Preclinical evaluation of new GnRH-I receptor radionuclide therapy with Lu-peptide tracer.

The purpose of this study was to develop preclinical evaluation of a novel radiolabeled gonadotropin-releasing hormone (GnRH) receptor targeting peptide for prostate cancer therapy. The new antiproliferative agent of GnRH-I analogue was developed on the basis of the D-Trp -GnRH-I scaffold, and in vivo pharmacokinetics and receptor binding affinity were enhanced by the substitution of Gly-NHNH for Gly-NH at position 10 in D-Trp -GnRH-I. To evaluate Lu-DOTA-triptorelin-hydrazide as radionuclide therapy of tumor, the quality control tests and preclinical stage assessment were carried out.

Preparation of a radiolabeled GnRH-I analogue derivative with In as a new anti-proliferative agent.

The new GnRH-Ιanalogue developed in this paper was based on the D-Trp -GnRH-Ι-scaffold, and its potency was increased by the replacement Gly-NH by NH-NH binding to the Gly at position 10. Triptorelin-Hydrazide analogue was synthesized using solid phase. For In labeling, synthesized peptide was followed by conjugation with DOTA using pSCN-Bn-DOTA.

Development of a (68)Ga-peptide tracer for PET GnRH1-imaging.

Objective: Total synthesis, quality control and preclinical evaluation of [(68)Ga]-DOTA-triptorelin ([(68)Ga]-DOTA-TRP) is reported as a possible PET radiotracer for GnRH receptor imaging.

Methods: DOTA-TRP was totally synthesized in two steps and after characterization went through radiolabelling optimization studies followed by tracer stability. The biodistribution of the tracer in normal male rats and 4T1 tumour-bearing mice was performed in 120 min after i.