Gene manipulation to enhance MIBG-targeted radionuclide therapy

Integration of organoids in peptide drug discovery: Rise of the high‐throughput screening

Organoids are three‐dimensional cell aggregates with near‐physiologic cell behaviors and can undergo long‐term expansion in vitro. They are amenable to high‐throughput drug screening processes, which renders them a viable preclinical model for drug development. The procedure of organoid‐based high‐throughput screening has been extensively employed to discover small‐molecule drugs, encompassing the steps of generating organoids, examining efficient drugs in organoid cultures, and data assessment. Compared to small molecules, peptides are more straightforward to synthesize, can be modified chemically, and demonstrate high target specificity and low cytotoxicity. Therefore, they have emerged as promising carriers to deliver drugs to disease‐associated targets and could be efficient therapeutic drugs for various diseases. To date, organoids have been used to evaluate the efficacy of certain peptide agents; however, no organoid‐based high‐throughput screening of peptide drugs has been reported. Given the advantages of peptide drugs, there is an urgent need to establish organoid‐based peptide high‐throughput screening platforms. In this review, we discuss the typical approach of screening small‐molecular drugs with the use of organoid cultures, as well as provide an overview of the studies that have incorporated organoids in peptide research. Drawing on the knowledge from small molecular screens, we explore the difficulties and potential avenues for creating new platforms to identify peptide agents using organoid models.

Three-Dimensional Cell Culture Systems in Radiopharmaceutical Cancer Research

In preclinical cancer research, three-dimensional (3D) cell culture systems such as multicellular spheroids and organoids are becoming increasingly important. They provide valuable information before studies on animal models begin and, in some cases, are even suitable for reducing or replacing animal experiments. Furthermore, they recapitulate microtumors, metastases, and the tumor microenvironment much better than monolayer culture systems could. Three-dimensional models show higher structural complexity and diverse cell interactions while reflecting (patho)physiological phenomena such as oxygen and nutrient gradients in the course of their growth or development. These interactions and properties are of great importance for understanding the pathophysiological importance of stromal cells and the extracellular matrix for tumor progression, treatment response, or resistance mechanisms of solid tumors. Special emphasis is placed on co-cultivation with tumor-associated cells, which further increases the predictive value of 3D models, e.g., for drug development. The aim of this overview is to shed light on selected 3D models and their advantages and disadvantages, especially from the radiopharmacist's point of view with focus on the suitability of 3D models for the radiopharmacological characterization of novel radiotracers and radiotherapeutics. Special attention is paid to pancreatic ductal adenocarcinoma (PDAC) as a predestined target for the development of new radionuclide-based theranostics.

Dosimetry study of [I-131] and [I-125]- meta-iodobenz guanidine in a simulating model for neuroblastoma metastasis

The physical properties of I-131 may be suboptimal for the delivery of therapeutic radiation to bone marrow metastases, which are common in the natural history of neuroblastoma. In vitro and preliminary clinical studies have implied improved efficacy of I-125 relative to I-131 in certain clinical situations, although areas of uncertainty remain regarding intratumoral dosimetry. This prompted our study using human neuroblastoma multicellular spheroids as a model of metastasis. 3D dose calculations were made using voxel-based Medical Internal Radiation Dosimetry (MIRD) and dose-point-kernel (DPK) techniques. Dose distributions for I-131 and I-125 labeled mIBG were calculated for spheroids (metastases) of various sizes from 0.01 cm to 3 cm diameter, and the relative dose delivered to the tumors was compared for the same limiting dose to the bone marrow. Based on the same data, arguments were advanced based upon the principles of tumor control probability (TCP) to emphasize the potential theoretical utility of I-125 over I-131 in specific clinical situations. I-125-mIBG can deliver a higher and more uniform dose to tumors compared to I-131 mIBG without increasing the dose to the bone marrow. Depending on the tumor size and biological half-life, the relative dose to tumors of less than 1 mm diameter can increase several-fold. TCP calculations indicate that tumor control increases with increasing administered activity, and that I-125 is more effective than I-131 for tumor diameters of 0.01 cm or less. This study suggests that I-125-mIBG is dosimetrically superior to I-131-mIBG therapy for small bone marrow metastases from neuroblastoma. It is logical to consider adding I-125-mIBG to I-131-mIBG in multi-modality therapy as these two isotopes could be complementary in terms of their cumulative dosimetry.

Recent advances in neuroblastoma

PURPOSE OF REVIEW

Although there have been recent advances with multimodal therapy, treatment of neuroblastoma remains a clinical challenge. Despite the identification of several genetic features, there has not been a significant increase in 5-year survival in the last decade. This review will highlight the current operative strategies along with new research developments aimed at improving survival.

RECENT FINDINGS

The goal of surgical intervention in the early stages of neuroblastoma is complete curative resection. In advanced-stage disease, tissue biopsy for staging is the initial goal. In recent years, minimally invasive surgery (MIS) is considered in carefully selected patients. Recent advances in neuroblastoma research have focused on tyrosine kinase inhibition, differentiation, pathway inhibition, and immunotherapy. Several of these targets have shown promising results in vivo and are currently under investigation for potential clinical trials.

SUMMARY

New information on the importance of cell signaling and the targeting of specific genes of interest are providing key insights into neuroblastoma. Only through the discovery of novel treatment strategies made available through the advancement of research will neuroblastoma be survivable for patients with advanced-stage disease.

Neuroblastoma

Neuroblastomas continue to remain a clinical challenge, despite advances in multimodal therapy. Currently, studies are aimed at novel targets for neuroblastoma directed toward poor prognostic indicators such as the MYCN oncogene and marked angiogenesis. There have also been recent discoveries in neuroblastoma pathogenesis involving epigenetic regulation and retinoic acid therapy. Understanding the intricate complexities of this tumor may lead to innovative agents for more effective combinational therapy.