A theranostic metallodrug modulates immunovascular crosstalk to combat immunosuppressive liver cancer.

Hepatocellular carcinoma (HCC) is a highly malignant, fatal disease with a complex tumor microenvironment (TME) characterized by severe immunosuppression and malformed vascular structures, thus most advanced HCC patients do not respond well to current mainstream pharmacotherapy and T-cell-related immunotherapy. Therefore, an efficient immunovascular crosstalk modulation strategy may help combat HCC by reversing immunosuppression and vessel normalization, especially by reprogramming tumor associated macrophages (TAMs). In this study, tyrosine kinase inhibitor lenvatinib (Len) was loaded into mesoporous Fe3O4 (mFe) nanoparticles (NPs), and bovine serum albumin (BSA) was attached to the NP surface to produce a metallodrug (BSA-mFe@Len NPs). In acidic TME, BSA allowed pH-responsive Len release and mFe exposure. Len directly triggered HCC apoptosis and changed the abnormal TME via vessel normalization, cytotoxic T-lymphocyte recruitment, and regulatory T-cell elimination at tailored dosages. After TAM phagocytosis, mFe NPs reprogrammed TAMs into M1 phenotypes to synergistically amplify antitumor immunity. The metallodrug achieved significant tumor growth inhibition, induced tumor vessel normalization effects, and acquired instant antitumor immunity as well as long-term immune memory in vivo. Furthermore, it displayed good T2 weighted magnetic resonance imaging performance, indicating potential theranostic applications. Collectively, this research provides new insights for unleashing the multifaceted potential of current pharmaceuticals in synergy with metallic nanomedicine for treating intractable liver cancer. STATEMENT OF SIGNIFICANCE: Current pharmacotherapy and immunotherapy have limited success in treating advanced hepatocellular carcinoma (HCC) due to its complex tumor microenvironment (TME). Hence, this work first put forward a theranostic metallodrug by loading lenvatinib (Len) into mesoporous Fe3O4 (mFe) nanoparticles (NPs) and coating a pH-degradable bovine serum albumin corona onto the surface. The metallodrug was able to modulate immunovascular TME for combating HCC via metalloimmunotherapy induced by the mFe NPs and Len's multiple functions (direct triggering of tumor apoptosis, vessel normalization, cytotoxic T-lymphocyte recruitment, and regulatory T-cell elimination). In vivo experiments showed that the metallodrug could significantly inhibit HCC growth and evoke long-term antitumor immune memory, paving a new avenue for treating advanced HCC patients.

Magnet-Guided Bionic System with LIFU Responsiveness and Natural Thrombus Tropism for Enhanced Thrombus-Targeting Ability.

Background: Arterial thrombosis is a serious threat to human health. Recently, many thrombus-targeted nanoparticles (NPs) have been constructed for detecting thrombi or monitoring thrombolysis, but their thrombus-targeting performance is limited. Considering this drawback, we designed a specific bionic system with enhanced thrombus-targeting ability. Materials and Methods: In the bionic system, gelatin was chosen as a carrier, and Fe3O4 served as a magnetic navigation medium and a magnetic resonance (MR) imaging agent. The CREKA peptide, which targets fibrin, was conjugated to the surface of gelatin to prepare targeted NPs (TNPs), which were then engulfed by macrophages to construct the bionic system. At the targeted site, the bionic system released its interior TNPs under low-intensity focused ultrasound (LIFU) irradiation. Moreover, the targeting performance was further improved by the conjugated CREKA peptide. Results: In this study, we successfully constructed a bionic system and demonstrated its targeting ability in vitro and in vivo. The results indicated that most TNPs were released from macrophages under LIFU irradiation at 2 W/cm2 for 10 min in vitro. Additionally, the enhanced thrombus-targeting ability, based on the natural tropism of macrophages toward inflammatory thrombi, magnetic navigation and the CREKA peptide, was verified ex vivo and in vivo. Moreover, compared with the bionic system group, the group treated with TNPs had significantly decreased liver and spleen signals in MR images and significantly enhanced liver and spleen signals in fluorescence images, indicating that the bionic system is less likely to be cleared by the reticuloendothelial system (RES) than TNPs, which may promote the accumulation of the bionic system at the site of the thrombus. Conclusion: These results suggest that the magnet-guided bionic system with LIFU responsiveness is an excellent candidate for targeting thrombi and holds promise as an innovative drug delivery system for thrombolytic therapy.

