Development of Indocyanine Green/Methyl-ß-cyclodextrin Complex-Loaded Liposomes for Enhanced Photothermal Cancer Therapy.

Photothermal therapy (PTT) is a promising cancer therapeutic approach due to its spatial selectivity and high potency. Indocyanine green (ICG) has been considered a biocompatible PTT agent. However, ICG has several challenges to hinder its clinical use including rapid blood clearance and instability to heat, light, and solvent, leading to a loss of photoactivation property and PTT efficacy. Herein, we leveraged stabilizing components, methyl-ß-cyclodextrin and liposomes, in one nanoplatform (ICD lipo) to enhance ICG stability and the photothermal therapeutic effect against cancer. Compared to ICG, ICD lipo displayed a 4.8-fold reduction in degradation in PBS solvent after 30 days and a 3.4-fold reduction in photobleaching after near-infrared laser irradiation. Moreover, in tumor-bearing mice, ICD lipo presented a 2.7-fold increase in tumor targetability and inhibited tumor growth 9.6 times more effectively than did ICG without any serious toxicity. We believe that ICD lipo could be a potential PTT agent for cancer therapeutics.

Development of finely tuned liposome nanoplatform for macrophage depletion.

BACKGROUND: Immunotherapy with clodronate-encapsulated liposomes, which induce macrophage depletion, has been studied extensively. However, previously reported liposomal formulation-based drugs (Clodrosome® and m-Clodrosome®) are limited by their inconsistent size and therapeutic efficacy. Thus, we aimed to achieve consistent therapeutic effects by effectively depleting macrophages with uniform-sized liposomes. RESULTS: We developed four types of click chemistry-based liposome nanoplatforms that were uniformly sized and encapsulated with clodronate, for effective macrophage depletion, followed by conjugation with Man-N3 and radiolabeling. Functionalization with Man-N3 improves the specific targeting of M2 macrophages, and radioisotope labeling enables in vivo imaging of the liposome nanoplatforms. The functionalized liposome nanoplatforms are stable under physiological conditions. The difference in the biodistribution of the four liposome nanoplatforms in vivo were recorded using positron emission tomography imaging. Among the four platforms, the clodronate-encapsulated mannosylated liposome effectively depleted M2 macrophages in the normal liver and tumor microenvironment ex vivo compared to that by Clodrosome® and m-Clodrosome®. CONCLUSION: The newly-developed liposome nanoplatform, with finely tuned size control, high in vivo stability, and excellent ex vivo M2 macrophage targeting and depletion effects, is a promising macrophage-depleting agent.

Injectable biocompatible nanocomposites of Prussian blue nanoparticles and bacterial cellulose as a safe and effective photothermal cancer therapy.

Photothermal therapy (PTT) is a novel cancer treatment using a photoabsorber to cause hyperthermia to kill tumors by laser irradiation. Prussian blue nanoparticles (PB NPs) are considered as next-generation photothermal agents due to the facile synthesis and excellent absorption of near-infrared light. Although PB NPs demonstrate remarkable PTT capabilities, their clinical application is limited due to their systemic toxicity. Bacterial cellulose (BC) has been applied to various bio-applications based on its unique properties and biocompatibility. Herein, we design composites with PB NPs and BC as an injectable, highly biocompatible PTT agent (IBC-PB composites). Injectable bacterial cellulose (IBC) is produced through the trituration of BC, with PB NPs synthesized on the IBC surface to prepare IBC-PB composites. IBC-PB composites show in vitro and in vivo photothermal therapeutic effects similar to those of PB NPs but with significantly greater biocompatibility. Specifically, in vitro therapeutic index of IBC-PB composites is 26.5-fold higher than that of PB NPs. Furthermore, unlike PB NPs, IBC-PB composites exhibit no overt toxicity in mice as assessed by blood biochemical analysis and histological images. Hence, it is worth pursuing further research and development of IBC-PB composites as they hold promise as safe and efficacious PTT agents for clinical application.

18F-FDG PET/CT in the Management of Osteosarcoma.

