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Radionuclide-based Diagnosis and Therapy of Prostate Cancer
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Sven-Erik Strand, Mohamed Altai, Joanna Strand, David Ulmert
The high-density expression of gastrin-releasing peptide receptors (GRPRs) in several human cancer forms, as PCa, compared to their low expression in surrounding healthy tissues, provided an opportunity to develop several theranostic agents targeting this tumour marker. Bombesin, a 14 amino acids peptide, was initially isolated from the skin of the European frog Bombina bombina in the early 1970s. Among several identified bombesin agonists, [Leu13]BN was found to have the highest affinity towards GRPR, and high homology to its endogenous ligand gastrin-releasing peptide (GRP). Agonists trigger internalization into the cell upon binding to GRPR. When labelled with residualizing labels efficient internalization, enables prominent accumulation of radioactivity in the tumour. High-affinity antagonists on the other hand have low internalization, but were still found to have superior tumour-targeting and pharmacokinetic properties compared to agonists [73]. The GRPR antagonist [111In]-RM1, showed superior in vivo targeting properties, that is, 3-fold higher tumour uptake, compared to the potent GRPR agonist [111In]- AMBA81 [74]. C-terminus modification of RM1, has led to the development of the more potent GRPR antagonist (D-Phe-Gln-Trp-Ala-Val-Gly-His-Leu-NHEt). Efforts to optimize targeting properties of this antagonist by conjugating it to different macrocyclic chelators as well as radiolabelling with several clinically relevant radionuclides resulted in developing 68Ga-DOTA-Sarabesin3 [75], which exhibited encouraging results in men [76]. By replacement of the C-terminal Leu13-Met14-NH2dipeptide of SB3 bySta13-Leu14-NH2, the novel GRPR antagonist NeoBOMB1 was generated [77]. NeoBOMB1, was labelled with 68Ga (for PET), 111In (for SPECT), and 177Lu (for therapy). 68Ga-Neo-BOMB1, 111In-NeoBOMB1, and 177Lu-NeoBOMB1 efficiently localized in PCa cell line PC-3. Successful visualization of PCa lesions in men was possible using 68Ga-NeoBOMB1 and PET/CT imaging [77]. The statine-based high affinity GRPR antagonist RM26 (also known as JMV594) formed the basis for various tracers that are under development for imaging and therapy in PCa [78]. RM26 was radiolabelled with cobalt isotopes and evaluated in PCa tumour-bearing mice. The cobalt-radiolabelled NOTA-PEG2-RM26 demonstrated favourable biodistribution, which translated into high-contrast preclinical PET/CT (using 55Co) and SPECT/CT (using 57Co) images of PC-3 xenografts [79]. Recently a study was designed to analyse the safety, biodistribution, and radiation dosimetry of 68Ga-RM26 in healthy human volunteers [80]. Moreover, a direct comparison between GRPR antagonist 68Ga-RM26 and agonist 68Ga-BBN was evaluated. This study demonstrated the safety and significant efficiency of 68Ga-RM26. The antagonist 68Ga-RM26 was shown to be better than the GRPR agonist as an imaging marker to evaluate GRPR expression in PCa.
Advanced materials and technologies for oral diseases
Published in Science and Technology of Advanced Materials, 2023
Hao Cui, Yan You, Guo-Wang Cheng, Zhou Lan, Ke-Long Zou, Qiu-Ying Mai, Yan-Hua Han, Hao Chen, Yu-Yue Zhao, Guang-Tao Yu
Optical imaging systems have been intensively studied for cancer diagnosis, respectively. Gastrin-releasing peptide receptor (GRPR) is an important target for OSCC imaging and therapy [243]. Li et al. successfully prepared gastrin-releasing peptide receptor-specific nGO nanoprobes for near-infrared fluorescence imaging of OSCC. The probe has the characteristics of large surface area, good water dispersibility, good biocompatibility, easy surface modification, and low manufacturing cost. Furthermore, it has a high binding affinity and specificity to GRPR-positive HSC-3 cells, which enhances the imaging effect [244]. In our previous experiments, we used the quantum dot (QD)-based overlap-free emission nanoprobes in a second NIR window (NIR-II, 1000) for analyzing the dynamic expression of MDSCs in the tumor microenvironment (TME) (Figure 10(b)). The result shows that NIR-II fluorescent nanoprobes with molecular targeting capability can be used as a real-time monitor for changes in the in vivo immune cell population to assess tumor progression [234]. These experimental results demonstrate the considerable potential of optical imaging systems for diagnosing oral cancer.
Theranostic approaches in nuclear medicine: current status and future prospects
Published in Expert Review of Medical Devices, 2020
Luca Filippi, Agostino Chiaravalloti, Orazio Schillaci, Roberto Cianni, Oreste Bagni
Beyond the theranostic applications based on the clinical use of radionuclide pairs (diagnostic/therapeutic), theranostics also consist in the detection of specific biomarkers (i.e. receptors, transporters), that can be successfully exploited for targeted therapy. As specifically concerns breast cancer (BC), in the past years many advances have been made for the identification of several molecular targets linked to specific tumor biology and behavior, such as human epidermal growth factor 2 (HER-2), hormone receptors, gastrin releasing peptide receptor (GRPR), folate receptor (FR), etc. [78]. In particular, 16alpha-[(18)F]fluoroestradiol-17beta (18 F-FES) has been applied for the PET detection of estradiol receptor (ER) in patients affected by advanced BC. In a study performed by Dehdashti et al., a cohort of 51 post-menopausal women with advanced estrogen-receptor positive BC was submitted to PET/CT scan with 18 F-FES before treatment with estradiol, among the enrolled subjects, 17 responded and 31 did not respond to hormone therapy [79]. Of note, responders showed higher SUV values in tumors than non-responders, thus suggesting that PET with 18 F-FES may present a predictive value on the response to hormone therapy.