LIFU-responsive nanomedicine enables acoustic droplet vaporization-induced apoptosis of macrophages for stabilizing vulnerable atherosclerotic plaques.

Due to the high risk of tearing and rupture, vulnerable atherosclerotic plaques would induce serious cardiovascular and cerebrovascular diseases. Despite the available clinical methods can evaluate the vulnerability of plaques and specifically treat vulnerable plaques before a cardiovascular event, but the efficiency is still low and undesirable. Herein, we rationally design and engineer the low-intensity focused ultrasound (LIFU)-responsive FPD@CD nanomedicine for the highly efficient treatment of vulnerable plaques by facilely loading phase transition agent perfluorohexane (PFH) into biocompatible PLGA-PEG-PLGA nanoparticles (PPP NPs) and then attaching dextran sulphate (DS) onto the surface of PPP NPs for targeting delivery. DS, as a typical macrophages-targeted molecule, can achieve the precise vaporization of NPs and subsequently controllable apoptosis of RAW 264.7 macrophages as induced by acoustic droplet vaporization (ADV) effect. In addition, the introduction of DiR and Fe3O4 endows nanomedicine with near-infrared fluorescence (NIRF) and magnetic resonance (MR) imaging capabilities. The engineered FPD@CD nanomedicine that uses macrophages as therapeutic targets achieve the conspicuous therapeutic effect of shrinking vulnerable plaques based on in vivo and in vitro evaluation outcomes. A reduction of 49.4% of vascular stenosis degree in gross pathology specimens were achieved throughout the treatment period. This specific, efficient and biosafe treatment modality potentiates the biomedical application in patients with cardiovascular and cerebrovascular diseases based on the relief of the plaque rupture concerns.

Theranostic Nanoplatform with Sequential SDT and ADV Effects in Response to Well-Programmed LIFU Irradiation for Cervical Cancer.

BACKGROUND: Some patients with cervical cancer have the need to preserve fertility; therefore, a minimally invasive treatment option that can effectively inactivate tumors in these patients is necessary. METHODS: In this paper, we designed and prepared nanoparticles (NPs) carrying IR780 and perfluorohexane (PFH) and characterized their properties. We focused on the promotion of programmed low-intensity focused ultrasound (LIFU) irradiation on the penetration and treatment of cervical cancer. First we used penetration-enhancing LIFU irradiation to promote the penetration of the NPs into 3D multicellular tumor spheroids (MCTSs) and tumors in tumor-bearing nude mice. Then we used re-therapeutic LIFU irradiation to achieve antitumor effects in vitro and in vivo. Photoacoustic (PA) and magnetic resonance (MR) imaging were used to monitor and evaluate the targeting and therapeutic effects of these NPs on tumor tissues. RESULTS: The NPs prepared in this paper exhibited high affinity for HeLa cells, and can selectively achieve mitochondrial localization in the cell due to IR780 assistance. The penetration-enhancing LIFU irradiation have the ability to promote the penetration of the NPs into cervical cancer models in vivo and in vitro. Under LIFU irradiation, the cytotoxic reactive oxygen species (ROS) produced by IR780 during the first half of the re-therapeutic LIFU irradiation and the physical acoustic droplet vaporization (ADV) effect after PFH phase transition during the second half of the re-therapeutic LIFU irradiation can achieve synergistic minimally invasive treatment of tumors, which can be visualized and evaluated by PA and MR imaging in vivo. CONCLUSION: Well-programmed LIFU irradiation can promote NP penetration into deep tumor tissue and achieve antitumor effects simultaneously. Linking ROS + ADV effects can induce cell coagulation necrosis and lead to a comprehensive, long-term impact on tumor tissue, providing a conceptual theranostic nanoplatform for cervical cancer.

Visualization of microRNA-21 Dynamics in Neuroblastoma Using Magnetic Resonance Imaging Based on a microRNA-21-Responsive Reporter Gene.