Osteosarcoma is the most common type of primary malignant bone tumor. 18F-FDG PET/CT is useful for staging, detecting recurrence, monitoring response to neoadjuvant chemotherapy, and predicting prognosis. Here, we review the clinical aspects of osteosarcoma management and assess the role of 18F-FDG PET/CT, in particular with regard to pediatric and young adult patients.

Development of Spleen Targeting H2S Donor Loaded Liposome for the Effective Systemic Immunomodulation and Treatment of Inflammatory Bowel Disease.

Nanoparticles are primarily taken up by immune cells after systemic administration. Thus, they are considered an ideal drug delivery vehicle for immunomodulation. Because the spleen is the largest lymphatic organ and regulates the systemic immune system, there have been studies to develop spleen targeting nanoparticles for immunomodulation of cancer and immunological disorders. Inflammatory bowel disease (IBD) includes disorders involving chronic inflammation in the gastrointestinal tract and is considered incurable despite a variety of treatment options. Hydrogen sulfide (H2S) is one of the gasotransmitters that carries out anti-inflammatory functions and has shown promising immunomodulatory effects in various inflammatory diseases including IBD. Herein, we developed a delicately tuned H2S donor delivering liposome for spleen targeting (ST-H2S lipo) and studied its therapeutic effects in a dextran sulfate sodium (DSS) induced colitis model. We identified the ideal PEG type and ratio of liposome for a high stability, loading efficiency, and spleen targeting effect. In the treatment of the DSS-induced colitis model, we found that ST-H2S lipo and conventional long-circulating liposomes loaded with H2S donors (LC-H2S lipo) reduced the severity of colitis, whereas unloaded H2S donors did not. Furthermore, the therapeutic effect of ST-H2S lipo was superior to that of LC-H2S lipo due to its better systemic immunomodulatory effect than that of LC-H2S lipo. Our findings demonstrate that spleen targeting H2S lipo may have therapeutic potential for IBD.

In vitro magnetic hyperthermia properties of angle-shaped superparamagnetic iron oxide nanoparticles synthesized by a bromide-assisted polyol method.

Currently, research on superparamagnetic iron oxide nanoparticles (SPIONs) for magnetic hyperthermia applications is steadily increasing. In this work, SPIONs were synthesized by the bromide-assisted polyol method and angle-shaped SPIONs were successfully generated with the optimized concentration of bromide. The influence of bromide concentration on the shape of the generated SPIONs as well as the heating characteristics under an alternating magnetic field (AMF) was thoroughly investigated. At a concentration of 20 mg mL-1 of the angle-shaped SPIONs, the highest temperature curve up to 23 °C was observed under AMF with 140 Oe and 100 kHz for 10 min. With the biotoxicity assay, no significant cytotoxicity was observed in the normal fibroblast of HFB-141103 as well as tumor cells of U87MG and FSall treated with the angle-shaped SPIONs at a concentration below 100 µg mL-1. However, significantly decreased cellular viability was observed in tumor cells of U87MG and FSall treated with 100 µg mL-1 of the angle-shaped SPIONs under AMF with 140 Oe and 100 kHz. Based on these results, it is thought that the angle-shaped SPIONs synthesized by the bromide-assisted polyol method will provide highly efficient magnetic hyperthermia therapy for cancers under biologically safe AMF with 140 Oe and 100 kHz.

Mannosylated-serum albumin nanoparticle imaging to monitor tumor-associated macrophages under anti-PD1 treatment.

