Preclinical Evaluation of NHS-Activated Gold Nanoparticles Functionalized with Bombesin or Neurotensin-Like Peptides for Targeting Colon and Prostate Tumours

Recent advances and large-scale use of hybrid imaging modalities like PET-CT have led to the necessity of improving nano-drug carriers that can facilitate both functional and metabolic screening in nuclear medicine applications. In this study, we focused on the evaluation of four potential imaging nanoparticle structures labelled with the (68)Ga positron emitter. For this purpose, we functionalized NHS-activated PEG-gold nanoparticles with (68)Ga-DOTA-Neuromedin B, (68)Ga-DOTA-PEG(4)-BBN(7-14), (68)Ga-DOTA-NT and (68)Ga-DOTA-Neuromedin N. In vitro binding kinetics and specific binding to human HT-29 colon carcinoma cells and DU-145 prostate carcinoma cells respectively were assessed, over 75% retention being obtained in the case of (68)Ga-DOTA-PEG(4)-BBN(7-14)-AuNP in prostate tumour cells and over 50% in colon carcinoma cells. Biodistribution in NU/J mice highlighted a three-fold uptake increase in tumours at 30 min post-injection of (68)Ga-DOTA-NT-AuNP and (68)Ga-DOTA-PEG(4)-BBN(7-14)-AuNP compared to (68)Ga-DOTA-NT and (68)Ga-DOTA-PEG(4)-BBN(7-14) respectively, therewith fast distribution in prostate and colon tumours and minimum accumulation in non-targeted tissues.