BACKGROUND: MicroRNAs (miRs) have been shown to be closely associated with the occurrence and development of tumors and to have potential as diagnostic and therapeutic targets. The detection of miRs by noninvasive imaging technology is crucial for deeply understanding their biological functions. Our aim was to develop a novel miR-21-responsive gene reporter system for magnetic resonance imaging (MRI) visualization of the miR-21 dynamics in neuroblastoma. METHODS: The reporter gene ferritin heavy chain (FTH1) was modified by the addition of 3 copies of the sequence completely complementary to miR-21 (3xC_miR-21) to its 3'-untranslated region (3' UTR) and transduced into SK-N-SH cells to obtain SK-N-SH/FTH1-3xC_miR-21 cells. Then, the antagomiR-21 was delivered into cells by graphene oxide functionalized with polyethylene glycol and dendrimer. Before and after antagomiR-21 delivery, FTH1 expression, MRI contrast and intracellular iron uptake were assayed in vitro and in vivo. RESULTS: In the SK-N-SH/FTH1-3xC_miR-21 cells, FTH1 expression was in an "off" state due to the combination of intratumoral miR-21 with the 3' UTR of the reporter gene. AntagomiR-21 delivered into the cells bound to miR-21 and thereby released it from the 3' UTR of the reporter gene, thus "switching on" FTH1 expression in a dose-dependent manner. This phenomenon resulted in intracellular iron accumulation and allowed MRI detection in vitro and in vivo. CONCLUSION: MRI based on the miR-21-responsive gene reporter may be a potential method for visualization of the endogenous miR-21 activity in neuroblastoma and its response to gene therapy.

Tumor-self-targeted "thermoferroptosis-sensitization" magnetic nanodroplets for multimodal imaging-guided tumor-specific therapy.

Ferroptosis-based nanomedicine has drawn increasing attention in antitumor therapy because of the advantages of this unconventional mode of apoptosis, but the difficulties of delivery to the tumor site and surface-to-core penetration after arrival seriously hinder further clinical transformation and application. Herein, we propose an unprecedented strategy of injecting magnetic nanodroplets (MNDs) to solve these two longstanding problems. MNDs are nanocarriers that can carry multifunctional drugs and imaging materials. MNDs can effectively accumulate in the tumor site by active tumor targeting (multifunctional drugs) and passive tumor targeting (enhanced permeability and retention effect), allowing diffusion of the MNDs from the surface to the core through mild-temperature magnetic fluid hyperthermia (MHT) under multimodal imaging guidance. Finally, the ferroptosis pathway is activated deep within the tumor site through the drug release. This approach was inspired by the ability of mild-temperature MHT to allow MNDs to quickly pass through the blood vessel-tumor barrier and deeply penetrate the tumor tissue from the surface to the core to amplify the antitumor efficacy of ferroptosis. This strategy is termed as "thermoferroptosis sensitization". Importantly, this behavior can be performed under the guidance of multimodal imaging, making the design of MNDs for cancer therapy safer and more reasonable.

Multifunctional nanozyme for multimodal imaging-guided enhanced sonodynamic therapy by regulating the tumor microenvironment.

Sonodynamic therapy (SDT) is a highly promising approach for cancer therapy, but its efficacy is severely hampered by the low specificity of sonosensitizers and the unfavorable characteristics of the tumor microenvironment (TME), such as hypoxia and glutathione (GSH) overexpression. To solve these problems, in this work, we encapsulated IR780 and MnO2 in PLGA and linked Angiopep-2 (Ang) to synthesize a multifunctional nanozyme (Ang-IR780-MnO2-PLGA, AIMP) to enhance SDT. With Ang functionalization to facilitate blood-brain barrier (BBB) penetration and glioma targeting, and through the function of IR780, these nanoparticles (NPs) showed improved targeting of cancer cells, especially mitochondria, and spread deep into tumor centers. Upon low-intensity focused ultrasound (LIFU) irradiation, reactive oxygen species (ROS) were produced and induced tumor cell apoptosis. Combined with the specific mitochondria-targeting ability of IR780, the sonodynamic effects were amplified because mitochondria are sensitive to ROS. In addition, MnO2 exhibited enzyme-like activity, reacting with the high levels of hydrogen protons (H+), H2O2 and GSH in the TME to continuously produce oxygen and consume GSH, which further enhanced the effect of SDT. Moreover, Mn2+ can be released in response to TME stimulation and used as a magnetic resonance (MR) contrast agent. In addition, IR780 has photoacoustic (PA)/fluorescence (FL) imaging capabilities. Our results demonstrated that AIMP NPs subjected to LIFU triggering maximally enhanced the therapeutic effect of SDT by multiple mechanisms, including multiple targeting, deep penetration, oxygen supply in situ and GSH depletion, thereby significantly inhibiting tumor growth and distal metastasis without systemic toxicity. In summary, this multifunctional nanozyme provides a promising strategy for cancer diagnosis and treatment under the intelligent guidance of multimodal imaging (PA/FL/MR) and may be a safe clinical translational method.