BACKGROUND: Immune checkpoint inhibitors such as anti-programmed cell death protein 1 (PD1) block tumor growth by reinvigorating the immune system; however, determining their efficacy only by the changes in tumor size may prove inaccurate. As the immune cells including macrophages in the tumor microenvironment (TME) are associated with the response to anti-PD1 therapy, tumor-associated macrophages (TAMs) imaging using nanoparticles can noninvasively provide the immune enrichment status of TME. Herein, the mannosylated-serum albumin (MSA) nanoparticle was labeled with radioactive isotope 68Ga to target the mannose receptors on macrophages for noninvasive monitoring of the TME according to anti-PD1 therapy. RESULTS: B16F10-Luc and MC38-Luc tumor-bearing mice were treated with anti-PD1, and the response to anti-PD1 was determined by the tumor volume. According to the flow cytometry, the responders to anti-PD1 showed an increased proportion of TAMs, as well as lymphocytes, and the most enriched immune cell population in the TME was also TAMs. For noninvasive imaging of TAMs as a surrogate of immune cell augmentation in the TME via anti-PD1, we acquired [68Ga] Ga-MSA positron emission tomography. According to the imaging study, an increased number of TAMs in responders at the early phase of anti-PD1 treatment was observed in both B16F10-Luc and MC38-Luc tumor-bearing mice models. CONCLUSION: As representative immune cells in the TME, non-invasive imaging of TAMs using MSA nanoparticles can reflect the immune cell enrichment status in the TME closely associated with the response to anti-PD1. As non-invasive imaging using MSA nanoparticles, this approach shows a potential to monitor and evaluate anti-tumor response to immune checkpoint inhibitors.

Dual imaging modality of fluorescence and transmission X-rays for gold nanoparticle-injected living mice.

BACKGROUND: X-ray fluorescence (XRF) imaging for metal nanoparticles (MNPs) is a promising molecular imaging modality that can determine dynamic biodistributions of MNPs. However, it has the limitation that it only provides functional information. PURPOSE: In this study, we aim to show the feasibility of acquiring functional and anatomic information on the same platform by demonstrating a dual imaging modality of pinhole XRF and computed tomography (CT) for gold nanoparticle (GNP)-injected living mice. METHODS: By installing a transmission CT detector in an existing pinhole XRF imaging system using a two-dimensional (2D) cadmium zinc telluride (CZT) gamma camera, XRF and CT images were acquired on the same platform. Due to the optimal X-ray spectra for XRF and CT image acquisition being different, XRF and CT imaging were performed by 140 and 50 kV X-rays, respectively. An amount of 40 mg GNPs (1.9 nm in diameter) suspended in 0.20 ml of phosphate-buffered saline were injected into the three BALB/c mice via a tail vein. Then, the kidney and tumor slices of mice were scanned at specific time points within 60 min to acquire time-lapse in vivo biodistributions of GNPs. XRF images were directly acquired without image reconstruction using a pinhole collimator and a 2D CZT gamma camera. Subsequently, CT images were acquired by performing CT scans. In order to confirm the validity of the functional information provided by the XRF image, the CT image was fused with the XRF image. After the XRF and CT scan, the mice were euthanized, and major organs (kidneys, tumor, liver, and spleen) were extracted. The ex vivo GNP concentrations of the extracted organs were measured by inductively coupled plasma mass spectrometry (ICP-MS) and L-shell XRF detection system using a silicon drift detector, then compared with the in vivo GNP concentrations measured by the pinhole XRF imaging system. RESULTS: Time-lapse XRF images were directly acquired without rotation and translation of imaging objects within an acquisition time of 2 min per slice. Due to the short image acquisition time, the time-lapse in vivo biodistribution of GNPs was acquired in the organs of the mice. CT images were fused with the XRF images and successfully confirmed the validity of the XRF images. The difference in ex vivo GNP concentrations measured by the L-shell XRF detection system and ICP-MS was 0.0005-0.02% by the weight of gold (wt%). Notably, the in vivo and ex vivo GNP concentrations in the kidneys of three mice were comparable with a difference of 0.01-0.08 wt%. CONCLUSIONS: A dual imaging modality of pinhole XRF and CT imaging system and L-shell XRF detection system were successfully developed. The developed systems are a promising modality for in vivo imaging and ex vivo quantification for preclinical studies using MNPs. In addition, we discussed further improvements for the routine preclinical applications of the systems.

Lipid nanoparticles for delivery of RNA therapeutics: Current status and the role of in vivo imaging.

