Insulinomas, neuroendocrine tumors arising from pancreatic beta cells, often show overexpression of the glucagon-like peptide-1 receptor. Therefore, imaging with glucagon-like peptide analog exendin-4 can be used for diagnosis and preoperative localization. This review presents an overview of the development and clinical implementation of exendin-based tracers for nuclear imaging, and the potential use of exendin-4 based tracers for optical imaging and therapeutic applications such as peptide receptor radionuclide therapy or targeted photodynamic therapy.
Insulinomas are neuroendocrine tumors arising from the pancreatic beta cells. Currently, surgical resection is the therapy of choice, and therefore, preoperative localization of insulinomas is essential. Nearly all insulinomas show overexpression of the glucagon-like peptide-1 receptor (GLP-1R), and therefore, radiolabeled GLP-1 peptide analog exendin-4 can be used for diagnosis and preoperative localization with nuclear imaging. Here, we present an overview of the development and clinical implementation of exendin-4-based tracers for single-photon emission computed tomography (SPECT) and positron emission tomography (PET) imaging of insulinomas, and we address the potential use of this molecule for optical imaging. At last, we discuss the possibilities and pitfalls of the use of exendin-4-based tracers for therapeutic applications such as peptide receptor radionuclide therapy (PRRT) or targeted photodynamic therapy (tPDT), giving a future outlook on the use of exendin-4 in insulinoma theranostics.
Keywords: GLP-1 receptor; exendin-4; insulinoma; peptide receptor radionuclide therapy (PRRT); positron emission tomography (PET); single-photon emission computed tomography (SPECT); targeted photodynamic therapy (tPDT); theranostics.
© 2019 The Authors Journal of Labelled Compounds and Radiopharmaceuticals Published by John Wiley & Sons Ltd.