Visualization and Quantification of Drug Release by GSH-Responsive Multimodal Integrated Micelles.

Using molecular imaging techniques to monitor biomarkers and drug release profiles simultaneously is highly advantageous for cancer diagnosis and treatment. However, achieving the accurate quantification of both biomarkers and drug release with a single imaging modality is challenging. This study presents the development of a glutathione (GSH)-responsive polymer-based micelle, PEG-SS-FCy7/PEG-SS-GEM (PSFG), which can precisely localize the tumor using bimodal imaging and prevent drug leakage. These PSFG micelles exhibit a small particle size of 106.3 ± 12.7 nm with a uniform size distribution, and the drug loading efficiency can also be easily controlled by changing the PEG-SS-FCy7 (PSF) and PEG-SS-GEM (PSG) feeding ratio. The PSFG micelles display weak fluorescence emission and minimal drug release under physiological conditions but collapse in the presence of GSH to trigger near-infrared fluorescence and the 19F magnetic resonance imaging signal, allowing for real-time monitoring of intracellular GSH levels and drug release. GSH could synergistically promote the disassembly of the micellar structure, resulting in accelerated probe and drug release of up to about 93.1% after 24 h. These prodrug micelles exhibit high in vitro and in vivo antitumor abilities with minimal side effects. The GSH-responsive drug delivery system with dual-modal imaging capability provides a promising imaging-guided chemotherapeutic platform to probe the tumor microenvironment and quantify real-time drug release profiles with minimal side effects.

Monitoring ROS Responsive Fe3O4-based Nanoparticle Mediated Ferroptosis and Immunotherapy via 129Xe MRI.

The immune checkpoint blockade strategy has improved the survival rate of late-stage lung cancer patients. However, the low immune response rate limits the immunotherapy efficiency. Here, we report a ROS-responsive Fe3O4-based nanoparticle that undergoes charge reversal and disassembly in the tumor microenvironment, enhancing the uptake of Fe3O4 by tumor cells and triggering a more severe ferroptosis. In the tumor microenvironment, the nanoparticle rapidly disassembles and releases the loaded GOx and the immune-activating peptide Tuftsin under overexpressed H2O2. GOx can consume the glucose of tumor cells and generate more H2O2, promoting the disassembly of the nanoparticle and drug release, thereby enhancing the therapeutic effect of ferroptosis. Combined with Tuftsin, it can more effectively reverse the immune-suppressive microenvironment and promote the recruitment of effector T cells in tumor tissues. Ultimately, in combination with α-PD-L1, there is significant inhibition of the growth of lung metastases. Additionally, the hyperpolarized 129Xe method has been used to evaluate the Fe3O4 nanoparticle-mediated immunotherapy, where the ventilation defects in lung metastases have been significantly improved with complete lung structure and function recovered. The ferroptosis-enhanced immunotherapy combined with non-radiation evaluation methodology paves a new way for designing novel theranostic agents for cancer therapy.

Augmenting Immunotherapy via Bioinspired MOF-Based ROS Homeostasis Disruptor with Nanozyme-Cascade Reaction.

Despite its remarkable clinical breakthroughs, immune checkpoint blockade (ICB) therapy remains limited by the insufficient immune response in the "cold" tumor. Nanozyme-based antitumor catalysis is associated with precise immune activation in the tumor microenvironment (TME). In this study, a cascade-augmented nanoimmunomodulator (CMZM) with multienzyme-like activities, which includes superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and glutathione oxidase (GSHOx), that dissociates under an acidic and abundant GSH TME, is proposed for multimodal imaging-guided chemodynamic therapy (CDT)/photodynamic therapy (PDT) enhanced immunotherapy. Vigorous multienzyme-like activities can not only produce O2 to alleviate hypoxia and promote the polarization of M2 to M1 macrophages, but also generate ROS (•OH and 1 O2 ) and deplete GSH in the TME to expose necrotic cell fragments and reverse immunosuppressive TME by eliciting the maturation of dendritic cells and infiltration of cytotoxic T lymphocytes (CTLs) in tumors. Therefore, inhibitory effects on both primary and distant tumors are achieved through synergy with an α-PD-L1 blocking antibody. This cascade multienzyme-based nanoplatform provides a smart strategy for highly efficient ICB immunotherapy against "cold" tumors by revising immunosuppressive TME.