Lipid nanoparticles (LNPs) have been one of the most successful nano-delivery vehicles that enable efficient delivery of cytotoxic chemotherapy agents, antibiotics, and nucleic acid therapeutics. During the coronavirus disease (COVID-19) pandemic, LNP-based COVID-19 messenger RNA (mRNA) vaccines from Pfizer/BioNTech and Moderna have been successfully developed, resulting in global sales of $37 billion and $17.7 billion, respectively, in 2021. Based on this success, the development of multiple LNP-based RNA therapeutics is gaining momentum due to its potential in vaccines and therapeutics for various genetic diseases and cancers. Furthermore, imaging techniques can be utilized to evaluate the pharmacokinetics and pharmacodynamics (PK/PD) effects, which helps target discovery and accelerates the development of LNP-based mRNA therapies. A thorough introduction and explanation of the components of LNPs and its functions along with various production methods of formulating LNPs are provided in this review. Furthermore, recent advances in LNP-based RNA therapeutics in clinics and clinical trials are explored. Additionally, the evaluation of PK/PD of LNPs for RNA delivery and the current and potential roles in developing LNP-based mRNA pharmaceutics through imaging techniques will be discussed.

Spatial Transcriptomics-Based Identification of Molecular Markers for Nanomedicine Distribution in Tumor Tissue.

The intratumoral accumulation of nanomedicine has been considered a passive process, referred to as the enhanced permeability and retention effect. Recent studies have suggested that the tumor uptake of nanomedicines follows an energy-dependent pathway rather than being a passive process. Herein, to explore the factor candidates that are associated with nanomedicine tumor uptake, a molecular marker identification platform is developed by integrating microscopic fluorescence images of a nanomedicine distribution with spatial transcriptomics information. When this approach is applied to PEGylated liposomes, molecular markers related to hypoxia, glycolysis, and apoptosis can be identified as being related to the intratumoral distribution of the nanomedicine. It is expected that the method can be applied to explain the distribution of a wide range of nanomedicines and that the data obtained from this analysis can enhance the precise utilization of nanomedicines.

Long-Term Outcomes of Bilateral Subthalamic Nucleus Deep Brain Stimulation for Patients With Parkinson's Disease: 10 Years and Beyond.

BACKGROUND: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) represents an effective treatment for severe Parkinson's disease (PD), but little is known about the long-term benefit. OBJECTIVE: To investigate the survival rate and long-term outcome of DBS. METHODS: We investigated all 81 patients including 37 males and 44 females who underwent bilateral STN DBS from March 2005 to March 2008 at a single institution. The current survival status of the patients was investigated. Preoperative and postoperative follow-up assessments were analyzed. RESULTS: The mean age at the time of surgery was 62 (range 27-82) years, and the median clinical follow-up duration was 145 months. Thirty-five patients (43%) died during the follow-up period. The mean duration from DBS surgery to death was 110.46 ± 40.8 (range 0-155) months. The cumulative survival rate is as follows: 98.8 ± 1.2% (1 year), 95.1 ± 2.4% (5 years), and 79.0 ± 4.5% (10 years). Of the 81 patients, 33 (40%) were ambulatory up to more than 11 years. The Unified Parkinson's Disease Rating Scale (UPDRS) score was significantly improved until 5 years after surgery although it showed a tendency to increase again after 10 years. The patient group with both electrodes located within the STN showed a higher rate of survival and maintained ambulation. CONCLUSION: STN DBS is a safe and effective treatment for patients with advanced PD. This study based on the long-term follow-up of large patient populations can be used to elucidate the long-term fate of patients who underwent bilateral STN DBS for PD.

Self-Assembled DNA-Protein Hybrid Nanospheres: Biocompatible Nano-Drug-Carriers for Targeted Cancer Therapy.

