Preclinical evaluation of 131I-Bevacizumab - A prospective agent for radioimmunotherapy in VEGF expressing cancers

Safety assessment, radioiodination and preclinical evaluation of antinuclear antibody as novel medication for prostate cancer in mouse xenograft model

This study aims to provide in vitro and in vivo data to support the utilization of antinuclear antibodies (ANAs) as novel tools for the diagnosis and treatment of prostate cancers. The hematological, biochemical, and histological toxicities of ANAs were assessed at the doses of 5 and 50 μg per mouse. Radiolabeling study was then conducted with ANA and 131I using the chloramine T method, and the biodistribution and treatment efficacy were subsequently investigated in a PC3 xenograft model. No changes in clinical behavior or signs of intoxication, necrosis, or malignancy were observed in ANA-treated mice. 131I-ANA was obtained in very high yield and radiochemical purity, at 94.97 ± 0.98% and 98.56 ± 0.29%, respectively. They achieved immunoreactivity fraction of 0.841 ± 0.17% with PC-3 cells. Levels of radiolabeled ANAs were 1.15-10.14 times higher in tumor tissues than in other examined organs at 24 h post-injection. The tumor growth inhibition rates were 28.33 ± 5.01% in PC3 xenografts mice treated with 131I-ANAs compared with controls and a nearly twofold improvement in median survival was observed. These results demonstrate that radioimmunotherapy of radiolabeled natural ANAs may be an effective treatment for prostate tumors.

Novel Receptor Tyrosine Kinase Pathway Inhibitors for Targeted Radionuclide Therapy of Glioblastoma

Glioblastoma (GB) remains the most fatal brain tumor characterized by a high infiltration rate and treatment resistance. Overexpression and/or mutation of receptor tyrosine kinases is common in GB, which subsequently leads to the activation of many downstream pathways that have a critical impact on tumor progression and therapy resistance. Therefore, receptor tyrosine kinase inhibitors (RTKIs) have been investigated to improve the dismal prognosis of GB in an effort to evolve into a personalized targeted therapy strategy with a better treatment outcome. Numerous RTKIs have been approved in the clinic and several radiopharmaceuticals are part of (pre)clinical trials as a non-invasive method to identify patients who could benefit from RTKI. The latter opens up the scope for theranostic applications. In this review, the present status of RTKIs for the treatment, nuclear imaging and targeted radionuclide therapy of GB is presented. The focus will be on seven tyrosine kinase receptors, based on their central role in GB: EGFR, VEGFR, MET, PDGFR, FGFR, Eph receptor and IGF1R. Finally, by way of analyzing structural and physiological characteristics of the TKIs with promising clinical trial results, four small molecule RTKIs were selected based on their potential to become new therapeutic GB radiopharmaceuticals.

The Role of VEGF Receptors as Molecular Target in Nuclear Medicine for Cancer Diagnosis and Combination Therapy

Simple Summary

The rapid development of diagnostic and therapeutic methods of the cancer treatment causes that these diseases are becoming better known and the fight against them is more and more effective. Substantial contribution in this development has nuclear medicine that enables very early cancer diagnosis and early start of the so-called targeted therapy. This therapeutic concept compared to the currently used chemotherapy, causes much fewer undesirable side effects, due to targeting a specific lesion in the body. This review article discusses the possible applications of radionuclide-labelled tracers (peptides, antibodies or synthetic organic molecules) that can visualise cancer cells through pathological blood vessel system in close tumour microenvironment. Hence, at a very early step of oncological disease, targeted therapy can involve in tumour formation and growth.

Abstract

One approach to anticancer treatment is targeted anti-angiogenic therapy (AAT) based on prevention of blood vessel formation around the developing cancer cells. It is known that vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptors (VEGFRs) play a pivotal role in angiogenesis process; hence, application of angiogenesis inhibitors can be an effective approach in anticancer combination therapeutic strategies. Currently, several types of molecules have been utilised in targeted VEGF/VEGFR anticancer therapy, including human VEGF ligands themselves and their derivatives, anti-VEGF or anti-VEGFR monoclonal antibodies, VEGF binding peptides and small molecular inhibitors of VEGFR tyrosine kinases. These molecules labelled with diagnostic or therapeutic radionuclides can become, respectively, diagnostic or therapeutic receptor radiopharmaceuticals. In targeted anti-angiogenic therapy, diagnostic radioagents play a unique role, allowing the determination of the emerging tumour, to monitor the course of treatment, to predict the treatment outcomes and, first of all, to refer patients for AAT. This review provides an overview of design, synthesis and study of radiolabelled VEGF/VEGFR targeting and imaging agents to date. Additionally, we will briefly discuss their physicochemical properties and possible application in combination targeted radionuclide tumour therapy.