Self-Assembly of Precisely Fluorinated Albumin for Dual Imaging-Guided Synergistic Chemo-Photothermal-Photodynamic Cancer Therapy.

Although albumin has been extensively used in nanomedicine, it is still challenging to fluorinate albumin into fluorine-19 magnetic resonance imaging (19F MRI)-traceable theranostics because existing strategies lead to severe 19F signal splitting, line broadening, and low 19F MRI sensitivity. To this end, 34-cysteine-selectively fluorinated bovine serum albumins (BSAs) with a sharp singlet 19F peak have been developed as 19F MRI-sensitive and self-assembled frameworks for cancer theranostics. It was found that fluorinated albumin with a non-binding fluorocarbon and a long linker is crucial for avoiding 19F signal splitting and line broadening. With the fluorinated BSAs, paclitaxel (PTX) and IR-780 were self-assembled into stable, monodisperse, and multifunctional nanoparticles in a framework-promoted self-emulsion way. The high tumor accumulation, efficient cancer cell uptake, and laser-triggered PTX sharp release of the BSA nanoparticles enabled 19F MRI-near infrared fluorescence imaging (NIR FLI)-guided synergistic chemotherapy (Chemo), photothermal and photodynamic therapy of xenograft MCF-7 cancer with a high therapeutical index in mice. This study developed a rational synthesis of 19F MRI-sensitive albumin and a framework-promoted self-emulsion of multifunctional BSA nanoparticles, which would promote the development of protein-based high-performance biomaterials for imaging, diagnosis, therapy, and beyond.

In Vivo Nitroreductase Imaging via Fluorescence and Chemical Shift Dependent 19 F NMR.

Nitroreductase (NTR) is an important biomarker widely used to evaluate the degree of tumor hypoxia. Although a few optical methods have been reported for detecting nitroreductase at low concentration ranges, an effective strategy for nitroreductase monitoring in vivo without limits to the imaging depth is still lacking. Herein, a novel dual-mode NIR fluorescence and 19 F MRI agent, FCy7-NO2 , is proposed for imaging tumor hypoxia. We show that FCy7-NO2 serves as not only a rapid NIR fluorescence enhanced probe for monitoring and bioimaging of nitroreductase in tumors, but also a novel 19 F MR chemical shift-sensitive contrast agent for selectively detecting nitroreductase catalyzed reduction. Notably, integrating two complementary imaging technologies into FCy7-NO2 enables sensitive detection of nitroreductase in a broad concentration range without tissue-depth limit. In general, this agent has a remarkable response to nitroreductase, which provides a promising method for understanding tumor evolution and its physiological role in the hypoxic microenvironment.

Photoactivated Nanohybrid for Dual-Nuclei MR/US/PA Multimodal-Guided Photothermal Therapy.

Nanohybrids have gained immense popularity for the diagnosis and chemotherapy of lung cancer for their excellent biocompatibility, biodegradability, and targeting ability. However, most of them suffer from limited imaging information, low tumor-to-background ratios, and multidrug resistance, limiting their potential clinical application. Herein, we engineered a photoresponsive nanohybrid by assembling polypyrrole@bovine serum albumin (PPy@BSA) encapsulating perfluoropentane (PFP)/129Xe for selective magnetic resonance (MR)/ultrasonic (US)/photoacoustic (PA) trimodal imaging and photothermal therapy of lung cancer, overcoming these drawbacks of single imaging modality and chemotherapy. The nanohybrid exhibited superior US, PA, and MR multimodal imaging performance for lung cancer detection. The high sensitivity of the nanohybrid to near-infrared light (NIR) resulted in a rapid increase in temperature in a low-intensity laser state, which initiated the phase transition of liquid PFP into the gas. The ultrasound signal inside the tumor, which is almost zero initially, is dramatically increased. Beyond this, it led to the complete depression of 19F/129Xe Hyper-CEST (chemical exchange saturation transfer) MRI during laser irradiation, which can precisely locate lung cancer. In vitro and in vivo results of the nanohybrid exhibited a successful therapeutic effect on lung cancer. Under the guidance of imaging results, a sound effect of photothermal therapy (PTT) for lung cancer was achieved. We expect this nanohybrid and photosensitive behavior will be helpful as fundamental tools to decipher lung cancer in an earlier stage through trimodality imaging methods.