We developed hybrid nanospheres comprised of two of the most important biomolecules in nature, DNA and proteins, which have excellent biocompatibility, high drug payload capacity, in vivo imaging ability, and in vitro/in vivo cancer targeting capability. The synthesis can be done in a facile one-pot assembly system that includes three steps: step-growth polymerization of two DNA oligomers, addition of streptavidin to assemble spherical hybrid nanostructures, and functionalization of hybrid nanospheres with biotinylated aptamers. To test the feasibility of cancer targeting and drug-loading capacity of the hybrid nanospheres, MUC1-specific aptamers (MA3) were conjugated to nanosphere surfaces (apt-nanospheres), and doxorubicin (Dox) was loaded into nanospheres by DNA intercalation. The successful construction of nanospheres and apt-nanospheres was confirmed by agarose gel electrophoresis and dynamic light scattering (DLS). Their uniform spherical morphology was confirmed by transmission electron microscopy (TEM). Fluorescence spectra of nanospheres demonstrated high Dox-loading capability and slow-release characteristics. In vitro MUC1-specific binding of the apt-nanospheres was confirmed by flow cytometry and confocal microscopy. Dox-loaded apt-nanospheres significantly increased cytotoxicity of the MUC1-positive cancer cells due to aptamer-mediated selective internalization, as shown via cell viability assays. Apt-nanospheres could also be imaged in vivo through the synthesis of hybrid nanospheres using fluorescent dye-conjugated DNA strands. Finally, in vivo specific targeting ability of apt-nanospheres was confirmed in a MUC1-positive 4T1 tumor-bearing mouse model, whereas apt-nanospheres did not cause any sign of systemic toxicity in normal mice. Taken together, our self-assembled DNA-streptavidin hybrid nanospheres show promise as a biocompatible cancer targeting material for contemporary nanomedical technology.

Circulation Time-Optimized Albumin Nanoplatform for Quantitative Visualization of Lung Metastasis via Targeting of Macrophages.

The development of molecular imaging probes to identify key cellular changes within lung metastases may lead to noninvasive detection of metastatic lesions in the lung. In this study, we constructed a macrophage-targeted clickable albumin nanoplatform (CAN) decorated with mannose as the targeting ligand using a click reaction to maintain the intrinsic properties of albumin in vivo. We also modified the number of mannose molecules on the CAN and found that mannosylated serum albumin (MSA) harboring six molecules of mannose displayed favorable pharmacokinetics that allowed high-contrast imaging of the lung, rendering it suitable for in vivo visualization of lung metastases. Due to the optimized control of functionalization and surface modification, MSA enhanced blood circulation time and active/passive targeting abilities and was specifically incorporated by mannose receptor (CD206)-expressing macrophages in the metastatic lung. Moreover, extensive in vivo imaging studies using single-photon emission computed tomography (SPECT)/CT and positron emission tomography (PET) revealed that blood circulation of time-optimized MSA can be used to discern metastatic lesions, with a strong correlation between its signal and metastatic burden in the lung.

Prognostic impact of an integrative analysis of [18F]FDG PET parameters and infiltrating immune cell scores in lung adenocarcinoma.

BACKGROUND: High levels of 18F-fluorodeoxyglucose (18F-FDG) tumor uptake are associated with worse prognosis in patients with non-small cell lung cancer (NSCLC). Meanwhile, high levels of immune cell infiltration in primary tumor have been linked to better prognosis in NSCLC. We conducted this study for precisely stratified prognosis of the lung adenocarcinoma patients using the integration of 18F-FDG positron emission tomography (PET) parameters and infiltrating immune cell scores as assessed by a genomic analysis. RESULTS: Using an RNA sequencing dataset, the patients were divided into three subtype groups. Additionally, 24 different immune cell scores and cytolytic scores (CYT) were obtained. In 18F-FDG PET scans, PET parameters of the primary tumors were obtained. An ANOVA test, a Chi-square test and a correlation analysis were also conducted. A Kaplan-Meier survival analysis with the log-rank test and multivariable Cox regression test was performed to evaluate prognostic values of the parameters. The terminal respiratory unit (TRU) group demonstrated lower 18F-FDG PET parameters, more females, and lower stages than the other groups. Meanwhile, the proximal inflammatory (PI) group showed a significantly higher CYT score compared to the other groups (P = .001). Also, CYT showed a positive correlation with tumor-to-liver maximum standardized uptake value ratio (TLR) in the PI group (P = .027). A high TLR (P = .01) score of 18F-FDG PET parameters and a high T follicular helper cell (TFH) score (P = .005) of immune cell scores were associated with prognosis with opposite tendencies. Furthermore, TLR and TFH were predictive of overall survival even after adjusting for clinicopathologic features and others (P = .024 and .047). CONCLUSIONS: A high TLR score was found to be associated with worse prognosis, while high CD8 T cell and TFH scores predicted better prognosis in lung adenocarcinoma. Furthermore, TLR and TFH can be used to predict prognosis independently in patients with lung adenocarcinoma.

