Preclinical evaluation and first in human study of Al18F radiolabeled ODAP-urea-based PSMA targeting ligand for PET imaging of prostate cancer

Inspired by novel radiopharmaceuticals: Rush hour of nuclear medicine

Nuclear medicine plays an irreplaceable role in the diagnosis and treatment of tumors. Radiopharmaceuticals are important components of nuclear medicine. Among the radiopharmaceuticals approved by the Food and Drug Administration (FDA), radio-tracers targeting prostate-specific membrane antigen (PSMA) and somatostatin receptor (SSTR) have held essential positions in the diagnosis and treatment of prostate cancers and neuroendocrine neoplasms, respectively. In recent years, FDA-approved serials of immune-therapy and targeted therapy drugs targeting programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1), human epidermal growth factor receptor 2 (HER2), and nectin cell adhesion molecule 4 (Nectin 4). How to screen patients suitable for these treatments and monitor the therapy? Nuclear medicine with specific radiopharmaceuticals can visualize the expression level of those targets in systemic lesions and evaluate the efficacy of treatment. In addition to radiopharmaceuticals, imaging equipment is also a key step for nuclear medicine. Advanced equipment including total-body positron emission tomography/computed tomography (PET/CT) and positron emission tomography/magnetic resonance imaging (PET/MRI) has been developed, which contribute to the diagnosis and treatment of tumors, as well as the development of new radiopharmaceuticals. Here, we conclude most recently advances of radiopharmaceuticals in nuclear medicine, and they substantially increase the "arsenal" of clinicians for tumor therapy.

Functional Materials for Subcellular Targeting Strategies in Cancer Therapy: Progress and Prospects

Neoadjuvant and adjuvant therapies have made significant progress in cancer treatment. However, tumor adjuvant therapy still faces challenges due to the intrinsic heterogeneity of cancer, genomic instability, and the formation of an immunosuppressive tumor microenvironment. Functional materials possess unique biological properties such as long circulation times, tumor-specific targeting, and immunomodulation. The combination of functional materials with natural substances and nanotechnology has led to the development of smart biomaterials with multiple functions, high biocompatibilities, and negligible immunogenicities, which can be used for precise cancer treatment. Recently, subcellular structure-targeting functional materials have received particular attention in various biomedical applications including the diagnosis, sensing, and imaging of tumors and drug delivery. Subcellular organelle-targeting materials can precisely accumulate therapeutic agents in organelles, considerably reduce the threshold dosages of therapeutic agents, and minimize drug-related side effects. This review provides a systematic and comprehensive overview of the research progress in subcellular organelle-targeted cancer therapy based on functional nanomaterials. Moreover, it explains the challenges and prospects of subcellular organelle-targeting functional materials in precision oncology. The review will serve as an excellent cutting-edge guide for researchers in the field of subcellular organelle-targeted cancer therapy.

Imageological/Structural Study regarding the Improved Pharmacokinetics by 68Ga-Labeled PEGylated PSMA Multimer in Prostate Cancer

PMSA (prostate-specific membrane antigen) is currently the most significant target for diagnosing and treating PCa (prostate cancer). Herein, we reported a series ⁶⁸Ga/¹⁷⁷Lu-labeled multimer PSMA tracer conjugating with PEG chain, including [⁶⁸Ga]Ga-DOTA-(1P-PEG₄), [⁶⁸Ga]Ga-DOTA-(2P-PEG₀), [⁶⁸Ga]Ga-DOTA-(2P-PEG₄), and [⁶⁸Ga]Ga/[¹⁷⁷Lu]Lu-DOTA-(2P-PEG₄)₂, which showed an advantage of a multivalent effect and PEGylation to achieve higher tumor accumulation and faster kidney clearance. To figure out how structural optimizations based on a PSMA multimer and PEGylation influence the probe's tumor-targeting ability, biodistribution, and metabolism, we examined PSMA molecular probes' affinities to PC-3 PIP (PSMA-highly-expressed PC-3 cell line), and conducted pharmacokinetics analysis, biodistribution detection, small animal PET/CT, and SPECT/CT imaging. The results showed that PEG₄ and PSMA dimer optimizations enhanced the probes' tumor-targeting ability in PC-3 PIP tumor-bearing mice models. Compared with the PSMA monomer, the PEGylated PSMA dimer reduced the elimination half-life in the blood and increased uptake in the tumor, and the biodistribution results were consistent with PET/CT imaging results. [⁶⁸Ga]Ga-DOTA-(2P-PEG₄)₂ exhibited higher tumor-to-organ ratios. When labeled by lutetium-177, relatively high accumulation of DOTA-(2P-PEG₄)₂ was still detected in PC-3 PIP tumor-bearing mice models after 48 h, indicating its prolonged tumor retention time. Given the superiority in imaging, simple synthetic processes, and structural stability, DOTA-(2P-PEG₄)₂ is expected to be a promising tumor-targeting diagnostic molecular probe in future clinical practice.