Aleuritolic Acid Impaired Autophagic Flux and Induced Apoptosis in Hepatocellular Carcinoma HepG2 Cells.

Aleuritolic acid (AA) is a triterpene that is isolated from the root of Croton crassifolius Geisel. In the present study, the cytotoxic effects of AA on hepatocellular carcinoma cells were evaluated. AA exerted dose- and time-dependent cytotoxicity by inducing mitochondria-dependent apoptosis in the hepatocellular carcinoma cell line, HepG2. Meanwhile, treatment with AA also caused dysregulation of autophagy, as evidenced by enhanced conversion of LC3-I to LC3-II, p62 accumulation, and co-localization of GFP and mCherry-tagged LC3 puncta. Notably, blockage of autophagosome formation by ATG5 knockdown or inhibitors of phosphatidylinositol 3-kinase (3-MA or Ly294002), significantly reversed AA-mediated cytotoxicity. These data indicated that AA retarded the clearance of autophagic cargos, resulting in the production of cytotoxic factors and led to apoptosis in hepatocellular carcinoma cells.

Diterpenoids from Croton crassifolius include a novel skeleton possibly generated via an intramolecular [2+2]-photocycloaddition reaction.

Five previously undescribed terpenoids (cracrosons D-H), including three clerodane diterpenoids, together with 16 known diterpenoids were isolated from Croton crassifolius (Euphorbiaceae). Cracroson D features a previously undescribed carbon skeleton with an unprecedented cyclobutane ring. Their structures, including their absolute configurations, were elucidated using spectroscopic and single-crystal X-ray diffraction analyses along with CD calculations. A plausible biogenetic pathway for cracroson D is also proposed, which was supported by the experimental results. Additionally, all of the compounds were evaluated in vitro for cytotoxicity against T24 and A549 cells using the CCK-8 method.

Triterpenoids with Antiplatelet Aggregation Activity from the Roots of Ilex pubescens.

Two new triterpenes and five new triterpene saponins, named ilexpusons A-G (1-7), as well as eight known compounds were isolated from Ilex pubescens. The structures of the new compounds were established by a combination of chemical and spectroscopic methods, including HRESIMS, 1H-NMR, 13C-NMR, 1H-1H COSY, HSQC, HMBC, and NOESY. Additionally, the biological activity of compounds 1 - 15 against adenosine diphosphate-induced platelet aggregation in rabbit plasma was determined. Among the tested compounds, 1, 2, 5, 6, 8, 13, 14, and 15 exhibited significant inhibition of platelet aggregation in vitro.

New clerodane diterpenoids from Croton crassifolius.

Two new clerodane diterpenoids (1-2), one new clerodane diterpenoid alkaloid (3), as well as thirteen known compounds were isolated from Croton crassifolius. The structures of new compounds were established by a combination of spectroscopic methods, including HRMS, (1)H NMR, (13)C NMR, (1)H (1)H COSY, HSQC, HMBC, NOESY and X-ray crystallographic analysis. Compound 3 is firstly reported as the clerodane-type diterpenoid alkaloid in natural products. All of the compounds were evaluated for in vitro cytotoxic activities against CT26.WT cell using the MTT method.