warranting further evaluation toward fluorescence-guided prostate cancer surgery.

Keyword(s): PSMA ; Theranostics ; dual-labeled ; fluorescence-guided surgery ; prostate cancer ; small peptide

Classification:

Note: #DKTKZFB26#

Contributing Institute(s):
  1. DKTK Koordinierungsstelle Freiburg (FR01)
  2. DKTK FR Radiopharmazeutische Entwicklung (FR03)
Research Program(s):
  1. 899 - ohne Topic (POF4-899) (POF4-899)

Appears in the scientific report 2026
Database coverage:
Medline ; Creative Commons Attribution CC BY (No Version) ; DOAJ ; Article Processing Charges ; Clarivate Analytics Master Journal List ; Current Contents - Life Sciences ; DOAJ Seal ; Ebsco Academic Search ; Essential Science Indicators ; Fees ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection
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 Record created 2026-08-28, last modified 2026-08-29



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