M1 Macrophage-Derived Exosome-Mimetic Nanovesicles with an Enhanced Cancer Targeting Ability.

Extracellular vesicles (EVs) have been found to be effective therapeutic drug delivery vehicles in a wide range of human diseases, including cancer and neurodegenerative diseases. Proinflammatory (M1) macrophages can modulate the suppressive immune environment of tumor tissues to be more inflammatory and have been considered as candidates for cancer immunotherapy. Furthermore, macrophage-derived exosome-mimetic nanovesicles (MNVs) could effectively induce antitumor response and enhance the efficacy of immune checkpoint inhibitors in a recent paper. However, multiple studies indicate that EVs were rapidly cleared by the reticuloendothelial system, and therefore, their tumor targeting efficiencies were limited. Herein, we developed a simple surface modification method of MNVs using polyethylene glycol (PEG) to enhance the in vivo tumor targeting efficiency. PEG-MNVs had 7-fold higher blood circulation than bare MNVs in the animal tumor model. Also, MNVs had a 25-fold higher protein amount than exosomes. Overall, the nanovesicle preparation strategies presented in this study may expedite the clinical translation of EV-based therapeutics in various diseases.

Development of theranostic dual-layered Au-liposome for effective tumor targeting and photothermal therapy.

BACKGROUND: Photothermal therapy (PTT) is an emerging anti-cancer therapeutic strategy that generates hyperthermia to ablate cancer cells under laser irradiation. Gold (Au) coated liposome (AL) was reported as an effective PTT agent with good biocompatibility and excretory property. However, exposed Au components on liposomes can cause instability in vivo and difficulty in further functionalization. RESULTS: Herein, we developed a theranostic dual-layered nanomaterial by adding liposomal layer to AL (LAL), followed by attaching polyethylene glycol (PEG) and radiolabeling. Functionalization with PEG improves the in vivo stability of LAL, and radioisotope labeling enables in vivo imaging of LAL. Functionalized LAL is stable in physiological conditions, and 64Cu labeled LAL (64Cu-LAL) shows a sufficient blood circulation property and an effective tumor targeting ability of 16.4%ID g-1 from in vivo positron emission tomography (PET) imaging. Also, intravenously injected LAL shows higher tumor targeting, temperature elevation in vivo, and better PTT effect in orthotopic breast cancer mouse model compared to AL. The tumor growth inhibition rate of LAL was 3.9-fold higher than AL. CONCLUSION: Based on these high stability, in vivo imaging ability, and tumor targeting efficiency, LAL could be a promising theranostic PTT agent.

Discovery of potential imaging and therapeutic targets for severe inflammation in COVID-19 patients.

The Coronavirus disease 2019 (COVID-19) has been spreading worldwide with rapidly increased number of deaths. Hyperinflammation mediated by dysregulated monocyte/macrophage function is considered to be the key factor that triggers severe illness in COVID-19. However, no specific targeting molecule has been identified for detecting or treating hyperinflammation related to dysregulated macrophages in severe COVID-19. In this study, previously published single-cell RNA-sequencing data of bronchoalveolar lavage fluid cells from thirteen COVID-19 patients were analyzed with publicly available databases for surface and imageable targets. Immune cell composition according to the severity was estimated with the clustering of gene expression data. Expression levels of imaging target molecules for inflammation were evaluated in macrophage clusters from single-cell RNA-sequencing data. In addition, candidate targetable molecules enriched in severe COVID-19 associated with hyperinflammation were filtered. We found that expression of SLC2A3, which can be imaged by [18F]fluorodeoxyglucose, was higher in macrophages from severe COVID-19 patients. Furthermore, by integrating the surface target and drug-target binding databases with RNA-sequencing data of severe COVID-19, we identified candidate surface and druggable targets including CCR1 and FPR1 for drug delivery as well as molecular imaging. Our results provide a resource in the development of specific imaging and therapy for COVID-19-related hyperinflammation.

