Differences in the Renal Accumulation of Radiogallium-Labeled (Glu) Peptides Containing Different Optical Isomers of Glutamic Acid.

Acidic amino acid peptides have a high affinity for bone. Previously, we demonstrated that radiogallium complex-conjugated oligo-acidic amino acids possess promising properties as bone-seeking radiopharmaceuticals. Here, to elucidate the effect of stereoisomers of Glu in Glu-containing peptides [(Glu)] on their accumulation in the kidney, the biodistributions of [Ga]Ga-,'-bis-[2-hydroxy-5-(carboxyethyl)benzyl]ethylenediamine-,'-diacetic acid-conjugated (l-Glu) ([Ga]Ga-HBED-CC-(l-Glu)), [Ga]Ga-HBED-CC-(d-Glu), [Ga]Ga-HBED-CC-(dl-Glu), and [Ga]Ga-HBED-CC-(d-Glu-l-Glu) were compared.

Optimizing the pharmacokinetics of an At-labeled RGD peptide with an albumin-binding moiety via the administration of an albumin-binding inhibitor.

Purpose: A probe for targeted alpha therapy (TAT) using the RGD peptide (Ga-DOTA-K([At]APBA)-c(RGDfK) ([At]1)) with albumin-binding moiety (ABM) was recently developed. [At]1 highly accumulated in tumors and significantly inhibited tumor growth in U-87 MG tumor-bearing mice. However, high [At]1 retention in blood may cause critical adverse events, such as hematotoxicity.

Astatine-211-labeled aza-vesamicol derivatives as sigma receptor ligands for targeted alpha therapy.

Introduction: As sigma receptors are abundantly expressed on different types of cancer cells, several radiolabeled sigma receptor ligands have been developed for cancer imaging and therapy. Previously, we synthesized and evaluated radioiodinated aza-vesamicol derivatives, [I]pICNV, [I]mICN5V, and [I]mICN5V. They accumulated in tumors, and [I]mICN5V and [I]mICN5V showed higher tumor to non-target tissue ratios than [I]pICNV.

Development and evaluation of a theranostic probe with RGD peptide introduced platinum complex to enable tumor-specific accumulation.

Cisplatin (CDDP) has been widely used for chemotherapy. However, it has several unfavorable side effects due to its low tumor selectivity. In this study, we designed, synthesized, and evaluated Pt(IV)-[c(RGDyK)] (9), in which two molecules of an RGD peptide are introduced as a carrier molecule to cancer into oxoplatin, a Pt(IV) prodrug of CDDP, to enhance cancer selectivity.

Synthesis and Evaluation of a Dimeric RGD Peptide as a Preliminary Study for Radiotheranostics with Radiohalogens.

We recently developed I- and At-labeled monomer RGD peptides using a novel radiolabeling method. Both labeled peptides showed high accumulation in the tumor and exhibited similar biodistribution, demonstrating their usefulness for radiotheranostics. This study applied the labeling method to a dimer RGD peptide with the aim of gaining higher accumulation in tumor tissues based on improved affinity with αβ integrin.

Ga- and At-Labeled RGD Peptides for Radiotheranostics with Multiradionuclides.

Probes for radiotheranostics could be produced by introducing radionuclides with similar chemical characteristics into the same precursors. We recently developed an At-labeled RGD peptide and a corresponding radioiodine-labeled RGD peptide. Both labeled peptides accumulated in large quantities in the tumor with similar biodistribution, demonstrating their usefulness for radiotheranostics.