EWVDV-Mediated Platelet-Targeting Nanoparticles for the Multimodal Imaging of Thrombi at Different Blood Flow Velocities.

BACKGROUND: There have been many recent reports of molecular probes for thrombi but with unsatisfactory in vivo targeting effects, which could be related to the blood flow velocity in vivo. Therefore, it is worth explaining the relationship between the targeting effect and the blood flow velocity. METHODS AND MATERIALS: In this study, we constructed a platelet-targeting nanoparticle (NP) based on EWVDV for targeting P-selectin combined with the phase transition material perfluorohexane and India ink to achieve the multimodal imaging of thrombi. We studied the targeting effect of the NPs for rabbit blood thrombi under different flow velocities simulating blood flow velocities in vivo. RESULTS: The results show the successful fabrication of NPs with the ability to undergo a phase transition via low-intensity focused ultrasound irradiation to achieve ultrasound imaging and with a high binding affinity for activated platelets. In vitro, low flow velocities (20 cm/s) hardly affected the targeting effect of the NPs, while moderate flow velocities (40 cm/s) reduced the number of NPs that target thrombi by 52.6% comparing to static fluid (0 cm/s). High flow velocities (60 cm/s) greatly reduced the targeting effect of the NPs by 83.5%. CONCLUSION: These results can serve as a reference for the design of NPs targeting thrombi at different sites and in different blood vessel types according to the blood flow velocity, thereby establishing a foundation for in vivo experiments.

SR-A-Targeted Phase-Transition Nanoparticles for the Detection and Treatment of Atherosclerotic Vulnerable Plaques.

Atherosclerosis is a major cause of sudden death and myocardial infarction, instigated by unstable plaques. Thus, the early detection of unstable plaques and corresponding treatment can improve the prognosis and reduce mortality. In this study, we describe a protocol for the preparation of nanoparticles (NPs) combined with the phase transitional material perfluorohexane (PFH) and with dextran sulfate (DS) targeting class A scavenger receptors (SR-A) for the diagnosis and treatment of atherosclerotic vulnerable plaques. The results showed that the Fe-PFH-poly(lactic- co-glycolic acid) (PLGA)/chitosan (CS)-DS NPs were fabricated successfully, with the ability to undergo phase transition by low-intensity focused ultrasound (LIFU) irradiation to achieve ultrasound imaging; a high carrier rate of Fe3O4 had a good negative enhancement effect on magnetic resonance imaging (MRI). The NPs had a high binding affinity for activated macrophages and could be endocytosed by the macrophages and notably induced apoptosis under LIFU irradiation by an acoustic droplet vaporization effect in vitro. Furthermore, in an ex vivo atherosclerotic plaque model of apolipoprotein E knockout (KO) (apoE-/-) mice induced by high cholesterol, the NPs selectively accumulated at the sites of SR-A expressed on the activated macrophages of the aortic region. This result was also confirmed by MRI in vivo, where the NPs could be targeted to the aortic plaque and reduced the T2* signal. The LIFU-induced phase transition could lead to the apoptosis of macrophages on plaques in vivo. In summary, Fe-PFH-PLGA/CS-DS NPs may be applied as multimodal and multifunctional probes and are expected to enable the specific diagnosis and targeted therapy of vulnerable plaques.