Head-to-Head Comparison of 68Ga-NOTA (68Ga-NGUL) and 68Ga-PSMA-11 in Patients with Metastatic Prostate Cancer: A Prospective Study.

68Ga-NOTA Glu-Urea-Lys (NGUL) is a novel prostate-specific membrane antigen (PSMA)-targeting tracer used for PET/CT imaging. This study aimed to compare performance in the detection of primary and metastatic lesions and to compare biodistribution between 68Ga-NGUL and 68Ga-PSMA-11 in the same patients with prostate cancer. Methods: Eleven patients with metastatic prostate cancer were prospectively recruited. The quantitative tracer uptake was determined in normal organs and in primary and metastatic lesions. Results:68Ga-NGUL showed significantly lower normal-organ uptake and rapid urinary clearance. The number and sites of detected PSMA-positive primary and metastatic lesions were identical, and no significant quantitative uptake difference was observed. 68Ga-NGUL showed a relatively lower tumor-to-background ratio than 68Ga-PSMA-11. Conclusion: In a head-to-head comparison with 68Ga-PSMA-11, 68Ga-NGUL showed lower uptake in normal organs and similar performance in detecting PSMA-avid primary and metastatic lesions. 68Ga-NGUL could be a valuable option for PSMA imaging.

Radiosensitizing high-Z metal nanoparticles for enhanced radiotherapy of glioblastoma multiforme.

Radiotherapy is an essential step during the treatment of glioblastoma multiforme (GBM), one of the most lethal malignancies. The survival in patients with GBM was improved by the current standard of care for GBM established in 2005 but has stagnated since then. Since GBM is a radioresistant malignancy and the most of GBM recurrences occur in the radiotherapy field, increasing the effectiveness of radiotherapy using high-Z metal nanoparticles (NPs) has recently attracted attention. This review summarizes the progress in radiotherapy approaches for the current treatment of GBM, the physical and biological mechanisms of radiosensitization through high-Z metal NPs, and the results of studies on radiosensitization in the in vitro and in vivo GBM models using high-Z metal NPs to date.

Europium-Diethylenetriaminepentaacetic Acid Loaded Radioluminescence Liposome Nanoplatform for Effective Radioisotope-Mediated Photodynamic Therapy.

Photodynamic therapy (PDT) is an effective anticancer strategy with a higher selectivity and fewer adverse effects than conventional therapies; however, shallow tissue penetration depth of light has hampered the clinical utility of PDT. Recently, reports have indicated that Cerenkov luminescence-induced PDT may overcome the tissue penetration limitation of conventional PDT. However, the effectiveness of this method is controversial because of its low luminescence intensity. Herein, we developed a radiolabeled diethylenetriaminepentaacetic acid chelated Eu3+ (Eu-DTPA)/photosensitizer (PS) loaded liposome (Eu/PS-lipo) that utilizes ionizing radiation from radioisotopes for effective in vivo imaging and radioluminescence-induced PDT. We utilized Victoria blue-BO (VBBO) as a PS and observed an efficient luminescence resonance energy transfer between Eu-DTPA and VBBO. Furthermore, 64Cu-labeled Eu lipo demonstrated a strong radioluminescence with a 2-fold higher intensity than Cerenkov luminescence from free 64Cu. In our radioluminescence liposome, radioluminescence energy transfer showed a 6-fold higher energy transfer efficiency to VBBO than Cerenkov luminescence energy transfer (CLET). 64Cu-labeled Eu/VBBO lipo (64Cu-Eu/VBBO lipo) showed a substantial tumor uptake of up to 19.3%ID/g by enhanced permeability and retention effects, as revealed by in vivo positron emission tomography. Finally, the PDT using 64Cu-Eu/VBBO lipo demonstrated significantly higher in vitro and in vivo therapeutic effects than Cerenkov luminescence-induced PDT using 64Cu-VBBO lipo. This study envisions a great opportunity for clinical PDT application by establishing the radioluminescence liposome which has high tumor targeting and efficient energy transfer capability from radioisotopes.